uncle jack's engine building tips
These apply to the Triumph TR-2, 3, and 4 engine, primarily for race motors.
These notes are from "uncle jack" Drews, with comments from Tony Drews and info from correspondence between Jack and Tim Murphy. Larry Young is also a contributor. This page is intended as a helpful guide to the Triumph community, additions / corrections / comments can be sent to email@example.com . Thanks.
Pictorial version of some of this is here.
Index: Block Bearing Note Crank Front Plate Camshaft Degree the Camshaft Timing Sprocket Cover Front Pulley Sleeves Lifters Rods Pistons Oil Pump Sump Head Rocker Assembly Pushrod Length Water Pump Housing / Bypass Hose Water Pump Distributor, Shaft, Key, Gear, Shimming Startup Torques Custom Fig 8 pictorial
Have it tanked. This cleans all the passages.
When it’s tanked, the aluminum plugs in the ends of the oil
gallery will melt. Replace them either by tapping the holes NPT or using
straight socket head setscrews. Be sure to not screw the front one in so far
that it blocks the passage to the front cam bearing.
Be sure the front plug is at least flush with the front of the block as
the engine mount plate covers it.
Have cam bearings installed, plus plug at rear of gallery. Check
to see if the shop installed the rear bearing correctly by blowing air down the
rocker feed hole and feeling to see if air comes out the hole in the rear cam
bearing. Put a bead of JB Weld around the edges of the rear cam expansion plug.
If you are going to plumb an Accusump into the main gallery, now
is a good time to drill and tap the center hole in the gallery to accept an NPT
fitting for the Accu hose. While doing this, you can also drill out the passages
to the center main, because it supplies oil to two crank throws, while the end
mains supply only one throw each. Be careful not to drill too deep, and remember
that when the holes intersect, the drill will catch and try to break your wrist.
When you are ready to install the plugs in the sides of the block,
make sure the holes in the cam bearings are exactly lined up. Install the
sealing bolts very slowly to make sure the little nubbin on the end goes into
the bearing hole. If misaligned, it ruins the bearing. In a worst case, you can
grind the nubbin off of the bolt. The cam bearings aren’t going to turn in the
block – this practice of locking the bearings in place was used very rarely in
the era and never today. Some
builders feel that the plugs in the side of the block should be drilled and
safety wired. I’ve never done that and have never had one come loose, but I
can’t criticize the practice.
Use emery cloth on the liner registers (where the figure 8 gaskets
at the base of the liners seal against) for good sealing of the liner bottoms.
(I cleaned the liner registers in the block with a
small wire brush on a long drill extension and a ¼ inch electric drill. TFM)
(I cleaned the liner registers in the block with a small wire brush on a long drill extension and a ¼ inch electric drill. TFM)
At about this point, check the water oulet hole in the side of the
block just above the starter. In old blocks, this hole will be rusted shut.
Drill it out so that the block will drain. I don’t trust the old spigot type
plugs – I use a capscrew and a nylon washer as a plug.
You can paint the inside of the block if you want to but I’ve
never seen a benefit from it.
Some folks think that the block should be resurfaced on the top
because these blocks are now pretty old. I don’t do that, because I’ve never
seen an engine on which this was done still have the top surface at exactly the
right relationship with the liner registers. In addition, the liner protrusion
will be even more difficult to set.
10. The head bolt holes should all be re-tapped (chase the existing
threads with a tap). You can buy a long tap from McMaster-Carr. Getting the old
studs out is sometimes a problem. As a next-to-last resort, weld a nut to the top
of the stud and use Kroil and a big
wrench. Breaking one off is not a good thing to do. As a truly last resort,
leave the old stud. (In a conversation with Jack he was of the opinion that if the studs
threads and studs looked good, just leave them in.
Can do more harm than good trying to take the old 40 year old studs out
of the 40 year old block, like breaking the stud off down in the threaded hole!
(In a conversation with Jack he was of the opinion that if the studs threads and studs looked good, just leave them in. Can do more harm than good trying to take the old 40 year old studs out of the 40 year old block, like breaking the stud off down in the threaded hole! TFM)
ARP nuts and ARP hardened and ground washers for the head nuts.
The stock washers or even Grade 8 washers will get “indented” from
the torque of the head nuts. TFM) RP
You must decide at this point which kind of lifters you are going
to use. If you are going to use “GT40” lifters, they have a smaller diameter
and the holes in the block must be
sleeved. They are very high quality and long lasting, but then you always have
to use them in this block because the sleeves will never come out. The sleeves
need to be honed at the very top after installation. Some cams require a larger
diameter lifter, so you use stock lifters. This requires no extensive block
preparation, but it’s a good idea to use a brake hone on the bores to make
sure they are okay.
There is a big hole on
the left side of the block in which the draft tube was originally installed.
This is the best place to install a nice big sump vent. If you install a little
one in the fuel pump plate, you run into many more problems of leakage and
inadequate venting. I make an elbow out of an old draft tube and attach a
flexible hose to it. You must install the catch tank pretty high in the engine
compartment or else the tank will fill up with oil that has slopped over to the
opening under hard cornering.
Message from Jack to the FOT on 11/7/2007:
Here's a link to Calico Coatings. They are the company that does my
machine shop's coatings. I highly recommend this process -- the
performance advantages described on this web site are really true. I
have two sets of bearings at their place right now. (no financial interest)
Tony Comment: I recently disassembled my engine and, using the coated main and rod bearings, found zero wear on the crank, and the coating was still largely intact - there were just a few places that it wore through the coating to the actual bearing material. I'm sold. Normally I'm through the first layer of bearing material in several areas.
If you are going to install the aftermarket rear seal, have the
seal surface of the crank turned to 2.525 – whatever the current instructions
may say. These seals are leaky and they need all the help they can get. The lip
tension is too low. Therefore, measure the length of the spring and alter it to
be exactly 8” long.
If using an old crank, remove the plugs and clean it out. Heat up
the area around the plugs with a propane torch to make the plugs easier to take
out. Tony note: I was never successful getting these out and have the
local GOOD crank shop do the plug removal, cleaning and installation of new
Tony note: I was never successful getting these out and have the local GOOD crank shop do the plug removal, cleaning and installation of new plugs.
3. If you have a Moldex crank, and have it reground, the grinder must very carefully match the wheel shape with the journal corner radii. After grinding, the crank must be nitrided again. No
Put a very small amount of RTV along one edge of the seal groove
in the aluminum housing. Also put a very light coat of liquid gasket sealer on
the surfaces against which the seal housing will go.
(This is for the aftermarket rear
(This is for the aftermarket rear seal. TFM)
Install the seal on the crank. Arrange the seal so the split will
be on the upside / top after the engine is right side up.
is for the aftermarket rear seal. TFM)
(This is for the aftermarket rear seal. TFM)
Main bearings – install in block, lather up with a good assembly
lube. Redline works really well but others do too.
Install the top halves of the thrust washers, grooved babbit side
toward the crank cheeks. (Tony Note: the grooved side toward the crank is
CRITICAL. Destroyed a block and crank by doing this wrong - was going to
have the Moldex welded up and reground when the found the cracks mentioned in
item #3 above)
Install main caps. Torque evenly.
Some builders swear by studs, some by capscrews. Studs eliminate the
problem of repeated disassembly and assembly damaging the threads in the block.
I also like to strap the center main to add rigidity to the bottom
end. To do this, mill off the cast
face of the main flush with the surfaces for the head bolts. Get a front strap
for a Chevy 400 block. You
must enlarge the holes in the strap and
you must use longer bolts. Some
builders feel that this is totally unnecessary, but since starting to do
this, I have never had a main bearing deteriorate faster than a rod bearing,
which is something that happens more frequently than you would expect.
Be sure to rotate the crank frequently during the assembly
sequence. It should turn VERY freely with the caps fully torqued.
Trial fit the new gasket and check to see if the holes actually
will line up with the holes in the block. They often do not. Enlarge the holes
in the gasket.
You can use lots of different sealants on this gasket. I use dumb
old old Permatex "Indian Head Gasket Shellac" (brown / black liquid in a container with a cotton ball looking thing
attached to the lid) .
3. Put in three or four bolts to hold it in place.
1. Orient this properly with the center pan hole showing. The little T shaped gaskets are a PITA. I trim them off to fit the grooves in the sealing block, smear them up good with RTV, and help the whole thing into the front block opening with the help of a thin, stiff knife blade.
Lather up the journals with assembly lube.
Lather up the lobes with cam lube from a cam company. It should be moly
or stiff grease. They (assembly lube and cam lube) are two different things.
(Tony Note: we also pour GM's EOS over the lobes before installing the lifters)
(Tony Note: we also pour GM's EOS over the lobes before installing the lifters)
2. Assemble the shaft to the block. Don’t damage the bearings in the process. You can make it easier by screwing a couple of 5 or 6” long bolts into the front of the camshaft and using them as a handle.
There are lots of
write-ups on how to do this so I’ll just touch on small tips and potential
Install #1 sleeve, piston, and rod. Lube the rod bearing but you
don’t have to install the rings yet.
Set piston #1 at Top Dead Center, using a dial indicator. The
keyways for the front pulley should be on the bottom.
Set the reading for zero degrees on the degree wheel you stick on the
Set the crank so that it is at the position you are going to set
the cam – that is, if the intake is to be at .050 at 28 BTDC, set the crank at
28 BTDC. With a dial indicator in the top of the pushrod for #1 intake, rotate
the camshaft until the valve is .050 open. The crank and cam are now in the
approximately correct relationship.
(Tony Note: the #1 Intake is the 2nd lifter from the front, NOT the front
lifter. Also, this is assuming that the cam spec is 0.050 at the lifter,
not the valve. If at the valve it would be 0.033 at the lifter)
(Tony Note: the #1 Intake is the 2nd lifter from the front, NOT the front lifter. Also, this is assuming that the cam spec is 0.050 at the lifter, not the valve. If at the valve it would be 0.033 at the lifter)
Install the sprockets and chains without moving the crank and cam.
Rotate the engine and see where the cam really is at .050 opening. You
probably won’t be able to get it exactly right the first time. You have to
loosen and reinstall the cam and crank sprocket repeatedly to get it to come out
Usually the most power is obtained with several degrees of
camshaft advance – most of them like three to five degrees advance – that
is, opening three to five degrees before the theoretical point specified by the
cam grinder, unless he has already
built that into his spec.
6. When everything is as you want it, throw away the sheet metal locking tabs, put some red Loctite on the threads of the cam gear attaching bolts, and torque them down.
The cover will seal a lot better if the area with the bolt holes
is flat. Use a hammer with something steel to back it up, and make it flat
around the bolt holes.
Install the seal in the cover, and then before assembly on the
engine, push the front pulley through the seal to make sure the supplier sent
you the right seal. Don’t ask why I recommend this. (Tony Note: some of
the narrow front pulleys use a non-stock diameter seal (ran for 2 years before I
found the cause of my leak). If you measure the diameter of the housing
and the diameter of the pulley a local bearing / seal house should be able to
supply you with a proper seal.)
1. If you have purchased a new front pulley with a harmonic dampener in it, you have to place timing marks on it. Do this now, before the head goes on. Set the crank at TDC using the dial indicator, attach the front cover, and mark the pulley for TDC, 10, 20, and 30 degrees. To make it easy to read with a timing light, paint the pulley black and the marks white. (If you have the harmonic balancer with the “rubber ring” sandwich, you may want to drill the 1/8 inch hole in from the periphery per one of the Kastner books to make it possible to see if the outside piece has “slipped” thus changing the timing mark! TFM)
This is one of the
two most vexing parts of the assembly.
First of all, the liners should be honed to give .004 - .005
clearance for the pistons. Anything
less and you are in danger of
“scuffing” the pistons – piston material sticks to the walls.
(Tony Note: 0.006 is the minimum clearance.
Also top ring gap of 0.014 min and 2nd ring gap of 0.011 min) .
(This is especially true for forged
pistons! May want to check with
piston supplier to make sure you are using the right clearance with the sleeves
you are using. TFM)
. (This is especially true for forged pistons! May want to check with piston supplier to make sure you are using the right clearance with the sleeves you are using. TFM)
Install the sleeves with a set of figure 8 gaskets in place,
without any sealant. Clamp them down in place with washers, tubes or long
sockets, and head nuts.
Measure the liner protrusion with a straight edge and feeler gauge
per the shop manual. If you are going to use a stock (sandwich) gasket, using
the .004 - .006 protrusion will work well. If you want to use a steel shim
gasket or a solid copper gasket, you must work with less protrusion. The figure
8 gaskets are almost always too thick. You can make new ones or buy them from
The Gasket Works. Generally, .004 - .006 is okay with stock gaskets, steel shim
gaskets are happier with .002 - .004, and solid gaskets need .002. There are
some other specific things you can do to help with the solid copper gaskets -
ask Mordy at Gasket Works. If
you need thinner fig 8’s, you can make them out of the proper thickness brass
shim stock, cutting them out with tin snips.
It takes about a half hour to
make a set, so it’s not an overwhelming task. Remember that the goo you put on
these fig 8’s has a thickness – using the thinnest sealant available like
Mohawk smeared on very thinly with
your fingers, you must allow for .001-.002 on each side of the sealing ring.
Don’t use anything thick ..
(I found that the stock figure 8
gaskets gave me the proper protrusion using the 87mm “racing” sleeves from
Ken Gillanders at British Frame and Engine.
Trying to measure the actual protrusion on a 40 year old block was a
PITA! I did not have any difference
in protrusion after installing with the Permatex “Indian Head Gasket
Shellac”. I did not
“allow for .001-.002 on each side of the sealing ring” as Jack said above.
I did clean the liner registers in the block with a small wire
brush on a long drill extension and a ¼ inch electric drill. TFM)
Larry Young's pictorial on how to make fig 8 gaskets is below.
.. (I found that the stock figure 8 gaskets gave me the proper protrusion using the 87mm “racing” sleeves from Ken Gillanders at British Frame and Engine. Trying to measure the actual protrusion on a 40 year old block was a PITA! I did not have any difference in protrusion after installing with the Permatex “Indian Head Gasket Shellac”. I did not “allow for .001-.002 on each side of the sealing ring” as Jack said above. I did clean the liner registers in the block with a small wire brush on a long drill extension and a ¼ inch electric drill. TFM) Larry Young's pictorial on how to make fig 8 gaskets is below.
This leads us to a brief exposition on type
of head gaskets to use. There
are three that I know of, each with pros and cons. Since this is a controversial
subject, I’ll just present the pros and cons as I know them.
– Pro – most forgiving of irregularities. Requires
the least attention to protrusion. – Con – the gasket will protrude into the
combustion chamber below the intake valve, because when the head is milled, the
combustion chamber lip is removed. This means
better initial sealing but
earlier failure. The gasket will last longer if you o-ring the tops of the
liners by machining a groove for .040 stainless steel wire.
shim gasket – Pro – thinner and gives slight increase in compression ratio.
With the embossing it seals reasonably well.
The combustion chamber opening is large enough on British Frame and
Engine’s version of this gasket that it will not stick out into the chamber.
Con – It is somewhat more finicky on protrusion than the stock gasket.
copper gasket – Pro – the combustion chamber hole is right and you can get
them in a number of thicknesses from The Gasket Works. They also make some
sealing rings that I will let them describe. Con – the most demanding in terms
of having everything flat and having proper liner protrusion. Some builders have
excellent results but some cannot make them work. Ya pays yer money and ya
takes yer choice.
You must chamfer or relieve in some way the tops of the liners
below the intake valves. There are a number of ways to do this and the marking
procedure is spelled out very well in the Kastner books. If you are milling the
head and using one of the modern very high lift cams, the valves will protrude
into the liner at full lift. Therefore
make the chamfers deep enough to allow for this. You can even make the chamfers
radiused instead of just angled. You want to avoid interference at all costs.
The objective here is to give adequate vertical clearance for the valves at full
lift, but if you make the chamfer too wide, there will be less sealing area on
the liner tops, resulting in leaking between the water jacket and combustion
(After chamfering the liners per the above, I installed the crank
(but not the pistons) with the head on, the cam installed and the timing chain
on. I turned the engine upside down
on the engine stand and rotated the crank while I watched for interference
between the valves and the sleeves. It
was very close on a couple of intake valves so I removed the head and
used Dykem or bluing to mark the sleeves where there was possible interference.
I then put the head back on and again rotated the crank to “mark” any
interference on the Dykem. After
removing the head again there were small marks in the Dykem on two sleeves so I
reground all the sleeves to give more clearance.
Maybe saved the engine by doing this. TFM)
At the time of this writing, there are no reliable sources of
lifters. BFE. Moss, TRF, and BPNW all sell lifters that vary greatly in
hardness. There are various philosophies on how hard they need to be, with
middle 50’s on the Rockwell C scale being the agreed-to standard. Have them
all checked, and use only lifters that are over 50 as an absolute minimum.
2. Lather the bottoms of the lifters with assembly lube, even though you have previously lubed the camshaft.
(Tony Note: if you are using a Larry Young cam grind and need full diameter of the stock lifter, make sure the manufacturer hasn't chamfered the "foot" of the lifter. If they HAVE chamfered the lifter, the lifters can be sent to Rimco Machine Company, 5530 East Dyer Road, Santa Ana CA 92707 phone 714-549-0672 and they will re-grind the base of the lifter to remove the chamfer. It only costs like $2 per lifter to do this. Also, we were checking for hardness on the side of the lifter - not the foot. When checking on the foot, the lifters from BP Northwest were better)
If you are using stock rods, limit your rpm’s to 6000. Throw
away the locking plates. Clean all the holes and bolts with lacquer thinner.
Apply red Loctite to the bolts and
tighten to factory torque. Research by leading companies has shown that the
sheet metal locking plates are the least effective means
of retaining thread fasteners, while Loctite is the most effective.
Of course you know that caps and rods must be assembled together
and not mixed. But if you lay down a
cap and can’t remember which way it goes on, remember that they are made so
that the bearing tab in the cap and in the rod always go on the same side. Same
with main bearings.
(The stock rods
and caps on my engine were stamped with the cylinder numbers, 1 to 4.
Don’t know if they come from the factory this way or the previous
engine builder stamped them. TFM)
3. If you are using aftermarket rods, treat the bolts per the manufacturers spec. If the bolts have a reduced diameter between the threads and the head, they are designed to stretch but if you stretch them too far they will yield and fail. If you don’t have a stretch gauge, cover the threads and the bottom face of the bolt heads with moly lube and torque them to 60 ft lb. (Tony note: aren’t there two types of bolts used with two different specs?) Further note from a 2004 e-mail exchange: You must look at the little printing on the bolt head to determine which brand bolt it is. Then the torques are: 3/8" CARR -- 65 ft lb; 3/8" WMCS - 45 ft lb
But before you use
the pistons, install rings dry on a couple of the pistons and measure the
clearance with between the top of the ring and its mating face on the ring
groove with a feeler gauge. If you
have more than .004 - .005, the pistons are not usable because the rings will
pound up and down in the grooves and will break.
It is assumed that you know how to put rings on pistons, and how
to assemble rods to pistons.
If you have occasion to measure pistons, remember that they are
barrel shaped and must be measured in the middle.
Have the pistons honed to give full floating pins.
4. You don’t have to put much oil on the walls or pistons. If you put a light smear of oil on the skirt of each piston, that is enough. Then when you start the engine, you absolutely must run it at 2500 rpm for five minutes or so initially. The rings will break in rapidly. This seats the rings quickly and breaks in the cam and lifter face properly. I can hear the screams of alarm even as I write this – but this is the practice recommended by the motorcycle division of BMW and it works. (Tony Note: we normally run 2000 RPM for 20 minutes if the lifters are new. You have to do this for proper break-in of the new lifters. A lot of times, I have to do this in two runs of 10 minutes or the car overheats. DO NOT BLIP THE THROTTLE, your lifters can go away if you do. It's not uncommon for the header to glow red during this initial run-in. Bring the car quickly up to 2,000 RPM, don't let it idle at 1000.)
These pumps are really good and long lasting. Do check the
clearances per the factory manual. If you buy a rebuild kit, the innards may be
too long for the cavity so beware of this.
Check the pin that holds the rotor to the shaft. These sometimes
fail with serious consequences. New pumps seem to be worse than old ones.
(You may want to check the FOT
archives for threads on new oil pumps and the problems and solutions associated
with them. TFM)
When I find a loose one, I drive out the pin and tap both sides
for a 3/16” set screw. If you have a hardened shaft, you can tap that only
so far and then the tap won’t cut it. Use Loctite on the setscrews.
The most common failure on these pumps is the two ears on the end
of the shaft, which drive the whole thing, tend to break off. To minimize this
possibility, the sharp corner at the bottom of the slot must be eliminated.
I’ve tried several approaches on this and so far they have all worked. The one
I now like the best is using a cutoff wheel in a die grinder to make the flat
bottom of the groove into one big radius, and then finishing the surface with a
tiny stone in a Dremel tool so the scratches go around the curve instead of
longways on the curved portion.
For quicker priming for startup, put a small amount of grease on
the rotating parts of the pump to give it more initial sealing and it will prime
6. Make sure you get the oil pump gasket on right, so the hole for the oil to go through the passage is not covered up.
Note: Steve Yott (aka "Drippy) is making a limited run of an uprated oil
pump that really deserves a look. I am putting one in my car for the 2009
season. The rotor is not a separate part from the shaft, so you can't have
that failure, and he's got the "shaft" protruding from the bottom of
the rotor into the housing as well. The rotor is then supported on both
ends. Oil passages are present ensuring that there is no metal to metal
contact on either end of the shaft. Very cool. Contact Drippy at firstname.lastname@example.org
. Link to article from
Snic Braaapp describing this excellent product is here.
Link to article from Snic Braaapp describing this excellent product is here.
As with the front cover, do a little bodywork on the gasket flange
to help it seal better.
It is best to install a baffling system in the pan. This can
become a separate hobby in itself and can challenge your imagination. If you
want a simple but effective approach, put a vertical baffle front to back, along
the slanted edge of the oil pump cutout hole in the windage tray. The bottom of
the baffle should be about 3/8” above the bottom of the pan. You can attach
the top of it to the windage tray by bending a flange on the top of the baffle,
drilling a row of holes in the windage tray, and plug welding the baffle and
tray in the holes.
3. You must also run the oil level right at the full mark on the dipstick. (This holds true regardless if you using the stock pan of a deeper aluminum pan. TFM)
Note: the sign of having the oil level too low is a drop in oil pressure on left
Porting the head. I will tell you what to do to get about 80% of
the flow improvement that a professional head flower (crazy term) will get.
Intake – Size the ports per Kas’s book, 1-1/2” all the way
from the manifold face to the valve
guide. Take most of the metal off of the short side.
Remove the bump that is just inside the manifold face in the port,
adjacent to the head bolt hole. Make
the short side radius just under the valve seat as smooth and consistent a
radius as possible. Feel it with your
Leave the port
just under the valve seat a little
smaller than the valve seat, so that when the machine shop puts in the three
angle competition valve seat, you get the full effect of the velocity-inducing
three angle seat.
3. Exhaust - with a long shank carbide cutter, remove the big bump in the floor of the bowl where the guide comes through. When viewed from above, if you had x-ray vision, you would see that the path of the port is S-shaped, Remove metal from the inside of the “S” closest to the valve. Removing more does not do much for flow. If you remove too much, you will cut into the water jacket, scrapping the head.
Note: be very careful with the whole "port matching" deal - it's very
easy to do more harm than good. Jack and the flowbench found a zillion
things that "obviously" would improve flow that actually hurt
flow instead. Unfortunately, I don't know all of the tricks. Having
a little step in between the manifold the the head is better than having the intake manifold suddenly go to
a larger diameter. You cannot go more than 7 degrees from a "straight
tube" or the flow separates from the sides and you generate turbulence that
actually reduces the effective diameter of the tube. My head flows almost
as good as the best one Jack did, and the intake ports are 1-9/16" at the
outer face and I run stock diameter valves.
Clean the head thoroughly. Replace the rear freeze plug.
If they accidentally put a head with aluminum pushrod tubes in a
caustic tank, the tubes will disappear. Do not despair. It is really easy to
replace them with ¾” aluminum tubing
The aluminum plug on the top of the head may leak. It is in a
threaded hole, and after removing, you can tap it to NPT and put a pipe plug in
Tell them how much to mill. If
they are a good shop, you can just tell them the cc’s you want in a combustion
chamber and they can mill to that. It is risky to take off more than .165 from
the stock head thickness of 3.325".
Install guides –if you are using the bronze guides, they MUST
have .004 stem clearance. The shops
take some convincing, but if clearance is less in these old engines, the heat
will cause the guide to shrink and the valve to stick, perhaps destroying the
When you get the head back, put a small bead of JB Weld around the
edge of the rear freeze plug. Also chamfer the edge of the combustion chamber to
remove the hot spot corner created by the milling operation.
G. Tell the machine shop the amount of lift of the valves, and have them machine the valve guide accordingly.
Tim Murphy conducted a survey on the valve to guide clearance needed for the Bronze valve guides in May 2012. The results are here:
Competition stands prevent the shaft from breaking on the very
outer ends where the stock stands support the shaft on only one side.
If you use competition stands, check for interference between the
head nuts and the stands. You may
have to remove some metal from the stands, and maybe use short head nuts.
Check the contact pattern of the rocker tip on the valve stem.
Theoretically you want it in the center of the stem at half valve lift. If the
contact is outside the center, you correct it by milling the stands. If it’s
inside the centerline, you shim up the stands. However, it’s really difficult
to get it theoretically correct, so if you get it to 60/40% that’s pretty
good. It’s easiest to check all this with the head on the bench and a very
light spring on one valve. The centering-up is entirely due to ratio of rocker
stand height to valve stem height. Pushrod length has nothing to do with it.
Note: some of the rocker stands have a certain amount of
“slop” in the stud holes. Just
sliding the whole rocker assembly toward or away from the valve can affect the
6. (Use ARP hardened and ground washers on the head studs. Anything else, even double Grade 8 washers, will get concave due to the large holes in the top of the pedestals. This will cause the nuts to loosen and possibly allow the stud to bend sideways causing failure. TFM)
Tony Note: Ken Gillanders / British Frame and Engine sells an ARP rocker stud kit with head nuts from a Mini that allow torques of 40 ft lb or so for the rocker pedestals. With high lift, fast event cams, rocker stud breakage is common, and this seems to be the total solution to the problem.
After installing the head, install a couple of stock length
pushrods and the rocker assembly. Adjust those valves to the proper lash. Look
at where the adjusting screw is. Determine how much shorter the pushrod must be
to center up the adjusting screw.
It used to be that you could shorten the pushrods in a lathe and
press the end in further. Nowadays the competition pushrods have such a tight
interference fit that this is nearly impossible to do.
rocker assembly to head - back off the adjusting screws a LONG way so you don't
accidentally push a valve too far into the bore, causing interference with the
sleeve top, bending the valve. Again, don't ask me how I know. Install the assembly. You must have all the adjustment screw balls in
the pushrod cups or you may bend valves from forcing the valves to interfere
with the chamfers on the sleeves.
4. Finally, adjust all the valves (but you knew this already, right?)
You may or may not want to use a bypass hose. Its function is
misunderstood. If your car has a thermostat, then the bypass allows coolant to
circulate through the head anyway while the thermostat is closed. If you’re
not running a thermostat, some coolant flows through it all the time, which
theoretically decreases cooling system capacity. I’ve run with and without the
bypass hose, using a thermostat and not using a thermostat. I can’t tell the
difference in cooling.
Anyway, if you want to run without it, tap the bypass hose outlet
and put in a pipe plug. The rear hole where the heater pipe screws can be
plugged or you can install a fitting and run a hose to the hole in the top of
the rear of the head where the heater valve is normally screwed in, to help
coolant fill and circulation.
1. The high capacity pumps that are available on the market are
pretty nice, but not necessary if you install a really big and efficient
radiator, which at $180 is cheaper than the expensive water pump anyway.
(Be aware that the water pumps with
a 5/16 threaded end for the retaining nut for the pulley have a known failure
problem. The threaded end breaks
off, the pulley beats the keyway out on the water pump shaft, the belt comes
off, the engine overheats from no water flow and expensive things happen.
As Jack has said, don’t ask how I know this.
The latest stock water pumps from Moss (May, 2008) have a ½ inch
threaded shaft but with a 12mm x 1.25mm pitch on it.
As of this writing, I haven’t been able to find another ½ inch nut
with 1.25mm pitch threads! I have to
contact Moss. TFM)
Tony Note: see my radiator page for more info on
a big radiator installation.
This is the second most difficult thing to do on these engines.
The bottom of the shaft has a tang which engages the oil pump. It
also has sharp corners. Eliminate the sharp corners. These shafts tend to break
Getting the gear, shafts, and pedestal parts aligned for first
assembly is a real pain. It can take a couple of minutes or an hour. The problem
is getting the oil pump slot in the right position so that the distributor
pedestal drops all the way in the hole. I
bought a really long screwdriver and filed a line across the end of the handle
parallel with the blade of the screwdriver. I stick this down the hole and turn
the pump so the slot is almost straight across, front to back. Maybe someone
else has a neat trick for doing this more quickly. I do all of this after
initial priming of the engine. See startup tips.
Another completely different approach to this bit of the assembly
is to leave the sump and oil pump off. With the cam where you want it, install
the distributor drive gear and shaft in the position where you want it, and bolt
down the distributor stand. Then turn the engine over and install the oil pump.
This way you have only to line up the slot and the three studs, since the gear
mesh is already taken care of.
(See TFM “TR4
Engine Service Note - Installing Distributor And Pedestal To Get Correct
Timing” of October, 2008.)
Link to this word document is here (click on the word "here" to open / download that document)
You don’t have to put much oil on the walls or pistons. If you put a light smear of oil on the skirt of each piston, that is enough. Then when you start the engine, you absolutely must run it at 2500 rpm for five minutes or so initially. The rings will break in rapidly. This seats the rings quickly and breaks in the cam and lifter face properly. I can hear the screams of alarm even as I write this – but this is the practice recommended by the motorcycle division of BMW and it works.
Note: we normally run 2000 RPM for 20 minutes if the lifters are new. This
is necessary for proper break-in of new lifters. A lot of times, I have to
do this in two runs of 10 minutes or the car overheats. DO NOT BLIP THE
THROTTLE, your lifters can go away if you do. It's not uncommon for the
header to glow red during this initial run-in.)
(This is repeated from the section on Pistons. TFM)
Larry Young note: A couple weeks ago I found a web page that actually explains why you break a cam using 2000 RPM. I didn't mark the page and now I can't find it. The reason is that the highest stresses are on the nose of the cam at zero RPM, because the nose has the smallest radius of curvature and when you spin the engine the forces due to the rotation (inertia forces) act to reduce the force between the lifter and the nose of the cam. I'd suggest you bring it up to 2,000 as quick as you can [ rather than slowly bringing it up to 2,000 - Tony ]. Of course, using only outer springs also reduces the stress on the cam.
If you start the engine up without first pressurizing the oil
system, you can count on damaging the bearings. Although it only takes a few
minutes of running for the oil pressure to come up, that few minutes is critical
to the life of the bearings. You can pressurize the system by
putting the distributor drive shaft in the chuck of a ½” drill
and rotating the pump
COUNTER clockwise. Watch the oil pressure gauge – after a little bit
you will see maybe 50-60 psi when being driven by the electric drill.
When you start a TR engine, expect the coolant to boil very
quickly – maybe four or five minutes. Shut it off before that happens, let it
cool, and restart. You may need to do this several times. Putting a big fan in
front of the radiator helps too.
Check and adjust everything, of course.
After starting it up several times and getting it hot, remove the
rocker assembly and re-torque the head. Some guys use really high torques – I
use 100 Ft-Lb.
– Triumph Workshop Manual
I always wonder what people do here. The problem with cutting them out by hand
is that it is hard to cut the inner circle. The outer circle is no
problem. Here are some photos, but I better add some explanation.