View Full Version : TR2/3/3A TR3 Cylinder Heads

08-30-2006, 09:51 AM
I "inherited" a nice TR3 with straight rust-free body, the only major problem with the car is that it has a cracked cylinder head according to my mechanic. My question is, what is the best approach for obtaining a head - are there used ones available and if so, where? I noticed Moss sells new ones with valves, a little pricey but I guess if that is the only way then that's it. Any suggestions?
Thanks, Toby

08-30-2006, 10:00 AM
go e-bay frequently. i got a spare for $27. sorry it's not for sale. remember with tr3 you can use a tr4 or tr4a head if originality is not an issue.

08-30-2006, 11:00 AM
speaking of originaltiy. I found out the hard way (after having it totaly machined and new hardened seats put in) that the head I have for my TR3A is actualy a low port TR2 head. I hope some day to find a person in dire need of an original TR2 head that has a TR3 or TR4 head they would like to swap. I would like the original high port head on my car some day.

Andrew Mace
08-30-2006, 11:33 AM
Where exactly is the crack? I have heard (but cannot provide evidence at the moment to back it up) that some cracks have little to no effect and can be ignored.

08-30-2006, 01:43 PM
You may want to get a second opinion on the head, mine went in the shop with what i thought was a bad valve, came back with a shopping list that included cracked head, sleeves, rings, crank, distributor... anyway, found a different mechanic who is taking a perfectionist, but pragmatic approach and has been pretty reasonable (he managed to get a new (old) steering column in under the original quote) - anyway, the long and the short of it is i do need to send my head out to have the seats hardened, but for now he's putting it back together with the old head so i can finish the summer with the car - he is convinced that it will run just fine with the crack and may last years until deposits build up to the state they were at when it went in...i'll get it back in the next couple of days and be able to decide if he was right...
kerry /ubbthreads/images/graemlins/canpatriot.GIF

08-30-2006, 03:38 PM
Where exactly is the crack? I have heard (but cannot provide evidence at the moment to back it up) that some cracks have little to no effect and can be ignored.

[/ QUOTE ]

It might also be possible to have it welded up and repaired.

There are shops that specialize in cylinder head work.

I'd check that out before trying to track down another head (that might have the same or even worse issues).


08-31-2006, 12:38 PM
Those of you that might know about reapair to a head. My spare TR3 head has a crack in the small space between the intake and exhaust valves. Any idea if this can be welded/repaired? being able to repair that head would solve my TR2 head in a TR3 (with a TR3 manifold) problem.

08-31-2006, 12:57 PM
i think your S.O.L.. that would be the one place least likely to be repaired. extreme temperatures. crack between water jacket holes at face-probably.
while were at it, with iron heads do you install hardened valve seats just on the exhaust ports or intake as well. usually its the exhaust thats the seat problem.

08-31-2006, 01:12 PM
In my case it was the exhaust that was the problem indeed, as you say, but given how little it cost to put a hardened seat in (compared to the total work involeved in my removing the head and getting it back to gether), I just had them do all eight seats while it was at the shop.

08-31-2006, 06:11 PM
Hi Adrio,

Rob is probably right, unfortunately. But I'd still take it to a specialist shop or two to get some additional opinions, before giving up on it completely. Look for a specialized cylinder head shop in your area. Some guys can perform miracles!

A problem with seats on both intake and exhaust is that installing them pretty much limits you to smaller valves, i.e. approx. stock sizes or, at best, not a lot larger. Heck, there is little enough room in there for the valves, period, and even less with seats installed on only the exhaust side.

All this really won't matter if you are sticking with stock size valves, of course. But IMHO, pretty much all TRs can benefit from larger exhaust valves, especially. I think about 9-10% increase is the upper limit of what's possible due to space limitations, but every little bit will help. (There's also some beneficial porting work that can be done, right behind the exhaust valve.)

I've been assured by folks who know more than me about this sort of thing, that a really lovely set of oversize valves that Moss sold me some years ago (polished Stellite, slimmmed, etc.) - still in my garage awaiting just the right engine - simply won't all fit in there, if hardened seats are installed.

These particular OS valves are 1.42" intake and 1.36" exhaust. Greg Solow at The Engine Room in Santa Cruz Calif., who is known for "maxxing out" TR 4 cyl. engines for vintage Morgan racers, uses 1.60" intakes and 1.41" exhausts that he has specially made or modified. BTW, stock valve sizes are 1.56" intake and 1.30" exhaust.

A solution I'm looking into it is induction hardening. This is a process where the head material itself is hardened right around the valve seat area, rather than having a hardened insert installed.

Triumph heads are made of sterner stuff than many older ones, anyway, and not praticularly prone to problems. The only catch is that the head needs to be in good condition to begin with, to use induction hardening. Any significant flaws around any of the original valve seats still might require hardened inserts be installed. I'll just have to wait and see if and how this works out on my TR4.


09-01-2006, 06:20 PM
Try a diesel truck machine shop. Phil