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TR2/3/3A TR3A Engine Wont Turn

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Although there were 3 different flywheels, the bolts that hold them to the crank are basically identical. I'm not sure of the change point offhand, but the bolts did get very slightly shorter at some point, when the factory deleted the locktabs.

As noted, the 4A flywheel is drilled differently for the clutch plate. If you are using the 4A clutch & flywheel, you'll also need to shorten the front cover on the gearbox (otherwise the clutch fingers will hit it when the clutch is disengaged); and use a 4A style throw-out bearing.

Also worth noting that the original bolts were "specials", so you probably shouldn't be substituting hardware store stuff (even if that's what you found on your donor engine).

I have heard other stories of the flywheel bolts hitting the seal bolts when the locktabs are deleted with the early stock bolts. Not sure why that is, mine seemed to have plenty of clearance when I deleted the locktabs. Could be manufacturing tolerances, or possibly some subtle early/late casting differences. Possibly even some seal housings are thicker than others.
 
prb51 said:
All of the TR3/TR4 trannies are interchangeable
Click to expand...
Pre-TS50000 boxes won't work with the later starter & flywheel; unless you cut a hole in the side or use an aftermarket gear-drive starter.

Not that that has anything to do with the problem at hand.
 
prb51 said:
Then that could be your issue if the bolts were too long.
All of the TR3/TR4 trannies are interchangeable as far as I know so shouldn't be a problem (since you have the app. engine etc). No experience with the latter stuff although you should have a synchro 1st gear with the latter unit.
Have you removed the tranny yet?
Click to expand...

Yes. Tranny is out.

Someone above said that the bolts would need to be 3/16th to 1/4 too long. Peering down from the top of the engine, I'd guess the gap to be 3/16ths, and the bolts appear firmly pressed into the aluminum, suggesting they are not the "correct" bolts.

I'm not sure how to tell the difference between the different flywheels. But I'd bet good money it's a TR4 unit.
 
I'm sure it is as there is no reason not to use the TR4 parts entotal, if the ring gear on the flywheel is a bolt on then it's a latter unit TR3a/b/4/4a. The early cars (like mine) had a press fit ring gear.
PITA to remove things but better now than latter and it's a simple fix, back them off and spin the motor by hand, you'll feel better.
 
rlandrum said:
I cannot say with absolute certainty that the flywheel bolts are stock originals. In fact, the entire engine is from a TR4A, and the transmission may be too... Making it possible that they are TR4 flywheel and clutch.
Click to expand...


<span style="color: #990000">Randy- for what it's worth.

My TR6 has a TR250 long block, a TR4A clutch and
a TR4A tranny. Everything seems to fit together.

Here is a photo of the flywheel- hope it helps you.

dale </span>

flywheel2.jpg
 
I installed a TR4A flywheel in my TR3 (HVDA conversion), and had no problem with the length of the original TR3 bolts. I did use locking tabs.
 
My vote would be to grind them down. I might also suggest doing them one at a time - i.e. remove and grind one bolt, reinsert, torque, and repeat for the rest of the bolts.

For some strange reason I am finding it quite easy to resolve this issue from a distance :smile:

My advice to you younger guys is to have kids early and often and when they are old enough, only buy them cars that need to be fixed up (i.e. cheap). That way they gain plenty of experience that will serve you well later in life :smile:

My son is a saint, gents. Of course I've listed him as co-owner on the registration....
 
it is for sure the flywheel bolts.
my friend paul had the same problem.
then guess what? i did also.
we both fitted the new rubber rear oil seal with the new and obviously different alumium casting.
i reused my old bolts, not sure about paul's
we where both only about 0.015" too long. paul used split washers i used a very tight washer under the tab locks.
frank
 
As was suggested before it does make me wonder if the housing for the oil seal is the primary culprit, particularly if the replacements are thicker than stock.

Randy
 
Yep... We used the aftermarket 1 piece oil seal. It was more work, but we wanted to ensure that it wasn't going to leak while it sat in one of our garages.

It required milling down the rear of the crank, then polishing it, then drilling two new oil galleys in the rear main cap.

I'd guess that the flange on the new aluminum seal is about 11/64ths, or just under 3/16ths. I'd also guess that the old one is 1/8th. But I'm going from memory alone.
 
I'll be interested in how it works for you.
Could be a combo of the two..long bolts and thicker seal unit.
Looking at your Dad's signature block I'm surprised you're not working on a Heally.
 
Rob: my 3A engine was rebuilt with a conventional rear seal and of course you know that I reported THIS problem back in Oct.

Don't take this the wrong way but don't you think it would be prudent to use brand new bolts and tab wahers? Just a suggestion.

Frank
 
Frank,
I missed that thread.
When I put my flywheel back on I didn't even know there could be an issue and I didn't have any lock tabs so reused the original bolts with locktite.
I just looked at a friends rebuilt 3a motor and there is at least 3/16th clearance in that area if not more. The tabs are 1/8" or less which would still leave some room.
Now if someone had 'faced' the crank or flywheel mating area that could reduce the gap or improper thrust washers.
Did you originally have the bolts/tabs or the stretch bolts?
I'm sure the Landrums will replace the long bolts (they're not sure they are original anyway as to length) with the right stuff.
So the original bolts locked into the seal body?
 
angelfj said:
Don't take this the wrong way but don't you think it would be prudent to use brand new bolts and tab wahers? Just a suggestion.
Click to expand...

In general, we have used new bolts and nuts everywhere.

However, the bolts used in the crank are not of the three standard sizes I have on hand (1/4, 5/16, 3/8, both course and fine). As I recall, they were 7/16. And they appeared in good enough condition to re-use without worry. Added to that is the fact that we were anxious to get the engine in the frame and the decision was made to make-do with the existing bolts.

Hindsight is always 20/20.
 
prb51 said:
Looking at your Dad's signature block I'm surprised you're not working on a Heally.
Click to expand...

Me too, actually. When I found this car, the plan was to get it running for him, then let him sell it to a true Triumph enthusiast so that he could purchase a Heally. He decided this one was too nice to sell, I guess.

Of course, now we're Triumph enthusiasts.
 
You guys are doing a great (and speedy) job on the TR3. Regardless as to it's final home you've saved another LBC for folks to enjoy.
I had a 100-6 in High School ( a real rat but it ran well) and also have a desire to acquire an early AH.
I'll keep the TR3 though, they really have a distinct personality and they are quick for an LBC.
I re use bolts all of the time...if I were racing etc. I'd be more replacement orriented.
 
rlandrum said:
angelfj said:
Don't take this the wrong way but don't you think it would be prudent to use brand new bolts and tab wahers? Just a suggestion.
Click to expand...

In general, we have used new bolts and nuts everywhere.

However, the bolts used in the crank are not of the three standard sizes I have on hand (1/4, 5/16, 3/8, both course and fine). As I recall, they were 7/16. And they appeared in good enough condition to re-use without worry. Added to that is the fact that we were anxious to get the engine in the frame and the decision was made to make-do with the existing bolts.

Hindsight is always 20/20.
Click to expand...

Rob,

www.aptfast.com (800)278-3278 sells ARP and ships out pretty quickly. I paid under $20 for the set for my 4A. Worth it!
 
FYI if I recall correctly my son had the crankshaft ground to accept the new type rear oil seal. He can confirm next time he's online. No clue if it makes any difference. Didn't get a chance to talk with him today so I don't know if he was able to resolve the issue with the bolts.
 
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