Triumphrat

908MD904 · 04-07-2008

This is my first post, hope it works.

I have an early 01 790, installed the 904 kit years ago, just never got much chance to rack up the miles.

Since getting that chance, I find I have an oil leak just above the third cooling fin from the bottom in front of the LH cylinder. I have been horsing around for way too long trying to stop the leak, of course, now it leaks severely from the brand new head & base gaskets, as well. So, 2 questions...

1. Do any of you guys who have installed the 101mm big bore kit have a cylinder block for sale, preferrably real cheap?

2. How many times can these cylinder studs be retightened before they should be replaced? There is no reference to this in the Triumph manual, and I've had this thing apart at least a half dozen times.

Thanks for any and all help.

SHILOH · 04-07-2008

I checked Haynes and can't find any reference on reusing the studs. For what its worth, there is a 904 kit that include new studs. And I really don't know if the last tidbit is meaningful at all.

Is it possible the leak is from the oil return tube?

Do you think that the studs are the issue?

908MD904 · 04-07-2008

The reason I'm concerned about the cylinder studs is that the manual says to tighten them all to 20Nm, then tighten them to 30Nm, then tighten further 90 degrees.

I used a torque wrench for the last 90 degrees a few times, and I am pretty sure it took about 40 ft-lbs, or more, the first few times I re-assembled the motor. This last time they were more on the lines of 35 ft-lbs or less. This makes me assume that they are stretched, but they don't look like it, or that they are loosing their temper.

I really am curious as to their ability to reach properly tightness.

908MD904 · 04-07-2008

Forgot to say:

Thanks, Shiloh, for checking the Haynes manual.

The leak is NOT coming from the vent tube. Wish it was, that would sure make life a lot easier.

Bottle_Fed · 04-07-2008

If I remember correctly the studs should be tq'd to 10nm prior to tightening the head bolts. I always use the sequence, then switch to a breaker bar for the final 90* tq. Are you sure it's a head gasket leaking?

Greg

sweatmachine · 04-07-2008

jojje1963 can mill you a new set of jugs, but you'll have to have them bored and sleeved just like when you installed the 904 kit.

SHILOH · 04-07-2008

Quote:

Originally Posted by 908MD904

Forgot to say:

Thanks, Shiloh, for checking the Haynes manual.

The leak is NOT coming from the vent tube. Wish it was, that would sure make life a lot easier.

It was a hope, (the tube). What was done the last time I was inside one of these guy, was to torque the heads down to the 30 nm per the sequence in the Triumph manual (which is different than the Haynes manual), let it set for an hour or so, and then with the torque wrench still set at 30 Nm retorque all the bolts in the correct sequence. Some of the inter bolts took at least 90 degrees to come up to the 30 Nm. Then I tightened all the bolts thru 90 degrees.

But, that doesn't help you. Sorry I can't be more useful.

Look for a PM in a few minutes.

908MD904 · 04-07-2008

To Bottle Fed:
I re-assembled this afternoon, while warming up, I could see the oil oozing from both the base and head gaskets, no doubt in my mind where it came from. By the way, what did you do with your original cylinder?

To Sweatmachine:
This is basically what I'm trying to accomplish, I just need a fresh, oil tight, cylinder. I figured I would send it to Advanced Sleeve since they are the people that Wiseco uses.

The leak from the casting only happens above 4000 rpm, when it is approaching, or over, 40 psi (I don't have an oil pressure gauge).

Jimi_X · 04-07-2008

A friend of mine here in Calgary had the exact thing happen. The shop discovered a porous casting in the same place as your leak. The oil was moving between the liner and the casting. It was resolved by having the liners removed, and new liners installed. The seal must have been better because the leak stopped.

908MD904 · 04-07-2008

To Jimi X:

I wondered about this possibility, just chickened out on popping the liners out of the casting. I will try this during the next go-round. I think I can stop the leak, I just need to find it first. The gas grill should work fine for liner removal.

Nobody has given anything concerning the studs, once the engine is disassembled I will measure them and see if I can find some class 10.9 or 12.9 studs as replacements.

I sure would feel better having a target tightening torque. Maybe Bill Gately can provide some insight.