MR2 Owners Club Forum banner

1 - 11 of 11 Posts

·
Premium Member
Joined
·
16,626 Posts
Discussion Starter · #1 ·
After the engine on the race car spat oil all over the floor and made a funny noise last summer, we abandoned the project for a while. Nico (my cage / suspension builder par excellence - from Kansas) came down Friday after I finally got the time (and I recovered from surgery enough) to tear down the ITA motor. We thought it had blown a front main seal. We were off by about a foot and a half. :shakeshea:

It turns out that the cam pulley bolt on the exhaust cam had extracted itself, dropping the pulley and sending oil through the cam and down the front of the engine. We both remembered having torqued the bolts, so that was not the problem. Thorough analysis leads us to believe that the effectiveness of the good ol' blue thread locker compound was negated by traces of sealer (our fault) in the cam core, allowing the bolt to unseat itself and unscrew.

There was no damage to any of the parts, but we were now seriously worried - since with design of the .040" over pistons it is now a very slight interference engine. Visions of holed pistons and bent valves haunted us. We pulled out the trusty leak-down tester and went to work.

WONDERFUL news . . .. Even considering the engine had less than 3 minutes runtime on it, it was cold, and the fact that it was essentially "dry" (only residual oil on the walls - from over 6 months ago) the worst cylinder checked out at less than 8% leakdown.

We replaced the brand new - but once oil-soaked - cam belt and reassembled the engine. After a throrough check out, we pushed the "go" button. Despite having sat for 6 months, it fired up after about 2 seconds and ran like a (very loud) top!

That project done, we went on to the "clean up" items abandoned last summer: fininshing the transponder install, charging the fire system, and a few other little chores.

Let's go racing!!

:woot:
 

·
Premium Member
Joined
·
16,626 Posts
Discussion Starter · #3 ·
They were, and are again. ;)
 

·
Premium Member
Joined
·
1,751 Posts
Nice, good to know it wasn't a painful fix!

I have a 1/2 page punch list for my car before she'll be race ready - but that's way down from a full page!
 

·
Charter Member - Group W
Joined
·
2,028 Posts
Are these standard cam sprox? Could be a job for safety wire?
 

·
Premium Member
Joined
·
16,626 Posts
Discussion Starter · #9 ·
IT rules prohibit aftermarket cam pulleys. We ran it long enough to get the temp up, set the timing, and bleed the cooling system (about 10 minutes), at speeds varying from 800 to 7000. I kept an eye on the bolts with the timing light (it does a really good job of showing even slight motion). Then we re-checked the torque on the bolts. Since they had a Loc-tite application, we didn't break them loose - just verified that there was no give at 37 ft/lb.

This has never happened to me before, even after hundreds of race miles. I believe what happened was just a case of not getting a bond with the Loc-Tite, made worse by the relative slipperiness of the silicone sealer. The intake bolt never came out.
 

·
Charter Member - Group W
Joined
·
2,028 Posts
Never before run cams?

I'd look real hard at the threads and make sure they are tapped deep enough to let the bolt head seat.

Loctite is a secondary retainer. The bolt should not have come out just because of a failure of thread locker.
 

·
Premium Member
Joined
·
16,626 Posts
Discussion Starter · #11 ·
We verified that before we put them in the first time. Like I said - the threads had evidently gotten contaminated with RTV and failed to grip correctly. Either that or we torqued the intake cam twice and not the exhaust. That was 6 months ago.

Anyhow - here it is in current configuration (and I still need to consider plug wires - but if it ain't broke . . .).



also - a shot of one of the rear strut assemblies -

 
1 - 11 of 11 Posts
Top