F18 March 24, 2003
The last week saw a mini crisis with F18 - the big end had an ominous knock, and silly old me pulled the cap to have a look

Yup - Buggered Big End.

It appears that the car has been run without enough oil, or the wrong type of oil, for some time. So "panic stations" ensued, but a new bearing arrived today via UPS from ever-reliable Dan Brown.

Don't believe the psycho raves that have been posted about Dan, I've met the man and dealt with him for the last 15 years. At least I know where his parts came from!

The car without the motor.

Gearbox was cracked open, and drained of some water. The Detent plug was cleaned up, and now all works well.

The new bearing arrived via UPS -Thanks a heap Dan

On the left is the old bearing, and on the right is the new one. The metal condition on the left is suggestive of lack of lubrication, and overheating.
The back of the shells. Left is the old one - note the colour changes of the brass!

I have always advocated the SAE30 oil. This is the main reason.

Also pulled the head on an M15 that had been running on SAE30 oil - nice and clean inside.

Have heard all the arguments for and against both types of oils, and diluting the richness below what Fairmont specify, and of course, I've been given a verbal spanking for being a dinosaur

Modern two stroke oils are designed for a much hotter, higher speed engine, usually one fitted with needle roller bearings on the big end, which themselves allow the mix to flow into the bearing. They also have all sorts of additives, worse than detergent, that do nasty things to your motor. These engines are babbit bearinged.

Fouled plugs - more an issue on slow runs, where there is a lot of stop-start, where your coil or maggie ain't firing right - or you've got the wrong plug. One of my cars has done 250k in a day and not missed a beat, no plug changes.

Just don't run your car lean!

If you have (factual) information otherwise - I'd be keen to hear it.

Heres a link that may be of interest.

the big end cap wasn't in too bad a shape so was whacked back in. Had to tinker to reset the bearing, and ended up adding 5 thou worth of shim to stop it locking up. The little shaped plates are the shims that were on the car.

Gently nipping up the big end - needs only 30ft.lbs of torque.

The test for a correctly set big end is that the motor should "bounce back" freely on the compression stroke. With the 5thou of shim, she is about spot on.


Page uploaded March 30, 2003 refreshed June 25, 2007

© Nic Doncaster