I have quite the vexing problem with a 1991 B230F motor. The engine produces a high-pitched, deisel-like clatter between 2800 and 3500 rpm, in gear or not, no matter the load.

Some history: I bough this engin w/ 75K on it to use a replacement for the original motor in my 87 240. The new motor came from a 91 740, and I did have to swap the intermidiate shaft as there was no distributor drive gear cut into it. The motor now has 100k on it, and has developed the clatter.

What I've done/checked: All driven accessories and brakets (alt, ps, ac), entire exhaust system, fan clutch, timing belt and tensioner, valave clearance, new rubber dampers, oil pump drive gear, distributor, and the axial and lateral play in the intermidiate shaft. The crank pully/vibration damper is solid and has not "spun". Oil pressure is 4.5 hot 2000rpm, and 2.5 hot idle. I pulled the head and examined every single bit... all the parts are pristine.

What I think: The end play in the intermidiate shaft is .7mm, while Volvo calls for .25mm. timing belt R&R seems to make the noise go away for a mile or two, then it comes back. This theory is a long shot at best, but could a bit of extra endplay in the shaft cause a diesel-like clatter?

I don't know what else to check, save for tearing the motor apart for a complere overhaul. That would be a shame, as 100K is still nearly new in Volvo terms......

Any ideas are greatly apriciated.

Best,

Beau MacGregor