Author Topic: Pistons meet valves - repairable? (Read 2316 times)

ajajliardo · « **on:** November 17, 2008, 11:05:52 AM »

I'll be picking up a 98 z3 this week with a broken timing chain.

I figure the m42 and m44 are similar enough that I would be able to get good advice from this forum.

What is the possibility that the valves are bent and the pistons are ok?

If so, when the valves bend, is that the only damage that usually takes place or am I looking at further head damage?

bearsbmw · « **Reply #1 on:** November 17, 2008, 11:12:03 AM »

A inspection is the only real way to tell the full extent of damage but if the chain break's it can bunch up and slap the wall of the chain housing and crack it... Holes in pistons sometimes.... can lead to alot of intresting fixes

roundel318 · « **Reply #2 on:** November 17, 2008, 11:17:09 AM »

In the M42/44 motors, I would imagine if the valves are bent, the pistons would probably have some damage.

twright · « **Reply #3 on:** November 17, 2008, 04:44:24 PM »

I bought an engine that had "jumped time". All of the valves were bent, except for the two that were broken.

Three of the pistons looked great. One of the pistons had a small indentation in it. I polished up the indentation and used the short block (block, pistons, crank, rods, etc) with another head.

It's running great and is my daily driver.