A mate has an old classic karmann beetle convertible. The engine became poorly earlier this summer and on strip down showed a broken valve, piston and cylinder damage on the #1 pot. The engine is a 1500.

So he's stripped it all down, refreshed the bottom end with new crank and conrod bearings and sourced a used good set of 1600 cylinders pistons and heads. So I was round at his last night as he was starting to slot it all back together and cylinders 2, 3, 4 all slot together perfectly. On fitting the #1 after installing the piston gudgeon pin and starting to slide the cylinder home it starts to bind up and the alignment is ever so slightly off so the cylinder won't slide into the block. We swapped the no.2 into the no 1 position and the same it binds up.

He reckons the crank has been checked and miked up all within spec so am I right in thinking he's probably got a slightly bent conrod? I know sod all about these engines but if we've eliminated most of the other bits and the issue is on the same cylinder that had the original damage I can only see it being a rod or crank issue?

Or am I missing something?

Cheers
Steve

yes i would say a bent rod,try swapping them around to test? :-)

My guess would be that when it dropped the valve it has "squashed" it between head & piston & thus put massive force on the rod, almost certainly bent, don't really see what else it could be

[Edited on 21/12/15 by russbost]

Thanks gents. Yes I did suggest swapping a rod but he decided to stop and leave it for last night and had beer instead!

He was a bit disheartened but rods are cheap as chips for these engines anyway.

make sure he fits all the tinwear with no air leaks, gromets on the spark plugs etc as these engines run hot and need all the air they can get. Dropped valves on them are very common.

there is a small deflector plate on the underside of the head inbetween the fins which is often missing (rusts and falls out) but very important in keeping the valves cool and another larger one on the barrel fins. Make sure they are both there.

Thanks whippy. I've pointed out your pic to him.

Confirmed as a slightly kinked rod this afternoon.

Shouldnt realy but......Ohhh Errr Misses, a kinky rod.

Only slightly............

A kink is a kink, straighten him out and get him motoring!