After much testing, measuring and accusations it seems that probably more like 20thou was taken of the head (a bit much)? and a 5 notch gasket fitted. Now assuming everthing has been running ok for 3-400 miles without anything touching why would the gasket compress spontanously and allow the pistons to hit the valves. I know that you pureists will all frown at the idea of fitting 2 gaskets (two x 2 notch)but that would give the necessary clearance although slightly less compression. And remember racing performance is not an issue here. The head has been checked and no damage has been done to the valves or cam. I take the point that keys on the shaft may have sheared or broken but the engine lined up when the head was taken off and when we double checked the timing. The mechanic in question has had 40 years experience in repairing diesel engines from tanks to JCBs so at the moment I have to go with him. Im afraid money is a big issue in this problem and perhaps im looking for an easy fix however please let me know if anyone has any ideas.
Thanks
1749CC VAN ENGINE
Moderator: RichardW
Hi.... it would be helpful to you as well as all if this topic were confined to one area...but.. for now..
your idea of two gaskets is not unheard of. It used to be, and probably still is , done on the Volvo (small one) to convert them to unleaded! as to reducing compression Im not sure about that one.
... The gasket would not compress whilst in use as you suspect.
... Were new head bolts fitted on the rebuild??????
mike
your idea of two gaskets is not unheard of. It used to be, and probably still is , done on the Volvo (small one) to convert them to unleaded! as to reducing compression Im not sure about that one.
... The gasket would not compress whilst in use as you suspect.
... Were new head bolts fitted on the rebuild??????
mike
Back again.
If you are sure everything is OK, timing, no bent valves, correct gaskets etc,etc. (I had a half sheared key once in the camshaft sprocket, the engine was noisey, loss of power etc., but the timing dowels/bolts etc. all lined up. Till I found this key problem, once sorted, everything was fine. Luckly the valves did not contact the pistons. So don't take for granted the Key in the cam and sprocket are always OK, check it!!, if you have problems like yours.)
How many miles has the motor done, its possible that the valve springs have gone weak, ie: causing valve bounce at high revs, possible cause of valves contacting the pistons ? and loss of power when revs are going up.
Its worth a check to check the free length of the springs against a new one.
Sooty
If you are sure everything is OK, timing, no bent valves, correct gaskets etc,etc. (I had a half sheared key once in the camshaft sprocket, the engine was noisey, loss of power etc., but the timing dowels/bolts etc. all lined up. Till I found this key problem, once sorted, everything was fine. Luckly the valves did not contact the pistons. So don't take for granted the Key in the cam and sprocket are always OK, check it!!, if you have problems like yours.)
How many miles has the motor done, its possible that the valve springs have gone weak, ie: causing valve bounce at high revs, possible cause of valves contacting the pistons ? and loss of power when revs are going up.
Its worth a check to check the free length of the springs against a new one.
Sooty