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Head Swap Or Engine Swap?


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#1 sadam_lfc

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Posted 07 April 2009 - 05:16 PM

Hi all.

My 1989 998cc Mini 30 is broken :D

The top end is bone dry, and one of the rocker arms has cracked into peices and come off.

There is plenty of oil in the engine, but there is back-firing through the carb, and a loud knocking noise when driving.

I have a replacement engine in my garage, however I have been told I could just swap the heads....

Would this fix the problem?

Thanks, adam.

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#2 Saxo-Fiesta-Mini

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Posted 07 April 2009 - 06:21 PM

likely the oil galleries are block or the oil pumps dead id get it check b4 sending more money

#3 Cooper-202S

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Posted 07 April 2009 - 10:17 PM

What you have is an engine that sadly needs a birthday, you could do a head swap but it sounds like there's more going on.
You best bet is to swap it out if the spare is a runner and strip it down.
The knocking is unlikely to come from the head, though it may have come from the knackered rocker.
If the knocking was of a deep pitch and was worse when decelerating then is proberbly big ends and mains.
If it was high pitched and tinny sounding then it could be valve train.
The lack of oil in the top end is a good sign of poor oiling generaly.
The back firing through the carb is either poor timming possibly a knackered chain or tensioner or a chipped valve or seat.


One thing is certain, there is no sweeter sound than an engine you have rebuilt yourself.

#4 Dan

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Posted 07 April 2009 - 10:38 PM

Your engine needs to come apart. There are very likely to be bits of rocker all over the inside of it (even without oil flowing some bits will probably have fallen down the back if it crumbled). Something is very wrong with the oil system, the pump or the PRV could be faulty or there could be blockages as said above. I very much doubt a new head will fix this. In terms of the oil system, all the head contains is a feed gallery and the return galleries around the pushrods. There's nothing there to go wrong. With the top end dry the cam has only been lubricated by splash and as the knocking points to the bottom end suffering too it's not likely there's been a lot of that going around. The carb back firing and the head oil problem could both be caused by a head gasket failure but I suspect there is a lot more going on. When was the filter last changed?

Edited by Dan, 07 April 2009 - 10:41 PM.





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