perkins prima car engine

[tel1]

got a price on a cylinder head today from perkins, i dont like the four figure sum they gave me! am i right in saying that the perkins prima m50 is the same engine from a austin montego? ie perkins prima 2litre diesel engine? i know the cooling system is different but major parts like the cylinder head? i assume are the same?? any help appreciated!

 

[capsco]

Yes basicaly the same engine, Cylinder head will be same casting.

 

[Hoolie]

Yes it's the same engine, but be aware that most car engines were turbo and the compression ratio is lower than the normally aspirated version. You may have to have the head skimmed if you acquire an engine as we did on eBay.

 

[tel1]

is that the only thing you had to do? just get the head skimmed?

 

[Latestarter1]

Prima

For Gods sake do not mess with the head as other poster advised.

This is a DI engine the combustion chamber is in the pistons which have different chamber for turbo version. May be worth getting head checked for flatness by a machine shop but that is all. Mess with the head deck hight at your peril!

Just fit the head and look happy.

 

[oldharry]

Er? Why not? Local machine shop skimmed my turbo Diesel Montego head foir me, no problem after it overheated and warped. Ran fine until the vehicle rotted (not long!). If the head was badly distorted Rover supplied thicker gaskets to compensate, but the machinist said he had rarely had to use one.

The Montego diesel was a Turbo engine, but the same block was fitted in Sherpa Vans in a no turbo version 1987 - 1990. You are unlikely to find one now - they all rotted away years back, and LDV, who could get spares went into administration earlier thiis year.

The two main differences between the turbo and the normally aspirated versions were the piston crown shape, and the turbo engines had an oil spray that played on the underside of the piston to help cool it with the higher combustion temprature. I think the camshaft profile was also modified in the turbo version

 

[Latestarter1]

Prima

You missed the point.

The poster linked higher compression ratio with head skimming. All changes as you rightly say in the piston combustion chambers. Head is flat deck.

Thicker service gasket required if head warped which happens. However if max spec of material removed to regain flatness thicker gasket increases deck hight back to nominal in order that cam timing not screwed up...........

 

[ALPHORA]

If you are still having problems I have a complete engine from a sherpa van. I took it from the van a few years ago intending to fit to a boat that I never finished. please pm if intereted, Dave

 

[oldharry]

You missed the point.

The poster linked higher compression ratio with head skimming. All changes as you rightly say in the piston combustion chambers. Head is flat deck.

Thicker service gasket required if head warped which happens. However if max spec of material removed to regain flatness thicker gasket increases deck hight back to nominal in order that cam timing not screwed up...........

The thicker gasket was needed to stop the valves connecting with the cylinders IIRC, there is very little clearance between the valves and the piston at TDC

The heads were made of soft cheese and you only had to look at them for them to curl up. It iss vital to set and release the head bolts in the right sequences and torques to have any chance of it re-seating. Any attempt to change compression ratio by skimming would cause the engine to lock up at the first turn of the crank, and any EBay sourced Prima will almost certainly need skimming anyway!

 

[tel1]

so would it need skimming if it was out of a sherpa van? apparently these were not the turbo version.

 

[heron]

This engine was also used in the Maestro vans without a Turbo, there were 1000`s of these around that rotted away before the engines died. They go on forever, we had a fleet of them that all did over 200k miles with hardly anything engine wise going wrong. They were also a popular donor engine for Land Rovers.

 

[oldharry]

so would it need skimming if it was out of a sherpa van? apparently these were not the turbo version.

No - afaik mine was the only turbo Sherpa: they were not supposed to fit the Sherpa engine bay. However application of a lump hammer, a welding torch, and fabrication of a modded exhaust header pipe, levered it in and made mine the fastest Sherpa (what am I saying!!!!) on the block.... no really! It could easily do 85+. A white knuckle ride at that speed.....


However, the soft heads were the same. If they were overheated even briefly, or suffered from 'enthusiastic rebuilding', then almost certainly there will be gasket trouble. Oil in the water, water in the oil, bubbles or even traces of detergent like foam in the coolant when warmed up all point to gasket failure and the need for a skim. Properly maintained, should be fine even on a high miler, as tel1 confirms.

If you are rebuilding one that has stood, make sure the small oilways in the head are blown through. If they clog, the camshaft gets starved of oil and breaks. Usually a simple (but expensive) replacement job.

Basically the Prima is a good solid engine, but one that does not tolerate being messed about, unlike its stablemate the BMC 1.8 which will take any amount of amateur abuse.