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Hi,
This is a project I have done but was too busy with projects and work/study to post up earlier.
I rebuilt a friend of mine Don’s 89 M3 engine & recommissioned his 1989 M3 ready for trouble free motoring, the engine arrived already fully disassembled on 26 Aug-2020 ready for a full restoration.
All the worn-out & half worn-out parts were set a side, the start of a very long parts list began.
The oil pump was rebuilt using new parts just the back housing, the big bypass valve and spring were carried over.
We retained the original cam and idler sprockets and replaced everything else in the valve train and opted to remove the E36 cam chain tensioner and installed a new original style tensioner. Keeping the E36 tensioner and it may come in handy when the new chain is old and has stretched.
The crankshaft and cylinder block were measured up and inspected for wear luckily the crank just needed a polish, the cylinders were worn and had light scoring which indicated needing a rebore.
After contacting the supplier of CP pistons in the USA, we chose 94.00 mm as they had that size on the shelf ready to send 11:1
They were ordered to suit Schruck 276-284 higher lift cams.
One problem which showed up was corrosion onside all the coolant pipes and passageways, most coolant related items were replaced, or glass bead blasted. Things like the water drain bung for the block hanging in by one thread all the rest corroded away and coolant pipes badly corroded where the hoses attach.
We finally got the block back and I got busy doing another mock build up using two pistons (no rings) one with plasticine in the valve cut outs and one dry.
The cylinder head need a skim, valve guides, valve grind, crack test and bead blast to clean it up.
New conrod small end bushes were installed, rods balanced and resized.
By this stage the pistons and some parts had arrived from the USA, I contacted the supplier who assured me the valve cut outs were sufficient and what others were using with these cams. Another long wait while the recon shop bored the block and line bored the crank tunnels.
The testing began with one piston for visual valve cut out correct placement and the other for clearance measuring.
The cam timing tool came in real handy and big thanks to Jake/Shaun for this, after a carful few hours setting checking clearances/ TDC, valve clearances etc we confirmed my suspicion PV clearance of 0.042” for inlet and 0.059” for exhaust
Okay so this is not good, I wanted to be minimum 0.065” .
Okay so what that means is,
The pistons were returned, it was 10 weeks wait for new ones (deeper pockets and 11.5:1 this time) to be made at the factory (what a pia) and then posted to NZ plus another four weeks wait until the engine shop started working in it.
This is a project I have done but was too busy with projects and work/study to post up earlier.
I rebuilt a friend of mine Don’s 89 M3 engine & recommissioned his 1989 M3 ready for trouble free motoring, the engine arrived already fully disassembled on 26 Aug-2020 ready for a full restoration.
All the worn-out & half worn-out parts were set a side, the start of a very long parts list began.
The oil pump was rebuilt using new parts just the back housing, the big bypass valve and spring were carried over.
We retained the original cam and idler sprockets and replaced everything else in the valve train and opted to remove the E36 cam chain tensioner and installed a new original style tensioner. Keeping the E36 tensioner and it may come in handy when the new chain is old and has stretched.
The crankshaft and cylinder block were measured up and inspected for wear luckily the crank just needed a polish, the cylinders were worn and had light scoring which indicated needing a rebore.
After contacting the supplier of CP pistons in the USA, we chose 94.00 mm as they had that size on the shelf ready to send 11:1
They were ordered to suit Schruck 276-284 higher lift cams.
One problem which showed up was corrosion onside all the coolant pipes and passageways, most coolant related items were replaced, or glass bead blasted. Things like the water drain bung for the block hanging in by one thread all the rest corroded away and coolant pipes badly corroded where the hoses attach.
We finally got the block back and I got busy doing another mock build up using two pistons (no rings) one with plasticine in the valve cut outs and one dry.
The cylinder head need a skim, valve guides, valve grind, crack test and bead blast to clean it up.
New conrod small end bushes were installed, rods balanced and resized.
By this stage the pistons and some parts had arrived from the USA, I contacted the supplier who assured me the valve cut outs were sufficient and what others were using with these cams. Another long wait while the recon shop bored the block and line bored the crank tunnels.
The testing began with one piston for visual valve cut out correct placement and the other for clearance measuring.
The cam timing tool came in real handy and big thanks to Jake/Shaun for this, after a carful few hours setting checking clearances/ TDC, valve clearances etc we confirmed my suspicion PV clearance of 0.042” for inlet and 0.059” for exhaust
Okay so this is not good, I wanted to be minimum 0.065” .
Okay so what that means is,
The pistons were returned, it was 10 weeks wait for new ones (deeper pockets and 11.5:1 this time) to be made at the factory (what a pia) and then posted to NZ plus another four weeks wait until the engine shop started working in it.
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