2.8 build

[goosiegander]

Amazing thread keep up the good work

[Phatz]

Nice work Jazzman... Your getting there now huh.

[JazzMan]

Yeah, waiting for parts to put the bottom end together now The sump still needs a good clean up as well.

[Phatz]

Gaskets, camshaft and seals aside, did you renew any other parts on your cylinder head?

[JazzMan]

I put new valve springs in, and the exhaust manifold studs are new

[Brianmoooore]

Apologise if I'm teaching you to suck eggs, but I notice you didn't mention the locking plate for the rocker shafts in the above.
Your nice new top end wouldn't last long without it!

[JazzMan]

Yeah I put that in (should have mentioned it) - you can just about see it to the left of this picture



And please anybody who sees me do something stupid please point it out (such as lapping the valves without the proper tools). This is the first time I have had an engine to bits so I'm still learning what I'm doing

[JazzMan]

New parts! Conrod bolts, main bearing shells, big end shells, water pump, cam belt and piston rings.



Quick question, will the engine run at all on standard motronic (with wild chip) or is it best I wait for megasquirt?

[ed325i]

will the engine run at all on standard motronic (with wild chip

I had a word with Ant and he can do a chip for the 2.8

Where did you get your bearings/rings from ?

[JazzMan]

I'm getting megasquirt from ant, my impatience was just wondering about it running from the 2.5 map - I'll be leaving it till I get MS Might get the engine back together at the weekend depending on much time I have.

I got all my bits from www.motormec.co.uk (I've been using them for more than 3 years now always had excellent service)

[DanThe]

I got all my bits from www.motormec.co.uk

Strangely they couldnt get any rings for my engine

[goosiegander]

nice chaps at motormec, i relieved them of their e30 bits when they had their last clearance sale!

[JazzMan]

I've spent so much money there since I started building the Sportster it's silly! I always deal with Andy

[JazzMan]

2.8 crank installed in the block with new bearings, bolts are torqued up.

Crank spacer in place

Many hours later all the pistons are installed with new bearings, all moving parts have been given a coat of assembly grease - this is more sticky than normal oil so it should stay put until the normal enigne oil is circulated round the engine before first start.

Front cover plate in place with new oil seals installed.

Oil seal around the crank spacer.

Water pump installed along with the gear for the oil pump.

Bottom view of engine with all parts installed. New conrod bolts have been torque, then turned to the approated settings!

Blue sump! Just resting on the engine for photos.

Its not quite this bright in real life, the flash has given it a much strong blue colour!

[Ritalin_Kid]

Sorry if I might have missed it, but are you using stock M20B25 rods and pistons?

[JazzMan]

Sorry if I might have missed it, but are you using stock M20B25 rods and pistons?

Stock pistons, but conrods from the M20B20 - they are 130mm, 5mm less than B25 conrods

[Ritalin_Kid]

Sweet... so that means I can use the rods from an M20B27 with my M20B25 Pistons on a M52B28 crank to pull off a 2.8l M20 stroker?

[daimlerman]

Will you be supplying eyeshades when you open the bonnet,Jazzman? Looking good....

[ed325i]

Sweet... so that means I can use the rods from an M20B27 with my M20B25 Pistons on a M52B28 crank to pull off a 2.8l M20 stroker?

Yes.

[JazzMan]

Final clean up and degrease of the head.

Mmm shiny! Also double check that the cam pulley is turned to the timing mark on the head.

Belt tensioner now also installed

Head gasket placed on the block.

Head placed on block ready for the head bolts to go in.

Bolts placed, these were all tighten up as per the Bentley manual and in the correct order. Its a 3 step process.

Everything bolted up, the rear oil seal needs to go and the sump bolted on.

Final thing was to install the cam belt - turned the engine over severa times and it all sounds good. No interference between valves and pistons from the sounds of it!

[ed325i]

what did you do about the piston hight in the end ?

[JazzMan]

I PM'ed Andyboy who assured me all was OK as it is

[Dantistas]

well done

[JazzMan]

Rear cover plated attached to block, sump bolted on and the flywheel on read to be bolted. The bolts need to be tightened up in a specific order and covered in loctite.

Clutch back on the fly wheel

Gear box slotted on "like a glove" [ace ventura]

After a lot of jiggling the engine is back in mated with the drive shaft and on all 4 mounts.

Just needs all the ancillaries bolted back on

Nice blue block, shame it has to be covered by the intake manifold!

My wild chip is in the post to Ant for a generic 2.8 map to get me going on motronic before I get megasquirt.

[Ritalin_Kid]

I'm in the middle of my 2.8 build when today we realized that your M20B25 pistons are much different from the M20B25 pistons that came from my 87 325i M20B25.

From your pictures it looks as if there is a definate different between the 2. The problem I'm having is that the crank is touching the piston skirt and once we cut those down it was barely rubbing the inside of the piston so we have to take 1-1.5mm off to make sure we have enough clearance.

Do the euro M20B25 engines have a special piston?

[ed325i]

What make are your pistons ?

[march109]

I'm in the middle of my 2.8 build when today we realized that your M20B25 pistons are much different from the M20B25 pistons that came from my 87 325i M20B25.

From your pictures it looks as if there is a definate different between the 2. The problem I'm having is that the crank is touching the piston skirt and once we cut those down it was barely rubbing the inside of the piston so we have to take 1-1.5mm off to make sure we have enough clearance.

Do the euro M20B25 engines have a special piston?

In the UK there are two different pistons depeding on if its an early or late M20.

Where are you?

If your in the states the high comp pistons are quite rare since most US spec e30's are fitted with a cat, and are therefore later 8.8:1 CR.

However I don't now what type of pistons JazzMan used or infact if the Euro pistons on the 8.8:1 CR Euro engine are different to the US pistons on the 8.8:1 CR US engine. Sorry I can't be more specific.

The 2.8 conversion isn't very popular in the states from what I know from reading e30tech.com, I don't know if this is because of the problems you are experiencing, and an educated guess would say so.

Both Metric Mechanics and Ireland Engineering list conversions based on the M52 2.8L crank but both start at 2.9L of displacement.

I'm aiming for 2.9L myself with a 1mm over bore, I ordered my pistons custom from JE pistons, the price is pretty reasonable, unless your machining works this may have to be the route you take if you want to complete your build.

If your set on 2.8 JE pistons can supply the right type they have most m20 custom and stroker piston patterns allready, but my personal opinion is that if your going for pistons anyway go for the biggest displacement you can.

[Ritalin_Kid]

My build is on a budget. So far I've collected everything I needed for free including the M52 crank.

The piston's are from an 87 325is engine and are the 8.8:1 CR.

TDC looks to be on par with the pictures in this thread and after doing some custom machine work to the pistons I was able to get a good 2mm gap between the crankshaft counter weights and the piston skirts.

I will note that it if I hadn't already had the crank polished and balanced I would have had the shop shave the counter weights 5mm so the skirt shave would not have to be as aggressive.

[Turbo-Brown]

I will note that it if I hadn't already had the crank polished and balanced I would have had the shop shave the counter weights 5mm so the skirt shave would not have to be as aggressive.

Ooh, wouldn't wanna do that meself.

The counter weights are there and the size they are for a reason so if you take weight from them, you need to correspondingly take weight from the opposite side of the crank

[Ritalin_Kid]

I will note that it if I hadn't already had the crank polished and balanced I would have had the shop shave the counter weights 5mm so the skirt shave would not have to be as aggressive.

Ooh, wouldn't wanna do that meself.

The counter weights are there and the size they are for a reason so if you take weight from them, you need to correspondingly take weight from the opposite side of the crank

I definately wouldn't attempt to do it myself... what I meant to say is that I would have had the shop shave and rebalance the crank in addition to the work I had done to it.

[Andyboy]

Rebalance a crank that's had the counterweights messed with? Where you would take the rest of the metal from?

[Templ8e30]

I'm in the middle of my 2.8 build when today we realized that your M20B25 pistons are much different from the M20B25 pistons that came from my 87 325i M20B25.

From your pictures it looks as if there is a definate different between the 2. The problem I'm having is that the crank is touching the piston skirt and once we cut those down it was barely rubbing the inside of the piston so we have to take 1-1.5mm off to make sure we have enough clearance.

Do the euro M20B25 engines have a special piston?

You're not using the m52b28TU double vanos crank are you ? (they have 3 threaded holes in the side of the end counterweight on number 6 cylinder). This crank has counterweights that catch the pistons almost all the way up to the pin when using 130mm conrods.

I've got a crank/rods/pistons setup here belonging to Neil at Quarry motors with high-comp early type long skirt pistons and they clear the counterweights no problem at all without machining. It's a single vanos crank.

Cheers,

Iain T

[Ritalin_Kid]

The crank didn't come out of a M52B25 double Vanos engine but it does have the 3 threaded holes on the number 6 cylinder counterweight where the CPS sensor wheel was mounted. Just as you said the counterweights almost catch the piston wrist pins.

I went ahead and machined one down until I wa able to get it to rotate but the problem is it looks like this:





Though it may hold up I just can't install this piston into my engine and still sleep good at night.

So... do I have any other options or do I pretty much have to go with custom JE pistons?

[HairyScreech]

m50/52 pistons?

[Turbo-Brown]

Holy shit!

I reckon that all the metal you've removed from around the little end pin was there for a reason, that reason being to stop the piston flying off into the cylinder head!

Can't think of a more tactful way of saying this, but that is a bad idea!

Dread to think how long those flappy little bits of unsupported skirt will hang on for too!

m50/52 pistons?

The M52 pistons I've got are slipper type with low friction skirt coatings.