2.8 build

[DanThe]

Yep, you will definitely need to put the crank back in the block to remove the bolt if it has been torqued up properly.

Ive had some nightmares with 24v engines, had one so tight I wedged the crank into the block with a lump of copper (wood was disintegrating under the pressure!) and had the block held down with a 3/4 ton pallet on a forklift while two of us got onto the scaffold tube extending the 3/4 drive bar by 6ft, it did crack I tell ya!

[bss325i]

What exactly is the tourque setting for M20 and M50/52 crank pulley bolt?!

[Jhonno]

Yep, you will definitely need to put the crank back in the block to remove the bolt if it has been torqued up properly.

Ive had some nightmares with 24v engines, had one so tight I wedged the crank into the block with a lump of copper (wood was disintegrating under the pressure!) and had the block held down with a 3/4 ton pallet on a forklift while two of us got onto the scaffold tube extending the 3/4 drive bar by 6ft, it did crack I tell ya!

Fook me!!

Awesome thread btw..

282/272 should be fine.. ive put 284/284 in my s50

[DanThe]

400 odd NM, my M50 has done about 50k with the bolt done up to less than half that.
Just gave it the max with my half inch impact gun and a bit of thread-lock

[stonesie]

That depends on the gun though, mine is suposed to have over 400 lb:ft (=542 Nm) and its not the most powerful of things, ive seen it stumped by a siezed wheelnut

(its a MAC/Ingersoll Rand AW4300)

Ive heard allsorts of methods of getting these bolts out, from tapping them with a hammer to using the cars starter motor or a blow torch to heat them up.

[koos]

I've used a long 1/2 bar and cranked the engine before, it worked well. Was'nt a BM though.

Whereabouts are you Jazzman?

[Andyboy]

You should try an M30 front pulley nut. I borrowed the tool from my local dealer that bolts to the front of the crank and rests on the chassis leg. Then you need a 3/4 inch drive bar, two blokes on a 6ft bar and it comes off - about 350lb.ft.

[DanThe]

M50 = 410 Nm
M30 = 440 Nm

Craaazy

[JazzMan]

I've got the bolt out, that was relatively easy. Its the pulley that the cam belt runs on that I can't pull off the front. The bolt at the front came out relatively easily with a locked crank and a breaker bar (it also helped keeping the engine mounts in place for leverage!

I'm in mid Hampshire near Winchester.

Once I've got the pistons off the conrods I've try a test fit of a M20B20 conrod in the block Don't have much time in the evenings (usually 1/2 asleep from work!)

[Simon13]

the crank sprocket as such which slides over the nose of the crank and holds the woodruff key in place? it should tickle off with a bit of persuasion!

M50 2.5 rods are the same as M20 2.5 rods are they not? Just a bit lighter?! Weigh them Jazz?

Those nose bolts make you sweat! Left hand thread too iirc?

[JazzMan]

Will do I need to pull one of the M50 pistons out the block, will let you know the weights!

I've left the crank with plus gas all over the end, hopefully that'll loosen it up!

[daimlerman]

I seem to remember that I made up a puller from a bit of plate and used two bolts into the pulley to ease it off, I found that the difficult one was the bolt you have already undone....glad that you have taken the plunge for a photo build,I would expect that you could earn a little bit of pocket money turning up crank spacers for zoners....

[Phatz]

And I would be your first customer....

[JazzMan]

I seem to remember that I made up a puller from a bit of plate and used two bolts into the pulley to ease it off, I found that the difficult one was the bolt you have already undone....glad that you have taken the plunge for a photo build,I would expect that you could earn a little bit of pocket money turning up crank spacers for zoners....

Have too see if I can make my own without buggering it up first

I'm going to try a metal plate bolted to it as you've suggested, a hole in the middle with a nut behind it an a long bolt see that will pry it free.

Should be hearing from the machine shop today about the condition of the head, he said something above valve seats on the phone but we'll see.

[JazzMan]

Well there are no cracks which is good news! But the guy at the shop refused to just clean it, check it was straight (and skim if needed) without overhauling the whole head which would cost £500 - £600!

So I'll try a different shop as I can't be bothered dealing with arrogant prats that won't listen to what the customer wants and telling you will do a crap job if you do it yourself.

[JazzMan]

Puller-me-jig in place. The metal plate is bolted to the bit that needs to come off. In the middle a long bolt (out of an M52 block!) and a nut. Theory is you do up the bolt in the middle and it pops off.

The metal is already bent from the first time it wont done up (it moved about 1/2 mm)

Carefully the middle bolt was done up until it started pulling off.

and here it is finally!

There were tiny amount of rust underneath which is what was causing it to stick.

Needs a good clean out and polish before test fitting on the M52 crank.

[JazzMan]

M20B25 piston test fitted with M20B20 conrod and M52B28 crank! Moves well.

Piston / conrod / crank combo at top dead centre - looks good

[Phatz]

Oh this thread just gets better and better. Can't wait to start mine now!

Whats the next step mate?

[JazzMan]

Oh this thread just gets better and better. Can't wait to start mine now!

Whats the next step mate?

Lots of cleaning!

Crank spacer - get the crank, flywheel and other bits that bolt to it balanced. Check the piston rings are within spec. See if I can get some one to make sure the block & head are straight. Order new shells for the block and for the conrods as well as bolts for the main bearings and conrods. Grind in the valves, assemble the head, assemble the bottom end, bolt it all back together an put back in the car!

Get megasquirt from Ant!

Then hope that it runs again

[Phatz]

Oh right... so not all that much then huh!? Seriously though it looks like its coming along smoothly.

Couple of questions:

- Are you happy with the condition of the bores and pistons enough not get the block re-bored and new pistons ordered?

- Will you be using the thicker head gasket on re-assembly?

Cheers mate,

Martin

[JazzMan]

Oh right... so not all that much then huh!? Seriously though it looks like its coming along smoothly.

Couple of questions:

- Are you happy with the condition of the bores and pistons enough not get the block re-bored and new pistons ordered?

- Will you be using the thicker head gasket on re-assembly?

Cheers mate,

Martin

yeah still a while to go!

Pistons & bores, I am happy with the condition as they are. Need to check if the rings are with in spec.

Head gasket, probably not but again want to so some measuring first.

The engine was good to start with which was good

[JazzMan]

I dropped the 25 crank in again with a standard piston / conrod (as I didn't look closely enough at the before taking it to bits)

The 28 crank / 130mm conrod pushes the piston higher up than the standard. Looks to be around 1mm. Is this likely to cause any problems with clearance to the head will I have to run a thicker head gasket as Martin has asked?

[Phatz]

I seem to remember reading in the E30 resto bible that the pistons may petrude about 0.4mm from the block and that a thicker gasket should be used.

Someone with more experience than myself, or someone who has actually done this conversio will be able to confirm this..... guys?

[DanThe]

Test build it. Use some plasticine on top of the piston and turn it over slowly, once the piston has gone past TDC (if it does) you will be able to check the depth of the plasticine

[ed325i]

I seem to remember reading in the E30 resto bible that the pistons may petrude about 0.4mm from the block and that a thicker gasket should be used.

Yes it does say that.

[hcetretsam]

what pistons do you use with this crank/rod combo?

[hcetretsam]

whoops.. did not see there were more pages.. So standard 8.8:1 325i piston m52 b28 crank and m20b20 rods? What compression does this yield? thanks!

[reggid]

84mm crank with 130mm rods should sit a bit lower as 42+130 = 172mm and 37.5+135=172.5 so it should sit 0.5mm lower (or another way of looking is 4.5mm extra throw but 5mm shorter rod = 0.5mm lower) and should be around ~9.3-9.4:1 static CR. One of the previous guys who did this perhaps it was Andyboy skimmed his block a tad IIRC.

[Andyboy]

I did one and I found the piston protruded 0.4mm (15 thou) - but maybe the block (1986 325i) had been skimmed before. I used early 9.75:1 pistons though which may be slightly taller to get the CR up. I can't remember if I skimmed the block again, but it would only have been a couple of thou to clean it up.

As with any engine build, you cannot take any figures for granted. You must always measure everything yourself but that piston height looks about right - a light clean up skim and it'll be fine.

[JazzMan]

I did one and I found the piston protruded 0.4mm (15 thou) - but maybe the block (1986 325i) had been skimmed before. I used early 9.75:1 pistons though which may be slightly taller to get the CR up. I can't remember if I skimmed the block again, but it would only have been a couple of thou to clean it up.

As with any engine build, you cannot take any figures for granted. You must always measure everything yourself but that piston height looks about right - a light clean up skim and it'll be fine.

I will do some measuring, but it sounds like its sitting about right from your description Did you use the standard thickness head gasket with yours?

[daimlerman]

I think yhat I would test fit the head with valves but no cam,then try the plasticene test.It should be easy enough to measure the drop on an open valve.

[JazzMan]

Block height is the 206mm (normal as Ant has said in the other 2.8 thread) I will give the plasticine test a go (need to buy some been years since I had a play with that stuff )

[daimlerman]

Block height is the 206mm (normal as Ant has said in the other 2.8 thread) I will give the plasticine test a go (need to buy some been years since I had a play with that stuff )

Being a dad does come in handy every now and then....

[DanThe]

Block height is the 206mm (normal as Ant has said in the other 2.8 thread) I will give the plasticine test a go (need to buy some been years since I had a play with that stuff )

Being a dad does come in handy every now and then....

Yeah, we get the job of scraping it off the wall

[JazzMan]

Crank spacer taking shape on the lathe


One step left is to machine down the spacer to the correct size - about 18mm