Cylinder Head Stripdown & possible 2.8 Stroker Build.

[B7]

Have you gone for oversize shells or standard? If the cranks had a grind and they've not seen to the thrust faces, oversize shells would then become an interferance fit!

Or it could be theyve sold you an oversiize shell instead of a standard when the crank is at standard size?

You cannot machine the shells as you would immediately remove the white metal bearing face.
The easiest option here Rob is to drop the crank back out and do the following:

With the crank out, can you place the cap with the bearing on that journal and spin it?

If not, take the crank and bearings both top and bottom, to the machine shop and get them to have a look. They can then machine the crank to suit.

OR

if you can place the end cap on the journal and spin it (you can also do the other half of the bearing out of the block) then this could be to do with "end float" where the 2.8 crank is sitting either too far fore or aft. i.e. the crank is being pulled in one direction.

Thats my slant but as I've never built a 2.8, I'm not sure if any meat has to be taken from the crank.

I've just checked the part number for one main thrust bearing and they say it's the same on a 2.8 m52 as an m20.

http://www.realoem.com/bmw/partxref.do?part=11211706829

Another thing to try is to remove all the other end caps and JUST bolt the problem one in. Then see if it spins. If it does then the issue is further along the crank. After all that shell does set the end float.

[gooner1]

Have you gone for oversize shells or standard? If the cranks had a grind and they've not seen to the thrust faces, oversize shells would then become an interferance fit!

Or it could be theyve sold you an oversiize shell instead of a standard when the crank is at standard size?

You cannot machine the shells as you would immediately remove the white metal bearing face.
The easiest option here Rob is to drop the crank back out and do the following:

With the crank out, can you place the cap with the bearing on that journal and spin it?

If not, take the crank and bearings both top and bottom, to the machine shop and get them to have a look. They can then machine the crank to suit.

OR

if you can place the end cap on the journal and spin it (you can also do the other half of the bearing out of the block) then this could be to do with "end float" where the 2.8 crank is sitting either too far fore or aft. i.e. the crank is being pulled in one direction.

Thats my slant but as I've never built a 2.8, I'm not sure if any meat has to be taken from the crank.

I've just checked the part number for one main thrust bearing and they say it's the same on a 2.8 m52 as an m20.

http://www.realoem.com/bmw/partxref.do?part=11211706829

Another thing to try is to remove all the other end caps and JUST bolt the problem one in. Then see if it spins. If it does then the issue is further along the crank. After all that shell does set the end float.

Will try all of the above, Trev.
Took all of the shells to the Machine shop and asked them to supply the same, Dan The had already confirmed that the M52
shells were the same as the M2O ones. So shouldn't have
been supplied with oversize ones, then again we all make mistakes so it;s possible. It's only a minor blip so i'm not too bothered. Again, thanks for your advice mate.

[gooner1]

Removed all the End caps and the Crank, noticed the Crank bearings were not sitting correctly
in No7 and 4 journals. Now i know they before i placed the Crank in, as in pic below


I could well of displaced them when fitting or subsequently removing the Crank, so took extra
care when i replaced it.
Spun crank with no End caps, all fine. Then tried with no 6 cap and new shells, again all ok.
So thought problem must be elsewhere. Placed each cap on, again spinning the Crank each time one was installed. Crank span ok untill No4 was put on.
Stripped the lot again and notice No4 bottom shell was again not seated right.
Reassembled, this time putting No6 and 4 on first.
Now with all end caps fitted and Crank turning ok.
Which made me wonder if there was a sequence to fitting the End caps, as in Cylinder head
bolt tightening, though if there is i can't find it anywhere.

[gooner1]

With new bearings fitted, End Caps torqued up, how freely/easily should the Crank spin

[B7]

With new bearings fitted, End Caps torqued up, how freely/easily should the Crank spin

You're getting there!

It should not spin freely. There should be some drag, not excessive. Mine felt quite tight to be honest but thats what running in is all about! This is where if I was round the corner, I'd come and have a "feel".

[gooner1]

With new bearings fitted, End Caps torqued up, how freely/easily should the Crank spin

It should not spin freely. There should be some drag, not excessive. Mine felt quite tight to be honest but thats what running in is all about!

That describes perfectly how mine turns.
Keep getting the urge to strip it down to check everything again.

[daimlerman]

Just a bit worried,Rob,that you seem to be building the engine outside...operating theatre conditions really should be your aim,here....just one speck of muck and all your hardearned goes to waste....

[gooner1]

Hear what you're saying, Malc. and i really am being as careful as i possibly can.
When i'm not working on it, the block is covered by a clean waterproof Tarpaulin,
i even wipe my sockets, tools before i do any work and during it.
It is more M.A.S.H than Holby City though, admitidley.

[B7]

As long has you are careful and avoid windy days, what else can you do. Not everyone has the luxury of a garage or shed.

Or perhaps a cheap gazebo with the sides could be an idea?

http://www.ebay.co.uk/itm/Outdoor-Gazeb ... 45fb49a252

[gooner1]

For peace of mind, I've decided to strip everything I've assembled,clean
it all and start again. Have rigged up a three sided tent affair, using an old car cover, that can be raised while i'm working and dropped when i'm not.

In the meantime, i had a good look at my Cylinder head and it seems that the Stem seals
have not been renewed, which i specifically asked for.
No biggie, but would have thought, with all the work carried out on the head, this would have been
done automatically.

[gooner1]

Not done much with this lately and what little i have done is, possibly, going to
give me problems. Left my Pistons in a solution of Paraffin and a degreaser to give them a
final clean, took them out of the solution and have now got what is best described as blisters
on them. With a bit of elbow grease and a Scotchbrite pad , i can erase them but am worried that i might be altering the dimensions\profile of the Pistons.

Might be hard to make out on these photos.







Unsure now as to whether i should scrap, rub down or use them
with the blisters/pimples on.

[CHR1S1990]

Can't really make it out from those pictures as you say, but Autosol metal polish brings up pistons well i've found.

[Jhonno]

Try taking the pics again, this time focusing on the piston rather than the decking

Any abrasive material will remove material at the end of the day.. However I can't imagine a light wire wool rub would be an issue.

[gooner1]

Try taking the pics again, this time focusing on the piston rather than the decking

Any abrasive material will remove material at the end of the day.. However I can't imagine a light wire wool rub would be an issue.

Will do, hard to get a good shot though, possibly due to the reflective surface and my bad skills.

[gooner1]

Well i'm back from a 3 week break in Greece and raring to get stuck in again.....
unfortunately, due to me acting like a Gentleman, i now have a grade 3 muscle tear
in my right arm and can't even grip a spanner without getting a severe pain.
That is the last time i pull a Bar stool out for the Mrs.

In the meantime my thoughts will be concentrated on what i want from this build.
Not really after Top end power, more interested in low, middle range torgue, so
to that effect what are my Cam options, do i stick with my original one or do i go aftermarket

Build spec is Early High 325i Block with 325i High Comp Pistons with
all shells, Gaskets, seals replaced.
320 i Conrods
Later 325i Engine Management
Lightened Flywheel
Full BTB Stainless Exhaust, 6 branch into single pipe into twin pipe silencer.
Skimmed, refaced , pressure tested and cleaned Cylinder head
with new exhaust valves and stem valve oil seals.
3.64 Open Diff, atm.
Fully refurbished and cleaned 325i injectors.
M52 2,8 Non Vanos Crank with machined Oil spacer.

Any comments on Camshaft appreciated.

[Jhonno]

Alpina(ish) spec 264-272 kind of figure?

[Simon13]

Thing is gooner you need horse power to get the torque up, they are related from what i know.

I'd be tempted for a 270ish cam, as it won't idle really badly or lose all your bottom end power.

A lightened flywheel is a must! RE your head get the guides checked, it will be the eshausts if there is any wear. The valves on the stems don't tend to wear out its the guides as a whole, and the exhuasts side at that. The inlets don't really wear out

[gooner1]

My bad Si, it is in fact the Exhaust guides not the valves that have been sorted.
Apparently it's going to take up to 6 months for my arm to heal properly, so plenty of time
to look further into Cam choice. See your build is coming along splendidly.

[e301988325i]

I suggest you try the standard cam, especially as it's free, if you want it revvier then you can replace it afterwards.Your BTB will give the engine lots of breathing at the top end anyway.

'Performance' cams just take torque from low in the rev range and deposit said torque further up the rev range to make more power at higher revs.

Ps) Power = torque x rpm (although I'm unsure of which units to use to get Bhp (1bhp = 745 watts))

[gooner1]

Thanks, while i'm not averse to laying out for a different Cam if needed, it would
make more sense to try my standard one first.

Having said that, as i will be using a later Ecu and Engine management due to using a lighter Flywheel, think i'm right in saying the 1.1 motronic will not be compatible with that, i presume i will need a remap to get the best from what i'm using. Would i then have to have it remapped if i find/feel that the standard Cam could be bettered

[Simon13]

the standard cam is crap its 252?! lawnmower. A 270 ish cam isn't so extreme as to lose the low end cam it will improve it through most of the rev range i expect.

[e301988325i]

Not really after Top end power, more interested in low, middle range torgue, so

252 seems to be the accepted consensus, it's just a profile, 'crap' is subjective dependant on requirements.

My friend's golf project started out with him wanting low and mid range torque, he's been sold on higher top BHP numbers and now it's getting a turbo with nothing below 3.5k. . . it wheelspan in third with a 2.1 NA with a quaife diff, now it's 2.0 Turbo (8v) with a late turbo delivery, hmm that'll work well. . . decide what you want and don't be swayed.

[reggid]

i think a 270 cam will make more power across the board with the appropriate CR there comes a point wheen too small is too small and a 2.8L with standard cam will die in the ass severely

[HairyScreech]

the m20 suffers from a square bore and 2 valves per cylinder, thus the valve area is relatively small even on the 2.5

when a stock head is put on a 2.8 the effect is made worse and a relatively large cam is required for good performance.

on a 4 valve engine a 270 cam would be large, on the m20 its not that mental.

can and will expand more if interested and once im back up to uni (bloody full time work)

[reggid]

the m20 suffers from a square bore and 2 valves per cylinder, thus the valve area is relatively small even on the 2.5

when a stock head is put on a 2.8 the effect is made worse and a relatively large cam is required for good performance.

on a 4 valve engine a 270 cam would be large, on the m20 its not that mental.

can and will expand more if interested and once im back up to uni (bloody full time work)

kinda raises the question why bigger valves are not more common on strokers especially on overbored blocks. I guess that slapping in bigger valves by itself won't do much without associated port work near the seat which most aren't willing to pay for the last 10%. The stock head will do 260ish hp so its probably not the first place to look when a large cam with proper exhuast and proper bore intake manifold with correct length and plenum setup will do wonders for an M20. i wish i had my time again

[gooner1]

I am taking your comments re Cams on board chaps.

Took the Cab out today for about an hour.
Not sure whether it's atmospheric conditions but the amount
of smoke/fumes being emitted seems to be much worse.
Not willing to chance damaging anything, so, for now, it's the last journey on the original
engine.

[daimlerman]

I used a stock 325 cam with my 2.7.

Engine came on cam at about 2000rpm and was all done by 5000rpm.

Before I stuck the 2.7 into it's current home,I swapped in a 323 cam.
Engine comes on cam at about 2300rpm and is still pulling strongly at the red line.

323 cam is the most 'aggressive' of BMW's own cams,only real downside to the swap is a drop in fuel consumption of around 10%,but the engine would not run at all properly before a 'live re-map' session with Gunni.Pre the re-map,fuel consumption hovered around the 28/29mpg mark,post Gunni it's returning 31/32mpg.With the 325 cam,33mpg was the norm,with 36/37 being achieved on touring holidays.

Bear in mind that a 2.8 build is somewhat different to my 'economy' 2.7,but choice of cam is crucial to the final performance of the engine,I would be thinking something more aggressive than a stock 325 cam,but nothing too aggressive.All of the 2.8 builds I have followed seem to have settled for the least aggressive cat cam or similar,and this bears out Hairyone's observations above regarding airflow.

At the end of the day,it's Gooner's build and Gooner's choice,I would expect that he is big enough to admit to getting it wrong!

[gooner1]

Gooner is also big enough to admit he knows SFA about combustion engines
and even less about Cams in particular. But he does know how to listen and
take good advice.

[Andyboy]

Given the significant increase in stroke, you will need a cam with more duration.

[reggid]

i plotted out a 323i and 325i cam a few weeks ago and found little difference to warrant spending time finding one. I can't say for sure if all 323i cams are the same or not but here is a bit of a writeup that i did on the cams i measured.

http://www.e30tech.com/forum/showthread.php?t=108802

[Jhonno]

i think a 270 cam will make more power across the board with the appropriate CR there comes a point wheen too small is too small and a 2.8L with standard cam will die in the ass severely

This..

No point giving it bigger lungs but still sucking through a small straw..

[Andyboy]

Yes, but more lift and longer duration will help it rather. The valves are a fairly decent size.

As for 323i cams, it was the E21 stick that was reckoned to be better - the E30 one was pretty tame. The E21 engine, even with the small port 200 head was a far more lively engine than the E30 unit.

[e301988325i]

I do accept that a 270 is normal for a 2.8, but the guy's asked for bottom and mid torque, not a flat wide torque curve or a revvy engine.

Removing all variables other than the cam; a given profile has a limit for the ammount of air it can flow. This is proportional to the RPM of a given engine (not ultimately as ports and valve size will restrict flow, but this applies to sensibleish road profiles), thus where a 286 would not be 'on cam' at 2k RPM, a 256 would be working better up to a crosover point higher in the rev range where the bigger profile will be working better.

This is essentially why Honda's VTEC system uses two cam profiles, one for lower revs, one for higher. We only have one profile so it has to be a compromise, a stock 325 is not a torque monster in the way an M30 b35 is which really couldn't take an extra 10% capacity without turning into a 'lawnmower' engine, an M20 b28 on the standard cam will be well suited to what the OP has asked for albeit compromising on the pub bragging BHP figures.

[reggid]

Yes, but more lift and longer duration will help it rather. The valves are a fairly decent size.

As for 323i cams, it was the E21 stick that was reckoned to be better - the E30 one was pretty tame. The E21 engine, even with the small port 200 head was a far more lively engine than the E30 unit.

interesting i just picked up a 200 head from an e21 323i and the cam is mint, may measure it out this weekend if i am not jet lagged.

[Andyboy]

That would be interesting, as you can still buy them new. The E30 323i cam was really lame, and early cars were barely faster than a 320i, and a real let down after the E21. The cam, exhaust and ECU were upgraded in '83, and a certain red 323i that was on a magazine test fleet was secretly upgraded without the mag staff knowing....