Cylinder Head Stripdown & possible 2.8 Stroker Build.

Post Sat Apr 16, 2011 6:34 pm

At the risk of cluttering up this forum some pics of the above.

The Head itself.

.

10 mm Rocker arm nuts loosened off.

Camshaft 10 mm Torx bolt removed and Gear wheel off.
This part was suprisingly easy, just stuck an extension bar under the wheel to hold it still and bolt came loose first try.

Torx bolt replaced so that i could turn the Camshaft until
No6 Exhaust Rocker was locked in place and all the others moved freely. Rocker shaft driven
back using a 1/2 inch extension bar until No1 Rocker arm could be slid off the shaft. Camshaft then turned again so all remaining
Rockers moved freely, shaft then slid out and all Exhaust side
Rocker arms removed.

Process then repeated on Inlet side of Head.

All baged up and labelled.

Camshaft retaining plate was not so easy to remove. In the end
i tightened a thick Cable tie round it, put a screwdriver on the Cable tie and tapped it a couple of times to free it up.
Camshaft out.

.

Got as far as removing 3 of the Exhaust side Valves, then the
Valve Compressing tool gave up the ghost.

Post Sat Apr 16, 2011 6:37 pm

nice thread man. i done the same as you not to long ago. i found it fun.

Post Sat Apr 16, 2011 6:55 pm

The offending Tool.

Clearly, the mighty Teutonic metal was too tough for the Chinese Tin.

Did notice that there was no Rocker shaft retaining plate on this Head. Didn't spot it
until i removed the 4 rubber seals.

.

Wasn't up for a trip to Halfords on account of having to work tonight, so i sat and watched
my Fish for a while.

The whole point of this thread is to encourage other Mechanical numpties, like myself,
to at least have a try.

Post Sat Apr 16, 2011 6:58 pm

mosh86 wrote:nice thread man. i done the same as you not to long ago. i found it fun.

I know exactly what you mean.

Post Sat Apr 16, 2011 8:49 pm

Take your time and do not force anything,doing well so far.

My valve spring compresser has survived several head stripdowns,though!

Post Sat Apr 16, 2011 10:00 pm

Excellent start that man! You'll have that sorted in no time.

Thats a disgrace with the valve tool though. Buy another make I reckon.

Post Sat Apr 16, 2011 10:37 pm

I did this for the first time recently, it's a very satisfying thing to do and it's nice to work on a part of the car that isn't caked in filth!

Post Sun Apr 17, 2011 9:49 am

Couple of questions.

1. What is the difference between a reface and a skim.

2. Can i check for lateral play on the Valves with the springs removed.

3.Where exactly are the Dimples, that could possibly tell me if my Head has
previously been skimmed, located.

Hope to complete this today, head is going to be pressure tested and either a light skim
or a reface. Depending on the answer to question 1.

Just remembered, are the Rocker shafts Inlet/Exhaust side exclusive?
Will take some pics of the Camshaft and Valves later, for your expert advice.
Thanks all.

Post Sun Apr 17, 2011 11:03 am

1 I think that a re-face applies to an iron surface,such as the cylinder block,a skim is usually applies to an alloy head's mating surface.

2 Yes,valve just off it's seat,does it have disernable sideways movement?

3 On the mating face of the head,on diagonaly opposite corners,more of a depression,perhaps,than a dimple.

Rocker shafts are identical and interchangeable,well,I have!

Post Sun Apr 17, 2011 3:10 pm

Both rocker shafts have the same part number, so both the same.
I would define a reface as taking off the minimum to obtain a gasket friendly surface, and a skim as taking off metal to straighten up a warped head or to up the compression ratio.

Post Sun Apr 17, 2011 4:57 pm

Thanks for the replies, especially the Rocker shaft one.
Head completely stripped now, apart from the Valve stem seals and the Oil spray bar.
One of the 8mm nuts on it is almost totally rounded off, will let the people testing the head sort that.

Had to settle for the same Valve spring compressor as there was only one ,of any kind, in the shop. The replacement was worse than the first one, even fully wound in it wouldn't
compress the springs far enough. So for once i used my brain.

Used a socket between the end of the compressor turning bar
and the Valve, gave me enough to be able to remove the rest of the springs and Valves. Tested for lateral movement with the valves withdrawn about an inch from the guides, minimal movement on a couple and the rest almost none if any.
Pics of one of the Exhaust side ones.

Couple from the Inlet side

Got a grinding stick and paste, so will have a pop at cleaning
them up, pretty suprised how clean the inlet ones were tbh.

Some shots of the Camshaft, not entirely sure what i should be looking for here, so if you spot anything relevant my gratefullness would know no bounds.

To round up just some random shots of ports and stuff.

.

Again, if you spot anything , well you know the drill.

Post Sun Apr 17, 2011 5:27 pm

Camshaft;

Pointy bits(lobes)run your fingernail across the top,where they operated the rockers,you should not feel any ridges.Same on the bearings.

What I do with valves is to mount my power drill in the vice,fit a valve in the chuck and clean them of with a strip of emery paper....mind your dinkies!

Try not to scratch the chamber surfaces,ask your machine shop to chemically clean the head for you,that will get most of the carbon off,then you can get to work polishing them.

Post Sun Apr 17, 2011 8:38 pm

The extreme edges of the cam lobes don't do anything, so if there is no ridge between the black band and the polished bit, then the cam isn't worn.
Check the exhaust valves for lateral movement in any direction carefully, or better, let the machine shop assess them. I would expect to find the exhaust valves worn on an average 885 head.
That head looks to have come from a well cared for engine. It's common to find the crescent shaped waterways on each side of the combustion chambers to be corroded away towards the fire ring, as a result of over diluted or time expired coolant. Yours look perfect.

Post Mon Apr 18, 2011 7:49 am

gooner1 wrote:Couple of questions.

1. What is the difference between a reface and a skim.

2. Can i check for lateral play on the Valves with the springs removed.

3.Where exactly are the Dimples, that could possibly tell me if my Head has
previously been skimmed, located.

Hope to complete this today, head is going to be pressure tested and either a light skim
or a reface. Depending on the answer to question 1.

Just remembered, are the Rocker shafts Inlet/Exhaust side exclusive?

Will take some pics of the Camshaft and Valves later, for your expert advice.
Thanks all.

1. As brian says, reface is just a flash off clean. A skim is a measured removal of a set amount, 2 though, 3 though etc.

2. The valve guides are checked with the valve stem head level with the top of the guide. Then with the mushroom protruding from the seat and the top of the valve still level with the top of the guide, you measure the rock with a Dial test indicator touching the side of the mushroom. The bentley manual states:

"the play should not exceed 0.8mm (0.031")"

3. The dimples are two round indents on the outer edge of the face. You can see one in one of your photos next to a washer

Yes the rocker shafts have the same part number but should reall be reassembled in the same position they came out as you would any moving part.

I hope thats dirt on the first cam lobe as it kinda looks like the hardend surface has started to break up.

With that oil feed pipe, just put a set of mole grips on the offending nut. It'll go and you be fitting a new pipe anyway.

You have PM as well mate.

Post Mon Apr 18, 2011 10:07 am

Top info here. I've got the cam out of mine but haven't taken it any further yet. It's good to get some answers to the questions I will soon be asking.

Post Mon Apr 18, 2011 12:41 pm

clarko74 wrote:Top info here. I've got the cam out of mine but haven't taken it any further yet. It's good to get some answers to the questions I will soon be asking.

You have my number if you need it Adrian

I also have a DTI and valve spring compressor if you want to set yourself up in my garage and do the valves and seals here? And a pillar drill to clean the valves up.

Post Mon Apr 18, 2011 12:49 pm

Thanks very much Trev, I may well be in touch, but it won't be for a while yet. The engine has taken a back seat at the moment as I'm mid way through a front suspension rebuild and e36 rack /power steering upgrade and then the rear will be getting a full rebuild with disks. It's about time really, I bought the disc trailing arms from Si about three years ago!

Post Mon Apr 18, 2011 3:30 pm

Big thanks from me tooTrev, and all others.

Head is now with the machine shop, quoted 70 sovs for a pressure test and refacing on friday,
now awaiting a fresh quote for adding a clean up, Valve play test ans to remove a broken
Exhaust stud, which is why the head was originally taken off.

Don't anyone take this the wrong way, but i asked them if the pressure test would
tell me if i needed a skim or if the reface would suffice. Their reply was that a reface is a skim, they also stated that any head that is removed from an Engine should have a skim carried out.
Can sort of see the sense in the reface/skim bit, as any amount of material removed could be classed as a skim. Wasn't aware of the second part though. When i swapped my original
head for the one now in the machine shop i didnt't have it skimmed, was i just lucky to not have any problems? Well up to now that is.

Trev, soon as the machine shop has rung me back, i'll return your PM mate.

Post Mon Apr 18, 2011 5:38 pm

gooner1 wrote:Big thanks from me tooTrev, and all others.
Head is now with the machine shop, quoted sovs for a pressure test and refacing on friday,
now awaiting a fresh quote for adding a clean up, Valve play test ans to remove a broken
Exhaust stud, which is why the head was originally taken off.

Don't anyone take this the wrong way, but i asked them if the pressure test would
tell me if i needed a skim or if the reface would suffice. Their reply was that a reface is a skim, they also stated that any head that is removed from an Engine should have a skim carried out.
Can sort of see the sense in the reface/skim bit, as any amount of material removed could be classed as a skim. Wasn't aware of the second part though. When i swapped my original
head for the one now in the machine shop i didnt't have it skimmed, was i just lucky to not have any problems? Well up to now that is.

Trev, soon as the machine shop has rung me back, i'll return your PM mate.

They are saying the same as my machine shop. They'll only skim. I asked my shop to just "face it off" to clean it up and they stated they didn't do this, only skim to the minimum removal of material required until gauranteed flat. And yes, All alloy heads should be skimmed before a refit.

And always store them flat down on a level serface and without the valve gear in. The tension at varios points along the head can cause twisting as can storing with it leaning up against the wall cause bowing.

Post Thu Apr 28, 2011 2:24 pm

Still waiting for my head back. In the meantime i have today picked up another
early 325i H/C Engine complete with head. The car suffered a broken Rocker arm but i'm more
interested in the bottom end tbh. Want to remove my original lump and 2.8 it, over a period of time.

Hopefully, the block i bought today will be installed into my car temporarily, so i can at least get some use of the car this summer. Will stick some pics of the new lump up soon so
i can get your unrivalled advice and opinions. Might as well strip down the head with the broken
arm while i'm at it. Back soon.

Post Thu Apr 28, 2011 2:32 pm

Seems like engine re-building is taking over your life,young sir!

Post Thu Apr 28, 2011 5:03 pm

daimlerman wrote:Seems like engine re-building is taking over your life,young sir!

Tbh Malc, it's just another thing i find myself wishing
i had took more interest in when i was a lot younger and
more capable of retaining info. Hey ho.

Anyway, pics as threatened.

Block and head in van, ready to remove head as me and
my daughter had to somehow get this lot out of the van

25 years of crud did,nt make it any lighter.

Off with it's head.

Wheel barrow came in handy.

Now the shots i need advice on , sorry about the amount of pics
but is it possible to tell if the Piston "bore walls ?" are ok ?

..... and relax.

Post Thu Apr 28, 2011 5:07 pm

That 'cross hatching' indicates honing marks to me,so I would suggest that the bores are good.

Post Thu Apr 28, 2011 6:36 pm

'cross hatching' was exactly what i was trying to show, wasn't sure it was visible
in the pics.

The nine bolts holding the clutch to the flywheel, are these undone with a male Torx socket
or an Allen key?

Post Thu Apr 28, 2011 6:51 pm

Usually it's an allen type fitting...I bought myself a set of bits that fit a 10mm socket so that I can use a ratchet,but any that are 'difficult' can be dealt with by Mr Angle Grinder and replaced with an M8? or perhaps an M6 bolt.

Post Thu Apr 28, 2011 7:06 pm

Blimey, Rob. Great thread and great work being done by yourself. I'd always blanked this thread assuming you had a problem I had nothing to offer to!

Keep up the good work, and keep posting updates

Post Thu Apr 28, 2011 9:35 pm

No worries Fi, besides i ain't actually done anything apart from dismantling
a few bits. Putting it back together and getting things to work as they should
is the hard part.

On the look out for an engine crane and stand now, as i've just been" asked"
to get that crap off the f&*()^%g decking.

Post Thu Apr 28, 2011 9:56 pm

gooner1 wrote: On the look out for an engine crane and stand now, as i've just been" asked"
to get that crap off the f&*()^%g decking.

Boody women, eh?

Post Fri Apr 29, 2011 12:26 pm

Want to start cleaning up the Engine block.

Obviously any method i use is going to involve a good hosing down to wash
it off, with the cylinder off will any water that gets into the block do any damage,
or will the amount of oil coating the insides nullify the water?

Post Fri Apr 29, 2011 1:04 pm

If you are stripping it to it's component parts,do not worry too much,just tip any surplus water out of the bores and wipe them dry.

If you are not stripping it any further,then covering the head face with a sheet of polythene or similar and tapeing the edges down would be better.Bear in mind that some of those holes along side the bores are oil drains into the sump,whereas some are waterways...

Post Sat Apr 30, 2011 7:55 pm

Only one way to clean a block, and that's completely. You cannot have an engine which is too clean. It only takes one spec of crap to ruin a crank bearing. Get both oil way end plugs out - you will get one out by drilling through, making the hole bigger with larger drills and breaking it out with a chisel. The other one can be drifted out with a long screwdriver/rod and a hammer - this one can be reused and the block 'staked' so it doesn't come out again. To clean the block, you need a stiff brush, Gunk and a power washer. I use the one at a car wash place on a crappy day when it's quiet.

It's important to get the oilways completely clean. Use pipe cleaners and that power washer to get all the shit out. It's also well worth getting the block face cleaned up with a light skim and have it cleaned again in a chemical bath. If it's rusty inside, leave it upside down in a suitable container with the waterways immersed in lime (path cleaner) to descale it. Use brake cleaner, an old head bolt and an airline to clean the head bolt threads.

Don't paint a block with think black paint - it's a heat barrier. A rattle can of etch primer and a light coat of satin black is all it needs.

Post Sun May 01, 2011 11:45 am

Thanks for that Andy.
Could yourself, or anybody else, point out exactly where these oil way end plugs are situated in the link below, and also what is meant by the term ' this one can be reused and the block 'staked' so it doesn't come out again."

http://www.realoem.com/bmw/showparts.do ... g=11&fg=10

Post Sun May 01, 2011 9:05 pm

Number 4.

The originals are either brass or a slug of steel, the replacements are pressed steel. By staking I mean peen over the edhes of the block so the plugs don't come out again - think of how propshaft UJ crosses are staked in rather than the old fashioned circlips.

Post Mon May 02, 2011 6:12 pm

Understood Andy, Ta.

Didn't get much done today, stripped the rockers from the " new cylinder head " and removed
the clutch cover/pressure plate from the "new bottom end"

Spot the broken rocker arm at No2 on the inlet side. Not a problem as i have a new replacement
arm and this head is going into storage anyway.

Nice chunk out of the clutch plate, luckily i have a spare i bought some time back.

.

:

Post Wed May 04, 2011 1:20 pm

Would the engine, currently in the car, suffer any lasting damage if it is driven
with suspected Piston ring/stem seal failure

Obviously i would keep an eye on the
oil level, drive sedately and not plan any long journeys.
Doesn't seem to have lost any power, is not using coolant or suffering any overheating,
but is burning oil.