R&R cylinder heads of M62TU engine in the car (BMW E39 540i)

[wagons ho]

The comment about why arp studs don't work on aluminum engines. I've seen many turbo m54s use arp headstuds and hold 400 hp, that's kinda what you do. Thicker hg and arp head studs.



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It's all about context.
I'm going to take your comment about thicker headgaskets (and arp studs) out of context, and say that you can't run thicker headgaskets on an m62. Why you ask?

I'm all in on the BMW V8. I've spent plenty and been schooled by the very best and knowledgeable machinists. We were referring to m62 and tu. Not aluminum engines with iron liners. There are many issues with the m62, s62, that do not apply to other engines.
But don't take my word for it, here's a quote from one of the premier BMW engine rebuilders.

Screenshot_20221025-085333_DuckDuckGo.jpg

[computiNATEor]

It's all about context.
I'm going to take your comment about thicker headgaskets (and arp studs) out of context, and say that you can't run thicker headgaskets on an m62. Why you ask?

I'm all in on the BMW V8. I've spent plenty and been schooled by the very best and knowledgeable machinists. We were referring to m62 and tu. Not aluminum engines with iron liners. There are many issues with the m62, s62, that do not apply to other engines.
But don't take my word for it, here's a quote from one of the premier BMW engine rebuilders.

I keep learning, time and time again, that manufacturers do things for a reason. They get it wrong sometimes, like with S85 rod bearings, but 99% of the time the BMW part will be better engineered than anything else

[MotorMouth93]

Better engineering has nothing to do with it (BMW is a pretty terrible example of OEM engineering prowess TBH), ARP head studs provide more clamping force than stock bolts and are great....if the block is properly machined for them, but (almost) nobody machines M62 block they just want to bolt on the boost and go. A block will typically experience cylinder distortion with the heads bolted down hence being honed with torque plates, so increasing the clamping force will distort the bores differently than the stock bolts resulting in poor ring seal and wear. On some blocks the difference is negligible and on others it's quite a bit.

FWIW BMW sells 2 thicknesses of MLS head gaskets to account for milling the heads. I assume the original comment was about lowering compression with a substantially thicker gasket though and not just the 0.3mm thicker one that BMW offers, but that's always been a lousy shadetree way of lowering compression...

[wagons ho]

We should really get all these conversations about head studs out of ched thread as it's irrelevant to the topic.
Head studs do not increase clamping force, they increase clamping force potential.
Arp torqspec is still the same as BMW tty bolts. Tension bolts allow for expansion which studs do not. This is the failure point of studs with factory gaskets. In effort to be brief I'm hitting the high points.
The gasket gets over compressed with engine expansion and ridged studs, then loses seal.
The deck pull and distortion can be honed into submission, but now you have just increased cylinder wall clearance. Let's just hone it out to the next oversize piston!! Only there is none.

[riverdadd]

Ched.... update this thread!! im following

[philly98540]

He’s out buying an engine lift and stand.

[Chedley]

Nope. Will still do it in the car -- the hard way I guess.

Waiting for the machine shop to finish the valve job and cleaning and re-surfaccing of the heads, in about a week.
Meanwhile, I am cleaning up the engine and top of cylinders as much as I can.

And no, I did not detect any sign of top piston damage that JimLev depicts in a previous post above--- and the engine certainly never experienced an overheating...

My plan is still to first to replace the head gasket and reinstall the heads with engine in the car. Then move on to the front and replace the chain, guides, vanos, oil separator and top left timing cover, gaskets,..etc..and re-time the engine.

[riverdadd]

I had an idea to assist with the placement of the heads .... maybe get a thin, stiff piece of plastic that u place over block. then maneuver the head into the proximity of where it needs to be. once the head is close. slide the plastic out of the way, this would minimize the chances of scratches and gouges trying to monkey the head into place.

just a suggestion

any thoughts?

a child snow sled is thin and flexible...the kind u straddle and sit on ....... like a saddle

[riverdadd]

hey Ched, if you don't mind , please post what the machine shop charges for their work. i'm curious

[Chedley]

@riverdadd--> Will PM you when the machine shop completes the valves and heads job.
They did find 6 bent valves on the Exhaust side, that must be replaced.

Meanwhile, I finished cleaning up the cylinders and removed the Jesus bolt and the lower timing cover and discovered more damage : few more chunks of broken plastic guides, and a damaged Uguide. The chain started eating up the lower part of the Uguide, before breaking. See pic...
InkedUguide-broken.jpg

[Chedley]

....
And chedley, do not scrape the block surface!!!
Lacquer thinner or solvent only to remove the gasket black residue.
......
Yes, the gasket moves even when clamped.
20ft lbs plus 80° twice is only 62 ft lbs of final torque. Gasket requires aluminum block expansion to reach operating torque load.
...

Well, the heads are back from the machine shop, almost like new. I cleaned the engine block surface and cylinders with acetone solvent, no scraping. I have a couple questions about the installation of the heads - I am doing it, with the engine in the car-:

-- I will be removing the cams and tappets again, to lighten the heads for installation. Then re-insert them after installation. Is that the proper or easier way of doing it?

-- When you install the new thicker (0.3 mm) head gaskets, I assume you do not use any rtv or such to hold them in place while maneuvering the heads ?

-- The TIS calls for torquing the new head bolts to "23ft lbs plus 80° twice" : Of course I'll do it in the specified criss-cross sequence. But do you really have to use a precise torque angle gauge ? Or can you just eye-ball it : torque the bolt to 30 Nm (or 22 Ft-lbs) , then turn the bolt a bit less than a 1/4 of a circle (90°), twice.

-- Any thread locker or oiling of the new bolts before screwing them in the heads ?

Other useful tips Do's and Do'nts are welcome.

[ross1]

CLEAN and DRY holes in the block! Small amount of oil on the washer/bottom of the bolt head, otherwise dry bolts unless going into a water jacket, then use sealer on the threads. NOTHING on the gasket. Tighten as per spec or face doing it again.
Since you've insisted on doing this the hard way it would be worth your time to read some books about engine building.

[JimLev]

Let’s see a pic of those “new” heads.
If they didn’t shave the heads you can use the standard head gasket.
The alignment pins on the block will keep the head gasket in place.
Get an angle gauge, they aren’t expensive.
https://www.amazon.com/Supercrazy-To...s%2C144&sr=8-3
Did you find the check valves in the top front corners of the block yet?
Get a friend to help you with the install of the heads.

[Chedley]

Here are the "new" heads, shiny clean and lubed...
new-heads.JPEG


Yes I did find those check valves and I removed them before taking the heads to the machine shop.
I do not plan on replacing them though. They wee pretty clean. I will just dip them in acetone to unclog any gunk, then reinstall them. Right ?

[sleuth255]

Shiny!

[JimLev]

Heads look nice, did they shave them?
Clean the check valves and then make sure they don’t leak, do the same for the ones that are behind the vanos solenoids.

[philly98540]

Looks good. How many bent valves in total? Just bent on one head or some on both? Curious if they did new valve seals?

Looks like a snapped chain instead of a jumped chain saved some valves from bending. The cams stopped rotating and likely came to rest at a position where the valve lift stayed low enough to prevent bending them. Very rare to see one of these engines with a snapped chain.

[MotorMouth93]

Yes I did find those check valves and I removed them before taking the heads to the machine shop.
I do not plan on replacing them though. They wee pretty clean. I will just dip them in acetone to unclog any gunk, then reinstall them. Right ?

Why would you cheap out on something that can't be accessed without removing the cylinder heads? Just replace them.

[philly98540]

Why would you cheap out on something that can't be accessed without removing the cylinder heads? Just replace them.

TBH and transparent, I re-used my old check valve that sat under the head. The shame of it. LOL. The check valve itself is very simple and all metal. I had zero sludge on any part of it and it sealed perfectly. Looked just fine. I did replace the rubber seal ring thingy though.

[Chedley]

Heads look nice, did they shave them?
Clean the check valves and then make sure they don’t leak, do the same for the ones that are behind the vanos solenoids.

The check valves on the top of the front corners of the block are deep entrenched, and I did not remove and could not remove them. I'll just clean them a bit.


I am talking about the check valves behind the solenoids -- those I removed before sending the heads to the machine shop.

Looks good. How many bent valves in total? Just bent on one head or some on both? Curious if they did new valve seals?
...
.

Yes, 6 bent valves , all on the exhaust side only. Although when they showed them to me, I saw only 2 clearly bent valves on the stems, the others had slightly distorted bases. The machine shop said they had to be replaced.
And yes, they replaced the seals on all 32 valves.
It looks like they shaved the heads, too.

Why would you cheap out on something that can't be accessed without removing the cylinder heads? Just replace them.

I am talking about the valves behind the vanos solenoids (BMW part # 11121706921). I will clean them and replace their O-ring seals.
@JimLev--> you sent me a bag of O-rings with the Beisan vanos things- I guess some of those O-rings should fit in the check valves, yes ??

[JimLev]

Chedley, those o-rings I sent with the vanos are not for the check valves, but they may fit.
The instruction sheet with p/n’s that was in the box specifies where they go.

[Chedley]

I had an idea to assist with the placement of the heads .... maybe get a thin, stiff piece of plastic that u place over block. then maneuver the head into the proximity of where it needs to be. once the head is close. slide the plastic out of the way, this would minimize the chances of scratches and gouges trying to monkey the head into place.

just a suggestion
....

So this week end I am starting to put the engine back together.
So I have started with the hardest part --for me at least : reinstalling the serviced heads with the engine in the car.

The bank-2 head, driver side is a b**ch. I have spent most part of the day -+5 hours working on it. I tell you , there is no way around making a couple scratches on the new +0.3 mm head gaskets, while monkeyeing that head in place, and aligning its studs with the 8 holes of the exhaust pipe gaskets. But at least now I got it well seated in place.

Question: would you bolt the head first with the 10 new bolts, following that criss-cross TIS procedure, before tying up the 8 nuts on the exhaust studs? is it the other way around ? Or does it matter....

[JimLev]

Bolt and torque the head down first, then connect the exhaust manifold.

[MotorMouth93]

Yeah you shouldn't be aligning the exhaust manifolds while trying to install the heads, those should be pushed out of the way during that part of the process. I hope the dowels didn't tear up the head surfaces too badly.

[Chedley]

Yeah you shouldn't be aligning the exhaust manifolds while trying to install the heads, those should be pushed out of the way during that part of the process. I hope the dowels didn't tear up the head surfaces too badly.

I could not push the exhaust manifolds out of the way on the driver side, not enough room.
And doing it bending 90 degrees was not not exactly fun...- But I do not think I teared the head surfaces -they were too much lubed -, though I probably scratched a couple locations.
Anyway, the heads are all bolted in now, per spec in the TIS. I will push in the exhaust manifolds and screw the nuts later.

But installing the head on the passenger side was comparatively a breeze...