(Yet another) M42 top end refresh and engine reseal (mid-2021)

[jsnppp]

Yeah, good point. Pre-installing the upper cover properly would simplify some things for sure.

The profile gaskets themselves are fine and I don't trim those. It is the skinny paper outer perimeter gaskets that I am referring to.

I need to think about it a bit more, but it might also be better to skip the cover gaskets entirely and just RTV the covers on. That would eliminate the tiny little gaps that I suspect result in oil seepage. Anyway, I'll see if I can make some diagrams later.

I'll keep thinking about it too, thanks for the dialog on it.

[Gkwan]

First off, great thread! I love seeing an amazingly documented m42 build up!

I was previously looking into the timing chain guide issue a while back and looking at RealOEM, the later model guide also uses a bolt and bushing (PN: 11311247452) instead of the early model post design. I had wondered if the bushing and later model guide could be swapped into the early timing case by replacing the post with the bolt. This seemingly would fix the issue with the new part having a larger pivot hole. This seems like too easy of a solution but it looks like you have all the parts except for the bushing and bolt, but might be something to consider!

good luck with the build regardless and keep the updates coming!

[jsnppp]

First off, great thread! I love seeing an amazingly documented m42 build up!

I was previously looking into the timing chain guide issue a while back and looking at RealOEM, the later model guide also uses a bolt and bushing (PN: 11311247452) instead of the early model post design. I had wondered if the bushing and later model guide could be swapped into the early timing case by replacing the post with the bolt. This seemingly would fix the issue with the new part having a larger pivot hole. This seems like too easy of a solution but it looks like you have all the parts except for the bushing and bolt, but might be something to consider!

good luck with the build regardless and keep the updates coming!

Thanks - hopefully make solid progress this weekend. Its about time to get this done..

I took a look at that PN and it indeed looks like it would work to permit the newer chain tensioner rail to bolt on. https://www.fcpeuro.com/products/bmw-bush-11311247452

I'm due for an FCP order and will put that in. Would be cool if so! Thanks for that tip.

~Jason

[jsnppp]

Wound up working on the exhaust system and interior. We have the carpet out for cleaning + taking care of some small spots of rust where paint had chipped. (sand, clean, soak in OSPHO for rust conversion, then clean again with water and paint. Works well.) We also have some rust spots behind the radiator to take care of. Now is the time while everything is out.

The goal is to pivot back to engine this week.

Anyone know how to repair a cracked center console?

[jsnppp]

This weekend is the weekend. Time to get it done! I was focused on some other bits and bobs this past week. All of it is required before the car is to start.

I'm going to go with my thoughts to install the upper timing cover BEFORE installing the head to block. Will see if this works in practice. I'll document everything and include on the front page.

[bmwman91]

Sounds good! I think that the only challenge will be getting the RTV in place if you are doing the head+upper cover. A couple of good dabs between the profile gaskets' butt ends and on top of them will hopefully work to seal where the top cover meets the head, although even a tiny pinhole there will cause oil weepage. Make sure to be 100% ready to drop the head on and start torqueing the bolts immediately after putting the RTV in place since it starts to skin-over in a few minutes. Of course, it is more important not to rush the head install too much too haha!

It is rare for a leak there to actually cause any significant loss of oil. Usually it is just an annoying small amount that wicks out and spreads all over the left side of the engine and top of the upper oil pan, caking with dirt and leaving the engine looking like a black crusty mess after a couple of years. Such is life, I suppose.

[jsnppp]

Sounds good! I think that the only challenge will be getting the RTV in place if you are doing the head+upper cover. A couple of good dabs between the profile gaskets' butt ends and on top of them will hopefully work to seal where the top cover meets the head, although even a tiny pinhole there will cause oil weepage. Make sure to be 100% ready to drop the head on and start torqueing the bolts immediately after putting the RTV in place since it starts to skin-over in a few minutes. Of course, it is more important not to rush the head install too much too haha!

It is rare for a leak there to actually cause any significant loss of oil. Usually it is just an annoying small amount that wicks out and spreads all over the left side of the engine and top of the upper oil pan, caking with dirt and leaving the engine looking like a black crusty mess after a couple of years. Such is life, I suppose.

My plan:

• Put tiny bit of sealant (hondabond, RTV, etc.) across the whole lower part of the profile gasket channel (lower timing chain case + cover). I mean tiny amount, very thin skim. A bit more in butt joint area.
• Immediately press on both sides of the profile gasket. Add a bit on the actual butt joint itself (not just top and bottom).
• Lay on head gasket to engine block
• Put another thin skim of RTV on the top, again a bit more in butt area.
• Lay head in place w/o front timing chain cover in place
• IMPORTANT --> Prop up head with 1/4 to 1/2 inch plastic blocks to keep head off of profile gasket.
• Thread timing chain over the camshaft ends, possibly put cam gears on (lightly) or tie it up
• install front top timing chain cover gasket (Permatex light spray) and install front top timing chain cover. Torque to spec.
• lift head, remove plastic blocks and set carefully down on engine block
• Oil head bolts and install.
• Torque as per directions.

Will see if that works! Hondabond is good stuff and may not skim over too fast but it is going to be a bit of a juggle timing wise. I'll dry run it once to see if it's even possible...

The point of this weird order of operations is to reduce the shear that occurs when install first the head and then the top timing cover on the profile gasket. To my mind, this can distort the gasket, leading to a gap and leaks. Installing as a unit should reduce/eliminate this issue.

Ask me how many times I've done this and that will give you an idea of how confident I am. :-)

Thanks for the good words and we'll see how it goes!

[bmwman91]

That mostly sounds good. Just be careful not to dent or damage the HG at all with the blocks and it sounds like a feasible plan.

[econti]

I'm going to use Hylomar on mine, its a non drying jointing compound and in theory should mean it'll never leak. If so then it'll make it much easier than using RTV

[jsnppp]

I'm going to use Hylomar on mine, its a non drying jointing compound and in theory should mean it'll never leak. If so then it'll make it much easier than using RTV

I'll take a look. I have several options to choose from. Hondabond is really good stuff but I'm not sure if it technically dries or not.

JasonP

[jsnppp]

Here is my collection of sealants. Hondabond and both Permatex (#2 and The Right Stuff) are non-hardening. Hondabond is good to 600 deg F.

I'm new to Right Stuff and Form-a-gasket but am leaning to Right Stuff as I've seen it referenced here to use on profile gasket.



Tomorrow is the day!

[jsnppp]

Drum roll - we prepped the head for installation but did not wind up installing it! Ideally tomorrow after work..

[jsnppp]

Some progress.

Layed the headgasket on the head.



Checked the gaskets between upper timing cover and cylinder head. I see they extend about a mllimeter too high. I trimmed them down to sit flush.






I plan to make sure there is sealant in that joint.

Tomorrow is the day.

[jsnppp]

Head is on. More photos to follow. It went a lot different than planned, a lot of lessons learned. But it's on!

Questions:

1. Which direction does engine turn when standing in front of it and looking back through the windshield?

ANSWER: Clockwise. Had to reference old M10 engine for that. Can figure it out by looking at the side opposite the tensioner. The running engine needs a straight shot up to the cams for the chain/belt. This is clockwise for the M42.

2. My head bolts did not come with washers. Far as I can tell my old did not have any either. Any feedback?

ANSWER: I don't think it does, but welcome corroboration on that.

[econti]

Yes they do use washers. Pretty sure it turns clockwise but not 100%