m52tu head bolt problems

[autocross97]

i'm replacing the headgasket on a m52tu that has an aluminum block, you might be able to guess where i'm going with this.... i torqued down the head bolts as directed by alldata. 40nm wait 20 min then 90 degrees wait 20 minutes and another 90 degrees. on the third torque sequence i felt the threads on two of the bolts let go, i stopped turning instantly when i felt them go. i finnised torquing the rest of the bolts with no problems. so that leads me to my questions, what do i do now? continue putting the car back to gether and see if it will hold or should i just pull the head back off now drill out the threads and insert helicoils?

[eye145]

Bummer,
Get a new set of bolts, remove head and repair block, reinstall.
Search the forum this has been delt with many times and is a common problem with the aluminium blocks.
Might as well fix it now . It will be more work to do it later and could cause more damage then whats already done. But you knew that already.
Also I have used timeserts in the past and these are a factory repair for another Manufacturer that had a recall with bolts pulling out on their v8's. I would highly recomend these for your repair
http://www.timesert.com/html/universalheadbolt.html

[SiGmA]

I agree with what eye145 said. You're gunna have problems if you run it like it is, you should fix it once, and fix it right. IMO.

[autocross97]

thanks for your help. i guess i suck at searching, i cant find anything useful about stripped threads in an aluminum block. those timeserts sound like a good solution, where is the best place to buy a set of them?

[fun2drive]

I am facing the same thing. Here is what I found which might help you some. I will begin this little chore sometime after Thanksgiving.
Please post what you experience is.

http://www.baumtools.com/pdf/Strippe...build_Kits.pdf

I will most likely use the time-sert.com kit but have been caustioned that if you don't install these perpendicular that you may have problems thus the reason for the template. Not sure what it costs to buy or if you can rent it but I know that would make it much easier to install these time-serts correctly...

[bjl4776]

Working at a dealer and seeing many people overheat the car and not stopping. I see this happen all the time. Infact, as per warranty if we are going to do a headgasket, we have to loosen all the head bolts and torque them to spec just to make the sure the block is ok. 7 out of 10 times they strip. As far as fixing it goes, dont waste your time with helicoils. Use a time-sert set, they work amazing and are much stronger than the stock alluminum threads. If u dont wanna deal with those at all u can get a 11mm head stud set and tap the holes bigger. Or even if u wanna go all the way you can put in 11mm time-serts with the larger stud set. But either way, pull they head offf and repair them, you WILL have sealing problems with even only one bolt missing.

[JamesM3M5]

I've also read from several different shops/mechanics that if you strip threads in the block that it is best that you replace the entire engine. The problem comes after the block is overheated from a loss of coolant, and the heat treat in the aluminum is lost. We've seen several M52TU engines running poorly after an overheat, and compression on these engines is terrible. Every time we get one in like this, we don't waste time doing timeserts. Used engines are easy to find.

[autocross97]

I am facing the same thing. Here is what I found which might help you some. I will begin this little chore sometime after Thanksgiving.
Please post what you experience is.

http://www.baumtools.com/pdf/Strippe...build_Kits.pdf

I will most likely use the time-sert.com kit but have been caustioned that if you don't install these perpendicular that you may have problems thus the reason for the template. Not sure what it costs to buy or if you can rent it but I know that would make it much easier to install these time-serts correctly...

yes i think would be important to use a plate to keep the drill an tap square to the block surface, but from watching the wurth time-sert videos on youtube it does not look that critical. with that being said i plan to make my own alignment plate with the machine tools i have access to at work, since the kit with an anlinement palte is $300+.

i was also hoping to time-sert my block over the long weekend but its not going to happen because no one local stocks time-sert set for the bmw and its too short notice to order them online.

[diffsonline]

Stupid questions...


You got the bolts for the aluminum block right? You know the iron block bolts are shorter and this is quite common. I had an issue with mine because it was fuel starving and popped the HG. Got lucky and there was no damage except for the gasket.

I have a good Alumn M52 here that I will do CHEAP if you are in need. Has 40k on it.

[autocross97]

yes i used the correct bolts for the aluminum block. i'm going to time-sert the block, but if that gives me problems i'll keep your motor in mind.

[jinshiyang]

but from watching the wurth time-sert videos on youtube it does not look that critical. with that being said i plan to make my own alignment plate with the machine tools i have access to thread insert helicoil

[autocross97]

the timesert kit from baum auto is less than $500 after shipping and that includes 24 timeserts, the timesert kit, the fixture plate and the bushings. i really dont think you could do one your self for less.

as a side note, are you reall located in china? if your in the us i would think about loaning/ renting you mine with a deposit that i would refund after i got it back.

[ScotcH]

the timesert kit from baum auto is less than $500 after shipping and that includes 24 timeserts, the timesert kit, the fixture plate and the bushings. i really dont think you could do one your self for less.

as a side note, are you reall located in china? if your in the us i would think about loaning/ renting you mine with a deposit that i would refund after i got it back.

So I assume you did this? Was it a success? Is the motor running? I have an AL block that has been nothing but problems. I had the head bolt holes timeserted as a precaution, but now the MAIN studs pulled out when torquing to spec. I guess I could go and do ALL the holes in the block, but I think at this point, I'm going back to iron, and keep my awesome $2000 aluminum paper weight

Btw, I think the post above yours is spam.

[jjvincent]

Drill out the block and install two 20mm long heli coils on top of each other. I've done this a number of times and it has worked like a champ.

[RangerGress]

Btw, I think the post above yours is spam.

Looks legit to me, even if he's a low # Chinese poster. Both his comment and the link are on message.