M52 head bolt thread

[Hazem83]

Hello bimmers, fixing a blown head gasket on m52 engine but found a head bolt thread in the block, recommended to reshape the thread. Anybody went through this ? And is it reliable ?

[bmwdirtracer]

Please post the last seven digits of your Vehicle Identification Number, so I can identify the engine type. (Generally only aluminum block engines have the threads ripped out, but I don't recall this in an E36)

[Hazem83]

I did change my original engine and now i have a m52b25 engine with aluminum block and the thread has stripped from the block.

[bmwdirtracer]

Okay then. Too bad I deleted my original reply.

Yes, you can rethread the block. This is a well-known procedure. In the U.S., I'd absolutely tell you to just buy a used engine, because it's much cheaper and far less time consuming.

If you're going to rethread the block, you should rethread every head bolt hole, not just the ones you know are bad. The reason for this is that if you do this job, and go to bolt the head back on, and can't achieve the proper torque, you're doing the whole job again, with yet another set of headbolts.

To do this job properly, you need to buy a fixture to align the rethreading drills, taps, and TimeSerts. You must use Timeserts, not Helicoils. The fixture, Timeserts, and Timesert kit are pretty expensive. You also need to send the head to a top quality machine shop for crack testing, and machining flat. (The threads ripped out of the block because the head warped badly.)

Maximum machining for the head is .009 ", and you'll need to use the thicker factory head gasket, and a new set of head bolts, of course. (They can only be used once!)

IF the entire job is done perfectly, using the correct tools and professional level care and expertise, then yes, it's reliable.

If you try to cheat on any of the above steps, no, it's not reliable.

If you can buy a used engine with a warranty, that's probably your best bet.

[Hazem83]

Thanks bro for the fruitful info, the machine shop will do the timeserts and will check for cracks as the mechanic told me btw i am in egypt and doing this in a machine shop is pretty cheaper than getting a used block here so thats why i am asking to decide to sell the car after or leave it. Thanks again

[bmwdirtracer]

Yes, I saw your location, and I understand that good used engines are not as easy to come by as they might be here, which is why I went into detail about how to fix it. My best wishes for your success.