Anyone not resurface their cylinder head after removal?

[sbay]

TIS is saying it must not be machined. Couple people I’ve spoken to and forum posts/DIYs alike say you can resurface it up to a certain amount of ~ 0.3 mm. Still deciding on which route I’ll take (leaning towards TIS), but wanted to know if anyone has just checked it for straightness, cleaned it up, did a leak down test, and reassembled the head with no issues to date? Or is the general consensus to just get it machined?

P.S. Failure was not due to a blown head gasket (spun rod bearing), which in that case machining would be warranted

[nextelbuddy]

I took my engine apart for my rebuild. I didn't know my head gasket was broken but when I took my head off I saw that cylinders one and three had bricks between the head gasket

I took the cylinder head to a local machine shop that deals with European engines often and I gave them the spec that you just quoted above and said when they resurfaced to make sure not to go beyond that amount

When I got the head back he said they didn't even get close to that

So I had no issues with mine

Mine is bolted on driving. Have about 5,000 mi on it with no issues

[bmwfnatic]

In theory you could use a straightedge and some feeler gauges to figure out if your head is staight enough (usually there's a spec for this).

0.3mm is a LOT, I have a head that has been machined a total of 2 times now, once due to heavy head gasket failure, and that one is 'only' missing 0.2mm.
I would always do a cleanup pass if the head is off, just to get an optimal new sealing surface for the MLS headgasket to seal as well.

[sbay]

I took my engine apart for my rebuild. I didn't know my head gasket was broken but when I took my head off I saw that cylinders one and three had bricks between the head gasket

I took the cylinder head to a local machine shop that deals with European engines often and I gave them the spec that you just quoted above and said when they resurfaced to make sure not to go beyond that amount

When I got the head back he said they didn't even get close to that

So I had no issues with mine

Mine is bolted on driving. Have about 5,000 mi on it with no issues

That is true, who knows what monsters lurk in the dark until I remove the head. If all seems well, I think a cleanup pass as bmwfnatic seems like a great option. Thanks for the help!

[sapote]

Still deciding on which route I’ll take

No reason to cut the head unless there is damages to the surface or it's not flat.

[Slideways]

In another thread, I asked about using the grinding stone BMW sells for cleaning the gasket material off the S65 block. It was concluded that it is not worth the effort since resurfacing the S54 cylinder head costs around 100 bucks.

[eacmen]

You need to make sure you have a machinists square or straight edge long enough to run the length of the head. Your average ruler wont cut it.

I bet if you call up some machine shops they will check it for you for free or very little cost.

[bimmerfan08]

I took my engine apart for my rebuild. I didn't know my head gasket was broken but when I took my head off I saw that cylinders one and three had bricks between the head gasket

I took the cylinder head to a local machine shop that deals with European engines often and I gave them the spec that you just quoted above and said when they resurfaced to make sure not to go beyond that amount

When I got the head back he said they didn't even get close to that

So I had no issues with mine

Mine is bolted on driving. Have about 5,000 mi on it with no issues

What does the word "bricks" in this case mean? Breaks?

[nextelbuddy]

What does the word "bricks" in this case mean? Breaks?

Yes correct, stupid auto correct

[WestBankM4]

There's nothing more satisfying than a freshly hot tanked and decked head, begging to be reassembled.

[BL92]

Mine HG failed between CYL 1 and CYL 2, any DIYs for this??? or should i just follow ISTA ?

i am about to start in the next few days

[Slideways]

What does the word "bricks" in this case mean? Breaks?

Highly recommend a leak down test for any S54 with over 100k. Up to 40 PSI (27%) down on one cylinder, it will still drive without registering a misfire. There will be a slight vibration in the steering wheel and seat due to the imbalance in pressure between cylinders, not to mention pinging at low RPM and high load. There are also three layers to the gasket, so if one layer is broken, it can leak some PSI into an adjacent cylinder. Also, as you drive the car harder, the engine will seem to lose power. The general loss in power is sometimes hard to perceive as it happens over time.

BL92

DIY - https://forums.m3cutters.co.uk/threa...e46-m3.205525/

[sbay]

There's nothing more satisfying than a freshly hot tanked and decked head, begging to be reassembled.

True that.

BL92 the link Slideways shared is definitely a go-to head gasket diy…good luck