Gonna need to have my head checked and maybe machined a bit

[glhs837]

B.I. Mattingly, in Compton. He'll take good care of it for ya.

Finally made it out there. Always cool to talk to him. His dogs are very cool. And you should take beer lessons from him, good taste. Wife not super happy about waiting in the driveway for 20 minutes while he and I chatted in the garage. Turns out we know a few of the same people.

 

[glhs837]

Well crap, turns out the head is trashed. Needs welded in maybe 4-5 places, and I'm told it looks like it's been welded before. Given that, best option is most likely to find a manufactured head.

 

[GURPS]

Well crap, turns out the head is trashed. Needs welded in maybe 4-5 places, and I'm told it looks like it's been welded before. Given that, best option is most likely to find a manufactured head.

Whoops .... that sucks, is it a poor design or poor maintenance

and did you mean 're-manufactured'

 

[glhs837]

Whoops .... that sucks, is it a poor design or poor maintenance

and did you mean 're-manufactured'

Well, these heads are a great design when used as designed. Reliability is great. Durability when exposed to overheat conditions, being aluminum, not so great. Combine that with letting Jimmy, the guy down the street who has always put new belts on our Chevys, do stuff like ahead gasket job, it's a recipe for disaster. Looks like there was a previous crack that was welded, and other cracks that either were not found and welded, or found and ignored. Or maybe resulted from Jimmy reusing one time use bolts, who knows.

I'll give this to Butch, he was right up front with saying he's not done BMW heads before and being willing to listen and learn about what's up with them. Sign of a true mechanic.

And yes, I meant remanufactured. Asked the BMW guys for recommendations, said I wanted to keep the bill as close to $500 as possible. Luckily, seems there's one shop in AL that are the go-to, forum members, have been for years, lots of guys report years of happy service from their heads, including one guy whose been running one at over 500hp (more than double stock power levels) for almost two years.

 

[Gilligan]

And you should take beer lessons from him, good taste.

Pffft. I take "beer lessons" from Butch every danged time I stop by. I leave about half lit most of the time.

And then I still buy Corona on the way home again.


Oh..and trust me...Sharon is quite used to it. Or did you mean your wife? ha ha haa...

 

[glhs837]

Get a good taste in your mouth, then rinse it out with that stuff? Maybe you inhaled too much oxidizer when you were young? Yes, my wife

 

[Gilligan]

Get a good taste in your mouth, then rinse it out with that stuff? Maybe you inhaled too much oxidizer when you were young?

 

[glhs837]

Well, crap, now this.....





Number four piston. No expert on pistons, but I cant see that putting a new head on top of that one is a viable long term solution.

 

[Gilligan]

That is strange looking....don't recall seeing anything like that before. Melt zone?

 

[glhs837]

Last time I actually saw pistons was around 1998 when I learned how to pull heads in my driveway on a 1968 vintage 302. So, I"ll bow to your superior knowedge. Damned if I know what caused it. Buildup gets soaked and blows a crater? Doesn't appear to be melted. it's all jagged.

 

[Gilligan]

Last time I actually saw pistons was around 1998 when I learned how to pull heads in my driveway on a 1968 vintage 302. So, I"ll bow to your superior knowedge. Damned if I know what caused it. Buildup gets soaked and blows a crater? Doesn't appear to be melted. it's all jagged.

Well I'm stumped..and I've torn down and rebuilt hundreds of engines. How deep is that ...spot?

 

[glhs837]

Well I'm stumped..and I've torn down and rebuilt hundreds of engines. How deep is that ...spot?

Not there, but I thin 3-4mm.

 

[Ken King]

Looks to be pre-ignition detonation, bet it was pinging hard at one time.

 

[glhs837]

Looks to be pre-ignition detonation, bet it was pinging hard at one time.

Dunno, bought it a few months back knowing it most likely needed a head gasket. Drove it up on the car dolly, then off the dolly, and one trip up to the end of the private road and back to verify the time to overheat. I think it had an overheat, which cracked the head, which was misdiagnosed as a bad gasket. they replaced the gasket, it kept overheating and they gave up. If I can get a decent used engine in the $800-1K range, I'm still ahead of the game financially, since I bought the car for $1500. I just don't see the time and money to rebuild the motor as being worth it.

 

[Ken King]

Dunno, bought it a few months back knowing it most likely needed a head gasket. Drove it up on the car dolly, then off the dolly, and one trip up to the end of the private road and back to verify the time to overheat. I think it had an overheat, which cracked the head, which was misdiagnosed as a bad gasket. they replaced the gasket, it kept overheating and they gave up. If I can get a decent used engine in the $800-1K range, I'm still ahead of the game financially, since I bought the car for $1500. I just don't see the time and money to rebuild the motor as being worth it.

What engine are you looking for? I'm sure you've checked sites like this - http://www.buyusedengine.com/used_engine.php?make=BMW

 

[GWguy]

Looks to be pre-ignition detonation, bet it was pinging hard at one time.

That was my thought. Mis-timed or low grade fuel, running very lean would do that too.

 

[Gilligan]

That was my thought. Mis-timed or low grade fuel, running very lean would do that too.

The damage I typically see from that usually has a smoother texture..melt damage. But it could still have been caused by that and more like flaked or chipped out. I'd be very tempted to take a round burr on the die grinder and see what it takes to blend that out...see how deep it really is. I'm real particular builder but not above just patching an engine back together if it's for my own occasional use. I've TIG welded defects up on piston tops too...a number of times.

 

[GURPS]

afaik detonation usually breaks off a ring land at the edge of the piston .... nice rust you have on your piston, and cylinder wall


scuff it up with a brillo pad and fill it with JB Weld :grin:

 

[glhs837]

What engine are you looking for? I'm sure you've checked sites like this - http://www.buyusedengine.com/used_engine.php?make=BMW

That was my thought. Mis-timed or low grade fuel, running very lean would do that too.

It's going to be a straight replacement, BMw M52, or 2.8 liter inline six. If by chance an M50, the M3 variant, were to pop up I would be willing to go with that

GW, given the size and location of the house, I would suspect that low grade fuel would be a real possibility.

Gurps, I know that looks like rust, but it's just deposits. I really don't want to pull a motor apart should a weld or piston fail. While it might be interesting to try and repair it, I don't have that kind of free time such a science experiment might entail.

 

[Gilligan]

. I really don't want to pull a motor apart should a weld or piston fail. While it might be interesting to try and repair it, I don't have that kind of free time such a science experiment might entail.

Weld-repair and then re-machining expensive pistons, aluminum heads, engine cases etc. is far from a "science experiment"...it's just standard (skilled) shop practice where expensive and/or rare components are involved.

Like this '47 U 74 ci Harley engine, for example.





You should see the lengths and expense someone will go to to weld-repair and re-machine a vintage set of aluminum Hemi or BBC heads after an engine grenaded and valves got eaten......

I don't keep all these expensive machines around just to look at 'em fondly...