Broken rockers cyl. head off, 56k beware - pics of parts

[Dave535Phoenix]

The head came off pretty quickly. Having done it once before helped quite a bit - a lot of that due to having all the tools needed on hand. My only brain fart was trying to turn the motor over with the car in 2nd gear.

Anyway, here are pictures of the internals. I included a pic of the #1 cylinder and a pic of the #4 for comparison. The only thing that jumped out was the carbon debris; there's a bunch of little specs on #1 while #4 is clean. I didn't see any obvious piston-to-valve contact point; a better trained eye might pick one up.

The only piston pic is of the #1 cylinder.

This is about both rocker arms of the #1 cylinder breaking off..see thread http://www.bimmer.info/forum/showthread.php?t=8797

Analysis anyone?

(and yes, I do know how to spell piston)

Dave

[e34bim]

From what I see there is excess carbon build up in # 1 and the the inlet valve looks to be stuck, probable cause could be carbon build up on the valve stems causing them to jam, tap the valve from the rocker side with a hammer to see if its free to move, i also notice that the engine is running rich

[632 Regal]

It doesnt look like you had any valve to piston contact from these pictures...a VERY good thing. All in all it looks pretty good concidering it was running with broken rocker arms. I would just clean it up, inspect things closer and put it back together.

[Bill R.]

indicated. And thats what it typically looks like when you tip one. You won't know for sure until you take the head to a machine shop and they put the valve in a valve grinder and try to lightly clean it up, if its bent it will be obvious when grinding.

[George M]

agree with Bill....may be some contact on the one valve. Will be apparent when all the valves come out of the head for inspection and clean up. The good new is as Jeff said, looks like you dodged a big time lower end debacle. Rebuilding your head should be pretty straight forward. Nice not having to touch the bottom end.
Should go quick to get it back together since you've done one before.
A further tip...you mentioned in your previous thread you loctited the bejesus out of your banjo bolts. You really don't want to for fear of blocking flow. Why BMW sells the updated banjo bolts with encapsulated loctite...to safe guard against mis-application. You would be well advised to purchase Don Gale's safety wire kit which many of us run including myself. You want belt and suspenders with your banjo bolts.
Good Luck,
George

[Bill R.]

This honda had had the timing belt changed by the dealer, 2 weeks later it lost the timing belt, The dealer eats the work and pulls the head, says everything looked good so they didn't bother doing a valve job while the head was off, Customer tells me that the car never really ran right after they got it back from the dealer, 1 year later and 12 to 15k miles the customer is driving on the highway and the miss that always was there a little suddenly becomes glaringly obvious and they lose power. I pull the head and the valve that had gotten tipped when it slammed the piston a year earlier had now broken of the piece where it bent...Local honda dealer denies all blame of course , I put the head back on after a valve job and replaced 3 valves that had been damaged all along
and car runs like it hasn't run for over a year...

[George M]

interesting comments Bill...makes a lot of sense.

[Dave535Phoenix]

Bill, where are you located? If shipping on the head is reasonable, you've talked yourself into some work if you want it.

[Bill R.]

have worked in a few. In fact i worked at one in phx. 30 years ago. Used to be called small car goodies at thomas and 31'st ave. just west of the thomas grand ave. intersection. They're long gone though.

Bill, where are you located? If shipping on the head is reasonable, you've talked yourself into some work if you want it.

[George M]

Dave...Bill would tell you this but work mentioning....the shipping cost of your head would really inflate your rebuild cost. Call a couple of local sports car mechanics in your area and ask who machines their heads and is familiar with BMW. You likely know the drill on supplying the upper timing chain cover with the head for a light skim if necessary. Believe most NAPA dealers will be able to rebuild your head but you may have a higher comfort level in talking to the man or supervisor overseeing the work to ask enough questions to make sure you are on the same page.
George