MTBSully

Well my head bolt/lifter swap was going well until just now. Snapped the front bridge on the passengers side head while slowly tightening the cam down. In hindsight I probably should have tightened this down last since I hadnt torwqued the other cam yet and it probably put a lot of stress on it.

Anyways. Anyone know the part number for this cap? Or have one they can sell me? Going to the dealer in the morning but something tells me that since I cant find a cylinder head exploded diagram or part number anywhere, they may not be able to find it. Any help or leads are appreciated.

roadkillrob

That is not good, they are matched to the head, the head is machined with the cam caps on it, so they are not a separate part and is why you always have to put them back in the same position you took them from. The dealer will sell you a whole head assembly. A machine shop maybe could fix but they would need the head off to machine it if they could fix or you could do a used head, but any option is not cheap or easy, just any old cap if you could get one could cause a lot of damage as it will never fit properly. Sorry for the bad news.

dowheelies

Man that sucks! In DOHC engines I have had these caps are specific in position and each individual head as they are final line honed once assembled. Just popping a random one in may not end well. Rule 1 is to mark/number each one before disassembly (if not already). I had one get tore up in the past and they had to redone the cam journals on that head. At an absolute minimum once you find one I would install the cam with no followers and make sure the cam turns freely before letting it rip. Clearance checked also. My .02

Good luck man.

go team

There is a sequence in torquing these down and it involves torquing down both cams in sequence and not just one cam. Like everyone else has said you really can’t use any used bearing cap and expect to not have issues down the road. They are machined to match the head. I know you can buy bridge caps on eBay. But to get one that lines up well and has the proper tolerance (not released by MB) to match your head you’d probably end up investing in a few used sets. That ID of that cap is critical as it is the oil supply for both of the camshafts so ensuring it is perfectly sealed with acceptable tolerance is a must otherwise you risk bleed out and running the journals dry.

f80lunatic

I have one from each side. Came off of a 507 amg

NZ-Merc

If it was me I would purchase the two caps f80lunatic has then have a short shaft turned in the lathe to exact same diameter as your camshaft journal at the cap position then install either of the new used ones torque up with out a camshafts installed.

Next I would run my finger in the hole see if there is a step between the head and cap at the internal jointing line, if and I really hope the interface is smooth then remove the cap and install the short shaft and slowly tighten the bolts to see the shaft locks or not.

If it does nip up,
Picking the best cap then either slightly bore out the bolt holes or use a bearing scraper to hone the new cap high points.

If it is miles out then it is head off for a machine shop or a replacement cylinder head.

I would think the caps wont be too far out mainly due modern CNC machining which would have been used at casting manufacture, not like a lot of earlier engines.

All the best.

MTBSully

PM sent.

skullbox15

That sucks man. You got all the way there and now something like this.

MTBSully

Sucks bigtime, but **** happens. In hindsight like I said it I should have torqued the bridge down last, which is actually contrary to what the WIS says at least the way I ready it, but common sense tells me you're putting a lot of load on that area if one cam is completely torqued down and the other isnt'. In the future i'll be torquing down both cams at the same time, little by little, or probably just put the bridge on last.

skullbox15

This should help:


Start around 17:50