Hollow bolts and cam lubrication

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Henrik

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Hi!

While assembling the cylinder head I noticed that the end of the rear hollow bolt was concave. I measured the bolt and found that it was too long. The rear camshaft bearing had "grinded" the bolt. Does anyone know if these bolts have different lengths?

Another question: I found this article on the internet. Has anyone done this modification to the spray bar?

http://paulaxford.com/html/bmw730i/cam_spray_bar.htm
 
as to the convave form, i doubt it is too long, may be not correct assembly ? two alu washers obviously the right thickness is important...

yes, i saw that article, but i am reluctant to do it, at the end i can see no advantages, can anyone explain on this ?

i say there are two hollow bolts comming to each center section of the oil spray bar if each one shares the same pressure and flux, i see no gain in clossing the central point in order to force left bolt to feed left section and right bolt the other

i see the drawback that if for any reason one bolt is blocked that section is dead
 
The mod is intended to prevent oil starvation to the forward lobes at hot idle due to the rearward tilt of the engine. It ensures that oil from the front oil port goes to the front lobes, instead of draining backwards. I did the mod.
 
DQ has a point- only the correct crush washers will work.
 
Only one alu washer was mounted on each bolt when I dismantled the cylinder head. That explains the case..

Thanks!
 
Cam Oiling Bar

There may be something to this modification. The attached is the cam out of my engine - a regrind that has only 41,000mi on it. Unlike all the other lobe pairs you can see both exhaust and intake are worn down creating a flat section where the peak should be. Maybe from lack of oil as Vraned suggests - can't see any other reason?

A cam I took out of my donor (soon to be installed) b35 head with over 247,000km on had no wear on the front pair. Same oil bar system.

So is there any reason not to do the modification?


 
Don't do this at home.....

I use a pair of linesman pliers on every one of them.
I cut a thread so they never come out.
Don't overdo it.
Takes practice.
 
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