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-   -   Stuck camshaft (http://forums.pelicanparts.com/911-engine-rebuilding-forum/265055-stuck-camshaft.html)

billd 02-06-2006 05:44 PM

Stuck camshaft
 
I test fit my left camshaft. It went in fairly smoothly and turned freely. However when I attempted to pull it out it hung up about 1/3 of the way out - when the end of the cam reached the journal between cylinders 2 and 3. No amount of twisting, jiggling, and pulling will get the bearing at the end of the cam past this journal. This is a Solex cam in a 1977 2.7L cam housing.

Does anyone have any tricks for extricating a stuck camshaft?

I'm tempted to leave it in and continue assembling.

Eagledriver 02-06-2006 08:31 PM

They can be difficult to get out. I find that the problem is usually the cam is angled slightly and hangs up on the bearing. If it went in easily I bet it will come out. Just need to hunt around for the correct angle. If you don't need it out however you could just leave it.

-Andy

billd 02-07-2006 01:24 PM

I put the camshaft back in and was able to get the chain housing on by loosening the head bolts a bit and then retorquing them after the chain housing was in place. I'll deal with getting the camshaft out the next time I rebuild this engine.

sand_man 02-07-2006 02:07 PM

Quote:

Originally posted by billd
I put the camshaft back in and was able to get the chain housing on by loosening the head bolts a bit and then retorquing them after the chain housing was in place. I'll deal with getting the camshaft out the next time I rebuild this engine.
Just curious - did you have anything machined (case spigots, heads, etc.)? If so, this could cause alignemnt issues between the chain housings and the cam decks (housings)...provided material wasn't also removed from the chain boxes. Just playing devil's advocate in case you didn't think of it. Good luck with your build!

Jeff

billd 02-07-2006 03:32 PM

Quote:

Just curious - did you have anything machined (case spigots, heads, etc.)? If so, this could cause alignemnt issues between the chain housings and the cam decks (housings)...provided material wasn't also removed from the chain boxes.
The heads were machined - guides replaced, several valves replaced, seats cut, valves ground, and mating surface resurfaced. However the resurfacing did not remove enough metal to make a difference. The cam is well centered on the hole in the chain housing.

billd 02-07-2006 03:35 PM

The shoulder of the bearings of the camshaft are very square. A small chamfer on this edge would make the shaft more easily align with the bearings in the housing as it is extracted.

Is there any reason why I shouldn't file a small 45 degree chamfer on the end bearing?

CliffBrown 02-07-2006 05:08 PM

Quote:

Originally posted by billd
I put the camshaft back in and was able to get the chain housing on by loosening the head bolts a bit and then retorquing them after the chain housing was in place. I'll deal with getting the camshaft out the next time I rebuild this engine.
Bill

I'm a little confused about the sequence of events you've taken so I'll just take a shot in the dark.

I assume the cam tower boss were well lubricated prior to installation of the cam. Did the cam turn easily while installed in the cam tower? Did you then retorque the head stud nuts? Were the cam tower nuts installed and torqued prior to installing the cam? Did you torque the heads first and then install the cam tower or simultaneously.

What's the status of the other cam?

It's possible to encounter problems with a binding cam especially when rebuilding a 7R case or after having work performed on the heads mating surface. Also the sequence of torquing the head studs is important.

billd 02-07-2006 05:25 PM

Quote:

Originally posted by CliffBrown
I'm a little confused about the sequence of events you've taken so I'll just take a shot in the dark.

I assume the cam tower boss were well lubricated prior to installation of the cam. Did the cam turn easily while installed in the cam tower? Did you then retorque the head stud nuts? Were the cam tower nuts installed and torqued prior to installing the cam? Did you torque the heads first and then install the cam tower or simultaneously.

What's the status of the other cam?

It's possible to encounter problems with a binding cam especially when rebuilding a 7R case or after having work performed on the heads mating surface. Also the sequence of torquing the head studs is important. [/B]
The sequence was as follows:

1. I assembled the engine up to Ps/Cs installed.
2. I installed the heads
3. I installed the cam tower - with Loctite 574
4. I torqued the cam tower to head nuts - per the sequence and spec in the workshop manual
5. I torqued the head nuts per the sequence and spec in the workshop manual
6. I applied assembly lube to the cam and the cam tower
7. I inserted the cam for a test fit - it went in smoothly and turned easily
8. I attempted to remove the cam and found it hung up 1/3 of the way out - where the end bearing of the cam hits the bearing in the cam tower between cylinders 2 and 3. I spent over an hour rotating, jiggling, etc with no improvement.
9. I sent the first message.
10. I attempted to install the chain housing with the cam in place and found it wouldn't quite clear the studs.
11. I loosened the head nuts two turns
12. I installed the chain housing with the cam in place.
13. I retorqued the head nuts per the workshop manual.
14. Assembly continued with alignment of the sprockets.
...

The right cam is fine. It came out with no problem after the test fit. It turns just slightly easier than the left cam. The difference is small.

camgrinder 02-07-2006 10:35 PM

It is easy to burr the edge of the cam carrier with the camshaft bearing surface. Once in a while I do this in my checking set up. I can usually spin the cam a few times with some pressure pulling it out and it seems to work.
If you chamfer the edge of the bearing it will help.

davidppp 02-08-2006 12:49 AM

Hello there.

I have had the same problem too.

I'm sure its a tiny dent in the aluminium housing..the cam is heavy and sooo easy to knock slightly off centre ..

A little sraaper on the corner of the housing ..or a BFH..wil do it..

Kind regards
david


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