Topic: 650 cam issues in 550 motor

[Aaron Richard]

Hey all, quick issue, I installed a 650 cam in my 550. its in there correctly, but my adjusters are now slightly hitting the tappet caps. Has this happened to anyone? do I need to grind down the adjusters some?

[buffalogt750]

I have a 650 cam in my '76 550 and do not have that problem. How many miles does the engine have on it? Is it possible the valves and valve seats are worn thereby pushing the valves further up into the head which would put the adjusters closer to the tappet caps?

[Gordon]

No issues with my cam swap either. 

Stupid question, but have you adjusted the valve clearances yet, or are they still backed out all the way?

[Aaron Richard]

head is all rebuilt, had no issues with the 550 cam in it. Everything is adjusted to specs.

[Gordon]

I just saw your post in the other thread about clearance issues.  Which problem are you having?  Is it a tappet clearance problem or a cam lobe/head clearance problem? 

[Aaron Richard]

when I installed the cam I had to shave a bit of the wall of the head where the cam lobe was hitting a bit, I finished the install and adjusted the valves. I noticed the tappet covers were being hit by the adjusters by flipping them over and seeing the wear marks. they didn't do that before. Not sure if the cam is rubbing somewhere else that would cause the tappets lifting too high

[buffalogt750]

Not sure if the cam is rubbing somewhere else that would cause the tappets lifting too high

Tappet adjusters are closest to the caps when the valves are closed, not when they open. The extra lift of the 650 cam will not put the adjusters any closer to the caps.

[Aaron Richard]

something is going on in there. the top end is louder than usual. I'll have to pull off the cover and see if its rubbing anywhere else.

[paulages]

Not sure if the cam is rubbing somewhere else that would cause the tappets lifting too high

Tappet adjusters are closest to the caps when the valves are closed, not when they open. The extra lift of the 650 cam will not put the adjusters any closer to the caps.

he's right here. the only thing i can think of that would cause this problem (aside from the adjuster being run out too far) is if the valve seat was cut too deep and he valve stem not trimmed accordingly. maybe go back through it and make sure you didn't make some silly error setting the valve lash?

[MRieck]

Not sure if the cam is rubbing somewhere else that would cause the tappets lifting too high

Tappet adjusters are closest to the caps when the valves are closed, not when they open. The extra lift of the 650 cam will not put the adjusters any closer to the caps.

he's right here. the only thing i can think of that would cause this problem (aside from the adjuster being run out too far) is if the valve seat was cut too deep and he valve stem not trimmed accordingly. maybe go back through it and make sure you didn't make some silly error setting the valve lash?

Boy, you would really have to sink the valves to have this problem. I'm thinking something wierd with the valve lash too.

[Gordon]

Take a look at this thread:

http://forums.sohc4.net/index.php?topic=59144.0

Could this be the problem? 

[paulages]

Not sure if the cam is rubbing somewhere else that would cause the tappets lifting too high

Tappet adjusters are closest to the caps when the valves are closed, not when they open. The extra lift of the 650 cam will not put the adjusters any closer to the caps.

he's right here. the only thing i can think of that would cause this problem (aside from the adjuster being run out too far) is if the valve seat was cut too deep and he valve stem not trimmed accordingly. maybe go back through it and make sure you didn't make some silly error setting the valve lash?

Boy, you would really have to sink the valves to have this problem. I'm thinking something wierd with the valve lash too.

you would... and would likely have some serious flow issues sunk that far.