Tight Rocker Arm / Valve - 1969 CL350 K1

spoore21

spoore21

Member
Joined
Jun 8, 2023
Total Posts
48
Total likes
26
Location
Mount Ayr, Iowa USA
Hello All,

I am in need of some expert advice. I recently had my top end rebuilt - bored the cylinder, new piston / rings, new valves, guides, and springs. I am having trouble doing re-assembly. The left intake guide is tight on the cam.

I install the rockers with the pin on the cam pointing at 4:30. I have the rocker pins tick marks all at 12:00. When I tightened the cam bearing holder screws, it becomes impossible to turn the left intake rocker pin to where the tick mark faces away from the plug. All the other rockers have some degree of play.

I have tried the following with no success. 1) Switching rocker arms and rocker pins (parts 4 and 5 circled in red below) 2) Switching the cam bearings (outside holders) 3) Switching cams.

My only other idea would be changing the cam carrier / holder assembly. I cleaned the cam carrier basket using high heat in an ultrasonic cleaner. I am wondering if that might be enough to warp the aluminum to make the hole where the rocker pin goes out of spec.




Additional question - Are the rockers and guides identical? I know they say to keep each identified to their correct position. I have a sac of unsorted rocker pins and rickers I considered switching. I think they may be from a fat cam. Initially I thought I had a fat cam and skinny cam rockers. I have that sorted and am using skinny cam and skinny cam rockers/pins.

Any help would be awesome!!!
1759763513845.png1759763513845.png1759763488032.png

1759763488032.png
 
Sounds more like you might need to get that valve stem tipped. When you install new guides, the valve seats have to be re-cut for the new valves to work with the new guides, so sometimes the valve depth in the seat is deeper and the stem is too long for the adjustment range of the eccentric valve adjuster shaft.
 
Sounds obvious but I'll ask ... are you rotating the engine to the correct spot to set the valves for the left side? At the 4:30 - 5 o'clock spot there is still some pressure on the cam .... on a 350 engine there is no spot on the cam that isn't in pressure on a rocker.

I mix and match rockers, cams and everything else in my engine rebuilds without issues.
 
Boomer343 said:
Sounds obvious but I'll ask ... are you rotating the engine to the correct spot to set the valves for the left side? At the 4:30 - 5 o'clock spot there is still some pressure on the cam .... on a 350 engine there is no spot on the cam that isn't in pressure on a rocker.

I mix and match rockers, cams and everything else in my engine rebuilds without issues.
Click to expand...
Thanks Boomer - I was confused on when to set the valves to where the tick marks are pointing away from the plug. My understanding was the left needs to be a TDC or LT mark. The right needs to be at TDC or RT mark. What confused me was what point during the re-assembly should this be done. I was thinking the tick marks on the rocker pins should remain at 12:00 until after the cam chain tensioner was installed, the 2 outside cam holders tightened, and maybe even after the final top bolts were torqued. Either way - each time I tightened the 4 screws on the outside cam holder, the tick mark for the left intake became impossible to turn like the others.
 
Boomer343 said:
Sounds obvious but I'll ask ... are you rotating the engine to the correct spot to set the valves for the left side? At the 4:30 - 5 o'clock spot there is still some pressure on the cam .... on a 350 engine there is no spot on the cam that isn't in pressure on a rocker.

I mix and match rockers, cams and everything else in my engine rebuilds without issues.
Click to expand...
I appreciate the note on the rockers and pins being interchangeable. I understand that fat cams and skinny cams all have the own set specific to them.
 
ancientdad said:
Sounds more like you might need to get that valve stem tipped. When you install new guides, the valve seats have to be re-cut for the new valves to work with the new guides, so sometimes the valve depth in the seat is deeper and the stem is too long for the adjustment range of the eccentric valve adjuster shaft.
Click to expand...
I sent the heads to those guys in Houston and had them do everything. But, we all know humans can make an error. I think your solution will solve the problem. I thinking maybe I remove the valve and send to CM to see if they will double check the length. I am also wondering if I could simply file the top of the valve very carefully to lower it to allow for proper clearance.

1759769222056.png1759769222056.png
 
Tipping valves has to be done with a proper machine to do it correctly and squarely to the valve stem, you don't want to be filing them yourself. IMO you should have sent your head to Chris Schumann for the work it needed, we have zero idea who is doing the work for those guys in Houston (and I sure wouldn't want them doing it themselves) and I'd be shocked if the price was any higher to have an actual cylinder head professional do the work. I'm surprised you didn't ask about a good source for getting head and valve work done, we are happy to offer the best sources we know of.
 
spoore21 said:
Thanks Boomer - I was confused on when to set the valves to where the tick marks are pointing away from the plug. My understanding was the left needs to be a TDC or LT mark. The right needs to be at TDC or RT mark. What confused me was what point during the re-assembly should this be done. I was thinking the tick marks on the rocker pins should remain at 12:00 until after the cam chain tensioner was installed, the 2 outside cam holders tightened, and maybe even after the final top bolts were torqued. Either way - each time I tightened the 4 screws on the outside cam holder, the tick mark for the left intake became impossible to turn like the others.
Click to expand...
The key is to have the engine on T or LT on compression stroke. As you rotate the engine with the valve covers off, watch the intake valve open, then close and immediately start watching for T or LT after that intake valve closes. Then you'll be on compression stroke and both valves of the cylinder you plan to adjust should be loose.
 
spoore21 said:
Hello All,

I am in need of some expert advice. I recently had my top end rebuilt - bored the cylinder, new piston / rings, new valves, guides, and springs. I am having trouble doing re-assembly. The left intake guide is tight on the cam.

I install the rockers with the pin on the cam pointing at 4:30. I have the rocker pins tick marks all at 12:00. When I tightened the cam bearing holder screws, it becomes impossible to turn the left intake rocker pin to where the tick mark faces away from the plug. All the other rockers have some degree of play.

I have tried the following with no success. 1) Switching rocker arms and rocker pins (parts 4 and 5 circled in red below) 2) Switching the cam bearings (outside holders) 3) Switching cams.

My only other idea would be changing the cam carrier / holder assembly. I cleaned the cam carrier basket using high heat in an ultrasonic cleaner. I am wondering if that might be enough to warp the aluminum to make the hole where the rocker pin goes out of spec.




Additional question - Are the rockers and guides identical? I know they say to keep each identified to their correct position. I have a sac of unsorted rocker pins and rickers I considered switching. I think they may be from a fat cam. Initially I thought I had a fat cam and skinny cam rockers. I have that sorted and am using skinny cam and skinny cam rockers/pins.

Any help would be awesome!!!
Click to expand...
The pin on the cam should be at 12 or 6 o'clock when setting the cam timing and adjusting the valves. IIRC LT is the 12 and T is 6.
When installing the cam bearing housings one side is easy because the valves are not being opened while the other side you're fighting the valves. Slowly rotate the crankshaft until both cam lobes are facing down to install the 2nd cam bearing.
 
ancientdad said:
Tipping valves has to be done with a proper machine to do it correctly and squarely to the valve stem, you don't want to be filing them yourself. IMO you should have sent your head to Chris Schumann for the work it needed, we have zero idea who is doing the work for those guys in Houston (and I sure wouldn't want them doing it themselves) and I'd be shocked if the price was any higher to have an actual cylinder head professional do the work. I'm surprised you didn't ask about a good source for getting head and valve work done, we are happy to offer the best sources we know of.
Click to expand...
Thanks for the advice AD. I am going to reach out to the guys at those guys in Houston. They have always treated me good and stand behind their products.
 
Finally figured out what the issue was adter multiple tear downs and reassemblies. The rocker pin oring included in my aftermarket gasket was too large. It kept binding the rocker making it difficult / impossible to adjust. My original one was fine so i used it. Was able to do the critical valve adjustments properly after it was replaced. Engine runs hard and like new.
 
LongDistanceRider said:
The pin on the cam should be at 12 or 6 o'clock when setting the cam timing and adjusting the valves. IIRC LT is the 12 and T is 6.
When installing the cam bearing housings one side is easy because the valves are not being opened while the other side you're fighting the valves. Slowly rotate the crankshaft until both cam lobes are facing down to install the 2nd cam bearing.
Click to expand...
LDR... not trying to hi-jack Spoore's topic but...
Your comment makes it sound like it could possible to remove the cam bearing holders without having to remove the engine or take apart the heads on a 350.
I have a small oil leak from behind the points-side cam cover and my thoughts were to attempt to to take off that holder without taking apart the head.
I would loosen all the rockers and, once I start removing the cam holder, not rotate the engine in any way until I re-install the holder.
Does that seem feasible or am I dreaming? I really do not want to take the engine out again.
 
BHSarc said:
LDR... not trying to hi-jack Spoore's topic but...
Your comment makes it sound like it could possible to remove the cam bearing holders without having to remove the engine or take apart the heads on a 350.
I have a small oil leak from behind the points-side cam cover and my thoughts were to attempt to to take off that holder without taking apart the head.
I would loosen all the rockers and, once I start removing the cam holder, not rotate the engine in any way until I re-install the holder.
Does that seem feasible or am I dreaming? I really do not want to take the engine out again.
Click to expand...
As long as you only do one side at a time, and set things up by pulling all the valve covers and watching the rocker arms while rotating the engine to the point 90° past LT on compression stroke where all valves are closed or virtually closed (and with at least the eccentric valve adjustment shafts turned to the loosest position on the side you plan to remove, if not both sides), you should be fine. Some also pull the cam chain tensioner but if you haven't adjusted the cam chain recently, and do the above so all valves are as loose a clearance as possible, it should go smoothly. And yes, under no circumstances do you rotate the engine until both cam bearing covers are back in place.
 
A couple more thoughts: you should NOT have to use force to put the cam bearing cover back on in any way, and do NOT forget the correct gasket orientation or you will be pulling it again when oil drizzles down the head on restart. (y)
 
BHSarc said:
LDR... not trying to hi-jack Spoore's topic but...
Your comment makes it sound like it could possible to remove the cam bearing holders without having to remove the engine or take apart the heads on a 350.
I have a small oil leak from behind the points-side cam cover and my thoughts were to attempt to to take off that holder without taking apart the head.
I would loosen all the rockers and, once I start removing the cam holder, not rotate the engine in any way until I re-install the holder.
Does that seem feasible or am I dreaming? I really do not want to take the engine out again.
Click to expand...
As Tom mentions it can be done with all the precautions listed.
 
You must log in or register to reply here.
Back
Top Bottom