Can you adjust lash with solid cam while engine is running?
06-01-2010, 12:58 PM
#5
You actually can. Seen it done. Bill "Grumpy" Jenkins used to set his that way.
It was on his big block '67 or '68 Camaro. Couldn't believe it first time I watched him do it. Crane roller rockers and a stud girdle. There were no Jessel or TRD rockers then. Those guys were still kids racing their own cars then. <G> I've never seen anyone else do it. It was at the 1967 (or '68?) NHRA World Finals here in Tulsa. I had to go get a witness before he buttoned it back up, nobody would have believed me if I had just told it with no witness.
Personally, I set mine warm, then find which feeler blades check correctly cold, so I can set them correctly when I put it back together. Actually, I don't even set mine warm anymore.
It was on his big block '67 or '68 Camaro. Couldn't believe it first time I watched him do it. Crane roller rockers and a stud girdle. There were no Jessel or TRD rockers then. Those guys were still kids racing their own cars then. <G> I've never seen anyone else do it. It was at the 1967 (or '68?) NHRA World Finals here in Tulsa. I had to go get a witness before he buttoned it back up, nobody would have believed me if I had just told it with no witness.
Personally, I set mine warm, then find which feeler blades check correctly cold, so I can set them correctly when I put it back together. Actually, I don't even set mine warm anymore.
Last edited by Ed Wright; 06-01-2010 at 01:05 PM.
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06-01-2010, 01:16 PM
#8
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Of course the feeler goes up and down, but that doesn't stop it from sliding in and out at the same time.
You just slide it in there (carefully, spring pinch HURTS!) like you would with it off. Takes a little messing around to get the feeler in, but it'll go. The one downside is that 2 or 3 times around the valves and you'll need a new set of feelers.
You just slide it in there (carefully, spring pinch HURTS!) like you would with it off. Takes a little messing around to get the feeler in, but it'll go. The one downside is that 2 or 3 times around the valves and you'll need a new set of feelers.
06-01-2010, 01:29 PM
#9
You just slide it in there (carefully, spring pinch HURTS!) like you would with it off. Takes a little messing around to get the feeler in, but it'll go. The one downside is that 2 or 3 times around the valves and you'll need a new set of feelers.
06-01-2010, 01:47 PM
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06-01-2010, 02:48 PM
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One can adjust them either way but the question REALLY is What Is the Recommended Way.
Just because someone comes up with some unorthodox, generally not recommended procedure doesn't mean it's the one to use. There never seems to be a shortage of convoluted, "one-off" ways of doing things.
Engine OFF but at normal operating temperature is what you'll see most often recommended and is the procedure I used over the years.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Just because someone comes up with some unorthodox, generally not recommended procedure doesn't mean it's the one to use. There never seems to be a shortage of convoluted, "one-off" ways of doing things.
Engine OFF but at normal operating temperature is what you'll see most often recommended and is the procedure I used over the years.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
06-01-2010, 03:09 PM
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06-01-2010, 03:25 PM
#16
As to the original question you are 100% right. You CAN do all kinds of things.
06-01-2010, 03:47 PM
#19
Setting Jessel's on an engine that idles at 1400 RPM (as mine does) would be fun. Imagine sticking that little allen wrench in the adjuster at that speed?
Some of the sharpest racers in the country (NHRA Pro Stock) sets them with the engine off. Most set the Intake with the Exhaust rocker near full lift, the Exhaust with the Intake just starting to close. Exactly where depends on the lobe profile and lobe centers. Find the loosest spot, not hard to do. I know of no competitive engine builder/racer that sets them running anymore. With the old stud mounted roller rockers the adjuster doesn't move. That would be easier. The self centering LT1 rockers would kill the feeler blades right off. You would need narrower than normal blades. What would be the point?
Bill Jenkins was bumping the engine over to set the valves last time I saw him with one of his pro Stock engines, a couple of years ago.
Some of the sharpest racers in the country (NHRA Pro Stock) sets them with the engine off. Most set the Intake with the Exhaust rocker near full lift, the Exhaust with the Intake just starting to close. Exactly where depends on the lobe profile and lobe centers. Find the loosest spot, not hard to do. I know of no competitive engine builder/racer that sets them running anymore. With the old stud mounted roller rockers the adjuster doesn't move. That would be easier. The self centering LT1 rockers would kill the feeler blades right off. You would need narrower than normal blades. What would be the point?
Bill Jenkins was bumping the engine over to set the valves last time I saw him with one of his pro Stock engines, a couple of years ago.
06-01-2010, 03:50 PM
#20
Intake and exhaust don't change the same amount. Aluminium heads get taller, loosening the lash. However, the exhaust valves grow in length more than the intakes (they run hotter), thus the intake lash changes more than the exaust from hot to cold.