Problem with lash closing up

[ss3011]

Today we were running an engine on the dyno . We broke in the engine , and afterwards re-lashed the valves hot . Ran a few more pulls and decided to check the lash again , and one of the cylinders had closed up .003" . The initial valve lash was done using the Honda valve lash method which has worked well for me for many years . Has anyone else had problems like this ? These are shaft rockers , with solid flat tappets . Thanks for any help and ideas .

[Mark Yacavone]

Russ,
All new parts? I'd be curious about the valves, and where they were made.

[ss3011]

Originally Posted by Mark Yacavone

Russ,
All new parts? I'd be curious about the valves, and where they were made.

Not new parts , same Manley valves that were used last year . I was wondering if they could possibly stretch , but will need to take apart the heads to compare the valves and seats with other cylinders that did not have any lash problems .

[slick5861]

Shaft rockers do have a torque setting when checking valve lash. Had a friend this summer setting the lash at the track. He says the lash was tightening up on the intakes. As I watched him, I noticed he was really over tightening the adjustors. I borrowed him my LSM torque wrench, preset at 24 ft. lbs and problem fixed. He was shocked because he has been setting them that way for years. Just a thought.

[bykr]

What's the Honda method? Never heard of it. I always set the intake when the exhaust just starts to move and the exhaust as the intake is almost closed.

[ss3011]

Originally Posted by bykr

What's the Honda method? Never heard of it. I always set the intake when the exhaust just starts to move and the exhaust as the intake is almost closed.

Yup , That's the Honda method , Honda wrote a SAE paper on that way of lashing valves years ago , documenting the benefits .

[Ed Wright]

Originally Posted by ss3011

Yup , That's the Honda method , Honda wrote a SAE paper on that way of lashing valves years ago , documenting the benefits .

Many of us old farts set our valves that way before we ever saw a Honda.

[Ralph A Powell]

You got that right Ed still got mine I ended up with two complete kit with various adapters. Learned about them from the late Les Ritchie

[ss3011]

Originally Posted by slick5861

Shaft rockers do have a torque setting when checking valve lash. Had a friend this summer setting the lash at the track. He says the lash was tightening up on the intakes. As I watched him, I noticed he was really over tightening the adjustors. I borrowed him my LSM torque wrench, preset at 24 ft. lbs and problem fixed. He was shocked because he has been setting them that way for years. Just a thought.

These shaft rockers are Harlan Sharp which have been on this engine for the last 4 years without any problems . They are tightened by hand , but not crammed down and the final adjustment is checked after the lash adjuster is tightened . We have a lot of experience using these rockers , and never had this problem . So that is why we are asking if other folks have had this problem . BTW , why would over torqueing the adjuster nut cause the lash to close up ?

[slick5861]

I would assume over tightening distorts the adjusters causing lash movement when heated up. Harlen Sharp website calls
for 20 ft lbs on their rockers.