no start after valve adjustment?
Thread Starter
Safety Car
Joined: Feb 2002
Posts: 3,726
Likes: 368
From: Montoursville Pa
no start after valve adjustment?
This weekend i atempedt ot adjust my valves. I used the procedure in the shop manual setting to one turn past zero lash on cylinders 1 and 6 when i tried it no start. I have spark, 45 psi fuel line press. one lonely pop from the exhaust. any good ideas? i have removed the dist top tom ake sure i had # 1 up and rechecked the right bank thats when I got the one pop but havent rechecked the left bank. I'll check for compression as soon as I can buy a new tester (misplaced mine )
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: no start after valve adjustment? (GusBustamanteJr)
This is the main reason why the Shop Manual procedure should be avoided.
Much too easy to make a mistake, adjust the wrong rocker. You won't know it until you button everything back up and try to fire the engine. Then when it doesn't start, or starts and runs terribly, how do you know which valve(s) it is?
I'll email you a file on how to do (re-do) it the easiest, most fool-proof way I know of.
Jake
Much too easy to make a mistake, adjust the wrong rocker. You won't know it until you button everything back up and try to fire the engine. Then when it doesn't start, or starts and runs terribly, how do you know which valve(s) it is?
I'll email you a file on how to do (re-do) it the easiest, most fool-proof way I know of.
Jake
Drifting
Joined: Jul 2001
Posts: 1,751
Likes: 1
From: Miami, FL, USA
Re: no start after valve adjustment? (JAKE)
Just put everything together, take the valve covers off, stick some cardboard in the head under the valvesprings to catch the oil. loosen them all up and start it up. Adjust them till they sound nice. I tried the other methods and with the rollers, one or two would always make a little more noise than I cared for, and taking it all apart is a hassle. Sometimes the old methods are still the best. At least for me.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Re: no start after valve adjustment? (ErnieN85)
The method in the manual is fine, I've never had a problem on any engine doing it that way, but requires an experienced touch. There's nothing better than doing it running when there's any doubt and would seem to optimize your adjustment. It can be messy, more on some engines than others. The full rollers are nice, they don't throw any oil at idle, I like that!
Drifting
Joined: Oct 1999
Posts: 1,722
Likes: 0
From: Gloucester Va
Re: no start after valve adjustment? (Corvette Kid NC)
Most people over adjust because the lifters are not pumped up. They tighten the rockers to much and you end up with the valves not closing. Also the shop book is a little off. It states to turn the push rod until it stops then tighten like 1/2 a turn more. THe tighten until it stops tunring is the problem. That's to much. I like to tighten until all the free play is out of the push rod/rocker, then tighten 1/2 to 3/4 more turns. THis has always worked well for me. Of course adjusting while the engine is running is the best.
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Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Re: no start after valve adjustment? (nobodyunknown)
On somebodies stocker I would just generally go by the book but on my LT1 I just went one half, don't even remember what the manual said. On one that was only going to be run hard, like a bracket racer, I might go just a quarter.
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Thread Starter
Safety Car
Joined: Feb 2002
Posts: 3,726
Likes: 368
From: Montoursville Pa
Re: no start after valve adjustment? (nobodyunknown)
I think i have it now it seems like the wait time after releasing the rocker is important as gthe lifter dosen't exted right away. that means if you do it fast, your always wrong! little things the book doesn't tell about. I had done this before, wasnt sure of myself that time so i must have gone slower and the lifters extended. this time i was too fast BTW I went 1/4 - 1/22 turn past the interference point and seem to have compression, I'll finish up tomorrow. thanks!
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Re: no start after valve adjustment? (ErnieN85)
Sounds like you ought to be in good shape now. Good luck.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: no start after valve adjustment? (Corvette Kid NC)
The most critical thing is NOT whether to preload the lifter 1/4, 1/2, 3/4 or 1 full turn from zero lash; it's making absolutle sure that the lifter is on the base circle (heel) of the camshaft lobe and NOT on the lobe's ramp.
Different books have different recommendations and guys who race have their favorite when it comes to lifter preload.
The guys that use the less preload, like 1/4 turn, do it because it gives them a little more top end RPM before lifter pump up. If you use too little preload, you could lose the engine when the lifter fails. The lifter plunger can continually crash against the little retainer which will cause it to fail over time.
Most of the camshaft companies, like Crane and CompCams caution about this.
For me, I follow the recommendation of the company that ground the camshaft.
Just my thoughts.
Jake
Different books have different recommendations and guys who race have their favorite when it comes to lifter preload.
The guys that use the less preload, like 1/4 turn, do it because it gives them a little more top end RPM before lifter pump up. If you use too little preload, you could lose the engine when the lifter fails. The lifter plunger can continually crash against the little retainer which will cause it to fail over time.
Most of the camshaft companies, like Crane and CompCams caution about this.
For me, I follow the recommendation of the company that ground the camshaft.
Just my thoughts.
Jake
Instructor
Joined: Dec 2003
Posts: 205
Likes: 0
From: Cupertino ca
Re: no start after valve adjustment? (JAKE)
The manual can seem pretty straight forward but alot of times i have seen it become way to tight! when i was 16 i went by the book on my camaro and it was to tight.. but it ran.. so basically loosen them up, obviosly make sure the rod is properly in its seat, tighen them till most of the lash is out, start the engine with the valve covers off and you will hear a chatter, turn the nut until the chatter or clicking noise goes away, then 3/4 of a turn.. simple... its best to do this with the engine running because the Lifters are getting oil... only problem is that you get oil everywhere... my class shop has a set of old chevy valve covers with slots cut out just over the nut.. its great for adjustment, thats why its nice to have an LT4 or any car with RR's... Tighten to 18 ft. lbs. and your done :)
