Valve Lash?
Thread Starter
Drifting
Joined: May 2000
Posts: 1,478
Likes: 38
From: Long Island NY
Valve Lash?
Has anyone adjusted valves while engine at op temp running? As opposed to a manual adjustment. Ive seen it done once on a small block in a boat. There are some Utube videos out there on the subject. Basically, Just want some feedback on it....
Thread Starter
Drifting
Joined: May 2000
Posts: 1,478
Likes: 38
From: Long Island NY
If you have a particular reason for wanting to do this (like a noisy rocker/lifter) and it is a stock valve train with press-in studs, good idea to eyeball or run a straight-edge across the tops of your studs, just to make sure nothing is pulling out or out of place.
Tech Contributor
Joined: Aug 1999
Posts: 14,375
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From: At my Bar drinking and wrenching in Lafayette Colorado
There is no good reason to adjust the valves with the engine running. Do you think the factory adjusted valves on the assembly line with the engine running? With hydraulic lifters, set the valves correctly with the engine off and cold. There is plenty of pre-load on the lifter to compensate for any temperature changes in the engine. If the valves clatter once warmed up, and the valves have been set cold with correct pre-load, you have other problems.
Solid lifters should be set cold with the engine not running, then checked again, with the engine hot and not running, making any minor changes needed.
No professional engine builder sets valves with the engine running.
Lars
Solid lifters should be set cold with the engine not running, then checked again, with the engine hot and not running, making any minor changes needed.
No professional engine builder sets valves with the engine running.
Lars
Pro
Joined: Jan 2016
Posts: 502
Likes: 103
From: Reno Nevada
Finding TDC for lash setting does not have to be super accurate. Just have to be within a few degrees. Use the timing marks and be sure you are on the right stroke. Put your finger over the #1 plug hole and be sure it is the compression stroke as it comes up to TDC. Once at the timing mark you are close enough for setting lash.
Race Director
Joined: May 2006
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Chassis Manual
Pull off both valve covers. Note on your distributor cap where the #1 and #6 cylinder wires are located. Remove the distributor cap. Remove all the spark plugs.
Turn the crankshaft till the rotor is pointing to the #1 cylinder wire location.
Adjust Exhaust 1,3,4,8
Adjust Intake 1,2,5,7
Rotate the engine so that rotor is pointing to the # 6 cylinder wire
Adjust Exhaust 2,5,6,7
Adjust Intake 3,4,6,8
You are adjusting for zero clearance plus 1/2 turn
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
if youre not confident in doing it right wiht the motor off theres nothing wrong with doing while running in fact makes it easy
Back it off til you hear clacking, slowly tighten til it gets quiet then do your 3/4, 1 turn etc. Pretty foolproof.
I heard somebody actually sells the valvecovers with holes already in them so you cna do it without making a mess.
If its a solid cam youll have to do it wiht the engine off
Back it off til you hear clacking, slowly tighten til it gets quiet then do your 3/4, 1 turn etc. Pretty foolproof.
I heard somebody actually sells the valvecovers with holes already in them so you cna do it without making a mess.
If its a solid cam youll have to do it wiht the engine off
Thread Starter
Drifting
Joined: May 2000
Posts: 1,478
Likes: 38
From: Long Island NY
if youre not confident in doing it right wiht the motor off theres nothing wrong with doing while running in fact makes it easy
Back it off til you hear clacking, slowly tighten til it gets quiet then do your 3/4, 1 turn etc. Pretty foolproof.
I heard somebody actually sells the valvecovers with holes already in them so you cna do it without making a mess.
If its a solid cam youll have to do it wiht the engine off
Back it off til you hear clacking, slowly tighten til it gets quiet then do your 3/4, 1 turn etc. Pretty foolproof.
I heard somebody actually sells the valvecovers with holes already in them so you cna do it without making a mess.
If its a solid cam youll have to do it wiht the engine off
I've actually made a makeshift valve cover you speak of from an old valve cover. Just cut out mid section with a dremmel tool. I'll go with the cold adjust at this point. As stated I've seen it done while engine running with good results. Melwff method sound good. Thanks.
Last edited by Vettesic; Apr 27, 2017 at 07:09 PM. Reason: Add
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Race Director
Joined: Apr 2003
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From: Tampa, Florida
There is no good reason to adjust the valves with the engine running. Do you think the factory adjusted valves on the assembly line with the engine running? With hydraulic lifters, set the valves correctly with the engine off and cold. There is plenty of pre-load on the lifter to compensate for any temperature changes in the engine. If the valves clatter once warmed up, and the valves have been set cold with correct pre-load, you have other problems.
Solid lifters should be set cold with the engine not running, then checked again, with the engine hot and not running, making any minor changes needed.
No professional engine builder sets valves with the engine running.
Lars
Solid lifters should be set cold with the engine not running, then checked again, with the engine hot and not running, making any minor changes needed.
No professional engine builder sets valves with the engine running.
Lars
I've seen 2 different write ups for setting lash cold with engine off. One method involves many turns off the crankshaft while the other only requires one. Is either sufficient?
Single turn method once #1 is at tdc:
https://www.jalopyjournal.com/forum/...valves.168345/
EDIT: skipped over melwiff post#6....
Last edited by jim2527; Apr 27, 2017 at 07:48 PM.
Pro
Joined: Jan 2016
Posts: 502
Likes: 103
From: Reno Nevada
Both are fine. Some choose to adjust each cylinder one at a time, others do the cylinders out of order. Same end result. One just takes more concentration to be sure you are adjusting the correct cylinder at the right time.
Race Director
Joined: Apr 2003
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From: Tampa, Florida
Last edited by jim2527; Apr 27, 2017 at 07:52 PM.
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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Iused Lars" write up for my LT1 motor, it works great with solid lifters, not sure about hydraulic lifters. With hydraulics I always did it with the motor running
Thread Starter
Drifting
Joined: May 2000
Posts: 1,478
Likes: 38
From: Long Island NY
If you dont have a copy of the factory Chassis manual it would be a good investment.
Pull off both valve covers. Note on your distributor cap where the #1 and #6 cylinder wires are located. Remove the distributor cap. Remove all the spark plugs.
Turn the crankshaft till the rotor is pointing to the #1 cylinder wire location.
Adjust Exhaust 1,3,4,8
Adjust Intake 1,2,5,7
Rotate the engine so that rotor is pointing to the # 6 cylinder wire
Adjust Exhaust 2,5,6,7
Adjust Intake 3,4,6,8
You are adjusting for zero clearance plus 1/2 turn
Pull off both valve covers. Note on your distributor cap where the #1 and #6 cylinder wires are located. Remove the distributor cap. Remove all the spark plugs.
Turn the crankshaft till the rotor is pointing to the #1 cylinder wire location.
Adjust Exhaust 1,3,4,8
Adjust Intake 1,2,5,7
Rotate the engine so that rotor is pointing to the # 6 cylinder wire
Adjust Exhaust 2,5,6,7
Adjust Intake 3,4,6,8
You are adjusting for zero clearance plus 1/2 turn
I was able to adjust valves this morning. Followed Melwff's procedure and with the help of Jim2527 chart it was quite easy. Did oil change and so far no tapping. Happy camper right now
Instructor
Joined: Apr 2014
Posts: 246
Likes: 143
After the cold set, we unfortunately had one still making a bit of noise. This time, using the covers, we warmed the engine close to regular temp but not so as to burn ourselves accidentally.
It went fine! No burns and most importantly, no cuts.