VALVE ADJUSTMENT

How do most of you adjust the valves? I have been told to do it while running or with the engine off and just at operating temperature. Thought I would ask all you guys who have done it and would know the best method. I did a compression test and had 90lbs on 5 cylinders 95lbs on 2 and 110 on 1. Seems an adjustment is in order. Thanks, Meteor

I get best settings by adjusting when the engine is hot, and running at idle. Use two feeler gages, one for correct setting and one thicker as a no-go gage.

Bob Engle

Adjusting with the engine running at idle is the best I've found, more difficult to do though. The problem I've had, is that as soon as you shut it down the rockers start to cool, and by the time I'm finished all 16, they've cooled enough to throw the adjustment off.

However, that may not be why the compression is down, that kind of spread could be due to normal wear. Did you test "wet", ie., with some oil in the cylinder, to see if there's a difference?

Keith

If I am starting an engine on a newly acquired project, I first make adjustments on the engine that is not running & just bump the starter or turn the crank to adjust all the valves. I mark each one with chalk so I know which ones are done. This insures that they are close to correct and will not bend a push-rod or break a rocker. Then I check all adjustments with the engine running.

When adjusting valve clearance on my "Straight-Eights", and if adjusting while NOT running, I also use two (2) feeler gauges ( go and no-go).

When the last one is rocking, the first can be adjusted;

when 2nd from last is rocking, then 2nd from first can be adjusted;

and so on until all 16 are adjusted.

The same method works for a 4-cylinder, at least in my experience, but there may be exceptions depending on firing order

Meteor, when I had my engine apart, I marked the flywheel every 90deg, so after I warm the engine up to operating temp., I kill the engine and start with #1 and work thru the firing order turning the engine manually 90deg after each intake and exhaust adjustment per cylinder, takes two complete revolutions and you`re done.. No oily mess.. Tom

Thanks everyone, Lots of good advice. Think I will try to adjust while running and see how it goes. No easy way to crank the engine. Like the go-no- go method. This is a great place to learn from all your experience. You guys have some really great cars.

I will let you know how I make out. Meteor

Make sure that you don't have them too tight, as that will cause the valves to burn. If during the adjustment, the engine gets a "roll" it, that's a sure fire sign that one at least is way too tight. The other point, is that a valve adjustment may or may not have any effect on the compression, if there're only off by a couple of thou it won't make a difference. If you have a lot of "clatter" then for sure it needs an adjustment.

Let us know how you make out.

Keith

What I do on the '38's is take the little cap off the relay on the top of the starter solenoid. If you push down on the top of the relay contact you can very easily and accurately "bump" the engine around to get the rocker arms in the right position for adjustment. You do not have to have the ignition on to do this.

Don

Don,

What a great and simple idea! I never would have thought of taking the cover off the starter solenoid relay. Makes perfect sense.

Pete Phillips, BCA #7338

If you adjust valves a lot, there is a special tool, looks like a 3/8 drive ratchet handle with a large knob on the top. This turns a slotted screwdriver end inside the socket. It's much easier to tighten the lock nut while the rocker arm is bouncing up and down. This is a great flea market tool to look for.

Bob Engle

Hey Don, The solenoid trick seems perfect, thanks. Bob, I just found that tool at the AACA show in Flohram Park. 2 bucks and a snap-on no less. I will check those valves as soon as I get the chance. Thanks to all, Roger

Hi. Don't have clatter, but valves are very quiet, and on downhill, lots of light back firing. I'm wondering if my valves may be too tight.

Thanks.

Bob

Hi Bob, I think that backfire is typical for these older cars. My Model A does this too, but if I enrich the mixture a little it ceases. Can't do this on my Buick, but you can increase the idle a little bit or pull your throttle out slightly. With a little more gas it will usually stop the backfiring. It will backfire more when slowing quickly from a high speed or downhill. Hope this helps. Roger

i know the book says to adjust them while idling, but how do you do that without mashing your feeler gauge?

I used 2 gauges and started out at .012 to see if any were that tight, then I worked my way up to .015

Idle the engine real low. Only a few seemed a little tight and I was able to adjust them. Roger

If the engine has many miles on it, the rocker arm may have a slight indentation where it has been wearing on the valve. 2 things happen, you get a smashed feeler gage and an incorrect valve setting (the feeler will "bridge" the wear on the rocker).

If I run into that I usually live with the slightly noisy valves rather than take up the lash by ear - that is lessen the gap until there is no noise.

One solution to that is to disassemble the rocker shaft and grind the depression out of the rocker and make it flat again, but Buick says not to do that - but I know that many do just that.

Anybody have better ideas on this?

A bit OTT, but you could have your worn rocker arms welded and ground back to spec I guess. As an aside, a wide screwdriver with a slot ground into the blade makes the adjustment easier with the car running if you don't want to spring for the flash tool!

Cheers

Grant

A bit OTT, but you could have your worn rocker arms welded and ground back to spec I guess. As an aside, a wide screwdriver with a slot ground into the blade makes the adjustment easier with the car running if you don't want to spring for the flash tool!

Cheers

Grant

Good idea, Grant!! I have never heard of that, but sounds like a no brainer.

Ben