Engine: Valves

[Tennessee hillbilly]

Getting ready to adjust valves on newly rebuilt 259. How can I adjust them while eng. is warmed up without oil running down the side of the engine and onto the floor/ I had an extra set of valve covers with the tops cut out years ago but they are long gone. Any ideas. Thanks

[Mike Van Veghten]

Easy...don't !

The engine should be cold, and not running. Some claim they can "properly" adjust the rockers with the engine running, so far, I've yet to see this done, accuratly.
Cold should be the method. If you want to adjust the rockers hot, this is also fine, no problem....but again, the engine should NOT be running. The only problem with doing the adjustments hot, is you need to do one side, restart the engine so it returns to full evenly (the whole engine) hot, then go to the other side. Again, no problem with this...just takes a little longer.

Mike

[SN-60]

To: Mike Van Veghten,----------- I don't know Mike,--- I understand what You're saying, but I think the only way to really 'nail down' valve lash is to adjust with the engine thoroughly warmed up
and running at as slow an idle as possible without stalling----oily mess or not! Just My opinion. GO PATRIOTS!!

[jlmccuan]

Cut the top from a valve cover and use it for hot adjustment. Or be just as accurate and set them cold with less hassle and mess.

[Bud]

I've always adjusted valves with the engine hot and running. I have an original factory cover that was modified to keep oil in the engine and not down the side of the block. I believe I get a more accurate setting with the engine at operating temperature, though I know that there are people that will disagree with me. The shop manual specifies adjusting valves with the engine running, so that's how I do it and have not had a problem with misadjusted valves. Bud

[Tennessee hillbilly]

I agree, the shop manual says do it hot but I might try it cold first and see how it works.

[jclary]

I have done it both ways, but always felt the results were better with the engine warm and running. When doing it with the engine running, keep the idle low, expose only one bank at the time, and drape the fenders, and engine compartment as good as you can. Like any potentially messy job, the most difficult part is accumulating the courage and determination to "just do it."

Once you get into the job, it gets easier. When you are done, you will have great satisfaction knowing you did your best. Use long-handled wrenches and the long feeler gauge. I always bought a new feeler gauge for the job.

(Now for the disclaimer)This was easy for me to type because it has been so long since I have done this job...I may have forgotten the difficulty.

[55 56 PREZ 4D]

It's been discussed on the forum before to warm up the engine to operating temp, turn OFF the engine. Adjust the valves on one side, button it up on that side. Then warm the engine up again, turn the engine OFF again and adjust the valves on the other side.
Seems like a good clean way to do it.

[Tennessee hillbilly]

Thanks, sounds like a good way to do it.

[jackb]

I'm not a metallurgist, nor an engineer.....but I do know there is a change in iron and metal at different temperatures. When you're talking .001's of an inch-you should be accurate. I invite a knowledgeable metal-type to chime in.....Beyond that, I've always adjusted the lifters engine running hot and messy. I do adjust cold whenever I have an engine on the stand after rebuild or block cleaning...just because. In reality, unless you've ground the valves and tended to the seats with or without inserts and resurfaced your lifters.....you've probably not going to obtain a clean setting anyway.......

[Mike Van Veghten]

SN-60 -

Well...never paid much attention at the race track have you..?
There isn't a racer around, be it boat, motorcycle, car or aircraft...that adjusts the valves hot. I've been to all of the noted vehicle races...NONE of them run the engine till hot, then adjust the rockers...they don't even "verify" an adjustment after a warmup..!
And as for a running engine...ha...that's just a waste of time if you are going for accuracy.

At one time I adjusted my valves hot.
I did some fact-finding MANY years ago, between hot adjust and cold adjustments. This is exactly why I adjust mine cold now..! Unless you can do this lightening fast...things cool down at different rates and too quickly to be accurate.
The block, the cam, the head gaskets, the heads, the valves, the rockers, the pushrods, the rocker stands, the rocker shafts.
At least cold...everything is and REMAINS equal thru-out the entire procedure..! You can't say that when the engine is hot and not running. And don't even get me started about a running engine valve adjustment. I proved this to a friend too many years ago to worry about this trick..! It's VERY easy to misadjust a rocker with the engine running. A hydraulic combination is the ONLY rocker that should be adjusted running. At least it's somewhat fool proof in the way a hydr. system is adjusted.

So yes, absolutely, cold is the most accurate. Funny how even the Stude factory also did it this way..!? And don't try to tell me (as one did) that they went over them hot before they shipped the car...yea..that'll be the day.

Each one of you may do your adjustments the way you like. It's not my engine.. But when a new guy/girl asks how it sould be done, they at least should be given the facts, and they can then do it their own way.

Being a "Test Engineer" for a living, I somewhat understand how various mechanical things work, and I understand there are many ways of doing a given task. Doing that given task "one way" for 40 years...does not make it the correct way. It makes it that persons way..!
It's when you give each of these various methods a try (an honest try !), check all of the parameters that are part of the subject...THEN, decide...what happened with each method, and how best it suites the item being adjusted, or modified, that gives a good hint at what works best.

Mike

[kmac530]

I am not sure what manual you guys are using that says to DO it warm/hot. I have the factory Stude service manual and it gives the specs IF you are going to do it hot and running, then it gives the specs IF you are going to do it cold and NOt running.
I doubt they would give you the option if it was not acceptable to do it either way. I have never {on other brands and MC} done them hot on any motor. I probably have 10 motorcycle service manual in my computer and that many car manuals on my shop shelf in paper form, and I do not recall one that says you have to do them hot. Most if not all {other than my Stude} only give a spec for setting them cold.
Even Chevy style hydraulic lifter with ball n socket adjuster nuts used to tell you to runn the motor and tighten them till they stop ticking and then 1/4 turn......but now they have usually have a non running format to adjust before start up and done.
My reason for including motorcycles in my description here is that MOST MC are solid lifter/cam so the adjusting procedures are more similar to the Stude than say a SBC hydraulic.

As Mike stated, I have been a MX racer, MC road racer, and drag bugs as well as many off road styles as a participant and spectator and I do not recall seeing valve adjustments while running.

Cold set for me.

[Paul Keller]

An additional hint: A feeler gage w/ a two thou' (.002") GO-NO GO step is available for those who have not devoloped the "feel" for accurately using the gage. It is avail. from Speedway and some local parts stores. It also is handy to use to adjust the intake and exhaust w/ one blade - I have found this method to be much more convenient (w/ less chance of dropping the gage while switching between to diff. gages).
Paul TK

[kmac530]

Paul,
My manual shows 0.025"-0.027" when adjusting cold for BOTH In and Ex valves. Only one gauge actually needed if you do them cold, no swapping.
When I do bike motors I have 2 sets of gauges I use if they are different for In and Ex that way I do not have to fiddle with them. Or even unscrew the pinch bolt and take the 2 sizes you need out of the pack and use them loose, which is really good on a motorcycle with close quarters.

[Tennessee hillbilly]

Well I adjusted the valves cold before the engine was ever started and it fired right up and sounds good so I will leave it at that.