Thread: Valve "holding" tool using compressed air, need help

Tweet

OK, I bought one of those hose valves that screws into the spark plug port to hold the valve closed so I can change my valve springs.

The problem is that when I hook it up, there is obvious excess air (minor, when I remove the hose, it takes a second to bleed down) bleeding off from the combustion chamber. The engine has not been running in over a month and I believe the oil in the cylinder walls has drained off, leaving no ability for compression.

When I do have pressure applied (with a small leak, not big), and try to compress the spring, the valve goes with it, and huge amount of air comes in through the open valve.

What am I doing wrong? How do I hold the valve properly using this tool? Maybe just the retainers are sticking to the valve? I don't want to remove the heads if I don't have to, I am confident the valve seals are good and that is not the issue.

Thanks Denny!

Is it normal to have some air leakage?

Also, where do I buy one of those tools to turn the crank to turn over the engine without using the bolt. All 4 auto parts stores I tried today did not have one.

You want to make sure you have the piston at the top on compression stroke. Reason ? If the air seal breaks loose, the valve will drop.

You got that right!!!

Don't ask how I know, it still haunts me, even 35 years later!!

Compressing the spring, pull the retainers and the line from the compressor ruptures.

Thonk ,,, valve disappears into the abyss.

Valuable lesson for a 16 year old...

I tried the other day and I'm still having one hell of a time. When I rotated the engine so that the piston below the valves I was working on was at the top, the compressed air pushed it back down!

I don't want to pound on the locks, so until now, I have been unsuccessful. It doesn't help that the springs are crazy-stiff.

My next try is to enlist some help from a neighbor to pull on the bar, while I tap in the lock. If that does not work, I will get another type of tool which compresses the spring itself (not against the head using the stud).

a guy told me the other day they use to use rope in the cylinder filled up through the spark plug hole then as the piston is moved up the rope holds the valves and you dont need air just remember to leave some rope tied on the outside so you can get it out when the job is done

Thanks Denny a bunch.

I tried to use the Lisle brand spring compressor, but it slid of the springs very easily and simply did not work. Could you post a link or two to the type of spring compress tool you might suggest for me? Thanks again.

Denny (or anyone else), I was not planning to replace the valve guides, or the valve stem seals. Is this somethig I should do? I know the cost for parts, but don't know if I need any special tools and how hard it is.

I'm wondering if I should do this or not. Especially since I know a few of the valves/lifter/rockers were getting banged pretty hard.

Thanks in advance

Is this what you mean (between the spring itself or on the head between 2 springs?).

Those springs look like triple springs to me (but I don't know much about valve springs). Instead of remving the inner spring like Lunati suggested, I just decided to buy and install the correct springs for my cam (100lb seat pressure) and remove these. I will say they are a bitch to compress.

Anyhow, let me know what you see. As always, thanks!

That's a double spring with a damper between them.

Just a bit of pertinent info.....If your engine uses 14mm plugs like Chevy, Mopar, etc., you can use a standard air hose end and just thread it in the hole. No adapters needed.

Originally Posted by DennyW

Sure is Henry. Should be pretty stable for higher rpm's.

Yeah, and pounds the heck out of your valvetrain. No thanks.

Originally Posted by DennyW

Not sure what you mean by: ((Yeah, and pounds the heck out of your valvetrain. No thanks.))

The seat pressure on these springs is 150+ lbs (don't recall the exact number) as they come on the Holley heads. Stock I believe is much lower. Therefore it is my feeling (wrong maybe) that the excess force puts added stress on the valvetrain components. Specifically increased friction and force on the pushrod, increased force on the lifters, and on the cam lobs, and increased force on the valves seating.

I don't like having all that extra stress compared to stock. Correct me here if I am wrong.

Originally Posted by DennyW

OK, so what is your goal ? To install springs with less pressure ?

Yes my goal is to install lighter springs. I was told by Lunati (correctly (I feel) that if I used these high force valve springs with these new lifters and this new cam, the cam and lifters will be toast.

I want to use hardware (springs) that are what I need for my purpose, not more. I don't want unecessary pressure and potential wear that goes with the unecessary force.

If more were better, all cars would have huge seat load springs. But they don't for good reasons. What reasons I don't know, but I'm guessing on those.

Thanks for all your help Denny, I'll repost when I do the work and let you know how it ends up.

Denny, could you look and see if I'm doing this correct:

The cylinder is at TDC (#1), no air compression, and the tool is being used to compress the spring.

The problem is that the locks are still holding tight, there is nothing to push back up on the valve. I am about ready to do the rope because that will hold the valve tight while I push down on the spring, helping to release the locks. I did push down on the system (with the spring compressed) and tapped on the top cap, but nothing released (or even close).


BTW - I did get a remote starter because I could use that for so many uses other than just this.

Thanks again Denny.

I am planning to re-use the retainer (top plate) and locks assuming they look good. OK or not OK?