New valves seal well? Passed the test without even lapping?

[dsm-onster]

I dropped my valves into my head (no springs). I poured kerosene in my combustion chambers just to see how bad they are before machining.

First of all, how much kerosene should you expect to leak out over a given time interval?... I waited 2+ hours before the level of kerosene had dropped enough for me to notice! Does that mean that these valves are fairly sealed now?

I know, ideally, there should be no leakage. But come on! Do you think i should just lap these suckers? I am on a very tight budget... I don't want to pay the little bit of change to cut these valves in if it will be OK just to lap them... Also, my head was just rebuilt 2000 miles ago (PO just LOVED his timing belt and kept it for 100,000 miles!).

 

[gsxtacy]

Sounds like they are sealed.

Lapping the valves couldn't hurt though, if you have the lapping compound and the time, why wouldn't you lap them?

If your head is 2000 miles "used" all the factory or rebuilt work should still be good.

Good luck.

gsxtacy

 

[dsm-onster]

Sounds like they are sealed.

Lapping the valves couldn't hurt though, if you have the lapping compound and the time, why wouldn't you lap them?

If your head is 2000 miles "used" all the factory or rebuilt work should still be good.

Good luck.

gsxtacy

This is good to hear. I do have lapping compound. Got that before i bought the valves . Oh! i got waterbased lapping compound. Is that fine here? OR should I have gotten the oil based.

 

[gsxtacy]

I dunno. Been so long since I lapped any valves, I cannot remember if I used oil based or water?

I am headed to the shop here in a bit to freshen my 1G head, I'll check and see.

gsxtacy

 

[Big Woo]

Both will work, but the water based is what I generally use.

 

[bfdahl]

I dropped my valves into my head (no springs). I poured kerosene in my combustion chambers just to see how bad they are before machining.

First of all, how much kerosene should you expect to leak out over a given time interval?... I waited 2+ hours before the level of kerosene had dropped enough for me to notice! Does that mean that these valves are fairly sealed now?

I know, ideally, there should be no leakage. But come on! Do you think i should just lap these suckers? I am on a very tight budget... I don't want to pay the little bit of change to cut these valves in if it will be OK just to lap them... Also, my head was just rebuilt 2000 miles ago (PO just LOVED his timing belt and kept it for 100,000 miles!).

generaly, the springs should be on the head and before you do any work on the head do you leak ck first! I use ATF usually and just let it sit for a while like you did and then make a judgment call as wether to grind valves or lap them.

 

[dsm-onster]

I went ahead and bought the grease compound form Autozoo. It comes with a coarse and a fine grit. No shame in getting more detailed results here. I wonder if it had put my springs on if that would have pulled my valves even tighter to the head enough to see no leakage at all.

Using atf to check for valve leakage? wow. that stuff is thick!

 

[BISHILVR]

Kerosene is actually too thick, you should be using a light solvent. I usually use thinner or something similar. Yea, you should have the springs on to check the seal. If you just had work done 2000 miles ago I would'nt touch them if they still seal ok, since you can overdo it and mess the seats up.

 

[bullettdsm]

Lap 'em. There is not a good reason not to. Any imperfections that are in the new valves or problems that you might have with the seats (too thin a contact area, unsteady contact area etc.) you will be able to see if you read your valves and seats after you lap. This would be just standard practice to me. ATF fluid? Hmm.... to each his own. It seems a bit thick. We just used the saftey clean machine and just blew them out afterward.
MB

 

[BISHILVR]

If the valves are brand new lap them LIGHTLY with light compound. If you are using used valves that are "new" to you then I would have them ground at a machine shop unless you like doing things twice.