Pablo

iTrader: (1)

..... with the engine together and in the car


I am changing my valve springs and am using compressed air so I had to remove my headers. Before I started I did a compression test and everything seemed pretty good, 2,4,6,8 were all around low 180s with the exeption of 4 which was at 175 which I thought was acceptable. 1,3,5,7 were all at 190 pretty much even. I figured that head was milled slightly more.

Anyway I start changing the springs, all is well till I get to #4 and im getting a ton of air shooting past the valve, I think a few expletives and wonder what can I do. Then out of desperation I think "Maybe I can chuck it into a drill and lap it with it all together" I stick my finger in the exhaust port and feel one spot where air is leaking past i figure the seat has a nick or something.

I try spinning it as is, dont think I really improved much, with the valve spun in one direction the leaking stops but once it gets back to a certain angle it leaks again. I consult an old sage at the shop Im working out of and he says its gonna need compound to do anything. So i get some, take off the compressed air with the valve chucked and put some lapping compound on my finger and start sticking it in the exhaust port on the valve and the seat area. I then proceed to lap the valve.

I reattached the compressed air and whoa its leaking a ****load now.. so I spin it on the seat again thinking its the lapping compound wedged between the valve and seat and sure enough it was

I spun it a couple of times and total silence, it seems as though it completely sealed, I spun it to different angles and all signs of a leak seem to be gone.

Anyone ever done this or heard of this done? What are the odds I was actually successful?

I thought this was the Zenith of shade tree mechanics, the guys at the shop said it wouldnt work and when it stopped leaking insisted there was no way it coulda worked.. whaddya think?

desperation has you come up with some silly ideas hehe

GTA matt

iTrader: (1)

yeah, definitely wouldn't want to put any valve lapping compound inside of my motor, but thats just me.

Pablo

iTrader: (1)

erm, on the exhaust valve seat? Do you realize whats going to happen to that compound the instant the engine fires? Or basically what happened when i hooked up the compressed air?

or are you just reacting negatively because its different

GTA matt

iTrader: (1)

no nothing negative against you. it seems like a good idea if it worked. its just that every head that i have lapped the valves on i have been sure to clean it out in a parts washer.

Pablo

iTrader: (1)

Sure, but its not like the compound is going into the oil, its gonna get shot out of the exhaust port instantly, and I sprayed a little lube down there so its definately not going to stick around.

And im not passing this off as an alternative to a good valve job or lapping the valves "correctly" just a "get me by" fix so i dont have to pull the head.

Of course If i had the option i would rather get another valve job on that seat which i did about 10k miles ago when i got a 3 angle and a back cut.

Frankly, i would never lap valves with the head off the car thats pretty shadetree considering how cheap valvejobs are, but thats just me.

Streetiron85

It's not exactly kosher, but desperate times call for desperate measures.
I think it's a matter of luck, whether any compound fell into the cyl or not.
And then too, it's a question of whether any compound that might have fallen into the cyl would do more damage than a burnt valve.
And you have to factor in how expendable the engine is as well.
And what the cost of repair is, including down time.

Basically... you rolled the dice, and if you win you saved yourself some $$.

Pablo

iTrader: (1)

exactly, its a cheapo 305 I could duplicate for 600 bux.


Im not too concerned about compound having fallen into the cyl, i used a tiny amount and im pretty darn sure worst case scenario if it fell on the piston it would get expelled instantly.

Streetiron85

And if you lost, you probably won't find out til next year anyhow.

eric17422001

I think it'll work just fine- have you ever heard of Red Green?

Pablo

iTrader: (1)

No is that a guy? The name has a shadetree jingle to it, like a guy named that would do such a thing or hone a cyl from the oil pan side with the engine in the car lol

eric17422001

Red green is this Canadian comedian who used to have a show our local public tv station carried and he showed viewers how to make a Zamboni out of a "K" car (Plymouth Reliant/Dodge Airies) using tools like a sledgehammer and duct tape. Or add a sunroof to your van using an old aquarium,(and duct tape) but to borrow someone else's van to try it first in case it didn't turn out. I have a coffee cup with his quote of "If the women don't find you handsome, they should at least find you handy"

Anyway, I'm about to toss some 081's on my 350 in place of the 882's and I'm just going to hose 'em off with some brake kleen and lap the valves in with clover.

88 350 tpi formula

iTrader: (9)

I think what you did is fine. it is funny how alot of people on here like to say "I wouldn't want that in my eng." or similar things. I would just ignore the responce.

I agree that you were not out anything trying that. if the fix lasts great. if not well now you know

meangene83

I commend you on your ingenuity!! Sometimes things aren't worth what it costs in time, money, and effort to do it the right way, so you do it the easy way.