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DYI Valve Lapping/Grinding... Am I doing something wrong?
(whoops title should read "DIY"...)
I've went the DIY approach and am trying to get the valves to seal.
below are pics of where I'm at -
Here's My most urgent questions-
If I get down to that untouched spot (upper right corner of opening) will this seal?
The brighter spot in the upper right quad is where the grinding hasn't touched.
How's the valve? I just wanna make sure in the end these seal. again, I have time not money.
A bit about how I got to now....
I started with the lapping stick and have hit all the valves a couple times. The intake valves seal and seat great, I think they are made of aluminum or something. those were easy. The smaller exhaust valves are steel.
my arms felt like they were gonna fall off so i went to using a drill with a piece of hose. I saw someone on youtube do it this way. Seems safe and it works smooth as far as I can tell.
This phase of my van repair is the latest in a secession of never-ending fixes...
I have a threads going on how I got to this point -
No, I'm sorry but IMO I would not expect this to work. However it is true that valve seat sealing can be tested with air after the cylinder heads are installed and torqued to spec, at least in theory.
If you have a 3.9L and your valves are leaking it usually means the heads are cracked and not repairable. If that is the case you will have to replace them .
I just finished reading through your trials and tribulations with this 3.9 engine. I am dismayed that the uninformed would tell you this is is an easy fix. Its not.
A running 3.9L chrysler goes for about $150 -$250 around here depending on milage.
However before giving up on it completely I would try the solvent test. Any suitable solvent ( toluene, acetone, even 90% alcohol) should be held by the cylinder head when it is placed upside down. This may assist you in identifiying the problem areas.
This normally works rather well for me. But please be extremely careful and raed the labels etc when working with volatile solvents. I really dont wish to hear about the resulting garage/house fire.
sorry i wasn't more specific - the heads were checked for cracks. they're fine.
When I brought the heads to a machine shop the lady at the front desk talked to me like I knew what I was doing... ha
she just asked what I wanted done so i got a quote or checking for cracks, warping and the have them cleaned. She didn't speak great english. and the technicians didn't talk too much; they kinda menacingly looked at me like I had three heads... (i'm a skinny longhair after all and they were good ol' boys.. haha)
anyways I only found out later what grinding valves is and why it's important (i am learning as I go) . anyways already had the heads back when I learned to inspect them for leaks. I don't blame them. I'm still on a pretty great learning curve and went in there knowing too little too late.
had someone there asked me about it and discussed what else the heads might require I would have absolutely been on board. as it is now Im dropping another 40$ in round trip cab fare plus whatever else they charge me .... Im EFFFFING done doing it by hand... worked one for an hour plus today. It was working but so slooooowwwwwwwww.... I just can't take it!
So with that said is There ANYTHING else I should ask them on this second trip?
However before giving up on it completely I would try the solvent test. Any suitable solvent ( toluene, acetone, even 90% alcohol) should be held by the cylinder head when it is placed upside down. This may assist you in identifiying the problem areas.
This normally works rather well for me. But please be extremely careful and raed the labels etc when working with volatile solvents. I really dont wish to hear about the resulting garage/house fire.
Yup- this is what I was doing btw. I can see my problem areas. Just couldn't grind down far enough so Im giving up (something I don't do well)-
as far as solvents - I'm very used to all that but I do like hearing reminder to be careful- it's so easy to take for granted that you're working with sloshing bombs.
DYI Valve Lapping/Grinding... Am I doing something wrong?
