Another Thing On Valve Jobs

[mEl]

Gee, I'm really in trouble with John today, my transition to this style forum was seamless as I only made a couple posts on the old one before switching in 2008 when I joined. To really finish me off with John, I have .100 off my head and another we were running at .125 off on a 467 CID DC. BTW as I stated previously here I use a hand operated carbide cutter system for doing seats, you have much better control and accuracy than a rotary high speed stone can give with much less material being removed.

 

[rustred]

and so am i .

 

[John Saeli]

Gee, I'm really in trouble with John today, my transition to this style forum was seamless as I only made a couple posts on the old one before switching in 2008 when I joined. To really finish me off with John, I have .100 off my head and another we were running at .125 off on a 467 CID DC. BTW as I stated previously here I use a hand operated carbide cutter system for doing seats, you have much better control and accuracy than a rotary high speed stone can give with much less material being removed.

Twice I tried to post under CasebyCase and twice the post appeared under Jon. You are referring to what you did to your DC head. I was specific about the CASE Lanova Heads.

 

[rustred]

Pulled these heads off an 800-B. I was told it ran when parked but cannot confirm. Are these heads going to need some rework? Definitely not flush.

looks pretty rough to me. be nice to see the valve seats and valve faces with the valves out. as thats the common practice for the inspection. yes has a coolant leak and kinda crazy the gasket surface is so rough.

 

[JOCCO]

I am staying out of this one and watching from the peanut gallery!

 

[Brown David]

I've noticed.

Good, glad you're paying attention.

 

[rustred]

I am staying out of this one and watching from the peanut gallery!

i actually wonder how many posters have actually done a valve job with their own hands , just saying as experience is key. maybe that would be a good topic to zoom in on. oops, gonna be in trouble again. but thought that was the whole idea of a forum is to discuss stuff. not intimidating anyone as just always open to learn even if old and stubborn.

 

[Brown David]

i actually wonder how many posters have actually done a valve job with their own hands , just saying as experience is key. maybe that would be a good topic to zoom in on. oops, gonna be in trouble again. but thought that was the whole idea of a forum is to discuss stuff. not intimidating anyone as just always open to learn even if old and stubborn.

I've never actually done any head/valve work other than an old beater K car years ago but I know what needs to be done to ensure a good job.

I'll admit it was a hack job on the K car. It was my rusty old back and forth to work beater, it was down on power and the head gasket was leaking. Pulled the head and saw one slightly burned exhaust valve and another one burned a fair bit more.

Grabbed a junk head, pulled two valves from it, pulled the burnt valves, lathered up the used valves and the seats with grinding compound and lapped them in with a reversible drill. Got a decent looking seat on one, the other just barely seated.

Slapped it back together and drove it another year or so. Pure hack job but times were hard and had to have something to get me to work.

Never would have done it for a customer.

Other than that, I've/we've always sent them to the local engine rebuilders. And yes, they vacuum check every head.

 

[rustred]

i was kinda checking into this vacuum testing and it dont make much sense to me. with the valve springs on and a good seat and face that is a lot of pressure holding the valve closed. from what i am gathering its a new thing on these aluminium heads. what ever happened to the gas in the chamber check? with that vacuum checking u would have to seal everything , then bring your vacuum up , then close the suppy valve and watch the vacuum to see if it drops. at least that's the way i have it figured out. i asked here about the interference valve angles and got no reply to that as that is for a more positive seal, and faster seating of the valve. so i guess its these guys rushing through a valve job they need to check their work. i know done properly, you dont need any vacuum for testing your job. i give my reasons , now like to know other reasons why its a must. thats why i asked who all has hands on experience rebuilding heads .

 

[mEl]

RR, to answer your question from my end I have done more than I can count in my life as a mechanic, I always use a 1 degree interference fit. As matter of discussion, I do not see how a perfect vacuum can be attained with a vacuum test, every stem has clearance and a perfect seal at that point is impossible without positive valve stem seals which most tractor engines did not have especially the vintage we deal with.. I guess I fall into the poor valve guy category I have used a liquid to watch for seepage on a few occasions. Also, a valve and seat have to wear to each other just like other any other moving parts.

 

[DRussell]

Good, glad you're paying attention.

I also noticed that you're not changing anyone's opinion.

 

[John Saeli]

RR, to answer your question from my end I have done more than I can count in my life as a mechanic, I always use a 1 degree interference fit. As matter of discussion, I do not see how a perfect vacuum can be attained with a vacuum test, every stem has clearance and a perfect seal at that point is impossible without positive valve stem seals which most tractor engines did not have especially the vintage we deal with.. I guess I fall into the poor valve guy category I have used a liquid to watch for seepage on a few occasions. Also, a valve and seat have to wear to each other just like other any other moving parts.

You are correct about interference angle and Guide leakage. I use grease on the guide to get a seal. When I am done w/ the valve, I put the tester intake over the port I'm working on, and when I get 22 inches of vacuum I close the valve and that port I'm testing MUST hold vacuum. The Kit I have is specially designed to check Valve Jobs. Heck Mel!! Just like I offered you to watch my settling disc, you come up, I'll furnish the beer and I'll show you the procedure. Even old dogs can learn new tricks!! Like I said earlier, I tell my customers w/ Diesel heads, if the shop they are using doesn't vacuum test, go find one that does.

 

[rustred]

RR, to answer your question from my end I have done more than I can count in my life as a mechanic, I always use a 1 degree interference fit. As matter of discussion, I do not see how a perfect vacuum can be attained with a vacuum test, every stem has clearance and a perfect seal at that point is impossible without positive valve stem seals which most tractor engines did not have especially the vintage we deal with.. I guess I fall into the poor valve guy category I have used a liquid to watch for seepage on a few occasions. Also, a valve and seat have to wear to each other just like other any other moving parts.

thanks mel, i am in exactly the same poor valve guy category also. lol. makes perfect sense to me, and thats the way i was taught in class , there was no talk of vacuum testing back then, or the instructors would have been teaching it.

 

[Tgrasher]

John, I'm going today to look at my 800B head that I left with the hired help at a machine shop. I left specific instructions as per your advice on what I wanted done. When I called to see if it was done, he said "oh yeah. We ground the seats and valves". I told him that wasn't what I had asked for while I was moaning uncontrollably. I then just asked him to order some new valves so I could see what the final measurements would be, and make a decision from there. I think I'll be looking for a new shop.

 

[John Saeli]

thanks mel, i am in exactly the same poor valve guy category also. lol. makes perfect sense to me, and thats the way i was taught in class , there was no talk of vacuum testing back then, or the instructors would have been teaching it.

Hey Red!! I'm poor also, but have to keep up w/ the latest whatever!! If you discovered you had a cancer, would you go to the doc who had been practicing 50 years and never went back to school. or would you look for the doc who had been back, and back again to school and kept up on the latest cures?

 

[Brown David]

I also noticed that you're not changing anyone's opinion.

Lol, you couldn't change some people's opinion with a hammer.

Do you think I really care if anyone does anything I suggest?

I give my opinion or advice freely, any and all are just as free to use it or not, suit yourself.

 

[Brown David]

Hey Red!! I'm poor also, but have to keep up w/ the latest whatever!! If you discovered you had a cancer, would you go to the doc who had been practicing 50 years and never went back to school. or would you look for the doc who had been back, and back again to school and kept up on the latest cures?

Exactly.

 

[nick831]

That was a fun one! I actually learned quite a lot along the way about my 830 diesel. Nick