Cracked valve seats

DISTURBED

DISTURBED

YEA WE RIDE THE SHORT BUS
Joined
Nov 22, 2007
Messages
6,417
So everybody is saying there isnt enough tech stuff on the site in the recent months, so here ya go a tech question.


So i had a customer bring a head to me yesterday and it still had the valves in the head. So i proceeded to take the valves out. He wants it decked, fire ringed, valve job and new springs put in it. So i get the valves out and each seat has atleast 6 cracks in it so the head is junk in its current state but he wants to use it because of money. So the question.

At what point would you draw the line on doing a head if the seats are cracked? Would you have new seats put in it, would you try and find another used head all the while knowing that a stock head will be more then likely be cracked also or would you just go ahead and use the one you have. So like i said what would you do and at what point would you just say its to far gone
 
wow spend all the money for things he DOESNT need but not what he DOES need. Id do what he asked and make sure his invoice clearly says AS IS no warranty obviously after you advise him to replace it and mark that on invoice also.
 
Well its in a slightly modded puller so he does kinda need that stuff but your right not real logical.
 
How bad are the cracks? I have asked the sane thing. I have very small cracks. But until you remove the seat you don't know the extent of the damage. My engine builder is gonna remove the seats and go to an oversized seat. We will machine all the "problem" seats and make sure the crack is just starting or not in the head at all. Just the seat. I bought three bare heads. One with 70k, one with 90k and one with unknown mileage. The mystery head is the cleanest strangely enough


---
- Sent from my iPhone using Tapatalk while pulling a 36ft gooseneck and not paying attention to the road.
 
if it were me, i'd tell him i wouldn't do the work. it'll just come back on you & bite you in the butt.
just an opinion, ed
 
I have a head that has a crack in the deck between the valves in each cylinder but they look to be just in the deck. It holds water pressure and really isn't anything serious but what you have is a complete other story. I would tell him to start looking for a new one. Once the head is decked and a valve job is done it will only be a matter of time before the cracks do the head in. Decking the head will take away a lot of the reinforcing thats probably keeping the cracks shallow. Same thing with the valve job. thats my $.02
 
DISTURBED said:
. So like i said what would you do and at what point would you just say its to far gone
Click to expand...

I would pull the seats and have the head magnafluxed. If you find no cracks in the head itself I would reuse the head, installing new seats (larger) and manufactured to withstand higher temps.
 
As long as it's not leaking coolant I would run it. I put a brand new non reman cummins head on the other puller and when we had to fix a hg problem it had cracks in it too. It's a puller, it's gonna get hot. Just run that sob.
 
I've seen quite a few 12v Cummins engines that run for years with cracked valve seats. Assuming it is a 12v head and as long as it's not leaking coolant, I would give him the option to patch it up but warn him of what may happen and offer him an alternative. Never offer a warranty on high performance engine parts. If warranty is a big deal, genuine Cummins parts come with that!
 
Last edited:
diesel_importer said:
which cummins heads have pressed in valve seats?
Click to expand...

I know in the 2002's the auto trucks do not and the stick trucks do. I think the pressed in valve seats protect the head from cracking. My first head did not have the pressed in seats. When magnafluxed we found 50 different cracks around all the exhaust valves. My replacement head has the pressed in seats. I took the head off because I dropped a seat (not cool). The seats were pulled and the head magnafluxed, no cracks found.
 
Warpig said:
I know in the 2002's the auto trucks do not and the stick trucks do. I think the pressed in valve seats protect the head from cracking. My first head did not have the pressed in seats. When magnafluxed we found 50 different cracks around all the exhaust valves. My replacement head has the pressed in seats. I took the head off because I dropped a seat (not cool). The seats were pulled and the head magnafluxed, no cracks found.
Click to expand...

This is what I'm hoping for on my three heads. We remove the seats and the head is in perfect shape.

Anyone have an idea what a machine shop is gonna charge for removing the seats and installing new ones?
 
jkidd_39 said:
This is what I'm hoping for on my three heads. We remove the seats and the head is in perfect shape.

Anyone have an idea what a machine shop is gonna charge for removing the seats and installing new ones?
Click to expand...

I paid around 700 to have head disassembled, magnafluxed, seats removed, new seats, new valves and reassembly. The machine shop also requested a cam card.
 
Warpig said:
I paid around 700 to have head disassembled, magnafluxed, seats removed, new seats, new valves and reassembly. The machine shop also requested a cam card.
Click to expand...

Cam card?? Wth is that?


---
- Sent from my iPhone using Tapatalk while pulling a 36ft gooseneck and not paying attention to the road.
 
Warpig said:
I know in the 2002's the auto trucks do not and the stick trucks do. I think the pressed in valve seats protect the head from cracking. My first head did not have the pressed in seats. When magnafluxed we found 50 different cracks around all the exhaust valves. My replacement head has the pressed in seats. I took the head off because I dropped a seat (not cool). The seats were pulled and the head magnafluxed, no cracks found.
Click to expand...

I have an 02 manual truck and it didnt have pressed in seats...
 
Ive got an 01 stick truck and it has the press in seats, it dropped one last fall. I have since put a head on it off a 2000 stick truck that did not have press in seats.


I have talked him into a new head but i like the insight you guys have so continue on with the discussion
 
When I had to pull my head off when my top charger blew up, we took out the valves and I had small hair line cracks in a few of the seats.

Took the head up to enterprise and they check it out and said it should be good to go. And its been fine.
 
Mine has the same problem right now. I'm curious if I should just run it. I mean how long have those cracks been in there? As far as I know, they could have been in there for the last 100,000 miles without issue.
 
You must log in or register to reply here.
Back
Top