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Possible head/valve problem - Printable Version

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RE: Possible head/valve problem - Chamberpains - 10-11-2019

Don't know. It was a long block so it came fully assembled and I was 600 miles away from the shop that put it in. It wasn't until the 2nd month of getting screwed around that I took my tools on down to Tennessee and took over the guys shop to finish my truck up. By the time I got there they already had it banged up and shoved in the frame and transmission attached. I basically got it finished up and fired off after 3 days and have been pulling everything they did back apart and doing it right since.

All I know is the new serial number on the valve cover starts with an LB, it was assembled 2/17 and cummins quickserve does not recognize the number at all. The head has a serial number written with a welder so that's the give away that its a reman head. I'm probably working with a Frankenstein time bomb.


RE: Possible head/valve problem - tree98 - 10-11-2019

All I can say is wow, I've been there man. It's just a damn shame.


RE: Possible head/valve problem - Rawze - 10-11-2019

(10-11-2019 )Chamberpains Wrote:  ...
The head has a serial number written with a welder ...

I have seen a lot of certified remans. Yet to see one written by hand, they are all stamped that I have seen. - Something is fishy there for sure.


RE: Possible head/valve problem - Downthehaul - 10-13-2019

Update on that motor

Cummins redid the overhead and said I had some valves loose when I did it. Hopefully they’re right and that explains my readings on the detent. They also said number 6 valve cam has micro “spald” wear, I think that means pitting. Said that cam will need to be replaced in a while, friend of mine said just keep an ear on that one and it’ll make noise when it gets worse. I’m still gonna look at it myself to see what it’s like. It burns about a gallon of oil every 10-15k and I’ve added maybe 0.5-1 gals of coolant over the 50k I’ve had it, those numbers ain’t bad from what I can tell.


RE: Possible head/valve problem - Chamberpains - 10-13-2019

The oil consumption is pretty normal. The coolant is going somewhere. More than likely an external leak(s). Pressurize the coolant system to 20 psi and let it sit for a couple hrs. Fix all the leaks that pop up. Some take time to appear that why you let it sit pressurized. You can find coolant pressure/vacuum kits for under $100 multiple places. They come with adapters to do almost any vehicle.


RE: Possible head/valve problem - Rawze - 10-13-2019

(10-13-2019 )Downthehaul Wrote:  Update on that motor

Cummins redid the overhead and said I had some valves loose when I did it....

I find that statement rather odd. Overhead valves get tighter as the engine wears, not "looser". - I would not trust the guy as far as I could throw him if he said that to me.


RE: Possible head/valve problem - Downthehaul - 10-13-2019

I set the overhead myself before i took it to them so it’s possible i left too much clearance. They also ran it on a dyno and the numbers came out real good. Boost pressure at 100% load was about 30 every time and the h20 was well within spec.


RE: Possible head/valve problem - Rawze - 10-14-2019

Only 30 psi boost on an 871 is too low. should be about 36 or a bit more at 100% engine load an a 435st. Something is amiss there for sure.


RE: Possible head/valve problem - Downthehaul - 10-14-2019

Interesting I wonder what might cause it. They also said the truck was turned up to 475hp, which made me suspicious. I asked them if that means someone changed the ecm settings in a major way and he said only the horse power was changed, that it wouldn’t cause a noticeable change in mpg. Might that account for the boost pressure?