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Discussion Starter #1
O.K. I started having issues with the cooling system staying pressurized, even after the vehicle sat overnight. I pulled the head and sure enough, there is some leakage and it looks like it has been leaking for some time. I checked the head it is .012 from being flat. However, If I get it milled, I will be right at the minimum thickness limit (or likely slightly under the min spec) per the service manual. If I need to get the head replaced, what US sources are you guys using. Is there any feedback on the China based replacement heads?

And yes, ARP studs will be going in when I put it all back together. For those that have used ARP's in the past, what did you torque them down to?

Thanks,

Adam
 

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My uncle used an eBay Chinese head on his 4bd2t box truck, and it’s still plugging away no prob.
Sucks to hear man, especially now that it’s getting dialed in so nice.
 

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Discussion Starter #3
I cleaned the head up with some scotchbrite and stiffened up my flexible stainless ruler with some aluminum angle stock and now my head is only .003" from being flat. The machine shop will be able to true it up and get me back in business. They will also check my valves and get them to seal better. One of the things I did recently was to install some stock chevy valve springs rated at 80 lbs closing force to replace the worn double spring setup that Isuzu had. I had to machine some new retainers, but they have worked out fine so far, but when I was installing them by pressurizing the cylinder to keep the valve from falling into the piston, I was getting a fair amount of leakage on pistons 2,3 and 4 on the exhaust side. Once the head done, I should be good for 30+ lbs of boost no problem.
 

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Discussion Starter #6
Well, the head stud project seems to be a success. Vehicle is running fine at 26 lbs of boost at the moment. As others have done, two holes under injectors 2 and 3 needed about 3 mm of threads removed from the block so the stud can sit 3 mm deeper. There is a bulge on the stud which is why threads get removed from the block. For the stud that sits under the front most part of the cam shaft, I ground about 3 mm of material off of it so it did not make contact with the camshaft. Other than those mods, the studs went right in. I'm now also running 80 lb Chevy springs in place of the factory dual valve spring set up. If anybody needs some Isuzu valve springs, spring retainers or keepers, hit me up before I decide to toss them.

Thanks,

Adam
 
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