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96 12 Valve Crank, No Start

GLTHFJ60 said:
For the compression to be that low across the board, every single valve would have to be fucked up. That seems unlikely to me, but I guess it's possible.
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Its entirely possible pdd couldnt get the head rebuilt in a timely fashion, so they hot tanked a head and prettied it up.

There is no such thing as lapping to a point, you do it right before hand so lapping is a no brainer.
 
It's a new head. Someone on a Cummins FB group has been fighting them on a head that came with nicked valve seats. I'm trying to not speculate too much until I get it pulled again.
 
Otis said:
But it ought to pass the water test, correct?
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If the valves+seats are sealing, yes. Can (probably should) used dyed iso alcohol instead of water now that I think about it. Should permeate better.
 
I've also had good luck spraying brake cleaner into the runners and seeing if there's a leak through the valve.
 
Here's a quick update after letting it sit for the past week...

I got the head pulled and started troubleshooting. Every intake and exhaust valve leaks when tested with brake cleaner. I can also see light at the exhaust valves while shining a flashlight into the exhaust ports. Guess I'll be on the phone Monday morning to see how they choose to take care of their lack of quality control.
 
They did make it right. It turns out they had a batch with cracked valve seats and mine was one of them. I'm not sure how they didn't notice during assembly, but they shipped another new head. It's nice to hear the 12 valve clattering away again.
 
Otis said:
They did make it right. It turns out they had a batch with cracked valve seats and mine was one of them. I'm not sure how they didn't notice during assembly, but they shipped another new head. It's nice to hear the 12 valve clattering away again.
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They didn't think to mention this when your engine had way low compression when just changing the head? I hope they paid for something for you. Bad batches happen I guess, but it still sucks. A lot of wasted effort on your part just because of a bad part they sold you.
 
Yeah, I have a hard time believing the Tech guy was unaware of the issue. And, I was so shocked they had one to ship the same day I didn't even think about asking for a discount. It's water under the bridge...

Now I need to fine tune the AFC to get rid of some low end smoke, but it's running strong now. Thanks for all the help!
 
Otis said:
Compression test failed...
200
160
180
210
220
220

I'm not too happy about pulling the head. I bought it complete, machined, valves, springs, seals, and o-rings installed. I assumed they lapped the valves?

The truck ran great until I started the upgrades..
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I'm not being an ass but with 12 valaves, this is why I upgrade one part at a time.
It is a lot more tedious but it does help mitigate chasing down non-problems.
I hope you finally start enjoying you truck again.
 
I didn't intend to get this deep into it... It started as just replacing the tired HX35 with the K27, upgrading delivery valves and injectors... Figuring head studs would also be good peace of mind, I lumped them in as well. I was swapping them 1 for 1 as to not pull the head and I stripped the head bolt threads out of the block behind cylinder #6 (I guessing I didn't get the hole completely cleaned of oil and i hydrolocked the threads...)

Of course, now the head had to come off to fix the block, so I might as well upgrade the head too and here we go......... I was planning on doing the timing and AFC work later but while I was waiting for the head I chose to get more done. I'm glad it's done now, but yeah it made for a lot of variables to sort through.

I have a couple hundred miles on it so far and this weekend will be towing the 5th wheel for the first time this summer.
 
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