1955 12 Valve NAPCO Clone

[blackdiesel]

I must be thinking of A nv4500 slave/master as far as the bleeder goes. However bleeding any slave and master cylinder is easiest from the bottom. break the line loose if you have to to purge the air

[Luther Grimace]

Originally Posted by blackdiesel

I must be thinking of A nv4500 slave/master as far as the bleeder goes. However bleeding any slave and master cylinder is easiest from the bottom. break the line loose if you have to to purge the air

You are the man blackdiesel! That did the trick last night. Bled the clutch right out after 10 pumps or so.

Got a wild hair last night.



I'm hoping to find the #6 knock I have had since a month after I bought this. Dieselwrencher had mentioned that it could possibly be a wrist pin bushing and that is what I am hoping for.

Here is the video I promised of it running.

[blackdiesel]

Did you crack your injector lines loose to find the down cylinder before you popped the had off?
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[Luther Grimace]

Yeah the noise comes from #6 and weakens when I crack the line. There is no telling how many miles this engine has. I was told it was up in the 300-400K range but who know since it didn't have an odometer. Is it really expensive to bore these engines and put new pistons in? I am just getting freaked out about having to spend money on this truck. The number 6 piston kinda rocks side to side when you push on it. But most of the others do as well. I was just happy not to see major scarring in any of the cylinders. I wish they had liners though.

[blackdiesel]

Originally Posted by Luther Grimace

I was just happy not to see major scarring in any of the cylinders.

And that didn't scar the cylinder? Machine shop can bore that cylinder out and press in a sleeve so you can run a standard piston or just leave it over bore and run one .010 or .020 in that cylinder. (yeah yeah i know what you're thinking... It'll "throw it of balance" but this was the recommended repair procedure they told us in Cummins class for the b series)
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[blackdiesel]

A sleeved engine would be nice. But my local machine shop charges 16 per hole to bore. But if you have no scarring, check out for a taper or out-of-round condition. Look closely at the top under the carbon ring and see if you can see any evidence of a broken top compression ring. These engines have two and an oilscraper. Not uncommon to break rings. Worst case scenario, pop that piston and rod out and look the wrist pin over, however I've never had much trouble out of those. Lastly slap a p-pump on there! Haha
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[blackdiesel]

Send me a pic of the head above #6. Check it for cracks in the valve seat. Had a lot of issues with the early first Gens trashing heads 8705777488
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[Dieselwrencher]

Also keep in mind these engines have more cylinder to piston clearance when they're new compared to a gas engine. This clearance is to allow the piston to swell without the piston sticking in the bore. Around here, I can get a block o-ringed, decked, bored and cleaned for $550. Without o-ringing it'll be $300.

And on the cracks in the valve seats, just because there is a crack doesn't mean it's junk. If the valve and seat seal, you can run it a very long time. Usually the heads that are junk have long and deep cracks. IH casted heads are really bad for this. But the non IC first gens were prone to cracking more due to the 9mm hole for the nozzle to pass through.

[blackdiesel]

Originally Posted by Dieselwrencher

And on the cracks in the valve seats, just because there is a crack doesn't mean it's junk. If the valve and seat seal, you can run it a very long time. Usually the heads that are junk have long and deep cracks. IH casted heads are really bad for this. But the non IC first gens were prone to cracking more due to the 9mm hole for the nozzle to pass through.

Exactly. However we're trouble shooting a down cylinder so gotta look @ all options!

Good price on the block work w/rings btw...

[Dieselwrencher]

Originally Posted by blackdiesel

Exactly. However we're trouble shooting a down cylinder so gotta look @ all options!

Good price on the block work w/rings btw...

I totally agree. I have a really good machine shop for the 5.9's. Technically this cylinder isn't dead, it's hitting and when it's hitting it's knocking. Since he's already ruled out injectors and rod and main bearings, the last piece to the equation is the wrist pin and bushing. If it were a valve it would be losing compression. Bla bla I have seen bad injectors create a knocking situation, but the noise doesn't go away. (Stuck pintle wasn't a cool find)

Luther, you get that rod/piston out yet?

[Luther Grimace]

Sorry if I have been a bit disconnected guys. It has been a hectic last couple of days at work. I managed to pull the pan and get the rod and piston out tonight and sadly this is what I found.




What are my options here? I checked on some machine work but I don't know if it wouldn't be better to just swap out the long blocks. I found a P-pump long block for $550 that had 250K on it. I'm almost thinking I should do that compared to machining this block. This is a major road block for me budget wise.

[blackdiesel]

I'm sure I've even got a good std piston laying around id give ya if you sleeve it
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[Luther Grimace]

It did scar the cylinder but it was down low in the bore and didn't see it til I got the piston out. I have heard that is a recommended repair. I guess because the mass is the same? If I just get one bored I guess I will still have to strip the block down completely for machine work? I just wonder what the cost would be compared to me buying a used long block. The machine shop I talked said 380 to clean, bore, hone, and install cam bearings and freeze plugs which seems high. I'm sure if I just bored 1 hole it would be considerably cheaper.
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[blackdiesel]

Like i said my machine shop is 16 per hole to bore. Personally since it could easily have half a million miles on it and the history is unknown, id freshen them all up but i have gotten by with much less in the past.
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[Dieselwrencher]

Don't let the machine shop bs you. There is only one cam bearing in the block and it is behind the gear housing. $550 for a long block isn't a bad price. Does it have the fuel system? Let's see a pic of the cylinder wall. If you can get all the aluminum off the wall, you might be able to hone it out and run it to save money. I've got a couple of non ic pistons. If you want send me your injectors and I'll have my brother check them while it's apart.
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[6BT 56]

Hi Luther

Crummy abt the # 6. I like what diesel wrencher said . Maby just give it a hone, get a std piston and run the old girl. I worked with a engine builder quite a few years ago and the boss always said there is nothing wrong with patching sumtin up to get going . Just dont mix parts. Ie if your running old , run old. just dont go mixing new and old and expect it to run like it's all new.

Hopefully this dosent set you bak too much as you have been doing real good.

[Luther Grimace]

I don't think it does have the fuel system. No injection pump, manifold or turbo either. Would I run into any trouble running a p pump long block with the VE pump? I will get some pics of that bore and post em. Could they bore just #6 without me having to disassemble the whole engine?
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[Dieselwrencher]

Originally Posted by Luther Grimace

I don't think it does have the fuel system. No injection pump, manifold or turbo either. Would I run into any trouble running a p pump long block with the VE pump? I will get some pics of that bore and post em. Could they bore just #6 without me having to disassemble the whole engine?
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No real trouble. You will have to pull the cam and swap gear housings. Your nozzles are 9mm and P-pump are 7mm so you will need to run adapters and they are kind of expensive now. The pistons on the p-pump engines have smaller bowls, so you'll have to becareful with timing and such to make sure you aren't spraying out of the bowl. On machining, I really don't like boring one hole. It just makes them that much more out of balance. You will need to pull the entire engine down. The reason is, metal shavings are going to get everywhere when they cut that cylinder wall. I don't know about you, but I don't want metal shavings near any of my engine components. However, you can have a sleeve installed, aquire a good used piston, and then get new rings and you are on to a cheap over haul. A good machine shop will bore/hone a block to fit the pistons you're running. That being said, he can match closely the piston to wall clearances on the other 5 so 6 will be close.

[Luther Grimace]

Originally Posted by Dieselwrencher

No real trouble. You will have to pull the cam and swap gear housings. Your nozzles are 9mm and P-pump are 7mm so you will need to run adapters and they are kind of expensive now. The pistons on the p-pump engines have smaller bowls, so you'll have to becareful with timing and such to make sure you aren't spraying out of the bowl. On machining, I really don't like boring one hole. It just makes them that much more out of balance. You will need to pull the entire engine down. The reason is, metal shavings are going to get everywhere when they cut that cylinder wall. I don't know about you, but I don't want metal shavings near any of my engine components. However, you can have a sleeve installed, aquire a good used piston, and then get new rings and you are on to a cheap over haul. A good machine shop will bore/hone a block to fit the pistons you're running. That being said, he can match closely the piston to wall clearances on the other 5 so 6 will be close.

Are you sure I have 9mm injectors? I thought intercooled trucks had the 7mm tips like the late models? I am very tempted to just get that long block. I have heard that you should swap cams, saying that I should stick the ve pump cam in the p pump engine. It's just comparing getting that one or machining mine and sleeving it which would prolly run me a lot too by the time I get all the gaskets also. And where do you get new head bolts from?
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[Dieselwrencher]

Originally Posted by Luther Grimace

Are you sure I have 9mm injectors? I thought intercooled trucks had the 7mm tips like the late models? I am very tempted to just get that long block. I have heard that you should swap cams, saying that I should stick the ve pump cam in the p pump engine. It's just comparing getting that one or machining mine and sleeving it which would prolly run me a lot too by the time I get all the gaskets also. And where do you get new head bolts from?
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Yep, yours should be 7mm. I thought for some dumb reason yours was a non IC. I've heard the VE engines have a better cam profile, but I've also heard they brake easier due to the smaller size behind the front journal. I haven't broken one, but know some guys that P-pumped their VE that did turning 4k in a puller. Since you have it out, if all of your tappets and lobes look good, I'd go ahead and use your cam. It can't hurt. If you want a price on any cummins parts, PM me and I'll get you a price on them.

[6BT 56]

Hi Luther.

Anything to report? How you maken out on the eng issue ?

[Luther Grimace]

Nothing to report. I'm waiting on some parts prices right now and just letting it fester. These old Cummins sure are expensive to repair. I am leaning more towards finding another engine because I feel like I would come out ahead if I did. My crank seems to have too much thrust from a life with a bad thrust bearing. By the time I buy a head gasket kit, head bolts, and piston with rings I will prolly be into it pretty seriously at price.

[RANDY COX]

awesome build I like the truck...and the panel..

[Luther Grimace]

Thanks Randy!

[6BT 56]

Have you thought any more abt just giving it a hone and a used piston and bolting it back together? I know it half assed and may not last forever but it would be running so you could get all the other bugs associated with this big of a build worked out . Then you can find a newer or better eng later . In the vids of the dodge off road it did seem to run ok even if it was noisey.