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Cummins NTC 350 Help

Truck Shop

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No winch out yet. Either the injector copper was leaking, liner leaking around head gasket or the simple fact that when you removed the head coolant dribbled out the water ports and landed on the piston crown.
Unless you have the heads PT'ed pressure tested it's only guessing, but more than likely it came out of the head when you removed it. If it's oil in the cooling jackets and T-stat housing more than likely it would
be a oil cooler issue. The diesel did a fine job of washing #1 cylinder.
 

BrianS11388

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I drained the radiator and the coolant was so discolored Its hard to tell what's in it. At the end of draining it all out, for a good 45 seconds its was completely brown.
 

Truck Shop

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When was the last time the coolant was changed, the fact it was brown means it was mostly water and possibly some oil.
 

DMiller

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Swapping Cummins to Cat is problematic, not much aligns from series to series so a great deal of adaptation will have to happen. Swapping from a SC to a BC1 or II is simple, stay away from Lo Flo Cooling engines as not gonna be happy with that outcome either. Agree on the coolant from pulling head, do not see any internal to liner Steaming damage but the potential of fuel in coolant can be cups/coppers too where higher pressure fuel while pulling will enter coolant, may not have coolant pressure to push water back into fuel galleries until engine off.
 

DMiller

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One less than explanatory note by Cummins, get the Block Clean and dry, get ALL the liquids out of head bolt holes, lube the head bolt threads and under the bolt heads to washers when go to reassemble but while handling the Head gaskets try to avoid hand contact to the sealant inserts or striping as the oils or just basic slop on our hands can disrupt the seal when installed. We were sloppy in the old days with injectors, essentially got the O-rings on them and then displaced the O-rings slightly to remove any roll in them, can either dip in a can of Clean oil to o-ring coverage or use a dribble nozzle and flood each o-ring with oil prior to install in the head. Gently set them into the home then take a Rubber handled hammer Handle end(CLEAN) and rapidly Shove/Pop the injector home. Does not feel right or does not pop down pull it and inspect the O-rings.

As to head bolts unless are just replacing ALL have to inspect shanks, any crusty or corroded areas or any detectable hair lines, replace those. Bad areas just above threads and just below head on bolts.
 
Last edited:

56wrench

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I had the copper tubes leak fuel into the coolant years back on my big cam 1. exchange recon heads from cummins were cheap. if you change liners, check to see if they are already .010" oversize before you order. there are some older engines that may have had the counterbores cut oversize. the .010" oversize liners were available from cummins and also the aftermarket. these engines were notorious for liner cavitation. had one with a pinhole about 1/2 way down the cyl wall. before I disturb the injector settings, I make a line with a sharpie horizontally across all the adjustment screw heads and after adjustment I can tell if the adjustment has changed by a large amount on one or more cylinders. this can help to indicate a possible follower/cam problem if the adjustment has changed significantly. this only works if the heads or rocker boxes have not been disturbed.
 

BrianS11388

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Thank you for the information on engine swaps. I've already removed one head. The head bolts were nasty. I figure itll be best to replace all of them. For now I may look into a donor cummins with fertilizing right around the corner here in the willamette valley and get the small cam fixed up and sell it.
 

Truck Shop

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Anymore and has been for several years is to machine counter bores for .020X.040 liners and if a person is going to have the block machined they may as well have the bottom
liner bores cut also for lower press fit. It will end the liner head gasket issues associated with the early blocks going all the way back. After the Big Cam IV's came the NT88 series
855 and that's when Cummins went to lower press fit liners and all engines after. None of those had counter bore/liner issues like Big Cam IV's and down. The problem is Cummins
also built Recon blocks with counter bore repair sleeves, the counter bore was cut then the repair sleeve installed, then the adjacent counter bore was cut and it cut a moon into the
repair sleeve just installed then the second repair sleeve was installed. What you had when done was a block with weak counter bores because there was no real block material left-
one counter bore repair sleeve cut into the other, Cummins came up with this idea because Cummins was short on blocks and they got so short on rebuildable blocks that some
of the Cummins Recon 855's came with new block and crank. If a block has repair sleeves removing the old liners can also pull up the repair sleeves and if that happens it's show over.
Problem is you never know when you buy a old Big Cam if it has the repair sleeves or not.

Two winch outs.
 

BrianS11388

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Its always somethin thats for sure... here in the valley we have snow and ice, I imagine its getting horrible anywhere about 500ft.
 

DMiller

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What of the third turd TS, just a friendly tug and gone? More of the mindless ones I presume!
 

RZucker

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He was able to move after using a set of singles, ramps were not sanded.
Did he put them on by himself? Funny story about chains today: I was getting fuel at Pac Pride in George and a Milky Way tanker was pulling out of the fuel island dragging a chain off his rack (JUST IN FRONT OF THE DRIVERS) so I yelled at him... He flipped me off and kept going. Have a nice day sir.
 
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