Dr. Evil

the bottom ends are tough for sure. Thanks Mike.

Mike Holmen

Does your truck smoke whitish color of smoke? How much cooltant you losing? Replacing just a head gasket isn't that difficult. I would at least pressurize the cylinders with shop air and see what you get. It may not be good but the good thing is 12v stuff is cheaper than 24v stuff. I've must had 10-12 heads that been cracked, I'm almost at the point of buying 100% new, forget trying to find a good useable core. Some guys don't care if the head is cracked and just keep driving them. I just bought a new china head complete with 60# springs. So far its looking good. Curious to see what the valve shops says about the valves finish and the seats quality.

Dr. Evil

Dont know - I havent even started it since I noticed it.

nickg

agreed Mike, it will still "smoke" even with grids, I guess I should have explained better, I use the grids to get it started, normally they should cycle after start up, but because mine are disconnected from the PCM, the engine will start to hammer and smoke heavily, soon as I reach down and hit the grid button the engine quiets down and the stinky smoke lessens by at least 80% then after 30sec to a min the noise and smoke start again.

I should have explained better, if you smell coolant out the tail pipe its burning it, some times "steam/smoke" can appear as if your burning coolant. And that can be quite decieving

it would be rare to see burning coolant(exhaust) and a external leak unless the leak is dripping on to a hot exhaust.

in the extreme cold weather we had lately its normal on alot of veh to spring a small seep/leak and as soon as it runs for a minuit it seals up (ford rads for example)

usually as mentioned above a head gasket can leak coolant into the oil, this usually produces no smoke out the tail pipe, just turns the oil into a gery/white milkshake, it acts like sandpaper and strips the bearings of their material.

it can also leak externally, and it may or may not burn the coolant, typically an engine burning coolant does not hydrolock while running (very rare, especially if you just started up the engine) it will usually hydrolock after you shut it off and the cyl fills up with coolant, and the next time you start up it "locks up" it may or may not bed rods. you would have to have abused the engine temp wise or driven it for a long time(extreme overheating abuse) to have it lock up while running

most of my automotive experience as not been on the cummins engine, but I doubt its much different than any other engine I've worked on. except I gotta say theses engines are so much more robust.


my headgasket sprung an external leak at the rear of the head, Back in March,(32,000kms ago) I re-torqued the head. and have driven it all the way to california and back hauling my 5thwheel, it has not leaked a drop since. not bad for a hi-mileage engine on the orginal gasket, I'm sure one day I will have to do it, when that day happens I'll likely freshen it up with rings and bearings as well.


Congrats on the new addition to the family, hopefully you get more sleep, it does get better as they get older, mine was a early riser, took a bit to fiqure him out and get him on a better schedule, in my son's case if you put him to bed earlier he'd sleep longer(after he was a yr old) go fiqure.

Dr. Evil

As usual, great info Nick. Thanks.

Mike Holmen

Shane, I just found that my injector return line is bent-up and I missed placed my pieces to support P7100 pump.

I was going thru my pieces for my 12V build-up. I thought that stored the injector lines properely. I hate having stuff apart way to long.

Question is can you just rig up you're own return lines? Its low pressure stuff right.

Dr. Evil

I started the truck finally today. After a bit, idled it at ~1400 rpm just like before. I couldnt recreate the problem. There was no coolant leak, nothing coming out the tailpipe other than a bit of black smoke (like it should be doing), no white smoke either (which i would assume would be present with a leaking head gasket).

I should also mention that I had a coolant leak (lost probably 1L+) before. I was also high idleing the truck and it was quite cold out. I would think that time, that the coolant was coming out the overflow (due to the amount) but couldnt confirm it.

So, I really dont know know whats going on here. I guess that could have been raw fuel coming out of the tailpipe. It was dark, so of course, it was hard to tell.

Im kind of at a loss here. These beasts run so much better in hot weather.

Dr. Evil

Return to tank?

Mike Holmen

The smaller line coming off the side of the injector, goes back to the filter on the 12v. The high pressure line goes to the top of the injector.

I'm going to see if I can still get the return line from cummins.

Bankdude

Could it possibly have been snow in the exhaust that melted and poured out the tailpipe? Just a thought.

ccmckee

No it doesn't Mike it just goes back to the tank. have replaced all of my lines from the tank to the filter and from the return to the tank with diesel rated rubber.I eliminated the switch from rubber to steel to rubber.

Tate

The injector return lines go back to the inlet banjo on the fuel filter housing, so it is seeing pressure. I doubt having pressure there is critical, because AFAIK, 1st gen injector return connects to the IP return back to tank. Hardest part would be finding fittings that fit the injector bodies. Not sure if 6mm to -4 JIC exist.

1-5-3-6-2-4

I think my injector return joins a tee and goes back to tank...... not 100% sure though.

but 6mm to -4jic should be an availiable fitting. theres no real jump in size there. When I put -8 fuel line through out my 24v. the metric jump size didn't exist to 1/2" Ability hose made the fittings for me on their lathe and silver soldered them. done deal. they can make any fitting you can dream up.

Tate

The actual availability of fittings is what I would be concerned with. A phone call should clear that up.

I know for sure my injector return connects back to the fuel filter. I had to take it off every time I retorqued my head studs.

Mike Holmen

I couldn't remember exactly if it connected to the filter or not. See a few different designs, so I wasn't 100% sure. I'm going to look into a factory drain line, just to keep everything stockish.

As for fittings, I don't think it would be to bad to find 6mm fittings, just probably will not be cheap. The factory justed banjo's.

Just trying to piece this engine back into a running engine. Going to look into some billet pieces in a few days. Hoping that my adjustable cam gear and injector gear is done. I also missed placed my pump P7100 support bracket.. as well... The old oil supply lines looks pretty beat-up, need new ones. Trying to do a decent build on this engine. The crank will be knifed edged, just don't like how it was knifed edged. Hopefully the balancing will works out. Each rod will be balanced, the small ends, big ends and the total weights. Hoping that Harry has my fluid dampner.

I want to run a 6.7L grid heater and air horn on this engine.