91 Suburban w/6.2 Head cracked
Diesel Bomber
Joined: Oct 2012
Posts: 1,848
Likes: 103
From: Scugog Island ONT.
got her started up tonight.
ended up pulling the drivers side head to inspect for peace of mind, and found that side had already been replaced with a 6.5 head. so, I put the 6.5 head I aquired on the bad side, and threw it back together. started up and runs good it seems, although at idle I'm noticing some white haze coming out the drivers side bank... don't know what that means exactly.
time will tell if the two bad cylinders I cleaned up will hold up or not. if I bring the engine just off of idle I can feel a slight miss, so we'll have to see how that progresses.
I'll finish buttoning her up tomorrow and take it for a test run.!
ended up pulling the drivers side head to inspect for peace of mind, and found that side had already been replaced with a 6.5 head. so, I put the 6.5 head I aquired on the bad side, and threw it back together. started up and runs good it seems, although at idle I'm noticing some white haze coming out the drivers side bank... don't know what that means exactly.
time will tell if the two bad cylinders I cleaned up will hold up or not. if I bring the engine just off of idle I can feel a slight miss, so we'll have to see how that progresses.
I'll finish buttoning her up tomorrow and take it for a test run.!
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Diesel Fan
Joined: Mar 2014
Posts: 11
Likes: 0
Started it up this morning again and found that I must have had a little air in the lines yet. once it bled off the thing ran great... I still have a little smoke, out both banks, but it's very light and I think only noticeable because it's in my shop running. No bubbles or compression in the cooling system either.
after it ran about 20 minutes while I did some chores, I cam back and did a cyl cutout test on every hole to make sure there wasn't anything missing. every hole was firing.
I did the test with the advance lever on the pump to see if it was too advanced or not, and when I push the plunger in the engine gets a little more of an aggressive rattle to it. maybe it's advanced too far?
The throttle response of these engines is amazing to me.
after it ran about 20 minutes while I did some chores, I cam back and did a cyl cutout test on every hole to make sure there wasn't anything missing. every hole was firing.
I did the test with the advance lever on the pump to see if it was too advanced or not, and when I push the plunger in the engine gets a little more of an aggressive rattle to it. maybe it's advanced too far?
The throttle response of these engines is amazing to me.
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Diesel Fan
Joined: Mar 2014
Posts: 11
Likes: 0
Naw, those were scratch marks.
If the block was cracked I'd still have compression in my cooling system.
I'm gonna take it for a 50 mile trip tomorrow... we'll know by the end of that weather or not this thing will hold it's nuts and bolts.
If the block was cracked I'd still have compression in my cooling system.
I'm gonna take it for a 50 mile trip tomorrow... we'll know by the end of that weather or not this thing will hold it's nuts and bolts.
Diesel Bomber
Joined: Oct 2012
Posts: 1,848
Likes: 103
From: Scugog Island ONT.
Give this a read:
6.5 blowing coolant everywhere (Total Rebuild) - Diesel Place : Chevrolet and GMC Diesel Truck Forums
Sometimes it has to have the right conditions for the compression to get past the crack.
6.5 blowing coolant everywhere (Total Rebuild) - Diesel Place : Chevrolet and GMC Diesel Truck Forums
Sometimes it has to have the right conditions for the compression to get past the crack.
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Diesel Fan
Joined: Mar 2014
Posts: 11
Likes: 0
ran it 50 miles yesterday. no heating, no smoking, runs strong. Got it home took radiator cap off and had only normal hot cooling system pressure. reserve tank and radiator were still full as well. started it up with the cap off and have no bubbles..
Also noticed that my blowby is much less than it was 50 miles ago. right after I put it together I had a fair amount of it. now it's not much to speak of. the two cylinders I honed must have broke in...
Only thing I'm really noticing now is on cold startup it takes longer for the passenger side bank to "clean up" and get hitting on all cylinders... you can see it in the exhaust that it stays white longer than the drivers side bank. But, that too was before I took it for a drive. it might be better now.
Also noticed that my blowby is much less than it was 50 miles ago. right after I put it together I had a fair amount of it. now it's not much to speak of. the two cylinders I honed must have broke in...
Only thing I'm really noticing now is on cold startup it takes longer for the passenger side bank to "clean up" and get hitting on all cylinders... you can see it in the exhaust that it stays white longer than the drivers side bank. But, that too was before I took it for a drive. it might be better now.
