383 build

[aznpersuasion]

kind of ghetto, but all of them held water well except for the #5 exhaust which had a very small drip every 5 second. probably just hand lap that one valve on this head

 

[lesterl]

Yeah, suspect you are pretty good on that.....

http://www.youtube.com/watch?v=7GEmuQa3dPY

This guy does a good job on his valves.....

 

[aznpersuasion]

well in light of how clean everything looks i will take off the other head tonight maybe, flip it over and inspect the bearing surfaces. if they are ok then i will just get some new bearings put it back together and run it. i thought about smoothing out the runners but they already look and feel pretty smooth. if i keep this setup with a .015" headgasket static compression will be around 10.8989 (piston is .025" in the hole right?). i cant calculate dynamic since the program wont go low enough for the stock cam.

EDIT: according to wallace racing DC calculator ill be sitting at ~8.8 DCR @ 0 feet altitude with a .04" quench

 

[aznpersuasion]

second pic is the #1 cylinder bore and the third pic is the #6 cylinder bore.

 

[amtronic1]

I missed you saying how many miles was on this motor. And did you absolutely find the source of your original problem, coolant in the oil?

 

[aznpersuasion]

130,000 miles. When I pulled the intake a portion of the gasket was very obviously cracked and I assume the coolant drained into the oil that way. Seems like a common.problem

 

[amtronic1]

At 130k miles, it deserves a complete rebuild. You should send the heads out for a valve job at least. In one post you spoke of a .030 over rebuild. Is that still a possibility? Because that means new pistons, rings, bearings, etc. It would be a shame to do all that and find later it wasn't a head gasket leak that was the problem.
And it all depends on your plans for your truck. If you plan to sell it in the next few years or keep it for good, that would definitely influence how far you should go on a rebuild.

 

[aznpersuasion]

I would love a full rebuild. I just don't know how good the carquest or Napa is yhats near me. I'm in Yuma and don't have many choices.

 

[amtronic1]

They are fine for filters and oil, but they won't be the ones boring out your block or doing the valve job, they send it out. Find some racers, either oval track or drag racers, and ask them for suggestions. They will point you in the right direction to the best places.

 

[aznpersuasion]

Ya, I just gotta find some people that do that. Thanks. I'll keep tearing down and posting pics

 

[lesterl]

He said it was INTAKE gasket that let loose, they are NOTORIOUS on these engines 96-2003 as GM used a plastic carrier and it tends to break allowing coolant/oil issues. A full rebuild would be great, but perhaps something simpler, could you lap the valves and how bad are the cylinders? Any ridge at the top? Crosshatch still in the cylinders?

I would probably just get the better gaskets, and if you have the heads off lap the valves, and reassemble.....

 

[aznpersuasion]

no ridge, so im thinking that it may have been rebuilt recently. crosshatching is still very visible and no scoring on any of the cylinder walls. further tear down will dictate. in a few im going to start pulling caps. if bearings/surfaces look ok i may just get new bearings, and new rear main seal while im at it. is it easy to pull the cam? obviously pull cover and timing set, but is it worth it if the mains/rods look ok? i know a way to lap valves with a drill, lapping compound and prussian blue. i also got new valve stem seals since i have the heads off.

 

[lesterl]

Never tore down my 96 when I had coolant mixing issues, ran fine after gaskets and an oilchange.

If you pull the main and rods and they look good, dont even mess with the cam IMHO....

Dont lap the valves with a drill, do it by hand instead..... http://www.youtube.com/watch?v=7GEmuQa3dPY Watch this guy he is pretty slick at it.....

 

[aznpersuasion]

ok cool. these engines seem pretty darn stout so far. i was watching him the other night actually. only thing i can really do that he did is the lapping.

 

[lesterl]

These engines have been around for quite a while, my first was a 77 1/2 ton truck. I have had several versions of these (the 4.3l is based on this engine also...) I currently drive a 1995 Tahoe with the L05 TBI 350 and drive a 2012 1/2 ton Express with a 4.3l in it.....

 

[aznpersuasion]

here are the mains, opinions? i think they look fine. working on rods right now
#1

#2

#3

#4

#5

 

[aznpersuasion]

These engines have been around for quite a while, my first was a 77 1/2 ton truck. I have had several versions of these (the 4.3l is based on this engine also...) I currently drive a 1995 Tahoe with the L05 TBI 350 and drive a 2012 1/2 ton Express with a 4.3l in it.....

right, i know these motors have been around for a long time. i just didnt know how durable they were. i drove this engine at speed for about 12 miles and am a little surprised its looks as good as it does.

 

[lesterl]

Put it back together, run it for a few miles with some cheap oil, then change the oil again.... IMHO.... Walmart has a jug of high mileage for around $15....

 

[aznpersuasion]

i had planned on atleast getting new bearings and rear main seal.
1/2

3/4

5/6

7/8

 

[lesterl]

Are/were the bearings loose? They dont look bad, might throw a rear main in it while it is out, but I bet the rest was pretty tight.......