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Possible Engine Build for my 93 Truck

I might have to do that. I did make some progress on the one intake valve in the last photo. I used some of the jewelers rouge and a dab of oil and did a quick couple of passes. also did a leak test with the compressed air. it's only leaking on the side that's between the valves on the head. in the pic it polished up almost half way around leaving the area where I see it leaking.

I've only done maybe two sessions about 5 minutes each on this valve using the lapping compound (sessions were apply compound lap, wipe off and reapply compound. do it again)

IMG_1423.jpg
 
I looked on RA but they don't list new valves. I had wondered if getting new ones would lap in and seal better if these have a lip.

correction: they do list them. exhaust valves are about $30 ea and intake are about $8 each.

I suspect that there not far from sealing all the way around, but I don't want to keep lapping if they are out of round or not perfectly straight. any advice on a poor man's valve job?
 
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Ok Update: I seem to be getting somewhere now.

I figured I would keep trying on one valve. intake for #8. I took my homemade doodad I made to fit the suction cup and chuck it into my drill. applied some lapping compound and went at it. spun the drill slow in both directions while lifting every couple of seconds same as hand lapping. I went at that for a little longer than I would do doing it by hand. then cleaned it all up and used the jewelers rouge to do a polish on them. again for a little longer.

wiped everything down real good, slid the valve back in the hole, spitzed some windex on the top and applied some air pressure while holding the valve down by hand. it's sealing!! YAY!!
 
I'm sure the seat widths are out of spec. I have now gotten three of them to seal using the same process. both the intake and exhaust for #8 and the intake for #6 all sealed up.

I'm not installing the springs, just holding them down by hand when pressurizing the head ports. I think maybe I just wasn't lapping them enough. after reading online I learned that this grinding compound is supposed to start out as a course grit and will slowly break down to a fine grit the more you lap them.
 
changing the subject and moving to the block. bearings have been a question on my mind. I have not pulled any of the main caps or rod caps yet. I know I will need to pull the rear main cap to get at the rear main seal, but as I inspect them, will I need to get some plasti-gauge to check them if they look good still? if so, which one do I need and what is acceptable and not for these old 6.2's

I assume all of those bolts will get re-used and get torqued and re-torqued as they are being checked with plasti-gauge. if not, that would be an expensive bolt replacement as I pull them and use the stuff to check clearances.

I was thinking about this mainly because if I can't get the upper portion of the rear main seal out, I will end up having to pull the crank out to get it out.
 
I found these two links that were originally posted by @WarWagon on a different thread. they have since disappeared from the web, but I managed to find them recorded on the wayback machine.



Here is the thread I found them on.

Missy Good Wench

Thread 'Internal clearances for the 6.2/6.5 engines'

There is always a lot of chatter about the bearing and piston clearances on these engines.

These are metric engines and everything on them, save a couple things like the bellhousing bolt holes on the pre 96 stuff is metric.

The specs book all call out the clearances in MM.

This is not a big issue, but here in the States, we are used to measuring in Inches.

Here are some good hard numbers that you can take to the bank.

Piston clearance
Cylinders 1,2,3,4,5,6 can be set at .004" and work very well
Cylinders 7 & 8 run a tad hotter and will be very happy at aroound .0045"

The book...


It seems the clearances for the mains are 0.045 - 0.083 for all except for #5 which is 0.055 - 0.093
And for the rods shows 0.045 - 0.100
 
I followed up with the rest of the valves on the passenger head. they are all sealing up good now. Finally I am making some good progress :D
 
dbrannon79 said:
changing the subject and moving to the block. bearings have been a question on my mind. I have not pulled any of the main caps or rod caps yet. I know I will need to pull the rear main cap to get at the rear main seal, but as I inspect them, will I need to get some plasti-gauge to check them if they look good still? if so, which one do I need and what is acceptable and not for these old 6.2's

I assume all of those bolts will get re-used and get torqued and re-torqued as they are being checked with plasti-gauge. if not, that would be an expensive bolt replacement as I pull them and use the stuff to check clearances.

I was thinking about this mainly because if I can't get the upper portion of the rear main seal out, I will end up having to pull the crank out to get it out.
Click to expand...
I’d use the green plastigauge and see if you have .002” clearance.
 
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