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1991 F-250 460 Rebuild

2K views 2 replies 2 participants last post by  Mike R 
#1 ·
Brand new to the forum but have heard very good and positive things about the help here and figured I’d introduce myself. I’ve been around aluminum i4 motorcycle engines awhile now and have quite a bit of experience under my belt, but am completely new to big block v-8’s, not that it scares me too much.

Story on the motor. Dad’s truck spun a rod bearing pretty bad and he had just finished paying it off so he insisted on getting it rebuild on a budget. Which is never the case we all know lol. So a year later some friends of his pull it for him and disappear, then it sits poorly secured on an engine stand and being held by a cherry picker, taking up half the usable space in our garage. Finally I got the courage to resecure it and tear it down. So, here we are.

Rod bearings 1&2 were both spun badly. Journal for 3 was chewed up pretty good too. Journal 1/2 was welded and the crank was ground .020 and polished. Mains were also ground polished down .020. Piston bores had marks where skirts had made contact and was already bored .030 over. My machinist said I could probably get away with it with a little slap but I had it bored to .040 and honed and got new pistons. I don’t want to do this twice. Block and heads hot tanked, heads inspected and all looked good. And I had the Flywheel resurfaced, the. oiled and wrapped up it until needed. I ordered a Sealed Power rebuild kit for the according specs and everything looks good and in spec so far.

Okay, now, since I’ve gotten everything back and mounted the block on the stand, I’ve: soaked the block in WD-40, scrubbed the outside with brushes, degreased with mineral spirits (minus the piston bores), masked the block, degreased one final time with mineral spirits again and wiped until clean with shop rags until they came out clean, reapplying spirits conservatively as needed. Finally, I blew any debris from the block with dry compressed air and lightly touched every bit of the outside with a microfiber. Finally I gave it 2 light coats of VHT, 1 medium and one heavy and have currently had the block curing under heat lamps about two days rotating it every 8 hours to ensure good curing as Michigan winters suck to work anything outside.

I’m sure I’ll have lot of questions along the way and have done a bit of research so far but do not know nearly as much about this motor as all the gurus around here. I plan to give it another day or two to let the paint harden almost 100% and I will unmask the block and finish final cleaning and start fitting rings and measuring oil clearances.

First question, probably dumb, but should I spend another $200-250 to have the rotating assembly balanced? The machinist said it should be alright, but whenever somebody tells me “should”, I take it with a block of salt. But I also had 3 rods reconditioned as well, so how much am I going to throw off my rotational balance??

Auto part Machine Engine Metal
 

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#2 ·
With the cylinders bored .040 over to 4.400, I was told that for a stock application I would be looking for a top ring gap of .0198 and a second ring gap of .0132. Attempting to keep the engine running on regular 87 pump gas, and under normal street and light towing/plowing application. What do you all make of this? I’m sort of lost.. thanks in advanced, Nick.
 
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