Hi all, ive had some problems with my one main cap.. 400 sbc main caps.. I lost it, idk how, bc i had em all organized. I tore it apart and then organize all of the parts in buckets. Even the babbits.... My engine builder told me to find all of these caps, i have only found the 4 needed front, two center caps, and the rear main cap. He said the block is just junk if i cant find that last one, i have been searching hi and low. I looked into replacing it, google all of i have looked around and seen many negative answers, many answers are true at that. But one answer (really relieving answer it was) that i could look around for used OEM main caps and some might be close enough to even get off with a align hone.. I was really looking forward to seeing this pull through, cause the block is standard bore 400 and one of these days theyl be worth $$ so im trying to keep it like an investment... If anything maybe i could build a 383, summit has some pretty good price reman 355 or 383. If any one could help suggest anything, let me know. Has any one ever tried a DIY main honing process? Thatd be neat to learn and very budget friendly thanks, Al
Same thing recently happened to a friend with an OT British 4 banger. Had two blocks, one needed a bore and the other was missing the main caps. Machinist said it was less expensive for a cylinder bore job (all 4) versus a line bore. I don't think there's any way to DIY a job like that.
I would have issue with my engine builder if he said the block was junk because of a missing main cap. Like Darkk said get a new cap and have it line bored. Most guy that build high end racing engine have them line bored because the last think you want is a crank that is flexing at high RPMs.
get it line bored it's cheap get splay bolt caps and get done at the same time and if it's a front cap that's missing, just cut the outer bolt holes off . as a investment it's not worth I just sold 2 blocks for $100 each and I would change machinist
It's true if you can find one that is close you can have it align honed but with a 400 you'll have to have the seal area bored first. You'll be very lucky if the first cap you try is a match, we have a stock pile of caps at our place for just such a problem. I've helped guys out with this before and alway tell them "when you take a block apart put the caps back on the block and keep them there!". Not too expencive, $100+ at our shop.
I get the impression you are not building this now, and are saving it for later? Just stick it in the corner, and I bet the cap will show up before you are ready to build it. If I get in a hurry and sort through my parts stash for something, I'll never find it. But sooner than later I'll stumble across it again.
o no i just looked it up, i was also thinking a quick fix would be a 383 crank with medium crank journals, 2 piece rear main and spacers. LOL i didnt know that it didnt cost much to have it aligned bored. Seen some stuff on here saying it would cost up to a $1000
this is what im trying to do. And idk how i lost it. I should have put the caps back on the block like suggested
should i just go with all new splayed mains? I mean wouldnt that mean id have to have them be machined to register? Then the addition of align bore, align hone ect?
Any machine shop that told me they couldn't save that block by align honing it would have me wondering how good they are. When GM or anyone puts an engine together for the first time the block and mains are not a matched set, they are turning into a matched set by the boring operation. Same can be done now. Don
Alchemy is correst here. A main cap is not something that you are going to toss in the trash by accident. Well maybe if you are in a meth induced coma. I find stuff all the time that I either don't know that I own or have forgotten where I put it when I am looking for something else. As for the machinist I am with the get another machinist crowd. Any good rebuild calls for an align honeing at the very least or an align bore job. The make for inexpensive torque by freeing up some of the torque lost by the saddles being slightly out of alignment on an ***embly line engine. If the cao never shows up either snag a new set of find a loose one and go for it. But like Alchemy said it will most likely show up if you are not in a hurry.
no coma here! i figured i can get a new set of main caps for it, and just stick em on. Geuss that idea wasnt the brightest in the world. But i didnt know of any engine machining needed to be required intil i was on a forum just looking around, seen someone pulling there hair out and freaked! Thats when i learned.
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