??'s about overboring F block

[BB]

I have had a 74 F (full flow oiling) motor sitting in the yard for awhile. I picked it up to eventually use it as a core to rebuild if/when my 72 F goes south. After pulling it apart and determining that it had spun a rod bearing, which chewed up the crank and rod and also noting that it has already been rebuilt and bored .020 over (marked on pistons), I am not sure if it is worth rebuilding again. A few of the cylinders are pretty badly scored as well. My question - how much can these blocks be bored out? Looks like .040 pistons are available, but with my experience on other motors (V8 Fords), overboring could cause overheating problems. I am thinking this block is a candidate for the scrapyard. Any thoughts? Thanks in advance...

Brian

 

[dd113]

Bore it out. You should have no problem at all. The block is very thick. I hve bored out .050 with no problems at all.

 

[Roadnoiz40]

Or bore it and sleeve the cylinders.

 

[jesterb]

I'm with David. Boring to .050 on this hunk of cast iron is no big deal.

 

[65swb45]

Toyota actually has pistons listed for .060 over; VERY SPENDY! You won't find rings anywhere but the dealer for them. You will be in for $500+ on the pistons and rings, which IMO isn't worth it. Especially when you can find block cores at giveaway prices on the board.

I would wait and watch the board.

 

[BB]

Thanks to all of you for your input. Sounds like overboring is not a problem, but will cost some $$ for parts. I think I will look around for one that is in better shape since I don't need a core to rebuild right this minute. This was essentially a motor I took because a 4-speed bellhousing and clutch parts were attached to it.

Brian

 

[bsilva132]

Sorry to hear that the block was no good. Hopefully you were able to use some of the stuff off it. I have heard that the head off the 74 F will net you a couple extra hp when bolted to a 2F. Did you get your Orion yet?
-Brian