Quote:
Originally Posted by Cliff R
I don't do either but it's still a good plan.
I will NOT use a block that needs line bored/honed. If the block has "moved" or not thru thru the center of the main bores or other line bore issue or problem, and the crank doesn't turn freely with two fingers (no rear seal installed) I woln't use it. I'm NOT saying here there is anything wrong with line honing and such, I've just had a few issues with machine shops NOT doing a good job and throwing more problems into the equation. In other words, from what I've seen with this sort of thing is that it's better to trust the work Pontiac did 50 years ago vs what a machine shop is going to do for you today. It's also rare to find a Pontiac block that isn't true thru the main bores right to start with. In all the years I built them can only remember a couple that didn't make the grade in that area. Same with having crankshafts machined. More come back WORSE than when you sent them out, so do your homework in that arena before you send out a crank that needs more than just polished and put back in service. I was actually lucky in that deal as I found the BEST crankshaft machinist on the planet early in the game and used him for every single engine I built here with absolutely ZERO issues anyplace. Sadly, like many other folks who do excellent work he retired a few years back, which was fine with me because I was done with engine builds anyhow and had also moved on to other things that pay the bills with a LOT less effort on my part.
Anyhow, back to zero decking. I used to have the blocks bored, bring them back to the shop, then go thru the process of mocking things up to determine how much to remove when decking/squaring for zero deck height. Of course that can lead to some "oh-chit" scenarios if you happend to buy pistons that were a bit shorter than they should have been!
Got better at it over the years and did the math instead. This simply involves measuring cranksahft center line to the existing deck and buying rods and pistons that would only require a small amount removed from the deck to square things up. This means only one to the machine shop instead of two. Of course you need to double and triple check your math, but every single build I did in that fashion came out dead nuts on the money when we checked them right before final assembly......
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Cliff, can you explain the proper way of measuring the deck height with a 12" caliper.
I have a block that needs measuring and had it explained to me once, just want to double check.
Measure from deck to main bore. Then divide the main bore diameter and subtract ? Something like that ?
Any of you other machinists/builders can give your thoughts and doing this too if you like.
Thanks for any help, I am sure others would like to know also.