Sonic test numbers, core shift and the not so good first time engine build experience

I recently sent my engine to the machine shop to be checked out for a build I've been planning for two years. The last two weeks has been quite a let down. I was told last week that my 68 430 heads were repaired once before by plugging and welding them due to being cracked and were not recommended to use for my type of build. Then I was told my crank was already 10/20 from a previous build and that it would have to go 20/30 to be usable, again not recommended for my type of build. So I bought a new crank that was fresh from machine shop 10/20 with all new main and rod clevite bearings ready to run, picked it up today happy as hell. Then the machine shop called and said that since my block was already .030 with .0025 of wear and .001 out of round and needing to take it to .038 to get it to be good again with the amount left due to core shift and previous work that the pin side of #6 cylinder was too thin and would be even worse after the boring that my block was basically not usable for my type of build. I know this is the name of the game and this happens sometimes but man does it ever suck! I've been extremely excited about this for two years now and it's back to square one. Oh and after that the machinist says you also have one bad rod from a previous spun bearing, just kick me in the manberries one more time wont ya! Here's my sonic numbers just for the hell of it.

 

If the block checks out otherwise, you could sleeve that one cylinder. Should be good as new if blocks are scarce in your area.

 

Hope they're not stroking you...

 

I would not start a build with that block....or a build with a crank. 020........there is nowhere left to go anywhere........030 bearings for bbb can be hard to find

 

Anything under .100 anywhere is fail...

It's always number 6 on the pin side for some reason.. usually the backside... when you sonic check a Buick 455, always have them check that hole first, and suspend the test if it fails. Should save you some money.

Sorry for the bad news.

JW

 

Well I just got a line on a 72 block and crank. If I can get it hopefully this one checks out fine and my build is back on track.

 

If your deal doesn't work let me know....not sure how right now is these way to get it to you but I have some blocks........

 

Thanks Ben! I'll let you know how I make out on this one.

 

So I picked up the block and crank today that was donated, yes donated to me free of charge buy a very nice fella and it turns out he's actually a member here. Everything looks very nice and clean and was stored oiled. The bores measure 4.30 and still look to have quite a bit of cross hatching left. The block is said to only have 47,000 miles on it and to have come from a 72 Riv. The oil passages are already 5/8" tubes. I'll attach some pics of numbers on the block. I'm going to try and get this off for sonic testing by end of the week.

 

4.30??? Stk 455 bore is 4.312

Looks like the lifter valley and other work has been done to stress prone areas

 

I was measuring at the top of the bore and there's probably a slight ridge of build up there so it measured a bit smaller. The guy who had the block before the guy I got it from did start to do some work to it by removing the casting flash in the lifter bore area and by the main caps, one of JW'S mods.

 

Looking at the block code on the deck surface I've never seen the code CF before?? Also what do the syampings on the oil pan surface mean?

 

So took the block to the shop this morning and before I took it out of the truck had the machinist sonic test #6 pin side and the results were less than appealing. The bottom came to 70, middle and top 86. Goes to show you how bad the core shift can be. It's a 72 stock bore from factory block. Well back to square one again.

 

That's worse than b4.........

 

I know right!! What are the odds of getting two bad blocks in a row?? First one was a 70 second was a 72, maybe I'll try to find a 74-76 block. Or how about a 430, can it be safely bored to 455 specs and hold up for a 500+ hp build?

 

I'm sure you can get that number without boring that far

 

This sounds so freaking familiar. I went thru the same thing back in October. Two blocks checked. Two blocks failed. I gave up and just sent all my parts to Jim Weise and just had him provide a block. For me the cost was worth getting rid of my anxiety and frustration at attempting to find a local block that checks out.

Speaking of, I am scheduled to have that block completed next week so I'm super excited to hear back what my engine dyno numbers end up being. :giggity

 

Yeh it sucks but hey atleast I'm weeding out all the bad blocks for everyone .

 

That block might not be a bad block for everyone.........it survived all these years running that way.....I'm sure for stk build on a budget it would work........maybe with block fill or a sleeve it would work.......its just not an optimal unit to start with

 

Yeh I was told a stock build its fine but for a performance build it's not a good candidate.