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400 block sonic tests in... is this block ok as a base for a 451 stroker?

S

skingjack

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The shop I was working with mentioned that it *should* be OK for use but did not seem too enthused imo. As I have no exposure to sonic test results, would any of the onsite engine gurus care to comment on the suitability of this block.

Goals for engine:
451 stroker using 440 crank plus factory rods and aftermarket pistons. Ported eddies or stealth
EFI planned
Max 6200 rpm, concerned with more torque than H.P.
4100lb, 727 auto (o/d), 3.55 auto, b-body.

Reliabilty, Streetability, low maintenance desired ( a sleeper like cruiser ...maybe 1% time on the track).

Sonic test results attached.

Thanks for any feedback.
 
Someone with more knowledge will correct me if I'm wrong but here is what I think.

Lets assume those are wall thickness The circled numbers are suspicious in their eyes.. Cyl 6 top of the bore 246,middle 133 bottom 266. Pretty sure you would want to numbers to be more closely matched. Take cyl 7 as an example 3rd column. 286 281 291. Where as cyl 6 has the worst problems. It has 2 seperate axis measurements circled. Middle and bottom. that would mean there was some piston rock for a while at the bottom and middle of the bore or some other issue like that.

When you use a caliper to do the same thing You measure on 3 separate axis's those 3 axis measurements will tell you if your cylinder is out of round.
 
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Do you know which measurements are for the major thrust side of the bores? If the thin measurements are not on the major thrust side you would probably be safe.
Mike
 
Years ago we had a 440 that Ray Barton checked and had 2 cylinders that were at 117. Since it was already machined we ran it anyway ended up with spider cracks in those 2 holes after a couple hundred passes in a racecar. Barton would only build a block that would check out so a different block was used for his project. But, I can not remember where our engine was thin to compare directly w yours. I want to say it was 117 in the middle...but I really can't remember.
What 493 mike is saying makes sense too.
 
I see some core shift, and possible corrosion damage (inside). Is the block std, 20,30,etc..? If you are going from std to 30, sleeve the two holes (3&6) and go for it. You subtract half of the oversize you are going to, and as long as the walls are 125 or better, you "should" be fine. This is more than likely why they circled those numbers.
 
Some people are afraid of sleeves.But I'm not. We did a 340 block as a bracket race engine and had 4 sleeves in it. The owner ran the crap out of that engine for 5-6 years before selling the car. It still may be running.
 
69Bee said:
I see some core shift, and possible corrosion damage (inside). Is the block std, 20,30,etc..? If you are going from std to 30, sleeve the two holes (3&6) and go for it. You subtract half of the oversize you are going to, and as long as the walls are 125 or better, you "should" be fine. This is more than likely why they circled those numbers.
Click to expand...

Agree, sleeve two and run it...
 
skingjack said:
View attachment 842642 The shop I was working with mentioned that it *should* be OK for use but did not seem too enthused imo. As I have no exposure to sonic test results, would any of the onsite engine gurus care to comment on the suitability of this block.

Goals for engine:
451 stroker using 440 crank plus factory rods and aftermarket pistons. Ported eddies or stealth
EFI planned
Max 6200 rpm, concerned with more torque than H.P.
4100lb, 727 auto (o/d), 3.55 auto, b-body.

Reliabilty, Streetability, low maintenance desired ( a sleeper like cruiser ...maybe 1% time on the track).

Sonic test results attached.

Thanks for any feedback.
Click to expand...

451", mostly street, and thin part is mostly the lower part of the cylinder. I would run it, not much cylinder pressure at the lower part of the cylinder. If you have issues later, just throw a sleeve in it.
 
My opinion FWIW two sleeves now, chasing another better block takes time and the cost of cleaning and sonic testing adds up... Throw it together and run it? If the wall collapses there won’t be much to save...
 
I've heard of people checking several blocks before they found a good one. But lots of machines shops just bore them and don't sonic test... probably more of those out there then ones that have been checked. I am sure a catastrophic block failures have happened...but I think it's more common for a stress crack to develop or a pit erodes and antifreeze gets in the oil. I'd talk to your machine shop on "Run it or sleeve it". Some shops are excellent installing sleeves...others...not so much. Of course the best plan is obvious...get another block and "cross your fingers" and hope its better.

Doing a lower block fill could make it last better too. Especially since your problems seemed to be lower...but opinions on that are all over the map. If it were mine I'd probably consider a lower block fill with something that didn't shrink...but I have heard of them cracking and leaking anyway...not sure on how much it really helps. But...I don't think it would hurt.
 
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looking closer at the numbers, sleeve #6. Less than 0.150" at the top and center can hurt ring seal.
 
The Major Thrust thrust sides are what you should concerned with.... and maybe it's just me but I don't see any real "identifier" of the Major sides measurements 1/2 way down ? nor their connector webs when a thin spot is located for context ?
Just me... but best when a guy finds a thin spot to start mapping around it to see what's going on ?
No matter.... some .160's and lower appear to be showing pretty much everywhere, and I dunno how you are planning to make the 1.34 CD 2618 Pistons run quiet on a mufflered street car ? without moving the break point on the skirts ?

That particular Block around here would be a BAIL !
 
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440 rods give you the better rod angle
build for tight quench so you get no detonation
short fill will not hurt and you can sleeve
lower compression motor and thin is on non thrust side I'd run it
 
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