Cylinder wall thickness

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younggun2.0

younggun2.0

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I am starting my 470" low deck stroker. It will be a street/strip engine that will be abused relentlessly. I will be ordering a muscle motors kit. Final bore will be 4.375. I have a block at the machine shop. I pressure washed and dried it prior to delivery. I am having them sonic check the bores first so that if its not a good block I can abort without too much money spent.

What would be a good wall thickness? What thickness would you not be comfortable with? They are checking all bores. Top bottom and middle on all 4 sides. They will give me a printout of results.

I am looking to build an eddy victor headed, solid roller cam, pump gas engine in the 550-600 hp range and all in by 6000 rpm. I want it to last. I will be using stick main caps with studs. New rotating assembly will be 2300g bob weight so it should rev quick and be easy on parts so long as rpm stays in check.
 
subscribed... like to hear what people say on this..i dont even know how safe you can go on these blocks..
 
.18 is the min you would really want in a cast iron block. But the thicker it is, the better. The "thrust" side is the thickness you should be concerned with. It can be thinner on the non-thrust side, but I would never go below .15 on the non thrust side.

I sonic all of mine, regardless how much I bore them. Too cheap of a process not to. One block with core shift could ruin a whole build.

Brian
 
wsuwrhr said:
.18 is the min you would really want in a cast iron block. But the thicker it is, the better. The "thrust" side is the thickness you should be concerned with. It can be thinner on the non-thrust side, but I would never go below .15 on the non thrust side.

I sonic all of mine, regardless how much I bore them. Too cheap of a process not to. One block with core shift could ruin a whole build.

Brian
Click to expand...

The builder told me that if it was marginal they could correct it slightly by shifting the overbore to a more favorable side? My build would have a final finished bore of 4.375 which is .033 over stock bore. I have no problem dumping this block if it's not up to snuff. I only have $75 into it.
 
I can tell you that the highest load on the cylinder wall will be when the crank is 90° to the direction of piston travel in the cylinder. That is where maximum side load occurs, and the piston is at it's fastest speed, and maximum wear is usually found.

As you increase stroke, you increase side load...

The more HP that you make, the thicker the wall needed to contain it...
 
540Valiant said:
Are you starting with a 400?
Click to expand...

Yes and on my second block already. First one had froze and crack the inside water jacket in the lifter valley. Now the one at the shop is a 75 block with really nice looking cylinder walls. Stock bore also.
 
younggun2.0 said:
Now the one at the shop is a 75 block with really nice looking cylinder walls. Stock bore also.
Click to expand...


Stock bore?

Then why not just cut what you need to clean it up and just stroke it??? Then you may be able to save it one more time in the future with another bore job..
 
krazykuda said:
Stock bore?

Then why not just cut what you need to clean it up and just stroke it??? Then you may be able to save it one more time in the future with another bore job..
Click to expand...

I plan to bore it .033 I am just wondering what good wall thickness numbers looked like. If I find out it has bad core shift or marginal wall thickness on the thrust sides then I will get another block. Trying to start with a good foundation
 
younggun2.0 said:
The builder told me that if it was marginal they could correct it slightly by shifting the overbore to a more favorable side? My build would have a final finished bore of 4.375 which is .033 over stock bore. I have no problem dumping this block if it's not up to snuff. I only have $75 into it.
Click to expand...

Your builder is correct.
 
krazykuda said:
As you increase stroke, you increase side load...

The more HP that you make, the thicker the wall needed to contain it...
Click to expand...

If the rod length isn't increased proportionately....

Your second statement is spot on.

Brian
 
4.375 on a 400 is .035 over! If everything mags out you won't have anything to worry about! Plenty of wall on that puppy! A 470 is a sweet combo! Your gonna love it! The only down side is.......Your gonna want more! Lol Stroking can become addictive! Good luck my friend. Shane
 
younggun2.0 said:
Great link! I have read this before but still a good read. I am considering having the metal hardness checked as well.
Click to expand...

I kinda figured you did, since you're a big block guy. But, that is great info. So many myths out there. I used to get newer 440's and 400's for nothing! We cut a couple apart along time ago in the machine/ speed shop I worked at and new what was up! Of course we were welding and offset grinding cranks too! Anyhoo, keep us posted young blood!
 
younggun2.0 said:
Now the one at the shop is a 75 block with really nice looking cylinder walls. Stock bore also.
Click to expand...

Do You (or Your machinist) have access to a borescope?... besides sonic tests a borescope
inserted into the 'freeze plug' openings can reveal a ton of info on INTERNAL casting integrity, Read ability to flow coolant :D

younggun2.0 said:
I am considering having the metal hardness checked as well.
Click to expand...

By all means do so, 'nip' a piece off the block and have the Nickel content checked...
A bit more $, But, 'rule of thumb', 1/2-3/4 % nickel content = no 'flexy flyer' Main saddle
alignment or 'bore wiggle' when pounded on :D

younggun2.0 said:
I plan to bore it .033 I am just wondering what good wall thickness numbers looked like. If I find out it has bad core shift or marginal wall thickness on the thrust sides then I will get another block. Trying to start with a good foundation
Click to expand...

wsuwrhr said:
.18 is the min you would really want in a cast iron block. But the thicker it is, the better. The "thrust" side is the thickness you should be concerned with. It can be thinner on the non-thrust side, but I would never go below .15 on the non thrust side.
Click to expand...

With respects I humbly disagree Sir, I would not go below .18

Notes on 'thrust sides',
Most all I.C.E's on the planet have a clockwise rotation, (with the exception of some Hondas, and Cummins)...
So...
The Major Thrust Side on the right bank is nearer the exhaust ports, While the Major
Thrust Side on the left bank is nearer the intake ports, regardless I would not go below
.18, EDIT, ON ANY SIDE, apologies .

P.s, subscribed.
 
mech1nxh said:
Do You (or Your machinist) have access to a borescope?... besides sonic tests a borescope
inserted into the 'freeze plug' openings can reveal a ton of info on INTERNAL casting integrity, Read ability to flow coolant :D



By all means do so, 'nip' a piece off the block and have the Nickel content checked...
A bit more $, But, 'rule of thumb', 1/2-3/4 % nickel content = no 'flexy flyer' Main saddle
alignment or 'bore wiggle' when pounded on :D


With respects I humbly disagree Sir, I would not go below .18

Notes on 'thrust sides',
Most all I.C.E's on the planet have a clockwise rotation, (with the exception of some Hondas, and Cummins)...
So...
The Major Thrust Side on the right bank is nearer the exhaust ports, While the Major
Thrust Side on the left bank is nearer the intake ports, regardless I would not go below
.18, EDIT, ON ANY SIDE, apologies .

P.s, subscribed.
Click to expand...

Never thought of the bore scope idea,out of the box Mr.Norm.
Agreed on piston speed & rod length concept.. A reason why 440's 340's Mopar,327-427 Chev's run so hard,minimal work.
 
younggun2.0 said:
Yes and on my second block already. First one had froze and crack the inside water jacket in the lifter valley. Now the one at the shop is a 75 block with really nice looking cylinder walls. Stock bore also.[/QUOTE


you need my 72 thick webbing block that i have.....
Click to expand...
 
540Valiant said:
4.375 on a 400 is .035 over! If everything mags out you won't have anything to worry about! Plenty of wall on that puppy! A 470 is a sweet combo! Your gonna love it! The only down side is.......Your gonna want more! Lol Stroking can become addictive! Good luck my friend. Shane
Click to expand...

The 400 bore is 4.342, so 4.375 is .033 over, not .035.
 
540Valiant said:
4.375 on a 400 is .035 over! If everything mags out you won't have anything to worry about! Plenty of wall on that puppy! A 470 is a sweet combo! Your gonna love it! The only down side is.......Your gonna want more! Lol Stroking can become addictive! Good luck my friend. Shane
Click to expand...

seriously, correcting for .002 of bore?

You realize a piece of hair is .003-.006?

The nerve of some people's kids.

Brian
 
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