Does anyone have the part # for the Ohio Pin & Piston flattop pistons for a 400?

 

Do you have a supplier? AFAIK they quit making those.

 

I want to go to the 3V alloy quench heads. I may buy a custom piston with the right CH to give me zero deck clearance, and an inverted dome to give me the right CR.

Also I am trying to find the CH of the Ohio piston, so I can check my deck height.

OR

I may just get a 400 block and crank and build a stroker motor using KB pistons.

In any case I need the part # for the Ohio pistons and the CH.

 

Ohio P/N 1282P. This number came from an article I found on the web.

http://www.projectbronco.com/Technic...e_build_up.htm

Can't vouch for authenticity.

Good luck,

Califasbob

 

From my files, pardon the caps:

COMPRESSION HEIGHT 1.637 +/-0.003
RINGS 5/64, 5/64, 3/16
P/N FOR FLAT-TOP PISTON FROM BADGER IS 40010F

Ditto on the Ohio P/N, same as the Ertel #1282P

The compression height is 0.010 less than the stock piston to give the same deck clearance with a nominal 0.010 milled off the deck. They are designed for a nominal 9.0:1 compression ratio with open chamber heads with a nominal 0.010 milled from the heads also.

 

If you can't find the pistons, just find and machine some pontiac rods. They will get you to 0 deck and you can even offset grind your crank if you want.

 

Nearly everything you are talking about can be done but it depends on your priorities and budget.
1. Have you measured the block's true deck height?
2. Is the block straight or does it have to be surfaced.
3. 1st preference for piston material, cast. hypereutectic, forged?
4. Did you get an estimate from anyone for the custom pistons?
5. If you're going with a custom piston, will the dish be a round, D shape, or a custom shape so it matches the chamber of the CHI head?
6. Is the Ohio a cast piston?
7. Have you looked into using 300 I 6 pistons?

They have a 1.74-1.76" CH. It would put you .020-.040 above the block but the dish is .3" deep so there should be plenty of thickness left if they were cut down slightly. The dish volume looks to be about 30cc. Early pins were .912, late was .975. If I figured the compression right, I got 9.9:1.
http://cgi.ebay.com/ebaymotors/ws/eB...tem=2429470696
This auction is over, it's just for a reference. It also said they were Hypereutectics.

More later.

 

I haven't measured the true deck height, that is why I needed the CH of the Ohio pistons. Now I can measure between the piston top and deck to determine the true deck height.

The block is straight. If I use the custom pistons, I don't have to pull the motor or remove the crank.

I would prefer hypereutectic, the custom pistons are forged and run about $725.00. Forged is the strongest, but they expand so much the clearance is greater and they can slap when cold. The hypereutectic are lighter and stronger than cast, and they don't expand as much as forged.

I need a 'D' shape inverted dome. about 10cc, not a dish. The flat of the piston has to line up with the flat of the quench area on the head.

The Ohio pistons are cast and are OK for a moderate compression engine.

What are the pin diameters and lengths on the Pontiac Rods?

 

I found info on the Pontiac rods. They are 6.625" long center to center. The pins are 2.249(big), and 0.980(little). The 400 crank is 2.311(std) a KB148 piston is 1.67 CH.

2 + 6.625 + 1.67 =10.295"
This is 0.002 below zero deck. The crank could be ground offset by 0.002 to get zero deck. A 1.65 CH piston with a 4.044" stroke

2.022 + 6.625 + 1.65 = 10.297

This is zero deck height and 412.7 cu inches.

The little end of the rod would have to be bushed to 0.912 since these are 351C pistons.

I will have to look at Pontiac pistons.

The only problem that I see is that Pontiac rods are weak. They need to be hardened for a high horsepower motor.

 

danlee, There are several aftermarket sources for Pontiac rods. Eagle is good, because they use aircraft quality steel, and they don't break the bank. Don't use 351c pistons, just bush the rods. The rods will have to be machined to fit the rod journals (thickness). The crank will also have to be ground to accept the smaller journal pontiac rods. The block will also have to be notched. I'm a machinist for a few performance shops here in Denver and I've developed this motor for myself and customers. It's a gem. I juiced close to 600 lb. ft of torque on the dyno out of the one I've been r&ding. The limit is of course the cast crank.

 

bushbee69,

If I don't use 351C pistons, what pistons do I use?

The pistons for the 400 put me back in the same problem.

Pontiac pistons are too small or too big, but the CH is great at 1.707"

 

Keep the bearing width in mind when you are looking at rods. By the time you rebush and narrow the Pontiac rod and bearing, you'll have $1000+ in to a set of aftermarket Pontiac rods. I would never trust a stock Pontiac rod.
Check into the price of an offset grind. If it's $175-200 like I believe, it's not worth doing a small change.

http://www.actionspeedparts.com/eagb3d.html

Pontiac 350, 400, 455
2.249" crank pin / .980" piston pin / .990" b.e. width
Part # Length Description Gram Weight Price Shipping
12-16 days Select
CRS6625P3D 6.625" stock bushed 780 $695.00 $8.00
CRS6625PP3D 6.625" stock press fit 780 $695.00 $8.00

Ford 351 Cleveland
2.310" crank pin / .912" piston pin / .8315" b.e. width
Part # Length Description Gram Weight Price Shipping
12-16 days Select
CRS5780F3D 5.780" stock-uses 351W rod bearings 695 $569.00 $8.00

I still think the 300 piston is worth considering. If not for this build, maybe someone else. The dish shape is much smaller than a 351c closed chamber and would not lose quench benefits. I put a comparison on my forum site. The piston could have the 351C chamber shape carved into the 300 piston for optimum quench benefits.

 

i've been to your forum site. i can't find any of things you refer to. where is the 300 L6 piston comparo?

thanx.

 

I didn't see your name in the member list. Go to my forum and look for Join this Group. Follow the directions to get Yahoo ID and password and submit it for my approval. It doesn't cost anything. http://autos.groups.yahoo.com/group/...1Boss351HO400/

The pistons image is on the second page in the Photos section.
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Brian,

I looked at the 300 I6 pistons. That does look like a good solution. By machining off 0.023 from the top(1.74), I get a CH of 1.717". This gives zero deck with a 400 rod.

Can I buy Hypereutectic 300 I6 pistons with a 0.975 pin at a reasonable price?

My only question is how many cc's are in the dish before and after machining?