Replacement for ACL Racing Pistons?

I posted this question on a Australian forum. I guess since I'm a Yank, no one posted a response.
I'm sure someone here will respond.

bookworm007 in the 144-250 'Small Block" Six Performance Section is trying to find a conrod/piston combination that will give a better rod/stroke ratio for the US 250. One of the pistons he found was for a Jeep-Chrysler 4.7L Modular V8. It wouldn't work with the 6.4" SBC rods that he was wanting to use, but I was wondering if they could be used as a replacement for the ACL Racing pistons for the 4.1L Crossflow with 200 conrods.

Here are the specs:

Hypereutectic; 2 - 1.50mm Groove, 1 - 3.00mm Groove
DurOshield® skirt coated piston
Flat top - Availability of recessed pistons?
Bore: 93mm - Can be purchased in 0.5mm to 1mm overbore for up to a 3.70" bore.
Compression height: 1.24" - 0.071" taller than the 1.169" ACL
Pin Diameter: 0.946" - 0.0338" larger than the 0.9122 Ford.

The pistons are easily found in the US, however, I found an Australian eBay seller who sells them and states that he has all sizes available:

http://cgi.ebay.com.au/JEEP-PISTON-SET- ... 21001r2095

The compression height would seem to be the major concern with this piston. However, if a crossflow head with the larger combustion chamber was used, it could keep the CR down to a reasonable level. The tops of the pistons may be able to be machined to reduce that height.

I don't have access to a 4.1L Crossflow to measure the clearances or piston recess, so I can only speculate.
If they could be used, it would allow more 200 conrod retrofits.

What do you all think?

I'm not sure if this will help but may add to your choices:

The US 250 performance engine I'm running, uses TRW/SealedPower # 470NP's pistons. The application is 79-89 AMC 4.2(258).

Ford 250: bore = 3.68 / comp distance = 1.5 / dish volume = 13cc
AMC 258: bore = 3.75 / comp distance = 1.633 / D-Sump = 21cc's

This utilizes the bore at @ .070 over and raise the piston toward the deck .133 . The specs list the pin diameter of the ford rods at .9122 and the AMC's at .9310 which the rod can easily accomodate.

The cc volume of the recess is 21ccs. With the .070" overbore the bore is 3.75", stroke of 3.91, a Felpro head gasket at .050", a zero deck height, chamber volume of 60ccs and a piston recess of 21 ccs, gives a street compression ratio of 8.8:1 with @ OEM deck/head before any milling.

Powerband

Thanks for the info.

0.70 overbore? Did you have the block sonic tested? The maximum overbore on the small block is listed at 0.60.

Dan,
You may have already found this but I'm looking around the same as you and bookworm007 are. I'll have an x-flow head/cam shortly.
I found this.Stan Weiss'-Piston page. Stan Weiss is a member on speedtalk.com and he has an extensive amount of information he's compiled for all.

keep me posted on what you come up with, I havn't had a chance to sift through the entire list yet.

Stephen

O.K. Dan check out my formula

Bore .40 over = 3.72"
Stroke = 3.91
Combustion Chamber= 48cc
Compressed ACL Gasket =.50"
Head Gasket Bore= 3.76
Piston to Deck= .045"
Piston Dish cc= 7.28 measured NPD Pistons

Static compression = 10.6/1

Cheers

Bayrunner":22ftbfhm said:

O.K. Dan check out my formula

Bore .40 over = 3.72"
Stroke = 3.91
Combustion Chamber= 48cc
Compressed ACL Gasket =.50"
Head Gasket Bore= 3.76
Piston to Deck= .045"
Piston Dish cc= 7.28 measured NPD Pistons

Static compression = 10.6/1

Cheers

Click to expand...

I got the same thing you did George, 10.6/1, except the compressed gasket thickness is 0.050".
I did the same thing in the post above 0.70, instead of 0.070. That's what you get when you try to touch type.

'68falconohio":oul4qoxd said:

Dan,
You may have already found this but I'm looking around the same as you and bookworm007 are. I'll have an x-flow head/cam shortly.
I found this.Stan Weiss'-Piston page. Stan Weiss is a member on speedtalk.com and he has an extensive amount of information he's compiled for all.

keep me posted on what you come up with, I havn't had a chance to sift through the entire list yet.

Stephen

Click to expand...

I looked at that website, but have a slight problem with it. Stan states that the 144 and 170 six has the same rod length (4.715), and the 200's is longer (4.977); on Mike's site, he states that the 144 has the longer rod (4.855) , and the 177 and 200 uses the same rod (4.715).

Which one is correct?

rocklord":oeeb3rg6 said:

Bayrunner":oeeb3rg6 said:

O.K. Dan check out my formula

Bore .40 over = 3.72"
Stroke = 3.91
Combustion Chamber= 48cc
Compressed ACL Gasket =.50"
Head Gasket Bore= 3.76
Piston to Deck= .045"
Piston Dish cc= 7.28 measured NPD Pistons

Static compression = 10.6/1

Cheers

Click to expand...

I got the same thing you did George, 10.6/1, except the compressed gasket thickness is 0.050".
I did the same thing in the post above 0.70, instead of 0.070. That's what you get when you try to touch type.

Click to expand...

You are so right! It makes me feel better when an Engineer agrees with my math. All those years of schooling, well I don't use it...so I loose it.
Cheers

rocklord":2oasp0ob said:

I looked at that website, but have a slight problem with it. Stan states that the 144 and 170 six has the same rod length (4.715), and the 200's is longer (4.977); on Mike's site, he states that the 144 has the longer rod (4.855) , and the 177 and 200 uses the same rod (4.715).

Which one is correct?

Click to expand...

With my '68 Ford Shop Manual as reference:
Ford says the rod length for a 170 AND 200 is 4.7135-4.7165". I don't have a shop manual that supports the 144 mill, so I don't know what the 144 rod length is for sure.