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Discussion Starter · #1 ·
http://www.crossracingproducts.com/servlet/the-template/about/Page

OR

http://www.ahmperformance.com/


I paid 199.99 via Money Order to these guys for the pistons we talked about on this thread two months ago ... they will not ship and owner Chris Crossont will not come to the phone to assist in any way ... I have called them daily for the past five weeks.

They acknowledge reciept of the money order.

They were booted off eBay in "mid transaction with me" and even though they were paid in full ZERO Pistons.

Below is the original thread ---------------------------------------------





I have some 351C parts I have been going to put together for a while ...

My problem revolves around the pistons which are Plain Jane cast "builder grade" pistons.

I mounted four pistons up in the bores and was disheartened to see that they sit about .065 in the hole. Way too far for my tastes.


I did my best to measure thier "compressed height" which appears (to my measurements and calculation) to be approx. 1.62"

In looking up some KB Hypers (the same pistons I used in the Nasty 351C I sold to Brian about a year and a half ago) they show a compressed height of 1.67"

Do those numbers (especially the one I measured) sound to be in the correct ball park ... assuming I'm not making a mistake on my end the 1.67 KBs would chew up most of the "in the hole" problem.

any informed input appreciated.


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<font size=-1>[ This Message was edited by: MonsterMach on 11/9/06 9:30am ]</font>
 

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I think you're right. A difference of .050" will surely bring them up.
the .015" thats left would fall within specs for a factory assembled motor.....sometimes they are even more than that!!
A slight decking would make everything legit.
 

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Discussion Starter · #3 ·
I will want to be less than .010 "in the hole" once complete ...

However ... taking .055 off a perfectly good 4 bolt "C" block just doesn't fit my style.

I'll gladly take a few thousandths off to perfect the deck and get to the desired piston location in the bore.

Thanks for the input just want to be sure I'm not "missing the boat" in some way before spending a couple a hundred dollars for new pistons ... and possibly a bit more to "re-balance"
 

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I'll put it to my machinist in the morning and see if we can get an opinion to go with the good one you already have. He's done several Clevelands fairly recently.

FE
 

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Larry, According to the books at the shop and my machinists opinion, the .065 in the hole is way too much and you might want to re-check it, this time using feeler gauges to square the piston into the block before testing.
He say's it shouldn't be more than 30 thousandths....


FE
 

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Discussion Starter · #6 ·
Gary ... yeap ... Clearly too far in the hole. Measurements are fairly uniform around the circumfrance of the bore so I don't think it's any sugnificant issue of the piston sitting "loop-sided" in the bore.

My question has more to do with my 1.62" measurement for compressed height on the Plain Jane "builder grade" Pistons as compared to the 1.67" KB compressed height.

I have been lead to believe the KBs stood a little taller in the bore ... just trying to determine if the 1.62 sounds about right for stock cast units ... there by helping me be more confident that the KBs would indeed solve most of the problem for me.

Having the current pistons assembled with the rods about all I can do is measure the wrist pin and divide by two then measure from the edge of the wrist pin hole on up to the top of the piston ... and add the two numbers.
 

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Ford Specs call out 1.631 for the '71 boss and 1.657 for the '72 HO.

Paul
 

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My book said 1.643 on compressed height for a stock piston....

The machinist did say that it's very important to beasure in the hole with ALL the rings installed or with feeler gauses on at least two sides of the piston because the amount in the hole you are sitting has to be a bad # because if it's depth...

I must say it but I think you had a "cocked" piston....


By the way, that is a POST '71 Block correct?

Gary
 

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Discussion Starter · #9 ·
After measuring several pistons ... and having nothing show up at more than 1.62."

I think it's safe to say these pistons are short ...

Why ... I can't tell you other than they must have been the cheapest thing that builder could find. They clearly sit too far in the hole and the compressed height measures short by about the amount in question.

Looks like it's going to be KBs for this motor.

Gary ... D2 block

I have a set of these on the way

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8058872753&sspagename=ADME%3AB%3ABOCOR%3AUS%3A1

Thanks for the input guys


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<font size=-1>[ This Message was edited by: MonsterMach on 9/16/06 7:05am ]</font>
 

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I know the old TRW/SpeedPro pistons used to be in the hole a good ways. If I recall correctly, the catalogue showed them to be something stupid like .032-.035 in the hole. Why make a piston you know is .030 too short? I know there was some casting variations back then, but thats a little extreme.
 

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I was thinking you try maybe some Speed Pro L2416F, but what you got seems appropriate.
 

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Discussion Starter · #12 ·
Kid ... this is actually an entire rotating assembly (damper to flywheel) from a motor I had built back in 1997 by a "Shop" ... the block $hit the Bed in about 2,000 miles but the rotating assembly was fine and ran great while it was running.

I kept it in the attic thinking I would rebuild the rotating assembly in a new block one day ... Well, One day finally came and here I am fitting things up ... and as stated "To My Unhappy Surprise" this is what I found I have ... totally NOT acceptable.

In that builders defense I will add ... The heads on the thing were Open Chamber ... so "Quench" was not a huge player in the thinking.

If these KBs are as they seem, (.050 taller than what I have now) ... I'm right back in the game and in fine fashion ... I'll most likely need to touch up the balance, but I suppose that's the price we pay.

These things never come together as cheaply as we might first hope ... do they


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<font size=-1>[ This Message was edited by: MonsterMach on 9/16/06 8:09am ]</font>
 

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Discussion Starter · #13 ·
Gary ... yes ... I think the KBs will be fine ...

This will be built as all the rest of my current motors ... Light Weight, Moderate Compression, Low End Torque, Juiced Roller Cam, Street Motor ... that breathes real well.

No stressfull "Hi Po Extremes" ... just normal drive it on the street "Hot Rod Fun" and possibly a tiny bit of "take it to the Drag Strip" messing around.

Helk the Motor I built with a set of KBs in 1999 and traded to Brian is still performing in his 70 Torino today ...

Should be good for my current purposes, Which is a stupid statment to make, since I don't even own a car to put this motor in


<font size=-1>[ This Message was edited by: MonsterMach on 9/16/06 8:51am ]</font>
 
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