MachinistOne

Go by the piston/ring manufacturers specs.

MachinistOne

I don't care what flatlander tells you, do they build motors or are they a parts house.......a 1.125 comp height piston is for a 3.75" stoke/6.0" rod combination.

CI Bore Stroke Rod Deck Comp height Compression Relief
383 4.030 3.750 6.000 9.000 1.125 11.9 11.1 9.7 -5.0

Theres a line from the JE catalog....

firebirdStud

Cool! I would be willing to bet that flatlander has not put a motor together.. They may sell a few parts here and there, but I would put my money on you mr machinistOne! Thanks again, you have been most helpful!

firebirdStud

flatlander checked their mahle catologe, and verified it was for a 6.125 rod. So, is there any way you can verify this machinistone? I don't know what else to do/check...

WS6T3RROR

the compression height is the only thing that really matters here when you're deciding what rod length/stroke works with what piston.

3.75/2 = 1.875" - half the stroke

1.875 half the stroke
6.000 rod length

add the two and get 7.875"

now subtract that from a 9" deck and you get a required compression height of 1.125" for your piston for a zero deck.

if you dont wanna take m1's word for it... call mahle

IllusionalTA

Damn.. Doubting M1.. that's rare.. These guy's do this for a living.. well some of them anyway.. Mahle's catalog is wrong as well as the info flatlander posted.. call them and they'll get ya straight..

STeve

MachinistOne

How about this, I talked to the Mahle rep at SEMA who when he gave me the catalog to show me their new inverted dome pistons(the ones I told you to get) commented on the typo. Flatlander just can't do the math for themselves...if that will not do it for ya; you are SOL.

MachinistOne

Ask Flatlander why when they look in their catalog it shows the SBC125030F05 piston kit as a 3.75 stroke/6.0"rod 5cc flat-top and yet the SBC125030I16 is listed as a 6.125" rod....mahles part numbers are very easy to use.

SBC125030F05 (SBC:SmallBlockChevy, 125:Compression Height, 030: Overbore, F05: Flat -5cc)

They are just idiots and cannot put two and two together.

The math is very simple as WS6 pointed out.

firebirdStud

Ok, first, I didn't doubt you per se MachinistOne, merely I was looking for supporting info, which you and another member pointed out. I was looking for the actual "math" behind it, so it could be verified that it is supposed to be a 6 inch rod, just their printer was an idiot and screwed it up! So, Now that it has been explained to me in detail, I do believe you, as the numbers don't lie. I believe in the philosophy measure twice, cut once. I may be a little ****, but I hate trying to return **** after its opened and been bolted to the crank. People don't like to take it back then... So, cool, its been explained, all is good, and I will be ordering those bad boys now!
(I did call flatlander, and I tried to explain the compression height to him, but he didn't care, cuz to him the book was gospel. Guess I will tell him to change what he tells his customers when I order from them. I will order from them, as they are the cheapest I can find)