Looking for some pics of...
05-06-2010, 12:13 AM
#1
Looking for some pics of...
Anyone have any pics of a piston protrusion @ BDC on a 408 and the same thing for a 370?
Basically I'm looking to see how much of the piston sticks out of the cylinder walls on a 4" crank vs 6.125" crank. If anyone has any of those pics please also indicate rod length.
Thanks.
Basically I'm looking to see how much of the piston sticks out of the cylinder walls on a 4" crank vs 6.125" crank. If anyone has any of those pics please also indicate rod length.
Thanks.
Last edited by Spoolin; 05-06-2010 at 11:36 AM.
05-06-2010, 11:07 AM
#5
There were marks of the on the bottom of my piston skirts where the bottom edge of the cylinder wall is. I wish I took pictures when it was apart, it was a little disappointing to see them. I am just guessing now, but it seems like they were about 5/8" above the bottom edge of the piston skirt. Just a line across the face, and a little wider mark towards the corners(?) of the pistons. The marks were only visible, you could not feel them. The builder tried to talk me out of a stroker from the beginning. He said a 370 was the way to go for the street. All four guys in the shop said that those were typical stroker marks, made when the piston rocks at BDC.
05-06-2010, 11:31 AM
#7
Dang, I would of liked to of seen those pics. How far below the oil rings was that mark and what length rod were you using? Stock or 6.125 or ??
I think I found a compromise for what I'm gonna do because 408 + boost + long term reliability is clearly a pick two of three scenario.
I think I found a compromise for what I'm gonna do because 408 + boost + long term reliability is clearly a pick two of three scenario.
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05-06-2010, 11:41 AM
#8
From a separate conversation...
Does the piston skirt sit exactly flush with the bottom of the cylinder wall at BDC on a stock stroke motor?
I don't have any engine laying around right now to make or take any measurements, hoping someone took some pictures one upon a time. But I see what your saying, and I've taken the stock piston, rod length and pin height into account, I'm just looking for some visual confirmation.
Originally Posted by Dezert1500
Stock stroke is 3.622 or 92mm, a stroker 408 is 4" or 101.6mm so at BDC you would be .378 further out of the cylinder which is equivelant to 9.6mm or 3/8th of an inch
Originally Posted by Dezert1500
You need to find out how much the piston skirt protrudes out of the cylinder at bdc then get the height of that piston. Then you can see how much piston is still left in the bore. Once you have that subtract 3/8" from how much of the piston is in the cylinder on the stock stroke and you will get how much is left in a stroker. Remember different pistons have different skirt lengths so make sure your comparing apples to apples. I'd go off a stock piston for measurements.
Originally Posted by Dezert1500
Its not a matter of how far the skirt sticks out. Its s matter of where the piston pin is in relation to the bottom of the cylinder bore and how much piston is still engaged in the cylinder
Last edited by Spoolin; 05-06-2010 at 12:03 PM.
05-06-2010, 02:09 PM
#10
Actually I already know what I'm doing, crank size, rod length, pin height, custom piston in order to minimize piston protusion. It's gonna turn out to be an odd number displacement, somewhere in the range of 390 ci, but I still want to see how much of the piston sticks out on a 408. This is just curiosity, you read around on the forum's and you hear about 408's burning a slight amount of oil and that after 40K miles they should get rebuild, etc... Most of that is regurgitated hearsay. So I just wanted to see some pics of it, etc...
Last edited by Spoolin; 05-06-2010 at 02:22 PM.