PTS Flowbench Forum

Have been getting my 91 Dodge Diesel ready for sale, and it did sell!

So, my flowbench/heads project, it's on hold, as i begin to build a 360 based block, stroked to a 408.
4" crank, in to a 4.030" bored Mopar block.

I've had this early virgin block for 10+ year waiting for this day!
It's not starting out well......found a ear broken off of the passanger side of the block(motor mount ear)

Pulled a piston and clean the carbon of it. Nope, not standard, it said .040". Yeah so much for the Virgin Grrrrrr

There is no ridge on the cyl wall and all the hone marks are steal there. Has cast piston and looks to be a fresh build(Yeah 10 years a go)

In desperation i think to my self, cast piston are tighter in the bore and i will be using forged that reqires more clearance so maybe it can just be honed out to fit the forged piston.......Yeah i know putting to much cash into the bottom end to cut corners.

Having my machinest looking for a better block to start with...........

Gordon,
Coming from the Auto machinist world what I found was that the clearance was usually built into the piston itself. So if you had a 4.040" engine and the cast piston called for .001" clearance it was usually measured about 1/2" up from the tip of the skirt of the piston and was 4.039" in size. Now most of the forged pistons I did had a barrel face on the skirt and we would measure the clearance in the middle of the skirt about pin center high. A forged piston, depending on material and intended usage would have about .0035 to .006 clearance built in so they would measure 4.0365 to 4.034.

But you should be able to still clean up the hone on the cylinders. Nowadays you are trying to get all the parasitic drag out of an engine so you want the cylinders pretty darn smooth. Also find rings that are meant to be used with a smooth hone..

Some of the cylinders I did almost looked like a mirror surface. We also used low tension rings.

John

Hmm was thinking the bore size was bigger for a forged piston, not the piston was smaller....makes total sence though.

the big problem is the rust. there is vary little as i greased up the cyl when i first started to store it, but there is a couple places that have rust and its not surfice rust either.

I'm going to take it down to him and then make a direction or plan.

Hmm just got to thinking here, the standard bore of the 360 is 4.00" and the 340 standard bore is 4.030. the 4.040(.040 over bored 360) is only .010 more then then the standard 340 piston. Sooo if i had a .020" over 340 piston(4.050) that would only be .010" over the .040" overbored 360. instead of a .060 over i have a .050 over bore with out the $800 set of custom pistons......Hmmmm

Flash, you gotta check the pin height between those pistons. I am assuming the stroke is shorter in the 340 vs the 360 from the bore difference.

Sorry Chris i wasnt quite clear. i'm comparting a 340 stroker piston to a 360 stroker piston aka both with a 4" crank.

The only differance with the 360 has larger mains then the 340 so cranks won't interchange.

Here's a post about my 408 build that I finished earlier this year. I am going to build another one this Winter and raise the compression on it to see how fast we can get one to go. Good luck on your build and keep us updated.
http://board.moparts.org/ubbthreads/sho ... ost6916562

Thanks for the link, nice ride! AND ET!!!!

Mine will be much milder then 9.xx's

Stock E Body with SS spring.....that eng would destroy my Unibody.

Thanks for the compliments. That's a nice looking car you have also.

Listening to you guys almost makes me want to dump my Chevy and build something everybody Doesn't have. I was thinking about an AMC Pacer. Wouldn't that be a cool racer. Well guess what I found on the internet? Go to this link and also note what engine he is running.
http://www.allpar.com/cotm/2009/february-pacer.html

John

gooooo for it John.
I will donate a .040 block to the project! Infact, for the price of rings and bearing, you could have a running 360.

will be down in Utah County Saterday