250 build
- Thread starter 69stang_250
- Start date
turbo2256b
Well-known member
69stang_250":17rncmcz said:
Personally wouldn't waist money on roller tip only rockers.
Well the up side to them over the stock that I have are roller tips and 1.6:1. My stocks are non adj and 1.5:1.
I'm looking around for the full roller sets right now.
I'm looking around for the full roller sets right now.
Gene Fiore
Famous Member
I think Yella Terra used to make them...not sure if they still do.69stang_250":y7u40ldq said:
I have found them on their website. I am looking into how much it will cost to ship them here. The price on the site is $608-609, not including tax and shipping. That honestly may not work out now, but may be what I do down the road.
On the short block, I am doing the following: balance, chamfering the oil holes, reconditioned and shot peen rods, APR rod bolts and main studs, moly rings, .020 over bore, 13cc stock pistons ( deck height will be determined by the CC of the AL Head that is on the way), stock timing set, 274/274 cams, sealed power bearings.
Are there any mods or anything that I have not mentioned I should do for performance or reliability?
I don't plan on going into this short block until its time for another rebuild.
On the short block, I am doing the following: balance, chamfering the oil holes, reconditioned and shot peen rods, APR rod bolts and main studs, moly rings, .020 over bore, 13cc stock pistons ( deck height will be determined by the CC of the AL Head that is on the way), stock timing set, 274/274 cams, sealed power bearings.
Are there any mods or anything that I have not mentioned I should do for performance or reliability?
I don't plan on going into this short block until its time for another rebuild.
80Stang
Well-known member
Info pieces related to this thread:
- I just had my 250 decked for 255-V8 pistons. 0.032" was all it took to have it zero deck. With the CI alum head at 56cc, and 250-V8 pistons custom milled to D-shaped dish of 8cc, this should give 11.0 CR. For me it is The Target, for some it may not be. What comes to pump gas vs CR let's remember it is the dynamic CR that counts, and you can drop that with a longer cam. I'm going to run only 230/230 cam so the dynamic is a little on high side for my build
- rear main seals; you can always have the rear of the block machined for 302-V8 1-piece rear main seal. The end of the 250 crankshaft is the same dia with 302 crankshaft...
- I just had my 250 decked for 255-V8 pistons. 0.032" was all it took to have it zero deck. With the CI alum head at 56cc, and 250-V8 pistons custom milled to D-shaped dish of 8cc, this should give 11.0 CR. For me it is The Target, for some it may not be. What comes to pump gas vs CR let's remember it is the dynamic CR that counts, and you can drop that with a longer cam. I'm going to run only 230/230 cam so the dynamic is a little on high side for my build
- rear main seals; you can always have the rear of the block machined for 302-V8 1-piece rear main seal. The end of the 250 crankshaft is the same dia with 302 crankshaft...
My goal for compression has changed after doing research. 10.2 CR is about max for me, but this is all based on getting those 13cc dish pistons and a 56 cc head, which I will not know till I get the head in. After hearing people talk about getting their pistons machined, that may be rout I go. How much did it run getting those pistons milled?
As for the one piece rear main seal, that sounds like a good mod for ease of maintenance. I will be considering this, when I contact my machinist with the laundry list.
As for the one piece rear main seal, that sounds like a good mod for ease of maintenance. I will be considering this, when I contact my machinist with the laundry list.
...- rear main seals; you can always have the rear of the block machined for 302-V8 1-piece rear main seal. The end of the 250 crankshaft is the same dia with 302 crankshaft…"
new news 2 me…hummm…? Y do it? That specked (1 piece) should seal ok, Y change?
thanx-
new news 2 me…hummm…? Y do it? That specked (1 piece) should seal ok, Y change?
thanx-
Doing that makes it easier to change the seal. With the 2 piece seal, you have to pull the crank in order to change both. The one piece, ya just drop the trans, pull the old out and then put the new seal in. It's just for ease of maintenance in my opinion.
Man, this place is all about learning. I am glad you are learning new stuff. I do every day I get on here.
Any of you guys ever get you Pistons machined for a specific dish cc?
Yeah, I wanted 8cc's. I gave him a drawing of the size, shape and orientation and Cal figured the depth to get the volume I needed. There's got to be a limit to how much material can or should be removed though...
But over that size of a dish 8cc was not a whole lot. If you look at the Silvolite pdf catalog you get an idea of how much material is in the top of the various pistons available, 2.3's, 2.5's, oems, and the 255's, the flat tops are thicker than the dished ones. They offer hypereutectic versions of the Australian falcon 6 pistons in flat top or various dish sizes, but they only raise the compression height .030". Those are new afaik. That's the trouble with the 250, it's really expensive or it's a compromise. If you haven't already, check out 62Ranchero200's 250 build threads, here's one.
http://fordsix.com/viewtopic.php?f=1&t=70677
https://www.uempistons.com/catalogs/silvolite_catalog.pdf
But over that size of a dish 8cc was not a whole lot. If you look at the Silvolite pdf catalog you get an idea of how much material is in the top of the various pistons available, 2.3's, 2.5's, oems, and the 255's, the flat tops are thicker than the dished ones. They offer hypereutectic versions of the Australian falcon 6 pistons in flat top or various dish sizes, but they only raise the compression height .030". Those are new afaik. That's the trouble with the 250, it's really expensive or it's a compromise. If you haven't already, check out 62Ranchero200's 250 build threads, here's one.
http://fordsix.com/viewtopic.php?f=1&t=70677
https://www.uempistons.com/catalogs/silvolite_catalog.pdf
80Stang
Well-known member
chad":2e4oxp27 said:
Yes I ordered the machining from the machine shop, but they forgot to do it. I was 40 miles out there to pick up the milled block and while this engine probably never goes to any of my cars, I thought "never mind"...
But more than ease of changing the seal I value the 1-piece to seal better. Those 2-piece seals seem more prone to leakage, based on my experience.
turbo2256b
Well-known member
hAVE HAD MORE LEAKS using 1 piece seals than the old 2 piece ones and have replaced some 2 piece seals just by dropping the pan and rear main cap. Didnt work on my 460 though due to tabs on the seal. Did replace the bottom half though. 400 351Ms and SBFs it has worked. My 400 has 75K on it and doesn't leak. Low millage on my 302 1 piece seal leaks a bit low millage since changed. Some of the 1 piece seal leakage in fords was due to change in mfg of the seals .
To be honest, I use to help my dad change rear main seals on 302's all the time when I was younger. After having a long conversation with him last night. His suggestion was to just use the 2 piece seal, remove that pin in the main cap and off set the seal 1/4 inch. Seems to be the standard to prevent leaks on these when I talk to older mechanics. So I think ill just stay with the 2 piece seal.
"...pin in the main cap and off set the seal 1/4 inch..."
I see the pin (actually just a hole now it's gone to the machinist) that held the rope seal. But that's not "the main cap".
How do U "off set the seal 1/4 inch" - it can only go in one groove. Is that by stretching it up, leaving it 1/4 inch proud of it's 'race' or grove?
Thanks,
I see the pin (actually just a hole now it's gone to the machinist) that held the rope seal. But that's not "the main cap".
How do U "off set the seal 1/4 inch" - it can only go in one groove. Is that by stretching it up, leaving it 1/4 inch proud of it's 'race' or grove?
Thanks,