250 main cap girdle

Well I just ordered a main cap girdle for my 250 turbo build I will be starting the summer. I also ordered the ARP stud kit he puts together. http://www.ebay.com/itm/371663065033?_t ... EBIDX%3AIT It was 411.00 US with shipping from Aus to the US.

You'll need to have the tops of the main caps machined flat and to all the same height to use that, but that design seems to work good.

CNC-Dude":1ms7sonr said:

You'll need to have the tops of the main caps machined flat and to all the same height to use that, but that design seems to work good.

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according to the description, it includes spacers to clear the hump in the main cap.

that said however, i recommend machining the main caps flat so that the girdle has full contact on each main cap for maximum effect.

I agree with that as well, having full contact will make the girdle much more effective.

My only problem with it is ..If it is that important why not a work around for the oil pump...I am sure something could be done...Of course that would make a lot more work and cost..Probably a selling issue.

drag-200stang":t89s695p said:

My only problem with it is ..If it is that important why not a work around for the oil pump...I am sure something could be done...Of course that would make a lot more work and cost..Probably a selling issue.

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cots effectiveness is an important factor, and most people that use a main cap girdle are not going ll out racing, and thus dont need maximum strength. and those that do go all out racing, and thus need the maximum strength, will most likely use a dry sump oil system, or a remote mount oil pump so that a maximum effort main cap girdle can be used.

A lot of what you see in the industry like this type of product is derived from the V8 sector of racing and performance market, it then trickles down to the inline niche where it often has to be adapted and modified to be used on those engines. Unfortunately with that adaption, it many times looses some of its design parameters to fit these other engines and thus some of its effectiveness. The first main girdle I ever saw was in the early 80's that was used on the then NASCAR Chevy engine of that era. Even at that time, the girdle was several years old and "old technology" even for 1982 or so. Billet caps were the new thing from that point on and still are. But the girdle does more than just tie all the mains together, it does strengthen each main cap by effectively making the main caps think they are thicker than they actually are, especially when you correctly mill the caps flat so the girdle sits flat on them. If you use spacers to raise the girdle above the caps, you can still have a cap break, because it provides no additional support the caps as they were originally intended to do.

Thanks guys I will have them milled down also. I will post picks as I build it. Mustang Monthly will be following along as I do my build.

Well done. Great baby steps for a US 250 engine that is bullet proof.


Since Ford sublet its oil pump supply you can even spend some time to copy the Aussie g rotor system. XR6-T big barra oil pump,billet gearset,steel reinforced backing plate

http://cdn2.bigcommerce.com/server1400/ ... 80.JPG?c=2




You can even G rotor the crank and copy the full crank girdle if you want to.


..There's a BA 10 weight crank.

It has a g rotor oil pump up fornt.
http://www.atomicperformanceproducts.co ... G_8355.jpg


The earlier, rather expensive and over engineered EF 12 counterweight crank is more like the US 200 in the front. See Balrics m90 supercharged 250 engine build.

The later BA BF FG FGX XR6 Turbo / F6 can use Billet Oil Pump Gears ie the Genuine Intune Motorsport ones, on a smaller 1.248" crank snout.


If your really keen, you can fit a g-rotor pump at the front. but its a lot of work. There are aslo factory 12 counterwight cranks which can take the BA front g rotor pump.


Mike1157 uses a remote pump.


Its all about How Far Do You Go, isn't it?




The Aussie 250 and 4.0 crank never moved to the US 1.375" so you can copy the 2002 to 2016 snout if you wanna.

Everything integrates if you copy the DOHC hard points.



http://www.nizpro.com.au/wp-content/upl ... -BA-20.jpg

65-coupe":6yivklr8 said:

Thanks guys I will have them milled down also. I will post picks as I build it. Mustang Monthly will be following along as I do my build.

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I would not mill the caps, it is not designed for that, to thin...Just use it as designed , it will be fine.
Has Will and Kelly had a problem or Fast 64 or Mike 11...?
On a NA 200 in the 7500-8000 range, I had cap walk, went to studs, turbo and a lower 6800 rpm and more than 400 HP, no more problems...A turbo is easier on the engine as long as the tune up is good.

I was going to ask why? What kind of power are you looking for? The 250 isn't a rev king, thus eliminating the need. If you search my name in the turbo section you will see I made pretty good power and never saw main cap walk with a 250. I'd worry about getting a cam chain setup first that was my main problem. maybe that problem has been cured by now? been out of the 250 game for a while...
Added insurance I guess... If you need a turbo, I still have mine from my build, it worked really well on mine... good luck

fast64ranchero":262knpad said:

I was going to ask why? What kind of power are you looking for? The 250 isn't a rev king, thus eliminating the need. If you search my name in the turbo section you will see I made pretty good power and never saw main cap walk with a 250. I'd worry about getting a cam chain setup first that was my main problem. maybe that problem has been cured by now? been out of the 250 game for a while...
Added insurance I guess... If you need a turbo, I still have mine from my build, it worked really well on mine... good luck

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Yeah I bought it just to make the bottom end stronger. I am shooting for 300+HP and 400+TQ. I have a turbo but not sure the size. It needs to be rebuilt but I will keep you in mind.

You should make that no problem with the CI head, I made over 440 whp and over 500 ft lbs to the wheels on 18 psi with my modified cast iron head. I think I was at 330 WHP at 12 psi. My setup was fully spooled at 2800 rpm with a 62-1 BB turbo, if I was going to do it again, I'd use a EFR 7670 or larger depending on if it was street or street strip. The EFR series are just flat out awesome turbo's. I'm making 525 WHP with a 7670 on my Ecoboost mustang, with more room if I want more.

fast64ranchero":39m00b5n said:

You should make that no problem with the CI head, I made over 440 whp and over 500 ft lbs to the wheels on 18 psi with my modified cast iron head. I think I was at 330 WHP at 12 psi. My setup was fully spooled at 2800 rpm with a 62-1 BB turbo, if I was going to do it again, I'd use a EFR 7670 or larger depending on if it was street or street strip. The EFR series are just flat out awesome turbo's. I'm making 525 WHP with a 7670 on my Ecoboost mustang, with more room if I want more.

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I am planning to run 12 to 15 of boost. Should be a fun build I will post when I start it later this year. I still have to finish my pint and body work.