250 rod sizes, any alternatives?
- Thread starter MRJLB84D
- Start date
), but besides the hemi rod option, what size are the 250 rods, compared to say, clevo 351 or 302 rods?
Rods. Scatt, Lunati, (Ridegcrest?) made after market Chevy 5.85".
I'd presonally use the interferenace fit wrist pin, but there are floating wrist pins available if you go for fully custom pistons.
That 1500 hp BA Turbo by Nispro has Chev rods and Jap rings on a kind of Subaru forged piston by Precision Crankshaft Regrinders.
The 5.7, 5.85, 6" and even 6.2" SB Chevy rod is cheap and very strong. You can grind the crank out to fit V8 bearings in large (2.10") or small journal (2.0") sizes. 0.927" Wrist pin needs bigger Chev or costom Ross pistons reworked by an Austrlaian supplier. You can bush the rod with phospher bronze for Spriolocks or teflon buttons. this is a favorite drag racers trick so the engine can be rebiult in the back of the panno or truck on site, rather than having a wrist pin get stock half way out when heating it and ruining a piston when your in a rash.
Old Hemi 215/245/265'S run 5.75" rods, with 0.927" wrist pins and 2.0" mains. Perhaps the strongest factory rod around.
Stock Ford rods in the 5.88, 6.06 and 6.27" length are not great. Rods wrist pins are 0.9112", big ends are 2.124". Past 260 kw or 350 hp on pump gas, they are a risk, mainly due to detonation. At a constant 400 hp, they will get close to breaking if they a leaned on. Rod bolts help, but the rest is too small in the beam section compared to any Hemi or SBC rod.
Holdens 5.622" rod is to short, but is also quite a nice rod.
Forget any SBF rod. No to 5.6 or 5.0. The Windsors are too short. The crank pin is the same, but wider. At a centre to centr espacing of 5.45 or 5.09".Wrist pins are 0.9112"
Not the 351C or 302C. They have 5.78 or 6.03" long rods. The Clevelands have a way too big crank pin, a massive 2.311". Wrist pins are 0.9112" No way it'll ever fit in the 250 crank case unless you weld up 4.7 mm of long run weld, and then regrind the crankgrind, the regirnd the cam shaft, block and rod bolts back. Ford had to modify the stock non cross flow cam fit the later 250 engines becasue the cam runs very close to the pistons.
The newer truck Romeo/Cleveland 'Cammer' 5.4 has rods about 6.21" or so from memory, and have smaller crank jornals of about 2.09", with smaller wrist pins for tiny 90 mm pistons. These rods are crack off items, which are not easy to reuse. I'd stay away unless you can get them cheap. A six leans on its rods more thana V8, and they have to be good, cheap, and if anything goes wrong, it must be a common kind of rod.
Pistons. Chevy 305 or 229 V6 forged items. Stock Chevy size is 3.736", or 56 thou over for a For 250.
It has a 12cc dish, 1.531" compression height. Open the cahmbers up from 49 to 53 cc to 62 cc, and run the thickest composite gasket you can find. Add the Isky O ring kit. Nispro do it for there Nissan guys. Check Kieth Black, Ross and Wiseco on the web.
Yes, Virgina, ACL's will cope with boost, but the forged pistons run cooler, and are stronger under the loads, and allow a full set of solid after market bits to be used.
Don't worry about the 250's wall thickness. It's a full thinwall casting for sure, but they are a dime a dozen, and as long as there is no core shift, you'll be set for years of abuse and fiendish
happiness!
I'd presonally use the interferenace fit wrist pin, but there are floating wrist pins available if you go for fully custom pistons.
That 1500 hp BA Turbo by Nispro has Chev rods and Jap rings on a kind of Subaru forged piston by Precision Crankshaft Regrinders.
The 5.7, 5.85, 6" and even 6.2" SB Chevy rod is cheap and very strong. You can grind the crank out to fit V8 bearings in large (2.10") or small journal (2.0") sizes. 0.927" Wrist pin needs bigger Chev or costom Ross pistons reworked by an Austrlaian supplier. You can bush the rod with phospher bronze for Spriolocks or teflon buttons. this is a favorite drag racers trick so the engine can be rebiult in the back of the panno or truck on site, rather than having a wrist pin get stock half way out when heating it and ruining a piston when your in a rash.
Old Hemi 215/245/265'S run 5.75" rods, with 0.927" wrist pins and 2.0" mains. Perhaps the strongest factory rod around.
Stock Ford rods in the 5.88, 6.06 and 6.27" length are not great. Rods wrist pins are 0.9112", big ends are 2.124". Past 260 kw or 350 hp on pump gas, they are a risk, mainly due to detonation. At a constant 400 hp, they will get close to breaking if they a leaned on. Rod bolts help, but the rest is too small in the beam section compared to any Hemi or SBC rod.
Holdens 5.622" rod is to short, but is also quite a nice rod.
Forget any SBF rod. No to 5.6 or 5.0. The Windsors are too short. The crank pin is the same, but wider. At a centre to centr espacing of 5.45 or 5.09".Wrist pins are 0.9112"
Not the 351C or 302C. They have 5.78 or 6.03" long rods. The Clevelands have a way too big crank pin, a massive 2.311". Wrist pins are 0.9112" No way it'll ever fit in the 250 crank case unless you weld up 4.7 mm of long run weld, and then regrind the crankgrind, the regirnd the cam shaft, block and rod bolts back. Ford had to modify the stock non cross flow cam fit the later 250 engines becasue the cam runs very close to the pistons.
The newer truck Romeo/Cleveland 'Cammer' 5.4 has rods about 6.21" or so from memory, and have smaller crank jornals of about 2.09", with smaller wrist pins for tiny 90 mm pistons. These rods are crack off items, which are not easy to reuse. I'd stay away unless you can get them cheap. A six leans on its rods more thana V8, and they have to be good, cheap, and if anything goes wrong, it must be a common kind of rod.
Pistons. Chevy 305 or 229 V6 forged items. Stock Chevy size is 3.736", or 56 thou over for a For 250.
It has a 12cc dish, 1.531" compression height. Open the cahmbers up from 49 to 53 cc to 62 cc, and run the thickest composite gasket you can find. Add the Isky O ring kit. Nispro do it for there Nissan guys. Check Kieth Black, Ross and Wiseco on the web.
Yes, Virgina, ACL's will cope with boost, but the forged pistons run cooler, and are stronger under the loads, and allow a full set of solid after market bits to be used.
Don't worry about the 250's wall thickness. It's a full thinwall casting for sure, but they are a dime a dozen, and as long as there is no core shift, you'll be set for years of abuse and fiendish
happiness!
Nice info X
gassed250
Well-known member
Nizpro engine is making 1226hp on pulp and they say it will do 1600hp with better fuel and more boost and ignition
The engine uses a custom forged crank and engine cradle, custom billet rods and a chromolly liner in number 1 only
As far as a set of rods go cant you just use a set of el 4ltr rods and get them peened
The engine uses a custom forged crank and engine cradle, custom billet rods and a chromolly liner in number 1 only
As far as a set of rods go cant you just use a set of el 4ltr rods and get them peened
so x ya saying i should go the chev rods? (cheaper too, one good thing about chev stuff its strong, popular and cheap compared to some ford gear)
As for the EL rods i hear they just as bad, but instead of having them shot peened, i read in ZOOM magazine, instead of heat treating parts, there is a new process that like deep freezes parts which makes them even stronger... i cant find the mag anywhere tho to check out the place so has anyone got an idea the place or the process im talking about? If its tru i got heaps of STD 250 rods and it will make things a lot easier!
As for the EL rods i hear they just as bad, but instead of having them shot peened, i read in ZOOM magazine, instead of heat treating parts, there is a new process that like deep freezes parts which makes them even stronger... i cant find the mag anywhere tho to check out the place so has anyone got an idea the place or the process im talking about? If its tru i got heaps of STD 250 rods and it will make things a lot easier!
A
Anonymous
Guest
im pretty sure some of the speedway guys are using the 200ci rods and sticking the 250 pistons on them to make them quicker. acl make the pistons to go onto the rods
The piston for 6.06" AU rods is the old 3.9 or 4.0 EA to early EL items. They are 1.37" deck, but it is 68 to 48 thou too small in diameter. Option is to get a 60 thou over EB II to EL piston, and hone a stock block out 12 thou to 3.692".
If a stock 250 is bored 20 thou or 30 thou over, then to run these OHC pistons, you have to sleave the block back. It's no hardship to spend 1000 bucks to sleave it to 3.632" (Stock EBII to EL size) if you want it to last for another 50 years. You could forseably run it for another 3 lots of +0.030 over bores with it sleaved to suit a D-series Ford truck, or 305 3.766" Chevy liner. I thinlk the Pug 505 had a 2.5 Diesel liner which may fit too. Depends what your machinist is comfortable with.
ACL's other oversize pistons are only 1.163 compression height and still run the small 0.9112" wrist pin. You need to run rods of x-flow 200 cube size (6.27") to work with these.
I'm sold on aftermarket, never been in a Chev, but Chevy spec rods, Chevy spec 305 pistons, and you won't have any hassles. Yair, 56 thou is up on the streach of a Ford 250, but is not a real problem, blocks are cheap.
Just tell them pesky Commodore drivers your getting your own back on letting the General use Ford diffs for every hot Holden V8 from 1986 to 1996.
If a stock 250 is bored 20 thou or 30 thou over, then to run these OHC pistons, you have to sleave the block back. It's no hardship to spend 1000 bucks to sleave it to 3.632" (Stock EBII to EL size) if you want it to last for another 50 years. You could forseably run it for another 3 lots of +0.030 over bores with it sleaved to suit a D-series Ford truck, or 305 3.766" Chevy liner. I thinlk the Pug 505 had a 2.5 Diesel liner which may fit too. Depends what your machinist is comfortable with.
ACL's other oversize pistons are only 1.163 compression height and still run the small 0.9112" wrist pin. You need to run rods of x-flow 200 cube size (6.27") to work with these.
I'm sold on aftermarket, never been in a Chev, but Chevy spec rods, Chevy spec 305 pistons, and you won't have any hassles. Yair, 56 thou is up on the streach of a Ford 250, but is not a real problem, blocks are cheap.
Just tell them pesky Commodore drivers your getting your own back on letting the General use Ford diffs for every hot Holden V8 from 1986 to 1996.
Similar threads
