200 rods in a 250.... info please!

[MRJLB84D]

Can anyone explain to me how the combo of using 200 rods in a 250 works?
are 200 rods longer or shorter?
does it make these ol babys wanna rev better wif this combo and has anyone done it with a 2v head?
what about pistons, do you use 250 or 200 pistons?

Im a thirst for information!



p.s a 2v head will bolt onto a XB block right??
Cheers gang!

 

[addo]

You need a special ACL piston set (about $450 with rings, from memory). These slugs have the pin hole closer to the crown. The 200 rods are longer, which improves the rod ratio. It works by actually slowing the piston speed as it approaches TDC, and the resultant effect is slightly less "slamming" of the fuel/air mixture, reducing knocking.

On a street only motor, you'd be hard pressed to notice the difference, except maybe at top revs, or possibly in longer service life.

Cheers, Adam.

 

[Anonymous]

If someone offered me a fully balanced re-built 250 or a re-built long rod 250 that had not been balanced I would take the balanced short rod 250 any day over the long rod one. Probably not worth putting in long rods unless did both anyway but much cheaper for just full balance.
My boss just bought a re-built Repco engine (cost him a fortune) and he has severe vibration problems since it was installed.
Cheers Tim

 

[addo]

Which does not surprise me one bit!

 

[MRJLB84D]

cant belive repco are still building engines! heard to many bad storeys and expensive ones too

 

[Anonymous]

You can buy the pistons i have for sale which are designed for the 200 rod

Can anyone explain to me how the combo of using 200 rods in a 250 works?
are 200 rods longer or shorter?
does it make these ol babys wanna rev better wif this combo and has anyone done it with a 2v head?
what about pistons, do you use 250 or 200 pistons?

Im a thirst for information!



p.s a 2v head will bolt onto a XB block right??
Cheers gang!

 

[MRJLB84D]

hey tags!

thanks mate but im just inquiring about the combo for now... my mind is goin a million miles an hr wif ideas.... decisions decisions!

cheers

 

[CZLN6]

Howdy All:

USA rods for a 170/200 measure 4.715". 250 rods measure 5.88". Is it possible the OZ rods are different?

Adios, David

 

[addo]

David, this is from the "long rod" 200 (6¼-odd inches approx). XE refers to it as the "Geelong motor". It's a 200 crank in a 250 block. Also longer than a 250 rod is (from memory) a 188 rod.

Regards, Adam.

 

[xctasy]

The Aussie 250 has the same rods as the US250.

All Aussie sixes use the same bearing widths as the little 144/188/200/221 engines, no special thrust and main bearings like the US 250. The US/Canadians did many upgrades for stregth on the US 250 crank. Front timing gear, block pattern, cam spacing, pan rail, oil-pump drive, water pump and balancer dimensions.

Rod bearings on all Ford sixes are the same (asside from crush and material, which is normally F500, but does vary)

For example the conrod bearings seem to be the same for basically every model falcon six including auusie and U.S models.

Read dilligently alloydave's post of the Aussie verses US 250.

http://fordsix.com/forum/viewtopic.php?t=3124&highlight=

The Aussie 200 from 1971 on had a taller 250 block. It was a really destroked 250 with the big main bearing crank, 3" crank bolt spacing at the flywheel, with a 3 5/8" diameter. All post 1961 Aussie con-rod stuff is forged in Australia with an ARD>>>> part number, so are as near as dammit to US items.

There are stock 144-170-200 rods, 4.71" just like yours.

The 1968 XT Falcon ran the first Argie/Aussie hybrid block. It was a 200 derivative with seven bearings, but another 617 thou on the block. Some of the info is found on Aussie7 Mains' brilliant Tech article on Aussie sixes, but has been wrong for the last 18 months because of a transposed figure. The two engines are the 188, with 5.4" long rods and a seven bearing 170 crank with 2.94" stroke, and the 221, with 5.15" long rods, and a seven bearing 3.46" stroke crank which is exactly the same as the 200 crank in all dimensions except 'throw'. No thrust, main, rod bearing or crank flange or snout changes.

The total amount of con-rod types for all Ford I6's of the 4.08" bore spacing familiy is six. 4.71, 5.15, 5.40, 5.88, 6.27, 6.06. There are of course the two 2.3/2.5 HSC I4 items for Tempo/Topaz engines. These are 5.45 and 6.00, bringing the count to 8 rods. All are swap prospects if you can find one of the 18 blocks Ford cast world wide for there passenger and truck lines. Happy hunting!

Here is my ammended list of http://fordsix.com/aussiesixes.htm


C.I.
BORE
STROKE
ROD
YEARS


144
3.5
2.5
4.7
1960-1966
Integral Manifold

170
3.5
2.94
4.7
1960-1966
Integral Manifold

188
3.68
2.94
5.4
1967-1969
Integral Manifold

200
3.68
3.13
4.7
1966-1967
Integral Manifold

200
3.68
3.13
6.27
1970-1988
Integral Manifold

221
3.68
3.46
5.51<<<<5.15"
1967-1969
Integral Manifold

250
3.68
3.91
5.88
1970-1976
2V head

250
3.68
3.91
5.88
1976-1978
Iron X-flow

250
3.68
3.91
5.88
1978-1987
Alloy X-flow

191
3.6
3.13
6.27
1988-1990
OHC

239
3.6
3.91
5.88
1988-1990
OHC

240
3.64
3.91
5.88
1990-1998
OHC

240
3.64
3.91
6.00<<<<6.06