Crank and rods interchange

[idvette]

I have a 2.4 175 in pieces, others have called it a fat block, but I'm not exactly sure if it is or not. A guy local to me needs to replace his 2.5 crank, brought his over to compare to mine and see if it would work for him. Main bearing journals matched, rod journal diameter matched but his rods were 2 mm narrower and had no windows in the caps. Mine also has 1 more sealing ring than his. It's a perfectly good crank and 5 good rods, what is my market for resale? 2.4 only?

[tlwjkw]

does your crank have tha "plastic caged" center main bearings??? if it does it should also have "shoulders" on tha journals also.... if thats tha case it can be used with justa 'bout any block with tha right bearings...

[idvette]

does your crank have tha two "plastic caged" center main bearings???

Yes, so did his.

[tlwjkw]

jus make sure tha O.D. of tha center bearings are tha same as his block..... have no idea on what anything sells for now days??? parts and prices are jus crazy seems like.

[idvette]

Od was the same, journals and bearings. But it's the rods that are different. Journal size is the same, but rod width between the counterweights is different. My crank has bigger shoulders on the counter weights with wider rods (2mm wider). Pretty sure his is standard 2.5 stuff. I'm not looking to know asking price, I'll sort that out if someone can use the parts. Just wondering who I can sell to, or maybe what else I'd have to sell to make it work (crank and rods together?)

[tlwjkw]

your crank probably used "bottom" guided rods (used in first "fat blocks") where his is for top guided.... can't remember for sure what tha measurements were.... do ya have tha rod numbers for yours and his?.. should be stamped on tha rods?

[idvette]

your crank probably used "bottom" guided rods (used in first "fat blocks") where his is for top guided.... can't remember for sure what tha measurements were.... do ya have tha rod numbers for yours and his?.. should be stamped on tha rods?

I'll post a few pictures tonight after work

[LakeFever]

Hmm i thought the cranks were the same except for the top bearing. Small/big. Im almost positive i recall a member rebuilding a 260 using a small cap 2.0L crank?

[tlwjkw]

top cap bearings came in two sizes.. think they are 1 3/8" and 1 1/2" ID.. ) OD same but different cranks.. think tha early production 2.0's and hi perf. 2.4's (pre fat blocks) were tha 1 1/2".. tha production 2.4's were 1 3/8"... when most reference big bearing they are talking later model top bearing.. it is very a large "ball bearing" type.. High Perf. only..

where it gets confused is when someone references tha 1 1/2" as a "big top bearing"............. jmo.

[rjdubiel]

Found this on here, not sure if 100% correct but most sounds correct to me.

V-6 Cranks (pre heavy metal ball bearing top journals Big Bearing 260/280/300)

The large / small main dia. Refers to the top journal only 1.375 small 1.500 large
The two center mains are all 1.375 Dia. on all
The 1.5 top cranks were used on 2.0 135s, 150s and on HP models.
The 1.375 tops were used on most all 2.4 & 2.5 production models.

However there are several important differences worth noting
1.5 tops have a narrow center journal with thrust faces that require plastic caged mains
this crank also has the thrust faces required for bottom guided rods. (top or bottom guided rods can be used in these cranks)

1.375 2.4 cranks have a wider center main journals for use with the wire caged mains and also have the thrust surfaces for the bottom guided rods (top or bottom guided rods can be used in these cranks)

1991 and later 2.0 & 2.5 cranks have the 1.375 on all three main journals with thrust faces for plastic cages with the large rollers but lack thrust faces on the rod journals (top guided rods must be used)

[idvette]

521728

521729

521730

521731

521732

521733

521734

[idvette]

So does anyone have some insight on the wide rods with cap windows vs narrow rods without? Can the narrow rods be used on my crankshaft, or would the crank and rods be a matched set?

[OnPad]

Wide rods are bottom guide (pre 1991).
Narrow are top guide (post 91).
You have to use the correct piston to match the rod.

Either rod should work on your crank.