Engine rebuild: 25 block, 26 crank

[Tom Dove Jr]

After reading a number of posts on engine building it appears the parts of choice are the 25 block due to better casting around water outlet), and 26 crank due to strength.

Are there any other bits of wisdom along those lines?

Tom
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[J and M Machine]

As with anything pushing 100 years old.
Really doesn't matter year it matters of it's condition.
Main thing is to have them crack checked; both block and crank.
Just because people in this forum rave about the EE crank, they crack just like any other.

[Adam]

You could be opening a can of worms if you don’t use “compatible” parts.

If you have a 4 dip pan, you really should use a ‘26-‘27 block and hogshead that have the provisions to be bolted together at the top. This makes the engine rigid. The 4 dip pan is too flexible between the block & hogshead and that is the reason Ford put lugs on the trans cover and bolted it to the back of the block. The flexibility of an incorrect combination can break a crank and or do other catastrophic transmission damage.

Generally, ‘26-‘27 crankshafts are less likely to have cracks but they are more susceptible to abrasion. That wear can be quite off center. Sometimes they will have what appears to be .010” or less wear on the 3rd main journal but they won’t clean up all the way around at .020” under.

Generally, Earlier cranks are more prone to cracks but seem less susceptible to that off center wear.

If you use a lugged hogshead with an earlier block, you usually have to grind the lugs away a bit to clear the block. The lugged hogshead only works with the ‘26-‘27 trans with the wider brake drum. The earlier hogshead will work with the ‘26-‘27 trans but you can only use a narrow band on the brake drum AND you have to inspect for any internal clearance issues and might have to machine a bit off the rear of the brake drum.

[Allan]

if you are putting together a motor with no particular year in mind, then a 25 block and EE 26-7 crankshaft will work , just as any other mix will.

If you use a standard 3 dip pan and transmission with the narrow brake drum, you will have the most usual combination.

Others have added various combinations in their responses, and their application will depend on other considerations than just the block and crankshaft.

Allan from down under.

[Tom Dove Jr]

What I have at my disposal is a 1925 engine (4 dipper) and transmission AND a 1926 engine, transmission, and rear axle.

The plan was to use the 1926 transmission and rear axle for the better braking, the block from the 1925 engine (better casting) and crankshaft (stronger?) from the 1926 engine.

I was looking for input on whether the 1926 C/S was significantly stronger than the 1925 for rebuilding purposes.

Thanks!

Tom
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[walber]

Condition matters most but if you want a stronger crank and engine, bite the bullet and get a new Scat crank. More money for sure but you will be spending a fair bit any way you go.

[Scott_Conger]

Tom

with respect, John Gulbankian, owner of a highly respected engine remanufacturing business has answered the question regarding the crank

good luck on the project

[Allan]

Letting us first know you have both engines to work with would enable more enlightened responses.

If you want the wider brake drum, you need the 4 dip pan and the hogshead with ears, so you might as well go with the 26-7 block.

Allan from down under.

[speedytinc]

Letting us first know you have both engines to work with would enable more enlightened responses.

If you want the wider brake drum, you need the 4 dip pan and the hogshead with ears, so you might as well go with the 26-7 block.

Allan from down under.

I would certainly lean this way. Do due diligence on the 26 block. If its usable, the bolt on H/H is a real advantage.

[Tom Dove Jr]

Thank you all for the replies!

Tom
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[J1MGOLDEN]

Then too, if your 1925 block number notes it was built after July 2, 1925, you have a 1926 EE Crankshaft and two holes drilled in the back to bolt the transmission cover to the block.

[Luke]

Condition matters most but if you want a stronger crank and engine, bite the bullet and get a new Scat crank...

If it were me I think I'd wait until I knew the outcome of this thread before purchasing one of those cranks: viewtopic.php?f=2&t=33084

Luke.

[Tom Dove Jr]

All valid points. I will contact a builder as to what THEY would like to see.

Thank you!!

Tom
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[Kerry]

This is just a speculation thought but a 25 block is at the end of the run of well used molds and the 26 is a re-designed block on fresh molds. I've come across several blocks over the years that only just pass, as in the push rod bosses and valve guides are drilled way off center to keep things aligned.