Crank confusion....need some help.

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Model T Ford Forum: Forum 2012: Crank confusion....need some help.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Tuesday, October 23, 2012 - 07:23 pm:

Since I found out that the crank for my '26 is cracked I've received a lot of offers to help my situation. Now I really need some advice. I've heard diamond, AA and EE, even put a A crank in a T engine. Can someone give me some advice on this matter, from what I have researched the EE is the better one. Is there that much difference to be concerned with and how can I tell visually? What about the A in the T motor?


Top of pagePrevious messageNext messageBottom of page Link to this message  By J and M Machine Co Inc on Tuesday, October 23, 2012 - 07:52 pm:

Jim: The EE crank is the what everyone looks for.

However, you still need to magnaflux the crank which ever one you find as AA - EE they still crack,it all depends on how the car was driven.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Tuesday, October 23, 2012 - 08:00 pm:

The EE crank is a bit beefier but still light when compared to the A crank. If it was me I would go for the A crank conversion if I was going to be doing a lot of driving. Otherwise, I would go for a new Skat crank. I have only had two crank failures in over 40 years of driving T's but both of them have been recently which makes me think that the original cranks only have so much useful life left in them. The crank in my '10 went first and then two years later the crank in the '12 broke. I will not do a rebuild with an original T crank again. If finances did not permit going with an A crank or a new Skat crank I would look for an EE crank that has not been cut and hope for the best. Good luck and whatever you do if you go for the EE crank have it magnifluxed and if possible X-rayed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, October 23, 2012 - 09:20 pm:

I will use a new Scat counterbalanced crank next time. It will be cheaper than buying 5 different EE cranks and having them all magnufluxed and throwing away the four bad ones. It will be cheaper than modifying an A crank to fit.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Tuesday, October 23, 2012 - 09:30 pm:

I have an A crank that's inserted and drilled for pressure. NO problems so far.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Robison on Tuesday, October 23, 2012 - 09:44 pm:

Lots of machine work is required to fit a Model A crank into a T. A reputable machinist will probably charge you about the cost of a Scat crank to fit it into a T.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Robison on Tuesday, October 23, 2012 - 09:53 pm:

The EE crank was used in late production 26-7. It is the same shape as the AA or AAX 26-7 crank. The main difference is the vanadium steel wasn't used. Then in 1928 the vanadium steel was reintroduced in the cranks. I have seen both AA, AAX, and EE cranks broken both Model A and T. The best advice I can offer is to align the tail shaft and make sure the oil pan is straight. This will help prolong the life of any crank.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Wednesday, October 24, 2012 - 06:21 am:

Era crankshafts for Model T Engine:

(The plus is a positive; the - is a negative, of course.)

1. Stock crank
' ' +A. Guaranteed fit
' ' +B. Flexibility may help durability
' ' +C. Ben Yumori claimed to have 260K miles on stock '26 crank
' ' -A. Forging voids lead to cracks
. . . . 1. Long history of breaking - the Bent Hairpin Crank
' ' -B. counterweights available, but found not to help

2. Model A crank

. . +A. Popular conversion - readily available

. . +B. Extra 1/4" stroke gives more low end torque

. . +C. Rod journals are 1.5"

. . +D. Counterweights are readily available

. . =C. Mains must be cut to 1.6" to clear T main bolt spacing

. . -A. Extra 1/4" stroke makes high rpm more problematic

. . -B. Extra 1/4" stroke requires many mods
. . . . 1. Stock A rods (longer than T rods)
. . . . . . -a. requires special short pistons with oil ring over pin boss
. . . . . . -b. need bumps in sides of pan to clear
. . . . 2. Special short rods
. . . . . . +a. fewer mods required
. . . . . . -a. wider rod to cylinder angle for more wear and lower efficiency
. . . . 3. 1/4" spacer under pan cover needed

. . -C. Crank is longer between rods than T.
. . . . -1. Rods are not under centers of pistons, for more wear
. . . . -2. #1 & #4 are worst for off center
. . . . -3. #1 rod running in forward part of dip - bad on hills

. . -D. Crank is 3/4" longer than T aft of rear main
. . . . 1. Leave crank full-length and move block 3/4" forward on pan
. . . . . . -a. fill and drill new mounting holes
. . . . . . -b. move front dam forward
. . . . . . -c. water outlet too close and steep
. . . . . . -d. 3/4" spacer needed between hogshead and block
. . . . . . -e. #1 rod dip must be extended to clear
. . . . . . -f. extra length largely unsupported
. . . . . . . . 1. bad news with heavy flywheel
. . . . . . . . 2. mine had 3 cracks in #4 journal at teardown

. . . . 2. Shorten crank 3/4"
. . . . . . -a. Heat and squish (!!)
. . . . . . -b. cut and weld - most popular
. . . . . . . . +(1) same steel both pieces eases welding
. . . . . . . . -(1) some welds have failed in less than 200 miles

3. Chevy crank 1923-28 (dunno about earlier)
. . +A. Same stroke as T
. . . . +1. Completely invisible from outside
. . . . +2. better for high rpm than A crank

. . +B. Super sturdy: 25 lb, compared to 15 lb for T crank.
. . . . +1. Rod journals are 1.5" dia. and 2" wide
. . . . =2. #2 & #3 mains must be cut to 1.6" to clear T bolt spacing
. . . . =3. Use same main caps as A crank

. . -A. Crank is shorter between rods than T.
. . . . -1. Rods are not under centers of pistons, for more wear
. . . . -2. #1 & #4 are farthest off center, but not as bad as A crank

. . -B. Chevy flywheel flange must be replaced
. . . . =1. pilot bushing must be removed or will pollute weld
. . . . -1. new flange will be dissimilar steel

. . -C. Chevy rods are 5/8" longer than T rods.
. . . . -1. Use Egge special pistons, with reinforced pins.
. . . . =1. Find a stock modern piston; 4.2L Ford is close.
. . . . ?1. Shorten the rods?
. . . . =1. Use custom Ross pistons, but with reinforced pins.

6:32 AM 9/15/2003 Ralph Ricks updated 10-24-12



Pix are from Rob Wolff, who I haven't seen post here in a long time.


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