scat crank issues

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
KenHaverhill
Posts: 88
Joined: Sun Jan 06, 2019 5:04 pm
First Name: Kenneth
Last Name: LeBlanc
* REQUIRED* Type and Year of Model Ts owned: 27 coupe 23 touring 26 TT Snowmobile 22 TT Dump Truck 26 Fordoor
Location: Atkinson NH 03811
MTFCA Number: 25458

scat crank issues

Post by KenHaverhill » Wed Apr 17, 2019 7:57 am

has anyone run into issues with thrust and a scat crank? I have done engine work with stock cranks with no issues , installing a scat crank for the first time in a 26. block has new babbit,line bored and radius cut on babbit ends. when crank is dropped into block 3rd main journal has no clearance in block ,no in or out thrust .third cap has almost all thrust surface removed and still will not fit onto crank . almost seems as though journal of crank is to narrow? there is a shoulder on both sides of crank journal which sits off of counter weight. I am missing something? even if babbit was removed from block all together crank would still be tight fit into third bearing saddle of block. thanks ahead of time


Adam
Posts: 1411
Joined: Sun Jan 06, 2019 11:57 am
First Name: Adam
Last Name: Doleshal
* REQUIRED* Type and Year of Model Ts owned: ‘13 Touring, ‘24 Touring, ‘25 TT dump truck, ‘26 Tudor, ‘20 Theiman harvester T powerplant, ‘20 T Staude tractor
Location: Wisconsin
MTFCA Number: 23809
MTFCI Number: 1
Board Member Since: 2000

Re: scat crank issues

Post by Adam » Wed Apr 17, 2019 9:45 am

There’s something missing from your post. Measurements should tell you everything you need to know.

A stock block has no babbitt thrust. The only thrust is on the cap. If you want thrust in the block, you have to mill some iron off the front and rear of the third main saddle before you babbitt.

The radius on the scat cranks is a little bigger than the stock Ford radius, (by maybe 1/64” if I remember correctly) so if you are using too small a radius, the crank could be hanging up on the radiuses.

Are you babbitting and line boring this yourself, and have you done this before, or did you have a shop do it to specifications, but without the crankshaft actually there?

User avatar

John.Zibell
Posts: 307
Joined: Mon Jan 07, 2019 9:09 am
First Name: John
Last Name: Zibell
* REQUIRED* Type and Year of Model Ts owned: 1926 Tudor
Location: Huntsville, AL
MTFCA Number: 30265
MTFCI Number: 24046

Re: scat crank issues

Post by John.Zibell » Wed Apr 17, 2019 10:53 am

kenhaverhill wrote:
Wed Apr 17, 2019 7:57 am
has anyone run into issues with thrust and a scat crank? I have done engine work with stock cranks with no issues , installing a scat crank for the first time in a 26. block has new babbit,line bored and radius cut on babbit ends. when crank is dropped into block 3rd main journal has no clearance in block ,no in or out thrust .third cap has almost all thrust surface removed and still will not fit onto crank . almost seems as though journal of crank is to narrow? there is a shoulder on both sides of crank journal which sits off of counter weight. I am missing something? even if babbit was removed from block all together crank would still be tight fit into third bearing saddle of block. thanks ahead of time

You will also have to modify the "horseshoe" for the pan inspection cover. Usually with the rear one you cut out a section for clearance, then weld the legs to the other horseshoe.
1926 Tudor


Topic author
KenHaverhill
Posts: 88
Joined: Sun Jan 06, 2019 5:04 pm
First Name: Kenneth
Last Name: LeBlanc
* REQUIRED* Type and Year of Model Ts owned: 27 coupe 23 touring 26 TT Snowmobile 22 TT Dump Truck 26 Fordoor
Location: Atkinson NH 03811
MTFCA Number: 25458

Re: scat crank issues

Post by KenHaverhill » Wed Apr 17, 2019 12:12 pm

I spoke with the people at scat and they tell me that they have made some changes including a much bigger radius , they feel that even though it looks like enough I still need more radius ground into babbit in block.


Adam
Posts: 1411
Joined: Sun Jan 06, 2019 11:57 am
First Name: Adam
Last Name: Doleshal
* REQUIRED* Type and Year of Model Ts owned: ‘13 Touring, ‘24 Touring, ‘25 TT dump truck, ‘26 Tudor, ‘20 Theiman harvester T powerplant, ‘20 T Staude tractor
Location: Wisconsin
MTFCA Number: 23809
MTFCI Number: 1
Board Member Since: 2000

Re: scat crank issues

Post by Adam » Wed Apr 17, 2019 1:34 pm

kenhaverhill wrote:
Wed Apr 17, 2019 12:12 pm
I spoke with the people at scat and they tell me that they have made some changes including a much bigger radius , they feel that even though it looks like enough I still need more radius ground into babbit in block.
Did they tell you what the “new” radius is that they are grinding on the cranks?


Kohnke Rebabbitting
Posts: 144
Joined: Sat Jan 26, 2019 3:12 pm
First Name: Herman
Last Name: Kohnke
* REQUIRED* Type and Year of Model Ts owned: 1914 Roadster, 1922 Coupe
Location: Clare, Iowa

Re: scat crank issues

Post by Kohnke Rebabbitting » Wed Apr 17, 2019 3:54 pm

Of all the scat cranks we used, 3 were about .052 to short, in the rear main, the flange was thicker also, so Vern opened them up. These came out of older production, I called them at that time, and made them aware. It was cheaper to fix, and had control on the fix, them send them back.

We always check New, or reground cranks before we even think about babbitt.

Anyway, when the crank was set, the center main had equal distance on either side, and the time gear on the crank was .010 short, of flush, to the cam gear, in length.

The rear cap, normally has more babbitt on the front of the rear main, then the back, because of front thrust wear.

Always punch the oil holes out, clean with a drill, at the last.

Herm.
Attachments
Bobs Model T Motor 019.jpg
Bobs Model T Motor 016.jpg
Bobs Model T Motor 015.jpg
Bobs Model T Motor 015.jpg (21.51 KiB) Viewed 3247 times
Bobs Model T Motor 002.jpg
Bobs Model T Motor 002.jpg (22.23 KiB) Viewed 3247 times
Bob's  Model T Motor 012.jpg

Post Reply Previous topicNext topic