#3083 Crank case arm block: which is better?

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Model T Ford Forum: Forum 2017: #3083 Crank case arm block: which is better?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, August 25, 2017 - 04:19 pm:

I don't know if this matters, so I'll ask. I'm going to make a couple of new blocks. Which of these is "correct"? The only significant difference between them is the bevel.






Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Friday, August 25, 2017 - 04:33 pm:

This might be of some help.

http://www.mtfca.com/discus/messages/118802/155696.html


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Eagle Idaho Falls on Friday, August 25, 2017 - 04:35 pm:

http://www.mtfca.com/discus/messages/118802/155696.html

This has some good info.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Friday, August 25, 2017 - 06:54 pm:

Don't use either one, leave them out.

They do more harm then good.

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Friday, August 25, 2017 - 06:57 pm:

Neither one of those are made correctly. Up until the early '20s, they were the early design. By 1923 they got smart and made a rectangular square block.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Friday, August 25, 2017 - 07:48 pm:

Steve, I have only seen originals with reliefs on the long sides. All have had the 45 degree chamfer, some have had a square rebate opposite the chamfer on the bigger face.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By R.V. Anderson on Friday, August 25, 2017 - 08:34 pm:

The chamfer is to clear the fuel line.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Saturday, August 26, 2017 - 09:35 am:

The diagram Jim posted shows why neither block is exactly right. While most of the dimensions are accurate, they both have a rectangular notch for the fuel line instead of a chamfer. I have no idea why the chamfer on the left one is there. It's vertical (!) and useless for the fuel line.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Saturday, August 26, 2017 - 11:05 am:

Steve: It wouldn't be useless if you had the correct block. As I mentioned above, neither of your blocks are correct! I wish I didn't hate taking photos so much. I have a whole bag of original genuine Ford blocks out in the garage.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Saturday, August 26, 2017 - 11:49 am:

I assume the diagram Jim posted is correct. I'll use that.


Top of pagePrevious messageNext messageBottom of page Link to this message  By john hardiman on Saturday, August 26, 2017 - 07:49 pm:

What type of wood would you use? Do you need it to be strong or a soft wood?

If strong--- Could you make them out of Black Locust? This wood is rot resistant and can withstand being in the ground for a long time.

I bought a bunch of it for a project of mine last spring from a guy named "Blue-Sky", in western Massachusetts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Sunday, August 27, 2017 - 12:10 am:

Since no one has posted a picture of the correct blocks, I'll try to remember to do it tomorrow!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dale Peterson College Place, WA on Sunday, August 27, 2017 - 12:38 am:

The block is there to help keep the frame rails from twisting, putting stress on the arms. But the cross bolts should not be tight or will cause the problems Herm is referring to. They are needed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Sunday, August 27, 2017 - 03:38 pm:

I just took a picture of three different designs of ORIGINAL used CC arm blocks. The one on the right was definitely used from 23-27, maybe earlier, the one on the left is early, definitely used through '13 and probably later, the middle one is in between somewhere. I'm going to the archives in a few weeks, and will definitely check on them while I'm there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, August 28, 2017 - 09:40 am:

The wood was hard maple. Never deviated from that. I have the drawings for these blocks and they did change a bit but only to make them simpler as you can see that for the purposes that the notches and grooves were added they can be simplified and still do the same job. That is the nature and reason why the blocks changed IMHO.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Monday, August 28, 2017 - 03:08 pm:

John, I looked in the "documents" section of your website and didn't see the blocks drawing. Is there a reason (licensing, etc.) why you can't post the drawings?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Rogers - South of the Adirondacks on Monday, August 28, 2017 - 04:34 pm:

What harm could these blocks possibly do?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Tuesday, August 29, 2017 - 11:03 pm:

The harm that the blocks do is they hold the Crankcase arm to rigid.

With the block in the frame, and it makes no difference if the block bolt is tight, loose, or anywhere in between, it hinders the crankcase Arm from moving to its full potential.

With the block out, when the motor twists, when the engine is revved, the crankcase arms will relieve the twisting from the top of the arm bolt, to the pan rail, or a little below.

Most of the crankcase arms, crack right at the pan rail, because at that point, it has to take all the stress, with a block.

In all these years, we have never used the blocks, and the same recommendation to all the engines we built, with out any cracked, or broken arms.

As far as the blocks holding the frame from twisting, it does nothing except throw stress on the pan arms.

Watching the old FORD videos, they show how the frame twists on uneven ground, Ford built them that way.

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Wednesday, August 30, 2017 - 12:14 am:

What you say Herm may be so but my only experience with a broken arm was in one of my own T's. I know for a fact that it was without the blocks since 2002 and some 13 years later, the engine arm let go with a big bang while just cruising down the road.
Many USA T'ers know and have meet Warwick Landy, he was passenger the day it happened if one needs to verify my post.
I run the blocks in all after that.
If someone feels the need to leave them out, at least fit the side bolts so if and I say 'IF' they let go, then the engine doesn't end up 1/2 way to the road.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, August 31, 2017 - 10:18 pm:

It is in fact a violation of the Ford Museum copyrights to post their drawings in any public place without their permission. I know many do that anyway but I signed an agreement to NOT copy or provide copies of their drawings. I love to research there so I don't want to lose my invite to go there. Museums are always hurting for $$ so they rightfully charge for copies of things. They own those drawings. Being a design engineer I am sensitive to that issue. It hurts when I have spent a goodly amount of time making up a product and instruction sheets for it that are copyrighted then only to have my instruction sheets furnished with a "copycat" product and to see a competitors name exactly in the place on my instruction sheet where my copyright notice was. It is illegal but some people sell their integrity pretty cheap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, September 01, 2017 - 07:38 am:

The TT trucks didn't have any blocks in the last years - and after the diagonal straps from the hogshead bolts to the rear motor mounts were introduced in november 1925, I don't think the car needs them either. Thus I drive without blocks and think it'll work fine since the sideway flex is very limited with the straps. With an older pre 26 engine I'd worry and probably use the blocks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Wednesday, September 13, 2017 - 10:45 am:

Just returned from the archives. The early style block was used from 09-20, the mid style was used in 21-22, and the late style was used from 22-27.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Brian Beatty _Kansas City on Wednesday, September 13, 2017 - 02:58 pm:

Thanks for researching that Larry!


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