This current project, the roadster, wasn't put together with the right fasteners in all places. Stopping to find or make the right ones makes it pretty slow going, but I'd like to get it as near correct as I can. There's a very thorough discussion of the #3083 wooden blocks here http://www.mtfca.com/discus/messages/50893/77802.html?1231642572, including good explanations of why wood was used, and suggestions for installation.
But the only specifications I've found for the #3073 side bolt and the #3074 top bolt are here: http://clubs.hemmings.com/ncmtc/Technical/Bolts_nuts_threaded_items.pdf. The length of 2.25" for #3073 looks right to me, but the same length for #3074 is obviously wrong. I gather that's why it's highlighted in yellow. It looks to me like 3/4" would be about right. Am I on target there?
Leave them out Steve, broke, and cracked more arms than any other thing.
Uh-oh. The fat's in the fire now.
Steve, I am not even close to a candle
Leave what out?
Steve, for what it's worth Ford left out these horizontal mounting bolts through the transmission ears on all the TT's after 1925. Also the wood block was omitted the year before. They claimed that this would stop the stress cracking in this area.
Fred - That may be so but Ford also added braces from the transmission/block ears to the frame when it deleted the horizontal bolt.
The upper short bolt is 3/8" x 13/16" long.
Use the wood block and both the bolts and castle nuts with cotters. Ford way is time tested, of course if you don't check the snugness and the condition of the wood block over 30 years of hard T driving back in the days of rough roads.....you will end up with cracked arms as found on old Fords today.
Balance that Ford engine and mount it with the factory way and smooth riding will result.
Ken that's true but the new support straps were added for 26 to allow for the frame to move under the transmission ears. The new upper straps used in the 26/27 TT's allow for the frame to move while still holding the top of the transmission ears from flexing so much. The straps were to prevent the common breakage of the transmission ears found in the model T's. I don't know why the cars still continued to have the Horizontal bolt through the frame. Maybe the TT's were more susceptible to frame cracks in this area than the cars were.
The bolts thru the frame web or the bolts thru the flange (you choose either) are a safety backup if nothing else.
I don't know about anybody else, but I'd be interested in seeing what the rest of the service bulletin says, it's teasing us by stopping at "the only purpose of this bolt ---"
The bolts thru the frame web or the bolts thru the flange (you choose either) are a safety backup if nothing else."END QUOTE
Ted, safety back up for what, just after it breaks off the pan, so that you don't have to pick it off the road.
They normally break at the Pan Rails.
How many hundreds of Accessorie pan arms, and belly bands, and pan Bra's has every one seen.
Arm breakage was a big problem. Do you really think it was because everybody left the side bolts out.
When the side bolt is used, it holds the arm to rigid, and then the only give is at the pan rail.
I have never put them in any cars we have done.
Check it out. I see no difference for the cars!
I put the blocks in and snug up the side bolts and use elastic stop nuts. I still think its a belt and suspenders deal. I have a lot of miles on my T's and have not had a broken pan arm. I really don't think broken pan arms are all that common.
FWIW, from the Ford parts book:
CRANKCASE ARM SIDE BOLT (3/8 x 2-1/4”)
Jan 09 479 1909-27 .05
Dec 11 479 .10 with nut
May 15 479 1909-15 .05
Nov 16 479/8 1909-16 .05
May 17 479/8 1909-17 .10
Dec 20 479 1909-20 .06 less nut
Jul 21 479 1909-21 .05
Oct 27 479 1909-27 .05
CRANKCASE ARM TOP BOLT (3/8 x 24 T.P.I.)
Jan 09 480 1909 .05 25/32” long
Feb 16 480/8 1909-16 .05 with nut
Nov 16 940/8 1909-16 .05 13/16” long
Feb 17 940/8 1909-17 .10
Dec 20 940 1909-20 .05 less nut
Aug 26 940 1909-26 .03
Oct 27 940 1909-27 .03