312 connecting rods length ????

[djfordmanjack]

I have a question concerning Y block connecting rods. I have had miscelanous confusing information on the internet and from books and og service manuals concerning what length (center to center) the 312 application connecting rods should be. Obviously there are 2 different lengths with 6.25 and 6.32 used in 272, 292 and 312. Can anybody confirm firsthand what would be used in a 312? are they different for 1956 vs 1957 ?

[Hoosier Hurricane]

312 rods are 6.25.  '56 and '57 Ford are the same, as are '56 thru '60 Mercury.   John

[Hoosier Hurricane]

I forgot.  '61 to '64 heavy duty trucks are also 6.25.  These have casting numbers C1TE.  Passenger car 312 rods have ECZ casting numbers.   John

[Ecode70D]

John
     I have been talking to Guenter about Y blocks, but unfortunately It has been  many years since  I  had my 312 apart so I'm a bit fuzzy on the connecting rods. 
     Please refresh my memory.   If I were to lay a 292 and a 312 connecting rod side by side on a table, is the 312 connecting rod visibly different?   I just picture the  ECZ 312 rods to be more beefy looking than  the 292 rods.    Thanks Jay

[Hoosier Hurricane]

Jay:

Lay one rod on top of the other.  The 292 rods are .070" longer center-to-center.  The rods are very similar in shape.  The C1TE truck and late 292 C2AE rods are shaped differently at the lower end of the beam than the 312 and early 292 rods.

John

[Ecode70D]

   John
    Thanks for clearing that up for us.  At my age, I'm glad that all of my major projects are done and I can drive them.  Now I'm at  the stage where I just go out to the garage and putter around and hope that the weather breaks soon so I can take the cars out and enjoy them.  Jay
 

[Zapato]

Now if one used a 312 crank in a 292 what is the correct rod piston combo to use.

Zap

[Ecode70D]

Zap
   I'm going to let Guenter in Austria tell you what is involved.  That's what he is doing and there is a  lot to it.   I'm sending him an email right now.  Jay

[Zapato]

Thanks Jay

Zap-

[hiball3985]

Now if one used a 312 crank in a 292 what is the correct rod piston combo to use.

Zap

Are you planning to turn the 312 crank main journals down to fit the 292 block? The crank center line doesn't change and the stroke remains the same to you would still use a 312 rod and piston..

[Zapato]

Am just gathering information, will decide later.

Zap-

[djfordmanjack]

Zap, Jim, Jay, that is what I plan to do. Yes you can use a 312 crank in a 292 and it has been done since they were brandnew. I have yet to assemble my engine, so I can't tell from experience, only what I read and heard. the 312 blocks were basically the same as 292 so there is no reason against using them as 312s. The only difference of course is the larger main bearing diameter. which turned out to be the 312s weakest point. Obviously the main caps were prone to cracks, more than the thicker 292 caps. Dragracers used to get 292 blocks with the smaller main journals and the crank mains themselves have to be turned down, as well as the rear seal and oil slinger area. As Jim mentioned, because of the taller throw of the new crank you have to use 312 rods AND pistons. 312 rods are shorter to make up for additional stroke of crank and the 312 piston skirts are shorter to clear the crank counterweight on Bottom DC. I was lucky enough to get a decent crank, while I was in the US last fall. Daniel ( from ford barn) already had it turned down for the same use. Thanx again Jay for helping with getting the crank.
Over the last days I collected a lot of information and can now confirm that the so called EBU ( 272,292) rod is taller than the ECZ and you need a short ECZ rod for using with a 312 crank and pistons, no matter if they are going in a 312 or 292 block.
I have my new Egge 312 pistons next to my old 292 and they have nearly the same compression height ( pin center to top) so the shorter rod makes up for the taller stroke. there is quite some confusing information all over the books and internet.
Egge sells their pistons for both the 56 and 57 312, so the 56 and 57 cranks and rods should basically be the same.
The most terrifying fact is that BOTH my 1957 service manual AND the 1957 Mechanics handbook say that the 312 has the same c/c lenght rods as the 292, stating 6.325. How could they get that wrong in a million of books ?
It should be 6.25.
That's as much as I know at the moment.

[lalessi1]

I found this on Mummert's site. It looks like a 292 HD truck engine has the same center to center rod dimension as the 312... Rod PN# C1TE. He also sells after market rods.

http://www.ford-y-block.com/dimensions.htm

[hiball3985]

As Guenter said the 312 had problems with the main caps cracking but I have also seen the blocks crack also. Using a 292 block is a good way to go.

I didn't think the 292 HD truck rod was produced until into the 60's so I don't know how they could have printed that to be correct info in a 57 manual?

[djfordmanjack]

Jim, the 57 manuals state con rod lenth is 6.32 ( longer EBU) for all 57 272, 292, 312 passenger. that is not correct. 312 has the short ECZ 6.25.
The C1T truck rods are shorter because the pistons have more compression height ( because HD truck had 4 rings instead of 3 with pssgr cars). You can use those rods with a 312 crank. must not use the pistons.