21 stud main cap bolts

[AZ34]

The 21 stud engines have bolts, not studs, for the main bearing caps. As seen in the attached links. Anyone know the size of the square head of the bolts?

I assume it is necessary to put a socket on the bolt head to remove the nut.

With insert mains. http://www.vanpeltsales.com/FH_web/FH_images/FH_engine-pics/Flathead_Engine_crankandcam_1937-38.jpg

With babbit mains.http://www.vanpeltsales.com/FH_web/...ics/Flathead_Engine_crankandcam_1933-34V8.jpg

 

[Oldtmtech]

They take a 1/2” or 5/8” square socket, I can’t remember which right now
The heads of those bolts are down in a hole in the lifter valley that will be filled with crud you will have to clean it out good to get the socket on properly

Edit
Mine is a Babbitt bearing’34

 

[Yoyodyne]

All the 36LB and 37-38 engines that I've worked on have all had short studs threaded into the block, just about the same as later engines.

 

[Ggmac]

The 2 that I have now also have studs . No bolts . Ive got picsof it cleaned and you can see where the main studs end . These are both late (?) 36 LB , they both have SPH stamped on the deck ? .

 

[21stud]

The 21 stud engines have bolts, not studs, for the main bearing caps. As seen in the attached links. Anyone know the size of the square head of the bolts?

I assume it is necessary to put a socket on the bolt head to remove the nut.

With insert mains. http://www.vanpeltsales.com/FH_web/FH_images/FH_engine-pics/Flathead_Engine_crankandcam_1937-38.jpg

With babbit mains.http://www.vanpeltsales.com/FH_web/...ics/Flathead_Engine_crankandcam_1933-34V8.jpg

Interesting, as I haven't seen those. all my blocks are insert type mains with studs.
Green bible tells that part numbers for 32-36 are: Bolt 18-6345 stud 40-6345 and 48-6345
1936up stud 68-6345

Anyone?

 

[Ronnieroadster]

Bolts with square heads are found on 1932 to 1934 blocks. Not sure about the 35 block never worked on one. The 1936 block has studs which continued until 1948. For those who have never seen this or worked on one of these early blocks 32-34 the head of the bolt is found in the valley of the block. The bolt heads are usually hidden with all the sludge found in an old motor.
Ronnieroadster

 

[AZ34]

Thanks for the comments the information provided helps me understand the evolution of the 21 stud engine.
I recently picked up a 21 stud running engine. Not an engine I had desire to own, however it was cheep so I couldn’t pass on it. It was removed from a 34 BB truck and turned out to be a 32 block. I removed the cast iron intake to install a 34 aluminum intake and was surprised to find the sludge filled bores in the lifter valley for the main cap bolts. Research led me to conclude, with the change to main bearing inserts would require wider spacing for the main cap fasteners and that it would not be possible to bore for bolts. It appeared to me that opening for the lifter valley would be too narrow to allow machining for wider spacing. Finding the diagrams at Vanpelts lead me to believe bolts were used on all 21 stud engines.
It has been an enjoyable experience working on this first edition Ford flathead V8.In addition to the intake, I also installed a set of 1935 40 6050 A2R high compression aluminum heads. According information I found they are 7.5 to 1 CR. It’s a display engine for now do to worn out rings. I may rebuild it someday. It has good oil pressure so I believe the babbitt main bearings are still good.
If anyone knows the size of the square head bolts it would be helpful.

 

[Brian]

The square head of the bolt is 9/16". There is a flange under the square 0.863" dia. The bolt is 4.6 long under that flange, 1/2" dia. The bottom of this shank is threaded 1/2" UNF for about 0.770", with a hole through the bottom for lock wire.

 

[Ronnieroadster]

Being a 1932 engien is a great find. There not common at all. Seems to me besides the shortened production run in 1932. The additional issue of poor oil consumption for the 1932 V-8 engine resulted in engine's being replaced by Ford for unhappy customers. Did the dealers replace them with improved 1932 engines or did this take place when the 1933 engines were in production thus now having the 33 as the replacement ?

I always wondered what became of those removed 32 V-8's. Did the dealers send them back to Ford or were they just scraped? Whatever took place back then now in the twenty first century just having one of the 1932 V-8 engine's that survived I think is extremally good luck.
Ronnieroadster

 

[Yoyodyne]

35 -36 babbit motors have studs, at least all that I've seen. AFAIK the blocks are the same 35-early36.

 

[21stud]

AZ34,

That's very nice early engine!
those heads, have measured chamber vol? Hard to find any info about those?

This thread is good info about early V8 development history. Again great example Fordbarn members knowledge, thank you all!

 

[Oldtmtech]

Here’s my center main cap assembly
When you remove the main cap look for a shim it could be stuck to the block or the underside of the cap real easy to lose

 

[Mart]

^^ Thanks for showing those parts. I've never seen the bolts or babbitted cap before. I suppose with the babbitted bearings, shim removal was a way of eking some extra miles from a worn motor.
Interesting.

 

[AZ34]

Thanks for the additional information. Curious why the Ford 21 stud 1937-38 illustration, found on Vanpelts indicates bolts through the end of 21 stud.

35 -36 babbit motors have studs, at least all that I've seen. AFAIK the blocks are the same 35-early36.

So the change from bolts to studs was implemented prior to the change to inserts. May have been prompted by the machining required to accommodate studs vs bolts and/or block strength.

Here are a couple more pics of the 32 block. The lack of recessed area between the timing gear cover and water inlet and water jacket drain petcocks on the same plain as the oil pan surface.

 

[David J]

Bolts with square heads are found on 1932 to 1934 blocks. Not sure about the 35 block never worked on one. The 1936 block has studs which continued until 1948. For those who have never seen this or worked on one of these early blocks 32-34 the head of the bolt is found in the valley of the block. The bolt heads are usually hidden with all the sludge found in an old motor.
Ronnieroadster

32-34 on bolts is the right answer.

 

[38 coupe]

I'm confident Ford switched from main bolts to main studs when adding crankcase ventilation with the 1935 blocks.

The first picture (provided by David J years ago) is a 33-34 block with main bolts and without crankcase ventilation

The second picture is a 35-36 Babbitt block with crankcase ventilation, notice the round casting to hold the air inlet tube around the fuel pump rod boss.

The third picture is a 36 LB block, notice the sheet metal tube on the top of the passage at the front that connects to the draft slot in the oil pan.

 

[rotorwrench]

I think going to the larger diameter bearing journal is what caused the change in fasteners. The LB design came in in early to mid 1936 and both were produced for a while. This was true for the change over from 21-stud to 24-stud engine block designs for late 1937.

 

[sjaakslinger]

This is my 36 I'm working on. Seems to have that same pipe as your 36 LB pictures. I hope to find out more this week.

Verstuurd vanaf mijn SM-G781B met Tapatalk

 

[David J]

Forgot about that old thread.
It cleared this kinda stuff up .

Simple fact of life = you cannot have bolts in all 6 holes on a vented block .
SO THEY DID NOT USE ANY BOLTS ON VENTED BLOCKS.
Pics show this clearly .

Another tidbit from that old thread is the studs are farther apart on LB=insert motors . Seem to remember 3" on babbit and 3 1/4 on inserts.

 

[Tim Ayers]

Those bolts look similar to the ones used on the Model B banger motors. Seems to be a really poor design IMHO.