More flathead questions.

Licensed to kill

Licensed to kill

Well-known member
So, I pulled the pan yesterday and checked the bearings today. From what I've read, it appeared that this was a "war period" flatty as it has a crab style dizzy although IIRC, this dizzy went to 48 or 49. However, checking the crank journals, I have 2.114 throws which, according to what I've found, suggested a 1946 or later, turned .025. Does this make it a safe assumption that this engine is 1946-1949?. Also, I was expecting babbit but it has bearing shells and they are REALLY thick (relative to any other bearings I've ever dealt with). Would this engine have been manufactured with shells or is it a babbit/shell conversion??. I'm having issues getting the centre main cap off so i have yet to check the journal size of the mains.
 
External parts get swaped around a lot so that doesn't tell you much. Babbit bearings were only used on the earlier 21 stud engines. The rod bearings should be floaters. Is there a 59 cast into the half bellhousing?
 
My research has been informative but confusing. From what I can gather, <48 used full floating bearings. Mine does not so I looked at '49. However, '49 had a Rod bore of 2.229 and the <48, with the floating bearings has a rod bore of 2.3595, mine with fixed bearing shells has a rod bore of 2.356 (measured at the top of the cap with callipers so that would account for the .003-.004 discrepancy). Unless I'm missing something, (which is likely) it almost looks like this came with floating bearings and someone had the rods cut to accept fixed bearing shells. Thoughts??.
 
JSeery said:
External parts get swaped around a lot so that doesn't tell you much. Babbit bearings were only used on the earlier 21 stud engines. The rod bearings should be floaters. Is there a 59 cast into the half bellhousing?
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There is just a 9 (or a 6) cast just to the right of centre. Another oddity I found while looking for the number on the half bellhouseing is that it appears to have an oil pressure sending unit (with a short wire attached but not going anywhere) but the truck did not have an oil pressure gauge or provisions for one.
 
A 2.229 rod bore is a .020 under crank size for a late 38 to 41 ford engine with 99a or 21A rods. I assume this is the crank in your engine. However this crank can be installed in any Block from 38 thru 53, and is a common racing practice.
 
Initially, the plan was to drop the pan to clean it out, check the bearings while the pan was off and put back together. However, the goo in the bottom of the pan felt gritty and, pulling one rod cap found copper showing so it needs bearings. I don't want to take the chance of any grit being in the lifter valley or anywhere else so will be pulling the motor tomorrow. Once I get it out and on a stand (will have to make an adapter to mount it), I will be able to take it apart and get better measurements off of the crank. I'm not expecting any other issues but we will see. Thanks for the input so far guys. very much appreciated.
 
Licensed to kill said:
Once I get it out and on a stand (will have to make an adapter to mount it)
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FYI stumpysfabworks.com sells an adapter to mount to the exhaust bolts to hang a flathead on a normal engine stand, runs about $69, YMMV
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Some Canadian 1948 blocks had insert bearings as opposed to floaters (rods). Think these should have a casting C69 somewhere on them (bell housing?). FOMOCO NZ got CKD fords ex FOMOCO Canada. I has a c69 block in a 47 coupe I had years ago...with the inset bearings. This was the start of transition to 8BA but was in the style of a 59 engine. It was a Ford Canada thing and didn't follow in the US I believe.

GB
 
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The 99a and the 21A rods are for the small 1.998 crank, and the 29A is for the 2.138 crank. I used both of these when racing. At present the new 258 race motor is with a late 38 crank and 99A rods. I hone these rods to 2.2215 for better oil flow. I also increase the rod side clearance to .012". You must realize that oil is also used for cooling the bearings, so flow is important.
 
Ol' Ron said:
The 99a and the 21A rods are for the small 1.998 crank, and the 29A is for the 2.138 crank. I used both of these when racing. At present the new 258 race motor is with a late 38 crank and 99A rods. I hone these rods to 2.2215 for better oil flow. I also increase the rod side clearance to .012". You must realize that oil is also used for cooling the bearings, so flow is important.
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The 91A and 21A rods are for the earlier 1.999 Ford crank journal prior to 1946 and the 99A and 29A rods are for the 2.139 journal used through 1948. The 99A rod was used in 1939 and up for the Mercury or truck engine with the larger bore. The 29A rods were used on both Ford and Mercury engines between 1946 and 1948.
 
Ol' Ron said:
A 2.229 rod bore is a .020 under crank size for a late 38 to 41 ford engine with 99a or 21A rods. I assume this is the crank in your engine. However this crank can be installed in any Block from 38 thru 53, and is a common racing practice.
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The rod bore does not indicate what the crankshaft undersize is. The rod bore defines the outer diameter for the bearing being used. Ford made engine bearings that fit oversize rod bore and undersize crankshaft diameter and these bearings can still be found today.
 
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