when are 3/4 grooved main bearings needed for bbc ?

General engine tech -- Drag Racing to Circle Track

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cjperformance
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by cjperformance »

Cubic_Cleveland wrote: Wed Dec 11, 2019 6:15 pm
cjperformance wrote: Wed Dec 11, 2019 1:19 am
Cubic_Cleveland wrote: Wed Dec 11, 2019 1:11 am
Craig, would you have a part number and supplier for these o.d grooved cam bearings?
Cheers,
Mick.
Hi Mick, T Meyer in USA do them. I do mine myself simply because im in Australia and i just order the bearings i need and machine them as required, using preferably FP26 or FP26T coated durabond bearings depending on what cam in using. Steel core i use the coated bearings, cast core the plain unless it has very heavy valve springs.
Cheers,
Thanks Craig
:D no problem
Craig.
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Geoff2 »

When the 351C's were raced here in Australia in the early 1970s in circle track racing, they continually blew up because of oiling problems. One of the most famous Ford race drivers of the period was quoted as saying they 'Blow up on the starter motor...' Not much of a street engine either, ports too large.
cjperformance
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by cjperformance »

Geoff2 wrote: Thu Dec 12, 2019 3:16 am When the 351C's were raced here in Australia in the early 1970s in circle track racing, they continually blew up because of oiling problems. One of the most famous Ford race drivers of the period was quoted as saying they 'Blow up on the starter motor...' Not much of a street engine either, ports too large.
Yes , the fault here is the cylinder head oil drain passages.
They are on such an angle that in an half reasonable turn the oil simply can not down them! So in any sustained turn situation to outter valve cover(reletive to turn direction) will flood with oil ! Most who raced them back then worked the problem out pretty quickly and solved it with an external drain, as was actually done on many other engines of the era aswell.
Craig.
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Ply496 »

I ran across this post last night and have a few things I would like to add. First off the oil hole alignment timing on a small block Chrysler is roughly 70 degree ATDC. In spite of the fact that the oil galley main feed is 20 degrees retarded. The crank on an OEM Chrysler is drilled 45 degrees retarded. On the Chrysler 45 + 45 - 20= 70 degrees. The SBC on the other hand has a oil hole alignment of roughly 55 degrees. There is zero retard in the block “12 o’clock position” and the crank is drilled 10 degrees retarded. 45 + 10 - 0 = 55 degrees. Whom ever said a Chrysler crank and Chevrolet crank or drilled the same this is simply not true. Now almost all after market forged Cranks are drilled to Correct the Small Chrysler to 55 degree ATDC. I have attached a picture of a small block Chrysler and small block Chevrolet crankshaft to show the difference in oil hole drill angle.
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Krooser »

I ran 351-c engines in my dirt cars in the 80's.

We restricted the oil to the top end with .020 set screws in the middle three main bearing galleries. Plus we ran a Ford Motorsport 100# oil pump spring.

Ran a home made 7 qt oil pan. No oiling issues.
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Re: when are 3/4 grooved main bearings needed for bbc ?

Post by Krooser »

Ply496 wrote: Wed Dec 25, 2019 3:33 pm I ran across this post last night and have a few things I would like to add. First off the oil hole alignment timing on a small block Chrysler is roughly 70 degree ATDC. In spite of the fact that the oil galley main feed is 20 degrees retarded. The crank on an OEM Chrysler is drilled 45 degrees retarded. On the Chrysler 45 + 45 - 20= 70 degrees. The SBC on the other hand has a oil hole alignment of roughly 55 degrees. There is zero retard in the block “12 o’clock position” and the crank is drilled 10 degrees retarded. 45 + 10 - 0 = 55 degrees. Whom ever said a Chrysler crank and Chevrolet crank or drilled the same this is simply not true. Now almost all after market forged Cranks are drilled to Correct the Small Chrysler to 55 degree ATDC. I have attached a picture of a small block Chrysler and small block Chevrolet crankshaft to show the difference in oil hole drill angle.
Heres my sbm crank....Mopar Performance item. Looks closer to the Chebby?
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