1967 SMALL Journal Crank...revisited

[kforce]

I was looking for the mixed journal sizes here for my Jan 1967 built SS350 engine. Was surprised to see that this subject has not been confirmed yet.
After reading a previous thread (http://www.camaros.org/forum/index.php?topic=8402.0) I became even more confused. The reason this ORG exists
is because GM didn't do well when it came to documenting anything in the late 60's. I was surprised at how quick some were to tell the previous poster
that the subject was closed for discussion. The mixed Journal crank does exist. I have one. My machinist here in Sacaramento knew it when I took it to him.
He just called it the ONE YEAR crank. Small main, large rod, journal crank. The previous discussion did not even mention that the MAIN CAPS are short as well as the MAIN BOLTS. The new main bolts I ordered are way too long. My block was still standard bore. (Casting number 3892657) (Date A97) (Crank Cast# 2690)
Original heads, intake, waterpump, alternator, ditributor, Starter. Balancer is a 6966 if that is correct?
So, as far as I can tell the block has not been rebuilt. (Still had the original paint splotches on the rear)
The mention that racers may have turned these cranks doesnt make up for the short caps and bolts.
Besides, if it was raced it wouldn't have ended up back in a bone stock engine. So that is out.
Also, how many people here with an original 1967 350 that THEY have rebuilt are the ones providing answers?

[lynnbilodeau]

Check the date code on the main bearings you just took out.

If they don't have a date code, they aren't gm originals.

Attached is a pic of a main bearing I just took out of a 10 of 69 built 350.  As you can see, it is dated 9 69.

Bearings dated prior to your engine build date would go a long way to convince folks that a small journal 350 crank came from the factory.

Although it wouldn't prove that the crank was originally a small journal crank, it could prove that it wasn't.

Also, what is the casting date, and the casting number of you block?  That would help.

[lynnbilodeau]

Check those main bearings for date codes yet?

[JohnZ]

<<The mixed Journal crank does exist. I have one. My machinist here in Sacaramento knew it when I took it to him.
He just called it the ONE YEAR crank. Small main, large rod, journal crank. The previous discussion did not even mention that the MAIN CAPS are short as well as the MAIN BOLTS. The new main bolts I ordered are way too long. >>

The main bolt issue should be no surprise, as the longer washer-head bolts and taller caps (which are also .040" wider), with deeper countersunk bolt holes in the bulkheads didn't start until 1969 production.

The issue of small main journals and large rod journals on the same 2690 crank says something odd has happened to that crank at some point after it was produced; 2690 forged cranks were all large-journal, and were used through 1976. I'm familiar with the huge Landis crankshaft grinders used at Flint and Tonawanda, and they only produced two main/rod journal combinations - large/large or small/small, with unique crankshaft forgings/castings required for each combination.

[jdv69z]

Were the grinders basically set up for one specific crankshaft  type, ie large/large for example, and used continuously for that operation? As opposed to being used for different types which would require the grinder to be setup for each different version? I'm guessing that a given grinder ran a lot of crankshafts before any change in setup occurred?

Jimmy V.

[vtfb68]

Is there any truth to the stories of the factory using 327's when they ran short of 350's ? I so were the 327's
 stamped as 350's ? Just wondering.
   VT

[tmodel66]

Is there any truth to the stories of the factory using 327's when they ran short of 350's ? I so were the 327's
 stamped as 350's ? Just wondering.
   VT

I'm just going by what Kurt said in another post about cars waiting on parts so I guess substitution would be the same. Kurt said if the parts weren't there the car wasn't built. I take this to mean if a car was to get a 350 and they didn't have one the car would not have been built therefore no substitution.

[kforce]

I took the block apart a couple of years ago, so I don't have the bearings. Had the heads done first, then eventually took the block and crank in. I ordered new bearings and main bolts for a 350. The block was not decked or line honed. Just bored and -20-20 on the crank. The rod bearings fit. Maybe the main caps seem short because the new bolts are long. The original main bolts are 1/2" shorter than the new ones I ordered. Did the bolt length change between '67 and later??? I never actually even tried the main bearings because I stopped when I tried to test fit the new bolts. (thinking this through as I type here.) Didn't want to take the bearings out of the plastic for return reasons. Going to go and measure those journals and bearings, then maybe test fit the new main bearings.  I'll try and get some good measurements on the caps and bolts. I'll try and get some comparison pics as well. Also going to call Mike at Parrish machine here in Sacramento to see what he meant by 'one year crank'. Maybe just a part number change?

[lynnbilodeau]

Can you provide the info for your block.  Casting number, casting date, and assemby date and code?

Thanks.

[kforce]

So, I have an answer that satisfies me. I hope this helps with the "mixed Journal" myth.
The "Journal" is NOT mixed, the bolts are. I finally bought a descent micrometer. My journals are both 'Large'. The caps are as well.
The 3rd picture below shows the bearing tang groove on small and large journal 2 bolt main caps and are easily identifiable.
Information I read on the Team Camaro web site states that the 350 blocks in '67 and '68 were drilled for the same short bolts used on the earlier small journal main caps.
The longer bolts did not start until '69. My block will only accept the short bolts.
Amazing where your brain takes you...the long bolts leave you to believe that the caps are short. Not that the threads in the block are.

My original bolt can be seen between the ARP bolts for '2 bolt main' small and large journal cranks. (Someone needs to call ARP...Not quite accurate with the 2 year 'layover' on the bolts)

It was also stated that the VIN PAD was longer on the blocks that had been drilled for the longer bolts.
Not sure how much longer. Or when it started. Would love to know.

My original...ARP small and large journal bolts.


VIN pad


2 bolt main caps

[kforce]

Can you provide the info for your block.  Casting number, casting date, and assemby date and code?

Thanks.

(Casting number - 3892657) (Casting Date A97 - Jan 9th '67) (Assembly V0113MV - Jan 13th)

[JohnZ]

It was also stated that the VIN PAD was longer on the blocks that had been drilled for the longer bolts.
Not sure how much longer. Or when it started. Would love to know.

The small-block VIN pad was 3-3/4" long until 1968, when it changed to 4-3/4"; the deeper bolt holes/longer bolts/wider caps didn't start until 1969.

[kforce]

The small-block VIN pad was 3-3/4" long until 1968, when it changed to 4-3/4"; the deeper bolt holes/longer bolts/wider caps didn't start until 1969.

Thanks John! Is the change model year '69?  Or a month and day in the 1969 actual year?

[JohnZ]

The small-block VIN pad was 3-3/4" long until 1968, when it changed to 4-3/4"; the deeper bolt holes/longer bolts/wider caps didn't start until 1969.

Thanks John! Is the change model year '69?  Or a month and day in the 1969 actual year?

I'm not positive, but I believe it was a model year change with the '69 blocks.

[KurtS]

It was a model year change. I've seen the info on it in 69 MY info.