Rod and Piston Identification

[John F.]

Good Day Fellas!

I'm on long term mission to determine if the block in my 63 FI is the correct original block. It's a long story that I'll post in another thread another day if anyone is interested.

Here goes..

I'm wondering if anyone can tell me the application and/or if these could be original pistons and rods. The number on the piston is 3795337 and it also has a GM number on it. I've read in an earlier post that these could be for a high horse motor depending on if they are cast or forged and/or domed or flat top. I'm unfortunately not smart enough to know the difference so I posted some pictures.

https://www.forums.ncrs.org/showthre...hlight=3795337

The rods are large journal (over 2") and it looks like they were stamped numerically for each number piston 1 thru 8. Was this something GM did at the factory when they built the motors?

Thanks in advance.

[John F.]

Re: Rod and Piston Identification

Piston3.jpgPiston4.jpgPiston5.jpg

Here are some additional photos.

[Patrick B.]

Re: Rod and Piston Identification

What is the casting number and casting date of the block? The Pistons are for 11:1 compression, so they could be for FI. the rod numbers are not factory, so it has been apart before.

[Duke W.]

Re: Rod and Piston Identification

This pistons appear to be the OE type domed forged aluminum. Joe L. can probably confirm with the forging number. Are they standard size or oversize?

The rods are early 327 small bearing type. The big end ID is greater than two inches to account for bearing shell thickness. Stamping the cylinder number on the rod and cap is typical of rebuilt engines. Flint did not stamp the cylinder number on the rods.

DO NOT REUSE THEM. They are weak near the bolt seats and subject to fatigue failure.

A new set of Eagle SIR5700 small bearing, pressed pin rods, which are stronger than any OE rod cost about $250.

Duke

[Joe L.]

Re: Rod and Piston Identification

Good Day Fellas!

I'm on long term mission to determine if the block in my 63 FI is the correct original block. It's a long story that I'll post in another thread another day if anyone is interested.

Here goes..

I'm wondering if anyone can tell me the application and/or if these could be original pistons and rods. The number on the piston is 3795337 and it also has a GM number on it. I've read in an earlier post that these could be for a high horse motor depending on if they are cast or forged and/or domed or flat top. I'm unfortunately not smart enough to know the difference so I posted some pictures.

https://www.forums.ncrs.org/showthre...hlight=3795337

The rods are large journal (over 2") and it looks like they were stamped numerically for each number piston 1 thru 8. Was this something GM did at the factory when they built the motors?

Thanks in advance.

John-------


I was off-base in that previous linked thread; I don't know where I came up with that information on piston identification. In any event, the GM forging number 3795337 was used for the 1963-64 SHP pistons, originally GM PART #3799501, 3799502, and 3799503. It's also possible the same forging was used for 1965 GM PART #3850137, 3850138, and 3850139, and 1966-68 GM PART #3871208 and 3871210.

IF these are standard size pistons, then I feel pretty confident that they're the original pistons. Of course, they MIGHT also be GM SERVICE pistons which would be identical. If they're oversize pistons, especially 0.030" over, then they're almost certainly SERVICE replacements. Personally, I don't think I'd re-use them if I were going to rebuild the engine even if an overbore is not necessary, especially if this engine has high miles.

As Duke mentions, the cylinder number stampings on the rods definitely indicates that this engine has been apart previously. The engine plants did not perform this type of stampings. Although it's been apart before, I don't think the engine was ever custom balanced as I see no sign of metal removal on the balance pads on the bottom of the rod caps.

Also, as Duke mentions, I would not recommend re-using these rods. The pre-1966 small block rods have weak points and it's just not worth using them. The best small journal small block rod was GM #3864881. If you could find a set of those, you'd be OK but they are long-since GM-discontinued. Sets show up on eBay from time-to-time but it might wind up cheaper just buying a set of good aftermarket rods.

[David L.]

Re: Rod and Piston Identification

This really does not help but I once had a low HP 1965 Chevrolet passenger 327 short block with casting number "3782870" that was stamped "F0313HC" (March 13 1965) with a casting date "C125" (March 12, 1965) that I bought back in the 1980's. Years ago I removed the pistons and rods. I still have the flat head pistons with 4 valve reliefs (casting number "3795704") and the 8 rods (casting numbers "72", "72", "135", "65", "124", "74", "134", and "65") and caps. The caps are stamped 1,2,3,4,5,6,7 and 8. The block has a new home in NJ with Andy.
According to my May 1965 Chevrolet Parts Catalog the GM part number is 3799491 (for std. size pistons) in Gr. 0.629 for 62-65 Pass., Corvette (exc. SHP, FI).

Dave

[Patrick B.]

Re: Rod and Piston Identification

The OP was trying to determine if his block was original. One assumes that the block has been decked otherwise he could have posted a picture of its pad. The discussion of pistons and rods is pretty much beside the point. These pistons and rods could have been in any SHP 327 from 62 to 65, and we know this engine has been apart (rod markings with inconsistent size stamps and block apparently decked). Without knowing the casting number, casting date and approx. car build date, there is no way to even speculate about the block's originality.

[John F.]

Re: Rod and Piston Identification

Cast date J 23 2
Block Cast # 3782870

[Patrick B.]

Re: Rod and Piston Identification

Cast date J 23 2
Block Cast # 3782870

an Oct 23, 1962 cast 327 block would likely be original for a 63 Corvette assembled in Nov 62. I assume there are no numbers remaining on the stamp pad. If there are numbers, it would go along way in confirming this.

[John F.]

Re: Rod and Piston Identification













So at this point in 1999, I bought the 1963 Riverside Red 327 Convertible with a Holly Carb, tan leather interior with intentions of restoring it back to original color and making it a FI. It was an experience and a fun project and I had a blast. I met guys like Gail Parsons who I became very close with. He took me under his wing and taught me everything I could absorb about Fuel Injections.


I tore the car apart and did a body off, had the engine rebuilt and preserved the engine stamp pad. As it turns out, nothing under the hood was original. Wrong heads, radiator, core support, overflow tank, alternator, exhaust manifolds, tranny, rear end, etc.





Cast date J 23 2 Oct 23, 1962 (Tuesday)
Engine Assembly Oct 25th, 1962 (Thursday)
Car was built November 5th (11 days later on a Monday)
Vin 2886
On Friday Nov 3rd they ended with 2879
On Monday Nov 5th they ended with 2940











I knew for sure the motor was apart at some point and I suspect the rods were replaced because three have red paint spilled on them. I suspect when the car was painted red, the rods accidentally had some paint splash.

[Patrick B.]

Re: Rod and Piston Identification

So at this point in 1999, I bought the 1963 Riverside Red 327 Convertible with a Holly Carb, tan leather interior with intentions of restoring it back to original color and making it a FI. It was an experience and a fun project and I had a blast. I met guys like Gail Parsons who I became very close with. He took me under his wing and taught me everything I could absorb about Fuel Injections.


I tore the car apart and did a body off, had the engine rebuilt and preserved the engine stamp pad. As it turns out, nothing under the hood was original. Wrong heads, radiator, core support, overflow tank, alternator, exhaust manifolds, tranny, rear end, etc.





Cast date J 23 2 Oct 23, 1962 (Tuesday)
Engine Assembly Oct 25th, 1962 (Thursday)
Car was built November 5th (11 days later on a Monday)
Vin 2886
On Friday Nov 3rd they ended with 2879
On Monday Nov 5th they ended with 2940











I knew for sure the motor was apart at some point and I suspect the rods were replaced because three have red paint spilled on them. I suspect when the car was painted red, the rods accidentally had some paint splash.

Thanks for telling the story of this engine block. I am not an NCRS judge but I have been a long time observer of engine stampings. Considering the provenance of the block, I think it is certainly possible that the block is original.

The vin stamping looks perfect in terms of font and alignment. The Flint stamping looks plausible. If the first "F" had a long lower horizontal bar, it would be more clearly a factory stamp, but ordinary "F"s also show up as both F's of RF engines. The 5 looks crooked while the other characters seem to line up fine. I don't know if this is an illusion from the camera angle or if the 5 was struck a second time with a hand stamp having not been imprinted well from using a gang stamp on an irregular surface. It is also likely that the factory gang stamp did not imprint 5 and the RF because of the grindout, and all three characters had to be applied with hand stamps. Do you have any photos of the pad taken before the head was installed in the rebuild?

It seems to be a question of whether a former owner rented some credible stamps but lacked the knowledge to stamp the block in the proper locations or whether the Flint plant ground off a previous stamp and then restamped it toward the left of the pad in an effort to find a spot flat enough for the gang stamp to make good contact. In the later case, when the engine would have arrived at St. Louis, they would have stamped the vin where ever they could find room. In this case, the right hand side of the pad slightly over stamping the RF was the only room left. The gang holder of small vin characters also has a better chance of making a legible stamp on a rough grind out area than the larger Flint gang hold.

I think the nature of the removal of the old stamp is the best indication of who did it. An owner doing a poor restamp would likely file off the previous stamp resulting in the pad being slanted slightly all the way to the forward end and removing most if not all of the grain. The Flint plant would use a power grinder to remove the previous stamp producing a local low spot but would probably not grind the whole pad. Under this senario, the left side of the pad would still have the original grain probably extending under the FI02. Also if you placed a straight edge from the head to the forward edge of the pad, the forward and rear surfaces of the block pad would be in the same plane with a groove under the straight edge where the first Flint stamping was located.

I certainly cannot tell from the photos if this is the case, but if you make these observatiions it should help you determine to your own satisfaction whether this block left Flint as a fuel injection engine. Since your car was sold in a very modified condition apparently with no representation as an original FI car, it is hard to see a motive for a former owner to stamp this block. I hope you find these indications of a factory grindout, but I am doubtful if many NCRS judges would buy the story for points. Even if the judges thought it was simply a terrible restamp, I don't think they would brand the car a counterfit. However, maybe some real judges could comment on that.

[John F.]

Re: Rod and Piston Identification

Patrick- Thank you for reply and honest opinion. I got the car out today and took some new photos with my new iPhone that does a pretty good job. Have a look. I unfortunately don't have any pictures of the pad before the head was assembled.

What are your thoughts on the timeframe between Cast Date, Engine Assembly Date and Car build date? Would 11 days be enough time to get the engine shipped by rail, unpacked and assembled in a car?

Also, it does appear that the pad was ground more to the right than the left after closer inspection.

I'd be curious if anyone else has an opinion. Engine Stamp 6.pngEngine Stamp 5.jpgEngine Stamp 4.jpgEngine Stamp3.jpg

[Dan H.]

Re: Rod and Piston Identification

Once had a 340 HP 63 Coupe that had the end two letters of the engine code ground off, similar to John's, and an RE stamped on top of RF that was on pad at Flint. This was from the original owner in 1986, who had ordered it new with a 300 hp engine and power steering. It arrived at the dealer with 340 hp and no power steering, oops! Dealer put on power steering, replaced oil pan for it to work etc. I had the order sheet and all papers, receipts etc. What is curious about John's engine is that it's stamped in reverse of normal with the engine code on top of the vin, which is on wrong side of pad. The vin looks ok, and the engine code could be. If this was a factory 'restamp' it had to be at St Louis after the car was built, but how did they get the engine code stamp? Why would St Louis restamp in a different sequence? Just curious, anything is possible as per my old 63.

[Joe L.]

Re: Rod and Piston Identification

Once had a 340 HP 63 Coupe that had the end two letters of the engine code ground off, similar to John's, and an RE stamped on top of RF that was on pad at Flint. This was from the original owner in 1986, who had ordered it new with a 300 hp engine and power steering. It arrived at the dealer with 340 hp and no power steering, oops! Dealer put on power steering, replaced oil pan for it to work etc. I had the order sheet and all papers, receipts etc. What is curious about John's engine is that it's stamped in reverse of normal with the engine code on top of the vin, which is on wrong side of pad. The vin looks ok, and the engine code could be. If this was a factory 'restamp' it had to be at St Louis after the car was built, but how did they get the engine code stamp? Why would St Louis restamp in a different sequence? Just curious, anything is possible as per my old 63.

Dan-------


What you mention is exactly what I think happened here. This stampings, both engine code and VIN derivative, were done at St. Louis for some unknown reason. Note that in addition to the reversed stamping locations, the engine code is much lower on the pad than usual. That's because the engine plant code was stamped on the block before the heads were installed. So, it was easier to get it close to the top of the pad.

For some reason, this engine had most of the pad surface ground off but note that the area at the very top was not ground because it was too close to the head to easily grind and it was not necessary.

To me, the engine code stamp does not look like a Flint stamping. However, also as you noted, the VIN derivative does look correct. So, I've got to conclude that the pad was ground off at St. Louis and the engine code re-stamped. All I can figure is that Flint had a set of engine codes stamps that they used for just such situations.

[Patrick B.]

Re: Rod and Piston Identification

Patrick- Thank you for reply and honest opinion. I got the car out today and took some new photos with my new iPhone that does a pretty good job. Have a look. I unfortunately don't have any pictures of the pad before the head was assembled.

What are your thoughts on the timeframe between Cast Date, Engine Assembly Date and Car build date? Would 11 days be enough time to get the engine shipped by rail, unpacked and assembled in a car?

Also, it does appear that the pad was ground more to the right than the left after closer inspection.

I'd be curious if anyone else has an opinion. [ATTACH=CONFIG]61929[/ATTACH][ATTACH=CONFIG]61930[/ATTACH][ATTACH=CONFIG]61931[/ATTACH][ATTACH=CONFIG]61932[/ATTACH]

John-- I think the date relationship between the block casting, engine and car build are perfectly reasonable. All of the Flint stamp characters are consistent with photos and rubbings I have of original Flint engine pads. The only character the least bit uncommon is the "R", and I have rubbings of that exact style R used as a handstamp on a Flint engine in which the last letter of the code was handstamped outside the gang holder. Your new photos show good details. Possibly the 5, R and F were skillfully hand stamped out side the holder. I am surprised that most of the pad shows evidence of grinding rather than just the right hand side. I am still of the opinion that the engine pad was ground and restamped at the Flint plant, but it may simply be impossible to tell for sure.

Dan and Joe believe the engine pad was altered at St. Louis, but I don't understand why they think that was the case. I was under the impression that St. Louis did not perform any engine modifications or repairs and simply returned problem engines to Flint. Also there is no reason why St. Louis would have had gang stamps identical to those at Flint. Flint size characters would not fit in the gang holders used for VIN characters at St. Louis. Unless they worked on engines routinely, they would probably use regular machine shop hand stamps for a rare emergency requiring restamping a block.