What numbers should be on a TySy block and heads?

[DaveP]

Re: What numbers should be on a TySy block and heads?

My rear pad has TM8802661, I assumed the T was for Tonawanda. Until you mentioned I didn't even realize the front pad had anythin on it. I didn't realize you were talking about the front pad. I double checked the front pad and that is what it is. I don't think that J6 is October, because my truck was built in June. I don't claim to be a number expert by any means.

I'm not an 'expert' either, but I know a lot about it, mostly self-taught by reading and observing, and trying to make things 'fit'. I've been doing it for quite a while, and it is a VERY big part of what we do in National Corvette Restorers Society, of which I am an active member and judge. The phrase "Matching Numbers" was probably first coined by NCRS members..

So, the date on your front pad doesn't 'fit' the door jamb date on your truck. Because I admit that the 'convention' used by Romulus is un-familiar, I'm sure I've got it wrong. We need input from someone who knows what it is.

Many of the parts on a car have a date on them. A VERY common convention is to use 4 carachters to denote a date. Commonly used as 'casting' dates on heads an blocks. Will look like this:

A051 = January, 05, 1971, 1981 or 1991. Not sure what they're doing about 2001. I'm starting to see "01, 02, 03, etc" to denote the new milennium, but I don't think it's 100% yet. USUALLY, a part doesn't last 2 decades where there could be a choice of year. Particullary a casting, where there is almost always a casting number that will help pick the 'decade' I.e., small block V8 cases. They made them for 47 years, but I can't think of a case # that went over ten years. Actually there is one. The '010' 350 block used in Corvette (and others I'm sure) It was used from 1969 through 1980. The casting dates on these cases would appear identical for the same day in 1980 and 1970. Might help if you're restoring a 1970.

Anyway, for the month A=January, B=february, etc until L(12th letter of the alphabet) = December. Distributors and Alternators do not use the letter 'I', so M= december on these items. But block stamp-pads and casting dates DO use the letter 'I'.

Ok, on your rear pad: The TM8802661 are the last 9 digits of your VIN.
The 'T' is in what's called the 'check digit' position. There is a 'secret' formula that assigns value to each of the other characters in the VIN. The sum of these values will result in a 'check digit'. Can be used in a number of ways to authenticate the VIN. Can't 'fake' a VIN, if you don't know the 'code'.
The M= 1991
The first 8=Shreveport, LA Assy plant (all S/T-10 pick-ups were produced here)
The second 8= An additional 'model' produced at the plant. All SyTys have an 8 in this location, and can be used along with 'D' in the third position, to authenticate a SyTy vin.
The last 5 positions are the sequential number of the 'build'.

So, there's an introduction to VIN and stamp pads.

Cheers,
DaveP

 

[Tooky]

Re: What numbers should be on a TySy block and heads?

Dave, this is what my '94 ZR9 warranty replacement longblock has on it:

Can you make anything of this? I'm very curious.

The motor also has the correct pistons, and I have pounded the piss out of it for the last 52,000 miles on the street, dragstrip, and road course. I just upgraded it to Vortec heads and a healthy custom camshaft, and I have revved it to 5500 RPM with no problems so far. When I had the cam out, I could see and verify the rods look just like stock SyTy rods.

So not all warranty replacement motors were "garbage" or "incorrect".

 

[DaveP]

Re: What numbers should be on a TySy block and heads?

Dave, this is what my '94 ZR9 warranty replacement longblock has on it:

Can you make anything of this? I'm very curious.

The 'W' is Romulus assy plant. I originally stated 'R', for Romulus. Incorrect on my part. The 'dots' are Romulus. My observations of orig SyTys have all been 'dots'. (Romulus).

The "11C6" is the assembly date of the engine. I do not know how to de-code this on a Romulus.Can you find the casting date and post it? We Might be able to figure it out, if we know when the block was cast. Usually only a few days before assy.

The TPE is the engine code. VERY INTERESTING! I don't recall anyone ever posting this code before. From your discoveries, this engine assy seems to be 'correct' for SyTy.

The motor also has the correct pistons, When I had the cam out, I could see and verify the rods look just like stock SyTy rods.

Your engine was replaced in1994. I believe later "replacement" engines were the ones under discussion in the 99-01 time frame I was refrencing.

The difference in the connecting rods is on the 'balance pad' on the bottom of the big end of the rod. These rods are used in Romulus engines. So, your Romulus engine has Romulus rods. Makes sense to me.

So not all warranty replacement motors were "garbage" or "incorrect".

I don't THINK I said this. What I said was "I don't trust any SyTy that has had engine work to be 'correct', without taking a close personal look". I also said MY engine was junk, because the work that had been performed on it couldn't be 'un-done', making it useless.

Your appears to be an exception. It was also done a LONG time ago. You lucked out. Others have not been as fortunate.

Regards,
DaveP

 

[Tooky]

Re: What numbers should be on a TySy block and heads?

The "11C6" is the assembly date of the engine. I do not know how to de-code this on a Romulus.Can you find the casting date and post it? We Might be able to figure it out, if we know when the block was cast. Usually only a few days before assy.

Where can I find the casting date? I took a lot of photos during the head/cam swap. I do know that the VIN flat in the rear of the block (near the knock sensor) was blank, since it's a replacement engine.

I don't THINK I said this. What I said was "I don't trust any SyTy that has had engine work to be 'correct', without taking a close personal look". I also said MY engine was junk, because the work that had been performed on it couldn't be 'un-done', making it useless.

Sorry, I didn't mean to direct that comment towards you specifically. I just know that the attitudes here towards replacement engines are very negative, and I wanted to show that engine replacement does not necessarily equal "imminent engine failure" (which is basically the advice I received here back in 2001 when I first learned my motor had been replaced.)

 

[DaveP]

Re: What numbers should be on a TySy block and heads?

Where can I find the casting date? I took a lot of photos during the head/cam swap.

The casting date is on the rear flange of the block. Between the 'vertical' part that the head bolts to, and the transmission. I have a Tonawanda block in m y shop. The date is on the Passenger side, upper half of the area. The casting P/N is below (bottom half). The date will look like it was on a 'pad' that was 'screwed' to the sand core, before the metal was poured. Should be a 'letter A-L' then 3 'numbers'. The block I have is H114 (Aug 11th, 1994)

I tried to see if it's possible to read the casting date on my Ty with the engine installed. It is NOT. (And I know where to look). There's too much stuff in the way. Mostly the engine wiring harness.

DaveP

 

[dgoodhue]

Re: What numbers should be on a TySy block and heads?

Mine is stamped F031, its right behind the passenger side of the intake on bellhousing flange ledge. Anyways that would make it June 3, 1991 which goes along nicely with my June Build date (per door jam sticker I have)

 

[DaveP]

Re: What numbers should be on a TySy block and heads?

Mine is stamped F031,. Anyways that would make it June 3, 1991 which goes along nicely with my June Build date (per door jam sticker I have)

Very good :tup:
Now: how does that correlate with the "6J6" portion on the assy date (front pad)

"June" 6th. OK, but J could be July, if we didn't know when it was installed. :dunno:

Still need more info.

DaveP