What numbers should be on a TySy block and heads?

[Skyhighsami]

I just found out that the engine in the Typhoon that I bought isn't the original and might very well not be a SyTy spec motor. I need to know what to look for on the motor and where to look, also if it isn't the correct motor and is a NA motor what is different. I realize that the pistons would be different but would the connecting rods and crank be different. Also if the comp ratio is 9.5-1 with a NA motor how much could the comp ratio be lowered with a thicker head gasket when I put the Vortec heads on it. Thanks for the help guys this is just very frustrating.

 

[typhoon92]

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

See if this helps you out?
http://www.syty.net/forums/showthread.php?t=20725

 

[Skyhighsami]

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

5) There was one more piston used in the 262. It’s a low compression (8.6:1), strutless, hypereutectic piston with a deeper dish that was used in the turbocharged Syclones and Typhoons from ’91 through ’93. The OEM standard piston is p/n 12508702 and the Zollner number is a H-8269-E.


So that is the piston PN right? I didn't see anything about what the number should be on a SyTy block. Thanks

 

[Skyhighsami]

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

I need to know what I should look for to verify that I have the correct motor in my truck. Someone please help me.

 

[DaveP]

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

I need to know what I should look for to verify that I have the correct motor in my truck. Someone please help me.

The only way to be sure you have the 'correct' motor in your truck is to take it apart, and see what's in it. I say that, because it seems that these things have been molested, repaired with incorrect parts, and screwed with mercillesily, by multipler owners, and dealerships and mechanics, etc, to the point that I don't think there IS an "original"or "correct" truck left. (An exception MIGHT be and original-owner truck, that has never had engine work. But, are there any of those???)

Now, to tell if you have the original block: On the pad in front of the RH cyl head, if it's not too rusty (probably is), you should be able to make out the Assembly plant stamping. It will be in "computer dots" Should end in 'LD' This is the suffix code for the SyTy turbo engine. Now, if that checks out, go to the pad above the oil filter adapter. There is a machined "flat" that is horizontal, centered on the lower bellhousing bolt hole. The "vin derivitive" will be stamped here. Again, computer dots. Should be the last 8, sometimes 9 digits of the VIN of the car.

If you find an Engine assy stamp in Letter stamps (not dots) that starts with 'T', this is a Tonawonda engine, common for replacement. The original SyTy's that I'VE seen have all been Romules built. ('Dots', and begins with 'R')

Just because you have the original block, doesn't mean it hasn't been apart, and wrong, or perhaps better, stuff put in it.

My 92 had the original block in it when I bought it in 96. I had no reason to suspect it had ever been out of the truck. I fought detonation for 3 years, because it had been rebuilt with 'flat top' LB4 pistons, and Tonawonda rods. The mains must have been spun as well, because the block had been line bored, and the center caps were in the wrong positions. So much for originality, on a 4 year old car.... I ended up throwing that engine in the scrap pile. Nothing worth using again...

So happy-hunting the numbers. You'll probably be frustrated by not being able to read the pads because of rust. Or, not being sure about where you're supposed to be looking. I can help you with that, if you ask. But if the block is out of the truck, you should be able to get them cleaned up. Tough to get the front pad cleaned, with the accessory bracket and A/C compressor installed, though.

DaveP

 

[Skyhighsami]

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

Thank you so much for the help. I hope to find out that the motor is correct, the person I bought it from said it was and that if it wasn't he would have blown it by now. But him not telling me in the beginning that it had been replaced doesn't set well with me, and the fact that since I confronted him on it he hasn't returned any calls.

 

[Skyhighsami]

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

Ok I am guessing that the blocks aren't correct? What makes the SyTy motor different from the NA motor other than the compression ratio? Are the pistons the only thing that was changed?

 

[DaveP]

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

Ok I am guessing that the blocks aren't correct? What makes the SyTy motor different from the NA motor other than the compression ratio? Are the pistons the only thing that was changed?

Pistons, which is compression ratio, and Camshaft. (Not sure what the differences in the cam from LB4 really are. I have a SyTy cam running in a NA LB4 in a Jeep, and can't tell any difference.) The original block has grey (nodular) iron center main caps, but I don't know why this was done. It doesn't seem to make any difference.

When I was fighting the detonation in my 92, I felt that incorrect piston selection might have been to blame. I also had high (175+) compression-test readings.This was discussed on SyTy.org in great detail. I looked into the cyl through the spark plug hole, and could plainly see the 4 "eyebrow" valve pockets. These are indicitive of the higher compresson, common 4.3 and 5.7) Because I had no reason to think the engine had been worked on (Original number-matching block, in a 4 year old car), this escaped my realization that this was INcorrect, and no one on .org figured it out at the time either.

Perhaps someone can post a pic of the top of an original piston, and the popular TRW forged replacement that a lot of us use, and you can compare it to what 's in your engine by just taking a look through the plug hole. I removed the wheelhousing on the driver's side to facilitate doing this.

Happy Hunting

DaveP

 

[Aeroking]

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

i used a friend's barscope to verify my pistons. very easy.

also the SyTy nodular main caps are stamped with a "N", if you can get the oil pan off to see them.

 

[Aeroking]

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

Perhaps someone can post a pic of the top of an original piston, and the popular TRW forged replacement that a lot of us use, and you can compare it to what 's in your engine by just taking a look through the plug hole

used stock piston, and a brand new SpeedPro/TRW piston

again, if you can find a barscope, or rent one from a parts store, you can see your piston tops through the sparkplug holes.

if they're not SyTy pistons, the will be entirely flat, or you'll just see the valve cleanance troughs. SyTy pistons have the negative dish to them.

 

[Skyhighsami]

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

Thanks for the help guys!! I meant to do that today but ended up putting up shelves in the laundry room for the wife. The sooner the honey do list gets done the sooner I get started on tearing down the Typhoon. I will try a scope to see what I see. Thanks again!!

 

[Skyhighsami]

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

Would it be possible to have gotten the correct motor from CarQuest? The person that I got the Typhoon from said that the first replacement motor blew and that the second one was replaced and it is correct.

 

[DaveP]

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

Would it be possible to have gotten the correct motor from CarQuest?

Go to CarQuest yourself, find a representitive who's knowledgeable with their 'engine program'. Explain your situation, and ask if there are any identifying marks / numbers on the engine that might reveal who the actual contractor was that built the engine. (CarQuest doesn't do it themselves. They buy it from a re-builder). If you can identify the actual builder and part number, and make contact with perhaps the shop foreman, you MAY be able to get a hint as to what might be in it.

But, there is no substitute for taking a peek yourself. You don't need a boroscope (I spelled it correctly ), but it helps. You can see enough of the top, with the piston located just below the hole to tell if there's a 'dish' or not, with a flashlight and your eye-ball.

I wish I'd had pictures of the correct pistons when I went through this 8 years ago.

You have no idea how helpful (and less expensive) this will be, if they're the wrong compression ...........

DaveP

 

[dgoodhue]

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

Now, to tell if you have the original block: On the pad in front of the RH cyl head, if it's not too rusty (probably is), you should be able to make out the Assembly plant stamping. It will be in "computer dots" Should end in 'LD' This is the suffix code for the SyTy turbo engine. Now, if that checks out, go to the pad above the oil filter adapter. There is a machined "flat" that is horizontal, centered on the lower bellhousing bolt hole. The "vin derivitive" will be stamped here. Again, computer dots. Should be the last 8, sometimes 9 digits of the VIN of the car.

If you find an Engine assy stamp in Letter stamps (not dots) that starts with 'T', this is a Tonawonda engine, common for replacement. The original SyTy's that I'VE seen have all been Romules built. ('Dots', and begins with 'R')..

I never know about the front pad, a little degreaser and sure enough I have W6J61LD. As for all of the SyTy being Romulus, mine is a Towonda.

 

[dgoodhue]

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

Pistons, which is compression ratio, and Camshaft. (Not sure what the differences in the cam from LB4 really are. I have a SyTy cam running in a NA LB4 in a Jeep, and can't tell any difference.) The original block has grey (nodular) iron center main caps, but I don't know why this was done. It doesn't seem to make any difference.

The cam is the same as the regular LB4, the part numbers in 91-93 GM part manual for 91-93 SyTy cams are the same number as 92 & 93 LB4 cam's (91 LB4 have a different part number). They all use the same anemic cam, you would be hard pressed to find a weaker 4.3 cam than what came in a SyTy.

 

[DaveP]

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

The cam is the same as the regular LB4, the part numbers in 91-93 GM part manual for 91-93 SyTy cams are the same number as 92 & 93 LB4 cam's (91 LB4 have a different part number). They all use the same anemic cam, you would be hard pressed to find a weaker 4.3 cam than what came in a SyTy.

Actually that's what I thought until 2 days ago. My microfisch has the same info.

HOWEVER: I was confused when the last three digits of the P/N on the cams didn't agree with the parts book. the cams also were NOT the same in the LB4 and the one known original SyTy cam I had.

Over the weekend, someone posted a link to an article in the archives that tells all about the evolution of the 4.3 They refrence about 10 different cams, including "There is also a special roller cam for the VIN "Z" turbocharged engines (p/n 10214714) "

this # is in my notes that I kept for the 'jeep' engine. I keep notes on most of the engines I build. ( I've probably built over 250, now. Both professionally, and for my own uses. Diesel and gas.) This # is not in my microfische.


There is also NO refrence in my microfische regarding the 2 different piston weights. These also are associated with 2 different WEIGHT connecting rods, and crank shaft balancing. No mention of the 2 different assembly plants, and the requirement to be careful about mixing Romulus rods with Tonawanda cranks.

All this makes sense, as I went through a bunch of 'mixing and matching' with 4.3's (about 5 engines in a 12 month period) about 5 years ago. I had some issues. My machinisht didn't know any of this stuff.

Anyway, there ARE differences. Sometimes it takes a LONG time to finally learn some things. I've been doing this stuff for about 40 years, now.

Just because you've never seen anything to the contray, doesn't make a belief fact.

DaveP

 

[DaveP]

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

I never know about the front pad, a little degreaser and sure enough I have W6J61LD. As for all of the SyTy being Romulus, mine is a Towonda.

What's "W"?? Tonawanda is "T" has been since the 60's. All Mark IV's werre Tonawanda. I don't have very comprehensive databases available for engine stamp pad deciphering. Do you have something that shows "W" as Tonawanda?

Also, these (SyTy) pads dates are different. they use letters for month, and include last digit of year. Yours: W (should be assembly plant) 6 (I don't know) J6 ( I think this is October 6th) 1LD (Year 1991, Engine 'model' LD)

Tonawanda and Flint (Smallblock from 1955 to 2002) used Assy plant letter, Month, Day, Engine code. My Tonawanda L35's use this convention. The Romulus (or W) are different. I'm still learning about these. they're not common.

DaveP

 

[dgoodhue]

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

Actually that's what I thought until 2 days ago. My microfisch has the same info.

HOWEVER: I was confused when the last three digits of the P/N on the cams didn't agree with the parts book. the cams also were NOT the same in the LB4 and the one known original SyTy cam I had.

Over the weekend, someone posted a link to an article in the archives that tells all about the evolution of the 4.3 They refrence about 10 different cams, including "There is also a special roller cam for the VIN "Z" turbocharged engines (p/n 10214714) "

this # is in my notes that I kept for the 'jeep' engine. I keep notes on most of the engines I build. ( I've probably built over 250, now. Both professionally, and for my own uses. Diesel and gas.) This # is not in my microfische.


There is also NO refrence in my microfische regarding the 2 different piston weights. These also are associated with 2 different WEIGHT connecting rods, and crank shaft balancing. No mention of the 2 different assembly plants, and the requirement to be careful about mixing Romulus rods with Tonawanda cranks.

All this makes sense, as I went through a bunch of 'mixing and matching' with 4.3's (about 5 engines in a 12 month period) about 5 years ago. I had some issues. My machinisht didn't know any of this stuff.

Anyway, there ARE differences. Sometimes it takes a LONG time to finally learn some things. I've been doing this stuff for about 40 years, now.

Just because you've never seen anything to the contray, doesn't make a belief fact.

DaveP

I looked up the spec in 92 SyTy Supplement and compared them to the Factory Service manual LB4 spec for 92 and atleast according them their is a slight difference. The SyTy cam lift number are .357/.390, the LB4 cam lifts numbers are .351/.386 (when multiplying the 1.50:1, they were only given in raw lift numbers)

 

[dgoodhue]

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

What's "W"?? Tonawanda is "T" has been since the 60's. All Mark IV's werre Tonawanda. I don't have very comprehensive databases available for engine stamp pad deciphering. Do you have something that shows "W" as Tonawanda?

Also, these (SyTy) pads dates are different. they use letters for month, and include last digit of year. Yours: W (should be assembly plant) 6 (I don't know) J6 ( I think this is October 6th) 1LD (Year 1991, Engine 'model' LD)

Tonawanda and Flint (Smallblock from 1955 to 2002) used Assy plant letter, Month, Day, Engine code. My Tonawanda L35's use this convention. The Romulus (or W) are different. I'm still learning about these. they're not common.

DaveP

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.

 

[DaveP]

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

I looked up the spec in 92 SyTy Supplement and compared them to the Factory Service manual LB4 spec for 92 and atleast according them their is a slight difference.

Another trip back. I remember seeing this same thing in the SyTy supplement when I was conducting my initial research into these engines back in 96. The parts book listed the same P/N. I assumed they were the same until 2004 when I had the two cams out of engines, and saw the different P/Ns on the cams. I remained confused / bewildered until this weekend, when a refrence to the SyTy # turned up.

I hope I continue to 'learn' until the day the lights go out for good....
DaveP