1997 3800Sc I've heard 2 different versions, the 3800SC MAIN Bolts are, and are NOT" reusable". Yet I can't find anyone who even "Lists" them ! Summit can't get them. Are they reusable ?? don't want studs. Thanks

Got some L67 engine bolt part #'s. The mains, cross bolts and rocker bolts are only available in bags of 5. So you need 2 bags of bolts for the mains & cross bolts and 3 bags for the rockers. The rod bolts are available in bags of 2, so you need 6.
Except for the Fel-Pro part, all others are GM part numbers available from a local GM dealer.

Main Bolts - 24503056
Main Cross Bolts - 24505576
Rod Bolts - 25531956
Rocker Arm Bolts - 24503515
Fel-Pro Head bolts - ES74033

As to the tty bolts, I would replace them. For a read on tty bolts have a look here and form your own opinion.
Torque to yield bolts

Can anyone "verify" that they indeed ARE TTY ? or is this "speculation? is there a" marking" on the head of TTY bolts ?? ( all bolts have a "grade" mark on top, shouldn't TTY ? )

I can't verify that the GM bolts are TTY, but I can tell you that I read that in many places when I did my rebuild.

I wanted to plastigage my mains, but I didn't want to buy two sets of bolts. I bought ARP studs, marked, and measured them prior to plastigaging. After the gaging, I removed the studs and remeasured them to check for deformation (none). Then I installed the new bearings and torqued the studs down for good.

I can check later in the day in my factory service manual, but I'm fairly certain that they are TTY.

When checking my series 1 I had to do a lot of research on the bottom end bolts.
All 3.8-3800 since 1985 have YTT connecting rod bolts.
1992 was a cross over year for main caps. Could use 1st design(resuable) or 2nd design YTT.
All 3800 after 1993 are YTT mains.
If you use after market bolts(ARP), non-YTT, the assembly has to be machined(line honed) with new bolts installed. Before final assembly.

If they are TTY your Tightening spec will be a base torque and then a deg of rotation after that, If your book or Spec sheet is just a Torque # they are most likely NOT TTY


And yes the ARP studs and even bolts are reusable but the increased torque spec of the ARP's will deform the main cap, so a Line hone is usually required, it's the same on rod bolts.


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1986 SE 3800SC/4t65eHD (12.871@104.96) I'll Sell it if you like
1985 GT 3800SC (swap in progress)

[This message has been edited by 1fast2m4 (edited 06-23-2013).]

If that is true, rebuilding these things is a waste of money. New" rod bolts", have to get the rods "resized", $$$, new main "bolts" have to get it align bored, more $$. That's almost $500 that would not have to be spent if this was a engine without TTY bolts. You can't just open them up to "check" the bearings without having to drop a small fortune, (all for the benefit of the" factory and the aftermarket bolt companies). I think I'm better off getting the new TTY bolts from GM, (NOT ARP) and just re torqueing them. I'm starting to see where putting a small block chevy in would have been a lot easier and cheaper. Has anyone here EVER seen a rod bolt actually BREAK ? In 45 years, I've seen broken rods, broken pistons, a rod go through a block, but never a "broken" rod bolt. And , I'm pretty sure if you torque a TTY bolt to say 50 lbs, then 1/4 turn, Or just torque it to say 70 pounds to begin with, (just an example) I'll bet you end up in the same place. I have the attachment for the angle after torqueing. I'm never going to believe that "TTY Bolts" make ANY engine "run better", or "last longer". I Don't mind spending money if "you actually benefit from it". It's a conspiracy ! gripe, gripe, ***** , ***** . OK , I'm done now. LOL

I wouldn't open up the 3800 other than to replace the lower intake manifold gaskets when swapping.

Look for a car with reasonable mileage that you can still drive. Drive it and make sure it is running good. Swap the gaskets and drop it in.

The 3800 is a very reliable engine except for the lower intake gasket failures.

You can also pour new babbet bearings in your Model T Ford engine but I wouldn't swap that into a Fiero either.

quote Originally posted by Lou6t4gto: If that is true, rebuilding these things is a waste of money. New" rod bolts", have to get the rods "resized", $$$, new main "bolts" have to get it align bored, more $$. That's almost $500 that would not have to be spent if this was a engine without TTY bolts. You can't just open them up to "check" the bearings without having to drop a small fortune, (all for the benefit of the" factory and the aftermarket bolt companies). I think I'm better off getting the new TTY bolts from GM, (NOT ARP) and just re torqueing them. I'm starting to see where putting a small block chevy in would have been a lot easier and cheaper. Has anyone here EVER seen a rod bolt actually BREAK ? In 45 years, I've seen broken rods, broken pistons, a rod go through a block, but never a "broken" rod bolt. And , I'm pretty sure if you torque a TTY bolt to say 50 lbs, then 1/4 turn, Or just torque it to say 70 pounds to begin with, (just an example) I'll bet you end up in the same place. I have the attachment for the angle after torqueing. I'm never going to believe that "TTY Bolts" make ANY engine "run better", or "last longer". I Don't mind spending money if "you actually benefit from it". It's a conspiracy ! gripe, gripe, ***** , ***** . OK , I'm done now. LOL

No no Only if you upgrade to a bolt that operates at A higher installed torque, stock hardware won't require any machine work on good parts. it's the extra clamping force that the ARP hardware provides that will distort the bores on the mains & the big ends of the rods.

and yes if you don't want to do any machine work on a other wise stock but good bottom end you are better off to get new TTY GM hardware rather than upgrading to ARP hardware.

I totally get your gripe, but I have seen failed rod bolts is early LS1's but only when those engines are run up over 6500rpm our 3800's stop making power well before the rod bolts become an issue, so I don't think it's a problem. the thing with the TTY bolts they are supposed to act like a spring.

I don't know what TTY hardware has to do with it, but we are averaging well over double the HP per cubic inch than we where in the 60's maybe 4x teh HP to CuIn ratio, just saying. Precision , Precision, Precision.

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1986 SE 3800SC/4t65eHD (12.871@104.96) I'll Sell it if you like
1985 GT 3800SC (swap in progress)

"That boat has sailed". I didn't find out about all this TTY bolt nonsense until After I opened it up and found a broken Crank Key "Groove" and Balancer. all the bearings were perfect .So now I'm in for a new crank and bearings, Bolts, ect. & It's already "open" ,& cleaned, so , new chain, Rings, gaskets, valve job, all because some fool didn't tighten the crank bolt to spec when installing a crank sensor ! Yes, now I see the wisdom in just getting a LOW mile engine to Begin with. "try to "save a buck", No free lunch ! But at least when it's done,( if I don't go crazy first), I'll Know exactly "what" I've got.

quote Originally posted by Lou6t4gto: Yes, the "precision "Machineing", Not the bolts. WHY would you want a bolt to act like a spring ?

Hell i'm not an engineer LOL, but this guy is

I've always bee told that TTY torqued to a angle are Superior to a standard bolt because you don't have the friction between the head of the bolt and the part your bolting on. and the bolt needs to stretch when you torque to angle so the treads keep pulling down as you run through the final sequence regardless of the resistance of the head of the bolt.

The catch 22 is if a TTY bolt is "Superior" why is the ARP replacement stronger? I guess the answer would be exotic alloys and more extreme installed torque.

[This message has been edited by 1fast2m4 (edited 06-23-2013).]

Very Interesting. "A well-respected OE engineer specializing in engines tells me that critical fasteners have about six rundowns in their useful life. They use four of those at the OE manufacturing operations, leaving rebuilders just two. One rundown for checking sizes puts us on the last rundown during final assembly."

Fastener quality
Some articles I’ve read indicate that TTY fasteners are somehow "special", metallurgically speaking. If you’re comparing them to the garden variety bolt from your local hardware store, then, yes, they are. If you’re comparing them to other critical fasteners in an engine, then, no, they are not. They’re high-grade fasteners, typically grade 8 for English and class 10.9 for metric applications .
Funny how no one else tells you that. things to consider.