LT5 Assembly Project - Page 8 - ZR-1 Net Registry Forums

LGAFF · 10-26-2008

To give everyone some perspective of the piston damage, I pulled one of the worst, this is #8.

Took pretty good pounding:

Opinions, I think it might be toast!

LGAFF
92 ZR1
#234

LGAFF · 10-26-2008

Here is the liner, a small nick at the top:

Rod bearing Surface:

LGAFF
92 ZR1
#234

Polo-1 · 10-26-2008

Marc has ARP replacement rod bolts

http://www.zr1specialist.com/HAT%20W...od%20bolts.htm

flyin ryan · 10-26-2008

ya...not looking great, is it

A26B · 10-26-2008

Stock rods & bolts are very strong & can handle the amount of horsepower you are anticipating. The only downside of stock rods is that they are heavy.

Your pistons don't look so good & I would recommend replacement of the scored cylinder. Used cylinders are frequently available. You might call Aaron Scott (SGC) Marc Haibeck or Corey Henderson. Considering the number of engines they have been through with replaced rods/pistons left over, I would expect them to have a stock cylinder laying around.

Ryan is the ultimate reference source for aftermarket parts, so he would know but it used to be that rings for stock pistons were crazy expensive and only available through GM. It wasn't the bore size, but rather a combination of dimensions. The "old" rule of thumb was that you coud buy repalcement cylinders, pistons & off the shelf rings for what stock rings would cost.

Last May at BG, a complete, new, OEM set of cylinders/pistons & rings went "no-sale" at the auction with a $500 min reserve. The reason is, virtually no one want's to incure the expense of a rebuild & not add a few more cubes.

My view of rebuilding an LT5 is that it is an expensive engine to rebuild compared to a typical mass produced engine. I would hate to see you use those pistons & the scratched cylinder and risk the outcome being unsatisfactory.

Polo-1 · 10-26-2008

looks like you could use these

These had not been decarboned yet, just washed off. just over 10k miles on them.

lbszr · 10-26-2008

Quote:

Originally Posted by Jeffvette

Is your regular manual a prelim manual (white copy). Red copy page 6A2-49 and page 6A2B-24 show the same diagram in removing the crank sprocket.

It's the red copy.

Actually the part of watch which side the wide shoulder of the primary gear is on when he removes it would make assembly easier since my 90 fmm says short shoulder should face forward page 6a2-48 fig.56 and the 90-93 supplement says wide shoulder must face forward page 6a2b-45 fig.60.

I used a straight edge to figure out alignment to idler gear since I didn't pay attention when I pulled it apart.

lbszr · 10-26-2008

Quote:

Originally Posted by Polo-1

Marc has ARP replacement rod bolts

http://www.zr1specialist.com/HAT%20W...od%20bolts.htm

LGAFF · 10-27-2008

Here is Piston #3

As you can see, when the edge gets hit, it is actually melting/deforming the edge of the piston:

I have one more piston with a few strikes towards the edge, I will pull and check.

I also had some discussion as to whether I should pull the crank, feedback is that if I do I would have to get into checking bore, and crank diameter, etc. Might be more than I want to take on, although would be interesting to learn.

Very possible, I might be pulling and replacing the three pistons and then moving into the heads, etc.

Let me know if this is getting too boring!

LGAFF
92 ZR1
#234

Polo-1 · 10-27-2008

I also had some discussion as to whether I should pull the crank, feedback is that if I do I would have to get into checking bore, and crank diameter, etc.

LGAFF
92 ZR1
#234[/QUOTE]

How are you going to pull the liners out, without removing the crank? I know they come out the top, but they are glued in place and use a tool (plate) from under side of the liner.
Also, how are you going to clean and check clearance on your parts.
I'm just saying I would hate to see you go this far, and not clean and check every part out. You"ll sleep much better at night knowing it's right.

If you need a copy of the FSM let me know.

10-26-2008	#71
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: LT5 Assembly Project To give everyone some perspective of the piston damage, I pulled one of the worst, this is #8. Took pretty good pounding: Opinions, I think it might be toast! LGAFF 92 ZR1 #234

10-26-2008	#72
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: LT5 Assembly Project Here is the liner, a small nick at the top: Rod bearing Surface: LGAFF 92 ZR1 #234

10-26-2008	#73
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: LT5 Assembly Project Marc has ARP replacement rod bolts http://www.zr1specialist.com/HAT%20W...od%20bolts.htm

10-26-2008	#74
flyin ryan Join Date: Aug 2006 Location: Edmonton, Alberta or Phoenix, Arizona Posts: 2,741	Re: LT5 Assembly Project ya...not looking great, is it __________________ There are no limit's mans ingenuity, just as mans ingenuity will never conquer the forces & behavior of this planet...Smokey Y.

10-26-2008	#75
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: LT5 Assembly Project Stock rods & bolts are very strong & can handle the amount of horsepower you are anticipating. The only downside of stock rods is that they are heavy. Your pistons don't look so good & I would recommend replacement of the scored cylinder. Used cylinders are frequently available. You might call Aaron Scott (SGC) Marc Haibeck or Corey Henderson. Considering the number of engines they have been through with replaced rods/pistons left over, I would expect them to have a stock cylinder laying around. Ryan is the ultimate reference source for aftermarket parts, so he would know but it used to be that rings for stock pistons were crazy expensive and only available through GM. It wasn't the bore size, but rather a combination of dimensions. The "old" rule of thumb was that you coud buy repalcement cylinders, pistons & off the shelf rings for what stock rings would cost. Last May at BG, a complete, new, OEM set of cylinders/pistons & rings went "no-sale" at the auction with a $500 min reserve. The reason is, virtually no one want's to incure the expense of a rebuild & not add a few more cubes. My view of rebuilding an LT5 is that it is an expensive engine to rebuild compared to a typical mass produced engine. I would hate to see you use those pistons & the scratched cylinder and risk the outcome being unsatisfactory. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

10-26-2008	#76
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: LT5 Assembly Project looks like you could use these These had not been decarboned yet, just washed off. just over 10k miles on them. Last edited by Polo-1; 10-26-2008 at 03:52 PM.

10-27-2008	#79
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: LT5 Assembly Project Here is Piston #3 As you can see, when the edge gets hit, it is actually melting/deforming the edge of the piston: I have one more piston with a few strikes towards the edge, I will pull and check. I also had some discussion as to whether I should pull the crank, feedback is that if I do I would have to get into checking bore, and crank diameter, etc. Might be more than I want to take on, although would be interesting to learn. Very possible, I might be pulling and replacing the three pistons and then moving into the heads, etc. Let me know if this is getting too boring! LGAFF 92 ZR1 #234 Last edited by LGAFF; 10-27-2008 at 08:52 PM.

10-27-2008	#80
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: LT5 Assembly Project I also had some discussion as to whether I should pull the crank, feedback is that if I do I would have to get into checking bore, and crank diameter, etc. LGAFF 92 ZR1 #234[/QUOTE] How are you going to pull the liners out, without removing the crank? I know they come out the top, but they are glued in place and use a tool (plate) from under side of the liner. Also, how are you going to clean and check clearance on your parts. I'm just saying I would hate to see you go this far, and not clean and check every part out. You"ll sleep much better at night knowing it's right. If you need a copy of the FSM let me know. Last edited by Polo-1; 10-27-2008 at 10:24 PM.