Rebuild Decision, Need Help!
Rebuild Decision, Need Help! Setting the stage:
1. I have a '99 Corvette with 90K miles. Stage I heads and mild cam with 70K miles on them. Engine needs a rebuild because I either have a bad rod bearing or bad wrist pin (I'm pretty sure its a rod bearing). Either way I need to pull the engine and rebuild it. Either way, I'm installing a new cam (either a 224/224 112 or a 231/237 112).
2. I am on a TIGHT budget. Around $4000.00 at the most.
Option I.
I have a chance to purchase an LS6 rotating mass (crank, rods, pistons, rings, etc.) that only has 2500 miles on it for $350.00. I am think of replacing the current rotating mass with this (no honing or anything) and spending my money on new heads and cam.
Pros:
- I will get more power with the new heads and cam.
- It is the cheaper option.
Cons:
- I am not an experienced engine build but I think I can do this.
- I will need to purchase additional tools.
- Will the LS6 rotating mass fit in an LS1 block?
Option II.
Purchase an assembled shortblock, with new cam and use my current heads.
Pros:
- I know the shortblock will be blueprinted and built to the highest standards.
Cons:
- I think the old heads will need the springs replaced anyway.
- The heads are almost 4 years old. They don't flow very well.
- I'd hate to have to replace the heads later (pain in the butt).
I would appreciate any opinions and answers to my questions (especially the LS6 crank question).
Thanks,
Tony
1. I have a '99 Corvette with 90K miles. Stage I heads and mild cam with 70K miles on them. Engine needs a rebuild because I either have a bad rod bearing or bad wrist pin (I'm pretty sure its a rod bearing). Either way I need to pull the engine and rebuild it. Either way, I'm installing a new cam (either a 224/224 112 or a 231/237 112).
2. I am on a TIGHT budget. Around $4000.00 at the most.
Option I.
I have a chance to purchase an LS6 rotating mass (crank, rods, pistons, rings, etc.) that only has 2500 miles on it for $350.00. I am think of replacing the current rotating mass with this (no honing or anything) and spending my money on new heads and cam.
Pros:
- I will get more power with the new heads and cam.
- It is the cheaper option.
Cons:
- I am not an experienced engine build but I think I can do this.
- I will need to purchase additional tools.
- Will the LS6 rotating mass fit in an LS1 block?
Option II.
Purchase an assembled shortblock, with new cam and use my current heads.
Pros:
- I know the shortblock will be blueprinted and built to the highest standards.
Cons:
- I think the old heads will need the springs replaced anyway.
- The heads are almost 4 years old. They don't flow very well.
- I'd hate to have to replace the heads later (pain in the butt).
I would appreciate any opinions and answers to my questions (especially the LS6 crank question).
Thanks,
Tony
On The Tree
Joined: Dec 2003
Posts: 114
Likes: 0
From: Little Rock, AR
BUY THAT LS6 rotating assembly, but if you dont, let me know. honestly, option I is no doubt the better option. as far as being an experienced engine builder.....its not like this is fragile glass or something, an engine is metal, you wont mess it up, just pay attention to what youre doing, and if you think youre doing something wrong, call a friend and ask, buy a service manual. they are a pretty cheap investment (and a good one to have.) besides, if worst comes to worse, you can always just have a mechanic assemble the shortblock for you. I had one assembled for $150. that would still make option I the cheaper option. As far as buying new tools....As you might know, autozone and oriellys both rent out rare tools. why buy your own? hell if you must buy your own, take them back and get a refund after youre finished 
do whatever you must, but trust me, the first option is the only one you WONT regret.
more money....less power....????
less money.....more power...bingo!!
do whatever you must, but trust me, the first option is the only one you WONT regret.more money....less power....????
less money.....more power...bingo!!
If you install the used rotating assembly in your used block without having the block honed the engine will smoke like a mosquito fogger.
At the very LEAST get new rings , bearings and have the block honed.
At the very LEAST get new rings , bearings and have the block honed.
Originally Posted by Whistler
If you install the used rotating assembly in your used block without having the block honed the engine will smoke like a mosquito fogger.
At the very LEAST get new rings , bearings and have the block honed.
At the very LEAST get new rings , bearings and have the block honed.
Thanks. I was already assuming new rings and bearings. Thanks for the advice on the honing. With the stock rings, what should I have it honed to?
Tony
Whistler,
Wait a second. What if I used my old rings with the new pistons. Wouldn't that be OK without re-honing as long as I match the rings with the cylinders?
Thanks,
Byter
Wait a second. What if I used my old rings with the new pistons. Wouldn't that be OK without re-honing as long as I match the rings with the cylinders?
Thanks,
Byter
TECH Fanatic
Joined: Nov 2001
Posts: 1,248
Likes: 0
From: Kansas City, MO
NO! NEVER BUY USED RINGS!
The way you are describing building this engine will leave you with nothing but an oil burning piece of ****.
The least it needs is an align bore and hone, new bearings, new rings, new rod bolts. Essentially, you'll be building a stock motor.
Take the bore out to 3.905", stock rods + bolts, new pistons and rings, good machining on the block. Have the crank polished or turned and balanced if necessary.
The way you are describing building this engine will leave you with nothing but an oil burning piece of ****.
The least it needs is an align bore and hone, new bearings, new rings, new rod bolts. Essentially, you'll be building a stock motor.
Take the bore out to 3.905", stock rods + bolts, new pistons and rings, good machining on the block. Have the crank polished or turned and balanced if necessary.
Byter,
It would be a roll of the dice. You more than likely would have a problem. I feel you on wanting to use the whole LS6 assembly... just dont cut corners in places that will cause you grief later.
You dont need to have the block honed "out" to any particular size. All you're getting the machine shop to do is resurface the cylinder walls to seat the new rings. Less than .001 will be removed. It's like 60$ for a cleanup hone from machine shops around here.
All stock assembly, there's no need to balance.
Get GM rod + main bearings and the clearances will be tighter, resulting in higher oil pressure.
It would be a roll of the dice. You more than likely would have a problem. I feel you on wanting to use the whole LS6 assembly... just dont cut corners in places that will cause you grief later.
You dont need to have the block honed "out" to any particular size. All you're getting the machine shop to do is resurface the cylinder walls to seat the new rings. Less than .001 will be removed. It's like 60$ for a cleanup hone from machine shops around here.
All stock assembly, there's no need to balance.
Get GM rod + main bearings and the clearances will be tighter, resulting in higher oil pressure.
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Verdad Gallardo Guys,
Thanks for all of your opinions. The more I research into it, the more I feel this shouldn't be my first engine rebuild. I've previously pulled the heads, replaced lifters and feel comfortable with things like that. I'm going to pull the engine and inspect it first. After all, I may get lucky only have to replace one rod bearing anyway (assuming the crank isn't damaged).
However, if I do have a crank problem, I think I'm going with a pre-built shortblock. It may be a little more costly than a rebuild with new heads but that assumes a rebuild would go perfectly, which I'm not so confident of. A bad rebuild will end up being a money pit, the shortblock has a warranty that it will work.
No matter what I do, a new 224/224 .581/.581 112 cam, upgraded 918 valve springs with current heads, double-roller timing chain, and tuning will get me the results I want. My car never goes to the track, I have a 3.42 rear and I use it to commute to work, so below-2000 RPM torque is more important than peak HP at 6500 RPM.
Thanks for your insights,
Tony
Thanks for all of your opinions. The more I research into it, the more I feel this shouldn't be my first engine rebuild. I've previously pulled the heads, replaced lifters and feel comfortable with things like that. I'm going to pull the engine and inspect it first. After all, I may get lucky only have to replace one rod bearing anyway (assuming the crank isn't damaged).
However, if I do have a crank problem, I think I'm going with a pre-built shortblock. It may be a little more costly than a rebuild with new heads but that assumes a rebuild would go perfectly, which I'm not so confident of. A bad rebuild will end up being a money pit, the shortblock has a warranty that it will work.
No matter what I do, a new 224/224 .581/.581 112 cam, upgraded 918 valve springs with current heads, double-roller timing chain, and tuning will get me the results I want. My car never goes to the track, I have a 3.42 rear and I use it to commute to work, so below-2000 RPM torque is more important than peak HP at 6500 RPM.
Thanks for your insights,
Tony
Eh, Tony I would just buy the rotating assembly man. Like was said have the bores lightly cleaned up basically scuffed reuse stock LS6 pistons. I don't know if I would have the block line bored but that is up to you. Lets to a price check here. $350 for rotating assembly. $200 for a set of new GM rings. $200 for GM bearings. You may or may not want a new set of cam bearings but that can't be more than $80 if you get them. Now you need head gaskets and bolts which will work out to be about $100. You will want a new oil pump lets go with a stock GM replacement LS6 pump for $75. Ok with that many miles you will also want a new timing set $150 for that. Lets take a rough guess at machine work because I have no idea of the cost but lets say $500. For that money that might even get the machine shop to assemble it I don't know. Anyways with my estimate you will have about $1655.00 in getting your shortblock together and having good to go. I may have omitted something here but this gives you a ballpark idea. Like I said $500 might have the machinist assemble the darn thing for all I know. It isn't hard to put one together though. An engine is an engine. It doesn't matter whether it is a LS1, LS6, LT1, SBC, Ford, or even Mopar motor. There are tolerances to follow which are specified by the engineers which designed the motor. Put in quality parts and adhear to those tolerances and you can't go wrong.
