Looking for some advice on my LS7 ('08 C6 Z06, 55k mi, stock, valve guides addressed 2 yrs ago by a reputable shop). While at an HPDE last week, oil pressure dropped to 5-10 psi and car went into limp mode. I finished lap, shut her down and then she rode to my local dealer on a flatbed. Before the tow, I started it a few times and let it idle in attempt to diagnose the problem. In general, once started, car was idling pretty smooth without any significant knocking or other abnormal noises, but I will say, cranking seemed slow/difficult. Before dropping off the car, I pulled a small oil sample off the dip stick which upon inspection is revealing some non-magnetic metal content. The senior engine tech at the dealership believes it's titanium from rod interference which has now caused bearing issues resulting in low oil pressures. He's recommending complete replacement of engine, oil tank, oil cooler and all associated plumbing to the tune of $20k+...obviously a hard pill to swallow...

Over the last couple years, car has primarily been used for HPDE (~10 days/yr) which will continue - I get more into it every year. Very limited street driving - mainly driving to and from events with an occasional weekend outing, but would like to keep it streetable and relatively civil (and maintain things like A/C). I'm not really looking for any extra power, more just looking for reliability / engine life.

Based on what happened and the few indicators I have, I suspect that the engine tech is correct and I'm now debating my options of:
1) Stock(ish) rebuild, mild cam - $14k from reputable shop
2) Replacing with a new LS7 crate engine from GM, having dealer complete work and walking away with a 3yr/100k mi warranty - $20-22k
3) New short block with forged components, ditch Ti rods + existing heads w/ upgrades to lifters, springs, etc + a few other extras (oil pump, balancer, etc) - $22-24k
4) Swapping to an LS3 to increase reliability and minimize cost - seems like it will require some significant research unless I opt for a Grand Sport motor
5) Bring car home, send oil sample out for analysis and then consider options
6) Other recommendations?

I'm in Atlanta so would appreciate any feedback on reputable shops to work with. Thanks in advance for any recommendations / advice.

 

GM discontinued the LS7 crate engine crate engine a few months ago, so that option is not available any longer. The GM aluminum LS7 bare block is still available, however, and there are several shops that will use that block to build a short block to your specs.

 

I’ve heard that from several people, but I’ve got a dealer and a couple other shops who are quoting them and say they can see inventory. So I assume GM did a sizable last time build of some sort.

 

I'd be looking at option 5. Your block, crank, and heads should be rebuildable. I'd bet on that. New pistons, rods, cam, lifters, etc. + machine work shouldn't cost near $20K. Maybe nothing wrong with your heads that need refurbishing. More money saved. I know you'll have to pay someone to put it all together, but damn, it shouldn't cost that much to get you back whole and having fun again.

 

Other
https://www.corvetteforum.com/forums...post1605287938

 

Call American heritage performance
they can build you something that would be reliable and powerful.

 

There's no way I'd fork out 20k to reinstall the problem!!! I have a wet sump LS7 in a 2000 C5 Vert. I may have missed something in your situation, but why not tear it down, go with a .005"-.010" overbore (the less the better, as LS7 sleeves, especially #7, are prone to cracking, and they're thin even at the OEM bore size), forged steel rods, and a forged crank? Much cheaper than 20k!! You may even be able to grind your stock crank undersized, and have it rebalanced for the extra weight of the steel rods, though I've heard it's a tough job getting the stock forged crank balanced for steel rods, but it's worth a shot.........

 

Thanks for the shout out!!!


https://americanheritageperformance.com/

 

I know prices have gone up recently but the quotes you've gotten are insane.

Here's my recommendation and it's based on personal experience rather than "uh, I think this will work".

• Buy an aftermarket rotating assembly from someplace like Texas Speed. These range from $2000 - $2500 for something decent depending on what options you pick.
• Have your heads redone because with the exception of probably needing the valve guides done as well as a valve job, are likely okay. The last time I had mine done it cost me $1200 from a small local shop. Expensive doesn't always equate to better as I've had zero problems with mine so far.
• Have a machine shop clean, prep and assemble the long block. This realistically shouldn't cost you more than $1000.
• Figure another $400 - $500 for things like gaskets, fluids, head bolts and other incidentals.

Even if you add in another $500 for sh*t happens you're only looking at $5700 not including the labor to re and re the engine. Not sure if your $14K stockish rebuild estimate included labor but assuming it did, that shouldn't cost you more than $2000 based on an hourly shop rate of around $135. I can pull an engine in my garage in 5 hours and have it back in in less than 10 as pulling all the external parts off and reinstalling them is fairly time consuming.

So the absolute worst case scenario with this option is under $8000 out the door and that's with an aftermarket rotating assembly that'll be a lot more durable than reusing stock replacement parts. And if you're feeling brave and wanted to pull it yourself, I also wrote an extensive How To guide. There's a lot of moving parts but it's really not rocket science.

Hope this helps.

 

I appreciate the feedback and advice. At this point, I would jump at the opportunity for a reliable rebuild at $8k...I'm just not finding anybody at that price point in the area. As far as I can tell, I'm being quoted between $3-5k in labor. Know anybody in Atlanta that you'd recommend?

 

Vengeance Racing is in Cummings, GA, 30-40 miles from Atlanta. They're one of the best shops in the country. I would give them a call.

 

Thanks for the recommendation - I've actually talked with them already. They are the ones proposing option 3) from my original post. I'd love to pull the trigger on it, I'm just having a really hard time digesting the cost...

3) New short block with forged components, ditch Ti rods + existing heads w/ upgrades to lifters, springs, etc + a few other extras (oil pump, balancer, etc) - $22-24k

 

Another option would be to find a good used short block. It wouldn't be the ideal plan since the same problem may just happen all over again, but it'd be the fastest way to get going again.

If you did go that route it'd be ideal (but challenging) to find a motor still in the car so you could see it running. If that's not an option then if you find one already out of the car I'd highly recommend pulling the oil pan and windage tray to measure the side clearance of the rods. This is something easy to do with feeler gauges, and pulling off one or two of the rod caps would also be a good idea so you can verify that the rods aren't already starting to grind into each other.

As for having to replace the oil tank, cooler and lines, that's something to do with a catastrophic failure, not a simple rebuild or swap.

 

If there is no inspection hole in the bock, why not rebuild it?

 

Biggest challenge I've run into thus far is finding somebody able to do it inside of the next 6 months. Second challenge is finding somebody local who can do it for a reasonable price. Only rebuild option / offer I've received thus far is $13-14k (albeit from a very reputable shop) - that cost includes pulling the motor, reinstalling and tuning.