kmagvette

After 13 years of abuse, the C5Z's LS6 finally let go spectacular fashion, got engine parts in the rear tire.

My needs are pure HDPE, no class restrictions or rules to worry about; my primary objective is reliability. I am (was) fairly fast; 2:05-2:06 at WGI w/ full stickies unimpeded.

The LS6 was putting out a touch over 500 HP (guestimate, it dynoed at 447), and a long, flat 400+ torque curve . I would like to replace it with something in the same power range, and it appears that most options come with more torque.

The LS3 seems to be the defacto replacement engine, with a dry sump. There are planty of aftermarlet engine builders that will help you part with even more cash. I have no idea if the aftermarket route makes sense for my needs.

Looking for suggestions based on experience; LS3 or other. I do my own work and am comfortable with starting from a Short Block or complete engine depending on what yields a more reliable build at reasonable cost. Other threads have prepared me for the wallet hit.

mika401

Summit carries some decently priced new 6.2L short blocks. For $7000 you can get a complete 6.2L with warranty.

63Corvette

I would recommend the GM crate 525hp LS3 engine WITH an ARE dry sump as the "best" replacement ($$$/reliability)
Please DO post your choice and results

Bill Dearborn

Keith,
LS3 with the ARE dry sump would be my recommendation as well. If you use the LS3 make sure you do the dry sump as a number of racers had issues with oil starvation when the LS3 first came out and the C6 GS with the GM dry sump was the resolution. Of course you will need some changes because there is a difference in the engine electronics between the C5 and C6.

Or you could get a crate LS6 but then I think you have to change a few things since it is set up as a Caddy replacement instead of a Corvette replacement.

How many track miles were on that engine?

Bill

C5 Hardtop

13 years of track abusage is doing pretty good. I'd be inclined to replace the engine with the same thing.

Millennium FRC

As others have mentioned above, LS3 525hp crate motor that comes with the ASA cam, then add a dry sump set up. Too many wanna be engine builders out there these days that would love to sale you a grenade. Unless you know someone local that has been building legit race engines for at least 20 years, get a GM crate motor.

93Polo

Agreed but I would change the valve springs on the crate engine, there have been a few reports of them breaking.

JHrinsin

GM LS3 crate engine is a great street engine but it does not have the hard core HD internals to put up with full duty track abuse - even when fitted with a try dry sump system. You should have a short block with forged rods, forged pistons, full floating wrist pins, maybe oil squirters, ARP fasteners, a high pressure oil pump and quality bearings. Valve train needs at least the LS7 lifters, quality push rods, the right timing chain, full roller rockers, the correct springs for the camshaft, etc...

Grabbed_Crow_Mobe

I was under the impression that the ls1/6 block wasn't being made any longer. I hope I'm wrong.

davidfarmer

Lots of expensive adapters required to put an LS3 into a c5. I’d build another ls6 based engine after having gone through this once.

MR Turco

out of curiosity, how many miles on the ls6 before it blew up? Any idea why it failed?

edge04

I went with this. Only have roughly 400 track miles on it I am happy with the decision.

https://www.chevrolet.com/performance/crate-engines/ls3

Note that I de-tune it and run one of these. Maybe a dry-sump is in the future.

http://www.improvedracing.com/oil-pa...kit-p-493.html

GSpeed

We have 92 hours on a customers Crate LS3 with LS3 OEM drysump, and LS3 OEM drysump tank. Pressure is good everywhere, and its on hoosiers with aero. It was changed over to a 24x crank trigger, and it does have a non stock cam. It makes 475rwhp when un restricted.

Id recommend the OEM LS3/LS7 dry sump WITH a larger than OEM tank, OR the 09+ tank with baby tank. They work well, and its all OEM.

GSpeed

This is for the casual racer, or track day goer. I recommend race engines for those competing and traveling, but for the person where the LS6 was more than enough, the LS3 IS the way to go.

93Polo

I thought so too. The closest you can get is a Gen 4 5.3 bored to a 5.7 built buy a few LSx shops.

The 5.3 I understood had the windage windows that the LS6 had. You still need to relocate the knock sensor, and cam sensor along with building a motor with a 24x reluctor wheel on the crank or a LPE 58x to 24x box.

kmagvette

Bill,

The LS6 exploded at 47K miles, about 35K of those were track miles. I have not dropped the drivetrain to see what failed. I suspect something in the middle-rear let go. No holes are directly visible from above or below.

The crate LS3 is tempting from an everything is new perspective, however, having a beefed up lower end is compelling.

I would like to keep cost reasonable, say 12K range, with a dry sump. The LS3/525 w/ ASA cam + Dry Sump is roughly in this range. The beefed up LS3 short blocks leave me in a position of having to get the cam, heads, intake, TB, etc. My preference is not to build a one-off; though the last one (LS6) worked out extremely well till it went BANG!

With respect to the Dry Sumps, it seems that the default provider here is ARE. I am a Dry Sump noob, but it appears that there are other options such as Avaid, Daily, Moroso, etc. What criteria is driving folks to ARE as the defacto Dry Sump solution; just trying to learn here.

I will certainly post my final decision(s) here, hopefully to help out C5 folks in the future.

Thanks for all the responses/suggestions thus far.

JHrinsin

Sounds like you LS6 was not a factory stock engine. It lasted 35K track miles, mind if I ask what you paid for that engine?

You can piece together a replacement short or long block based on the carnage involved with your LS6 or you can buy a crate motor. The only issue with some crate motors is they will be Gen IV LS3 based, not Gen III LS1/LS6/L33 based. The later LS3 based engines will require some extra effort and expense to get them to work correctly in the C5 or you will have to update the car to receive the engine.

The PO of my car (a very good friend of mine) nuked the original LS1 short block in the '99 FRC on the track back in late 2015 - ring land failure #7 piston. He then bought a 5.7L TMP stage 2 short block and a set of freshened 243 heads to replace it and moved over the bolt-on-stage parts to the new engine. He had the engine work professional done and re-tuned. Cost him about $9.5K - but its still running the factory wet sump setup. You can use that as a price guide.

You can also talk to someone like Jason at Katech (Katech_Jason) about your needs if you want a fully vetted and proven race crate engine package. IIRC, their Motorsports 550 is about $18K.

Best of luck with the project.

GSpeed

The Dailey Dry sump is really your best option. Its a positive displacement pump, and you can run a scavenge filter on it, unlike the other systems. This is important for maintenance.

Also, there are no oil lines from the pan to the pump, its all integral. This makes it a super nice package, and nothing to fail or come loose.

0HP RESEARCH

There are tons of options out there when it comes to engines, pull out units, crate engines, performance aftermarket units, or having one custom built.



For the weekend racer or occasional HPDE guy looking at some of the GM crate options isn't a horrible idea as a few have said. They offer OEM parts, factory quality assembly, economical pricing as they push hundreds of them out the door.



Now the +/- of this is that you get OE parts, OE tolerances, and OE specs. While that may work for some it doesn't always workout for everyone. The OE's are forced to use a aluminum style main and rod bearing in their engines which, again can work just fine so long as temps are kept in check and it has enough clearance for good oil flow. Now what do I mean by that? Same as you read about on the forums...one person puts 150k track miles on a car with no issues and yet another fails first day on track. GM does a great job of building production engines to meet production use but there are still tolerances when you build 200k engines a year down a production line. It's amazing they do what they do, but there is always a few that have just a little tight of a ring gap or has just a light to tight of a rod bearing clearance and you read the head line "my LS(x) threw a rod at (enter track here)". We have a few LS7's here in the shop now with spun main bearings and chewed up rods. Not all of them are going to do this...but there are those that do.

Like GSpeed has said above...with the addition of dry sump...cooling....... Not going to lie all of those are great things to do no matter if it is the OE engine that came with your car, or a $85k custom solid roller. Those are great things to do and will most certainly aid in the life span of your engine on track. That being said those are key things to take note of for those doing this. The engine needs a great support system of water, oil, gas, air, and spark to make them live under the stresses on track. To much of one thing or not enough of the other and things go south in a hurry.





Most road racers do not NEED to have a forged crank, rods, and pistons in their engines. Forged pistons do offer a bit more strength and will hold up better when engines are pushed that is true but for the power levels most are using it isn't required, nor would any high dollar part. If high RPM is required...then you might be spending some $$. The nice thing about a forged piston is that they do not crack and explode if something goes south in that cylinder. Forged units will hold up much better. Also offers you the ability to run custom rings, thinner ring sets...or a change in compression.


As the engine itself goes, one of the more critical parts is going to be the valve train. Stable cam lobes, good springs, attention to detail on setup is going to go a long way here.





There are tons of options out there, OE or having someone like ourselves build something for you. Just lay your options out and see what fits your needs the best.



Now my shameless plug. We are working this summer to offer pre-built, engines with solid quality parts assembled no different than our custom engines you have seen on here. We just kill the options to reduce time and that might be a good solution for a number of you. Of course we can and will still do all of the custom ones too.


I'm free to help anyway I can, and I know GSpeed has a lot of great supporting systems to help too!

93Polo

I always understood Dailey was the best/cleanest install but more than ARE or Aviaid, any ballpark on how much of a price difference?