71CamaroLS1

I notice some of the tuners - Katech, LG - upgrade the LS7 to forged pistons when installing cam or head/cam packages. Are there known issues with piston failure on normally aspirated LS7s, or are the forged pistons more a matter of comfort in creating a bigger margin of safety?

Obviously, nitrous and/or forced induction almost demand forged, but normally aspirated there are a bunch of folks out there, including me, who have put a ton of hard use on stock hyperuetectic pistons in 346 bottom ends without issues ...

I'm trying to figure out what route to go for an LS7-style 427 - crate motor, or aftermarket short block with LS7 heads. The aftermarket short is stronger, but the crate motor is overall less labor to assemble/install. In either case, I would go with a fairly mild cam/valvetrain upgrade, such as Katech Torquer or LG G7x3, all of this for a '69 Camaro Pro-Touring build.

Thanks for any advice.

ChucksZ06

iTrader: (9)

It would not be a choice for me...I would go with the short block and forged pistons. You will have a much more durable engine for less money. You could put the extra money in a better cam and valve train...like double springs...get the quench dialed in and do some port matching. Good luck.

71CamaroLS1

Well, by the time you add up all of the stuff you need to complete a motor to crate-level specifications (oil system and pan, cam, timing set, lifters, pushrods, rockers, complete head assys, valve covers, intake manifold, ignition coils, water pump, etc, etc) the short block approach is just as expensive - actually, possibly somewhat more - than buying a crate engine, even if you assemble it yourself. And although I've assembled a few engines in my time, I would no longer choose to do it myself on a $13K+ motor - too many little things you can get wrong that won't show up until you're running 160 MPH on the front straight at the local road course (I do several HPDE events a year).

Of course, the aftermarket short block is likely more durable under some kinds of abuse, particularly detonation. The question for me still is, under the conditions I plan to use it, does the factory LS7 bottom end have reliability issues that are documented, rather than speculative? I wouldn't be surprised if there were real issues, but so far my searching of forums has yielded nothing conclusive ... Hence the question which will hopefully be addressed by the tuners themselves.

ss dave

I'm putting the finishing touches on my wet LS7 69 camaro. Ported the exhaust to flow better with the Hooker headers, improved the valve assembly to better handle the upgraded cam. The valve assembly for the stock cam is at max, you will need to do this esp with the K torquer cam. I upgraded the mains, no problems but I've heard rumors that the mains are suspect, probably just that: rumors. I'll post if any problems, can't wait to find out however!

71CamaroLS1

I definitely know that can't wait feeling! My project is in the early stages, but it's going to be mostly pro-built, with my help, and will therefore take "only" 6-9 months or so.

Did you go with an actual LS7 and convert to wet sump, or start with an aftermarket bottom end?

ss dave

Chevy LS7 block, Eagle 4340 crank, Canton pan, LS7 heads, manifold, TB; different internals. The builder estimated 615-635 crank hp. I'm shooting for better than 500rwhp.

trumperZ06

Hhmmm.... I've heard of a few problems with the oil pump & valve train on the LS7. Not enough to cause major worries...

GM may have changed valve springs last year.

As far as I know...

No problems with the bottom end have been reported.

11 Bravo

iTrader: (3)

If you are staying n/a the stock LS7 is fine.

ss dave

Mine is N/A but we upgraded the valve assembly for the pumped up cam. According to Jason at Ktech the Katech torquer cam requires this also. I agree about the mains, they are 6 bolt, how can that be bad. As far as the pistons and the rest of the internals if N/A I agree with Bravo. However, I decided to upgrade my internals for future (ab)use.

the_merv

iTrader: (88)

I have seen that as well, some friends at the Dealership up the road showed me what was left of a LS7 that dropped a Valve due to Spring failure. There wasn't much..

ChucksZ06

iTrader: (9)

sounds like your mind was already made up to go with the crate engine. If you are not comfortable with building and engine go with the crate. The reason pros like Katech replace the cast pistons and bush the titanium connecting rods is those are areas of durability if you run the engine hard. You evidently do not plan on that. You can definitely save money building one. You will fine that you have to buy or replace items on the crate motor depending on your application. I do not like to buy things twice. Good luck with your project.

ss dave

Not only did we improve the valve assembly but we also replaced the rockers. I was told to upgrade the rockers due to needle bearing issues. true/false, not sure, but with the $ spent it was probably wise, I too hate to do things twice.

71CamaroLS1

I definitely have not decided to go with a crate motor, I've actually only just begun to consider it. And I do plan on driving it hard - HPDE events where you run the motor to redline repeatedly for 20 minutes are much harder on a motor than drag racing, IMO. I'm just carefully considering my options - if the crate motor will stand up to hard use, then it's potentially a simpler, cheaper solution with less margin for error.

Hence the thread: I appreciate that Katech does what they do for a reason, but that reason may have more to do with what's comfortable and familiar to them based on previous experience as race engine builders, than actual failures with the GM parts.

All that said, my likely plan from the beginning has been Katech short block, LS7 top end, and that's probably where I'll end up.

Thanks to those who've posted.

trumperZ06

I've run both an 01 and an 04... Z06 for > 50,000 miles with ~ 26to 30 track days/year. I am an instructor, so you know the cars were pushed.

With the exception of safety equipment, brakes, track alignment and dot "R" tires, both cars were stock. Oh, and a Rippie combo heavy duty radiator/oil cooler was added to the 04. The 04 tended to run "Hot".

I had a few warranty items, leaking left rear axle (both cars), steering box (on the 04), and right bearing assy ( on the 01), which were covered.

My 07 has also track prep'ed... so far no problems, but I only have ~ 4000 miles on her.

Gm's crate motors, LS6 or an LS2... would probably be my choice.

IMO, the LS7... is a bit of an overkill, unless you have made substancial changes to your Camaro.

Best of luck on whatever you decide to do.

71CamaroLS1

Thanks for the feedback.

The car will indeed have substantial mods - a C6-vette derived front suspension and multi-link rear suspension from Detroit Speed, 6 piston/14" front/rear Baer Brakes, 275 front 335 rear DOT track tires, 6 point bar, substantial chassis reinforcement.

The goal is to be able to hang with a well-driven Viper or Z06. The '71 in my sig comes surprisingly close, so I'm figuring that 525 reliable rear wheel HP along with the suspension/brake mods above will make me a very happy camper

pist0lpete

iTrader: (3)

My personal opinion is that on a an LS7 500 crank hp is getting fairly close to the limit of what hyper pistons can reliably handle for long miles and hard use. Of course in stock form they are gonna be fine because the OEMs overengineer thes things. However when you start throwing a cam and intake and headers and stuff at it I think you are really pushing those Hyper pistons. Its cheap insurance in the long run to go with forged IMO.

ss dave

I agree with the above, forged internals went into my build. I wanted reliabilty and durability. The powerplant was built to last a loooong time on the street. I also wanted a real 427 block, as opposed to a resleeved one. The 69 COPO came with a rare all aluminum 427, so in a sense, I'm paying reverence to the heritage of the first gen. Right or wrong it just felt better personally, oh, it's also an LS7: that feels good too, lol. Either way you can't go wrong with an aluminum BDSB