Hi,
My 2007 C6 (LS2 motor, 243 heads) has worn valveguides, and needs new valve lifters too. I think ticking sound comes from one of the lifters.
I also heard many good things about the LS3 heads.
The car is in CA Bay area and it is a daily driver. What kind of cam can I throw in there (along with LS3 heads?) and still pass smog test?

Thanks,

Sonner

 

Call Comp cams and ask them. Everything else is just opinions.

 

Not to disagree w. Tim above, but I'd do a little more research on CF before calling Comp Cams. Go to advanced search and type in cam, Calif., etc as your key words. Limit to C6 Gen and TEch,, and also limit time to say, last 1 year.

IIRC, there was a shop in NCal. named Synergy Motorsports and I thought someone referenced them as a good knowledge-base re what works and what doesn't for CARB.

 

The tic sound you have could be many different things like a header leak a faulty or loose spark plug, loose / worn rocker arm bent push rod broken lifter or even a leaking head gasket many of these things are easy and inexpensive to fix my advise search before an expensive tear down you may not need.

If you want to know which head ls3 hands down you'll need an ls3 intake and an ls3 cam the ls3 heads like a little different cam profile than the cathedral port heads.

 

The ticking sound comes and goes. I would drive the car for 4-5 days, and the ticking would not be there. Then, next day it would be ticking loud. It starts after engine warms up. Then, I shut off the motor, let it cool down overnight, and next morning motor would run with no ticking.
The sound comes from under the driver side head or middle of the engine. I can't tell. It is definitely a reciprocal motion sound. It goes tick-tick-tick, rather than ticky-ticky-ticky. And because it comes and goes intermittently, I am suspecting hydraulics related component - lifter. Worn, bent or off-round rotating components would not make sounds that come and go intermittently. Although, worn gaskets and sparkplugs may.
I'll open the valve covers and also check header gasket this weekend.

Thanks for the advice about LS3 heads. Since they are Corvette heads and come from higher year model car (08 and up), they should be ok for passing smog. And, they look stock by not having fancy engravings. I'll start looking for intake and fuel rails as well.

Thanks,

Sonner

 

Being in California is a huge part of your issue. When you start changing parts you can run into compliance issues. Also, keep in mind that you will need an intake to go with the heads.

I work for an oil company in California and they want to make sure that oil doesn't contribute to exhaust emissions, so when you start changing cams and such, need to make sure that they are CARB approved to avoid issues.

 

- LS3 heads and LS3 intake needed.
- LS3 specific rockers required.
- LS2 fuel rails and TB work fine. Many prefer the LS2 TB due to the TB servo.
- LS3 injectors required, or space the fuel rails in some manner. This may lead to issues on the CA visual inspection.
- LS2 cam is fine, but certainly might want a bit of an upgrade while you are in the engine.
- Factory head gasket or the LS9 MLS gasket will result in an ~0.5 loss in SCR due to the 68.4cc LS3 chamber (vs 64cc LS2 chamber). You can move to the 0.040" thick MLS gasket and it will move you back to ~10.75:1 SCR (vs stock LS2 at 10.9:1 SCR).


I hope this helps...

 

L92 heads are dirt cheap too. Factory intakes are cheap as well--not a bad mod if you're going to be working on the heads anyways

 

For the price you going to spend on ls3 heads, you can have the LS2 head reworked isntead.

Valve guides are easy to replace, and if your valve stems have not over worn, then the vavles can just be cleaned up and reused. Same goes the rockers that may still be good.

Hence this leaves a lot of money on the table to have the 243 heads ported to end up with more HP, and not have to change a lot of parts to use the LS3 heads instead (like intake manifold).

 

Thanks for the useful advice.
I am inclined to use LS3 heads.
I was worried about the compression reduction when going to LS3 heads. Using thinner head gaskets and/or milling the heads certainly helps with SCR. Spinmonster has this thread about heads/cam package:
https://www.corvetteforum.com/forums...cam-specs.html
He recommends increasing SCR by milling the heads. Milling the heads, valve brand/types and cam profile might reduce piston-to-valve clearance. It require carving valve reliefs on the pistons - fly-cuting.
Because of CA smog, I won't be able to go crazy on the cam profile. Also, I can't increase compression to much, because we only have 91 octane gas. The cam will need to be a sleeper type cam with no noticeable lope.

Do you know what max lift/ duration should I be looking for, without running into PTV clearance issues?
Here is Craigster05's setup that uses spinmonster's cam. And no fly-cutting.
https://www.corvetteforum.com/forums...in-begins.html

Thanks for the help.

Sonner

 

I started with an LS2 and put an LS3 top on it before I bought a forged 416 LS3.
This is the cam I uses with no issues. Picked up 100RWHP between heads, cam, FAST intake, etc.

http://www.compcams.com/Company/CC/c...csid=1411&sb=0

Lots of "secret sauce" cams out there, but this what I used based on the recommendations of my engine job and Comp Cams.

 

Your description is a header leak.

 

Heres what I would go with if I was buying an LS3 head. Probably the best bang for the buck in ported LS heads out there.

https://www.summitracing.com/int/par...8758/overview/

I personally would get a custom cam spec'ed for these heads, since porting changes the intake to exhaust flow ratio significantly, since stock LS3/L92 heads are more "intake-centric" and porting really wakes up the exhaust flow on these heads, so an LS3 specific cam with the typical 10 degree split between intake/exhaust duration would not be ideal for these hands for optimum power. But I don't have to worry about smog police down here.
However, if you wanted the best bang for the buck without a ported head, you could buy a set of L92 truck heads, as these are cheaper than the LS3 heads, with the only difference being that they come with heavier solid intake valves (and possibly weaker springs?)
To avoid smog police detection, you could combine that with something like the LS9 cam which is really not ideal (it's a GM blower specific grind) but would make more power than the stock LS2 cam. The list price on that cam is like $<140.00. Best case would be to get a mild custom grind with "negative overlap" so that it doesn't affect your idle characteristics.
You'll need the LS3 intake/injectors as pointed out above, but the best case would be to get a take off unit from one of us who has done a PD blower install. I have one sitting in my garage with everything you would need on it, that I would love to sell you cheap, but I'm overseas, so shipping is cost prohibitive and US Customs would probably drill some holes in it for you) like they did with some shocks that I shipped to schpenxel once!).
The beauty is that if you did the CNC LS3 heads now, you probably would not need to change heads in the future if you built a 6.2 or 416, 427, etc., unless you're going for like 1,000+HP.
Truth be told, you really don't need the LS3 head, and you could save some money now by just getting a set of CNC ported cathedral port (243 series) heads. Of course, then you're stuck with the lousy stock LS2 manifold, but you could upgrade later to a FAST intake, which would put your total investment right around what you would spend on an entire LS3 topend.
It's your call. Of course, whether it has a lifter ticking or not, you should probably upgrade the lifters if you pull the heads, because that's what you have to do to change them.
I would think carefully about what your long terms goals are with the car before buying anything.
Good luck with whichever way you go.