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Hello I'm building a c6Zo6 for DE events road race use. I bought the car out of the Huston flood and it was set up to drag race.
I have the engine down to the short block and I'm planning on new cam rod and main bearings. I need a new cam as the one I have is a Drag cam with way too much duration. It's forsale BTW , with the lifters.
Planning on putting forged pistons and I'm looking for advice on where to buy the cam rockers, pistons , and lifters. Who do I call to get a good complete package?
Thanks for the help
I know I could use the search function but wouldn't t get a straight answer.
Pistons: You should really let the engine builder spec the pistons. The cylinders need to be bored/honed. The crank needs to be re-balanced. Bearings need to be inspected and should be replaced. Etc. Mahle, Diamond, CP, Wiseco, Racetech etc all make good forged pistons for an LS7. I run CP Carillo Bullets 2618 alloy on a 4.13" bore.
Bearings: I have Clevite bearings, but again the engine builder should spec these and set clearances.
Lifters: Johnson or Morel. I run Johnson 2126LSR Axle Oiling.
You need to find a good engine machine shop to do the bottom end work. Contact HPR, HPA or a good shop near you that can help you put it together.
Alright, that is good. So when I rebuilt my LS7 I did quite a bit of research on the bottom end. I came to the conclusion that I was going to install one of the following pistons:
- Mahle LS7 Flat-Top Forged Piston Set, 4.130" Bore, 4.00" Stroke, 6.067" Rod Length, -3cc
or
- CP Carrillo LS7 Bullet Forged Pistons BLS1202-005 4.130" Bore, 4" Stroke, -4.6cc FT
The Mahle are 4032 aluminum and the CP are 2618 aluminum. You can research the differences. But basically the 4032 has more silicon and doesn't expand as much. It is therefore a bit harder and lasts longer, but it doesn't hold up as well to detonation because it is a less ductile alloy, as compared to the 2618 which is more malleable and expands. I chose the 2618 after alot of debate (with myself). They are simply more durable.
Both of these pistons will work with your stock titanium rods. Also, the LS7 stock bore is 4.125". If the cylinder walls are still in good shape, they will easily take a bore to 4.13" (but not much more). This will also allow the builder to re-hone the walls. So both of the pistons above are perfect. And lastly, they both are close to stock dome valve relief specs at -3cc and -4.6cc, (stock pistons are around -5.3cc) so compression won't change too much.
So then you need all new bearings. Clevite are good, but the builder should spec which exact ones and set clearances.
Exact lifters I use are: Johnson 2126LSR Slow leak down race style axle oiling lifters (these are NOT the "short travel"). Got them from Texas Speed
Exact rockers I use are: OEM w/ CHE trunnions that I got from American Heritage Performance.
Exact Pushrods I use are: Trend Hardened 3/8” .135” wall pushrods 7.925”. But you need to measure for length.
And again, contact Pat G to spec your cam. If you want my cam specs I will post them, along with a dyno.
Is the LS7 system not enough ? I thought it was a real dry sump.
As it sits, the LS7 oiling system is not adequate for hard core road racing. You have two choices:
1) Do your best to correct it
2) Replace it
To correct it as best as possible it needs: Larger dry sump tank (if your car is an '07 or '08). Get it from Lingenfelter.
Pan and tank baffle. Get pan baffle from Improved Racing and tank baffle from AVIAID.
Better cooling. Get new Setrab oil cooler, lines and thermostat from Improved Racing.
Oil pump. Get a new oil pump from Katech (Red or blue). I have the Red.
Or, ditch the whole system and go with a Dailey, ARE etc. Still need to address cooling, pump, lines etc.
I'll call Scot crank and get a reciprocating assembly from them with the compression you want for pump gas about 11.3 is good is you can get a set Of Trick flow 260 cc ls7 heads then go to;
Pay the $40. so you don't have to wait for ever and let Patrick G do your cam specs reason been he has a archive of road race cam lobes that are easy on valve train and make a ton of power.
Take your time and fill out the questions as best and complete as possible he likes light weight valve train.
The dailey dry sump system is the best but costs about 2000 more than a ARE system. don't waste your time with bandaids to the stock ls7 system if you truly want a engine that rev's and handle sustained g force.
I would also go with a head that will take a jessel style rocker arm with with a low lash solid roller cam. Brodex, mast or all pro cylinder heads would be my choice.
Last edited by sccaGT1racer; 02-21-2018 at 09:31 AM.
I'm going to give you some advice but it will be a tough pill to swallow. However at the end of the day you will have a better time out road racing your car. First, if your not an engine building and don't have 15K to waste, stop and do not build your own engine.
Put the LS7 back together and put it under a bench and cover. Go get a new LS3/525 motor from GM. That has GM's race asa cam in it. Call ARE and buy a real drysump system, get the whole stage 3 system and not the 4. Make sure you get the Peterson tank with the kit. Install and go have allot of fun. If you run a lot, in 2 years, sell the motor and buy a new one. You will recover some of the cost of the new motor by selling the old one. This way will keep a fast engine in the Vette and it will not cost a lot to maintain or keep it running. I am telling you this from experience, building your own motor is going to cost you way more than just the 525 LS3. My old car is below.
Last edited by Zip Corvettes; 02-21-2018 at 01:53 PM.
02-20-2018, 08:36 PM
Building a road race engine and need some advice
