fatbillybob

Many reasons for engine failure. Most reliable motor is the factory untouched one with only the known issues addressed. If building for power or specific use then all bets are off. If the LS7 failure is always a rod then maybe there is more to that. But often the guys who build these motors are barely capable of doing so. I'm on my 4th rebuild in 2 years trying to find a decent builder. If my choice was a low mile pull out LS7 or a refreshed LS7 from anyone but the best builder in the business, I would take the pull out.

mp4659

exracer28

I use the ARE parts but Dailey should be fine. The stock dry sump is not as robust as I would like and smarter people than I have documented the issues with using the stock system in race conditions. There seems to be some question about replacing the rod bolts with aftermarket bolts causing problems and I stay with the factory parts. I have not seen the documentation to back it up but I have seen two different LS7 rod configurations. The early rods have a slight difference in machining at the rod to crankshaft interface. Again I have not seen anything proving the change but I suggest using the latest part number for replacement. Unless there a valid reason not to put new bearings I would do that but make sure clearances are checked correctly. I use micrometers and Plastigauge .
With a true dry sump and good bearings the only other item I would think about is the timing chain. I am not a fan of high volume or high pressure oil pumps as they cost power and end up filling the heads with oil. I do use a 115vac heater on the dry sump tank to warm it prior to starting the engine. It sounds like you have to dial back power to fit within your class and if so you might think about a lower redline. RPM helps little motors but with a 427 you have torque on your side and it should help with reliability including the valve train. If you are using data collection I like the ARM oil pressure sender as it is reported to be faster and increased accurately.
John

GSpeed

Remove stock LS7, sell stock LS7. Take Cash from sale, and call Horsepower research. We have a zero failure rate at the moment, across 7 cars, total of over 400 track hours in the last two years. I used to worry about engines. Now, with them building them, I dont worry a bit.


For those wondering, while its nice to have the light weight Ti Rod, the Big ends scuff eventually, and you end up with a paperweight.

sccaGT1racer

You need to find a new engine builder. To make a engine live under road race conditions you have to pay extreme attention to the oiling system and all clearances. there are a lot of engine assemblers but very few engine builders.

KEZ06

I just had my LS7 motor rebuilt by Gwatney Performance for the purpose of road racing. The process with Aaron Salisbury was awesome. Very communicative through out. It is not stock. So far I cannot be happier with it. To confess I only have run a mile event and do my first road race event with it in early December. The build started with the block I had which was an erl 427 non superdeck. It has compstar rods and crank, Gwatney custom grind cam for road racing to have more torque early in the rpm band, Jim Koons, who works for Gwatney and built Nascar heads, built heads with a Jesel shaft system to take out any concern of valve geometry on the valve guides. Manganese Bronze valve guides Mahle flat top pistons for an NA motor build compression is 12.37:1. Lightly ported Msd atomic intake nick williams 102 mm throttlebody haltech cai with a vetteair scoop oil pump reworked and a Lingenfelter larger dry sump tank instalked. It is tuned for 3 fuels: e85, M110, and 93. I can select the tune thru an Ngauge on the a pillar pod. It will also record any knock retard as a result of knock being detected shown on the ngauge as well. Car makes 642 whp on E, 632 whp on 110, and 619 whp on 93. What I like most is torque is over 500 ft/lbs from 4100 to 6700. I will run E if the track I am at at the time has it so the motor will run cooler. I expect that as I get more accomplished with the car that I will need to upgrade the dry sump system. I have a ways to go as a driver before I get to that point.

mp4659

very cool! track down a good instructor for your first track day...my application is a bit different, dedicated race car-- for nasa st2 its 8:1 power to weight, so 3200 car = 400whp. Scca gt2 is a bit stricter and its not power to weight but you are limited to factory gm head casting, intake, tb, cam lift .600 (as far i can tell) and a dedicated restrictor plate depending on which Ls motor you are running.