david_12121

Hey guys.

I have a c5 vette(non-Z, so LS1) that I take to the racetrack every now and then. It had a few bolt ons on stock internals and was making ~420whp. My last event, it developed rod knock and lost oil pressure, and then seized. I believe it's a spun bearing but haven't torn it apart yet.
It had an ls6 ported oil pump and an oil cooler, so the failure was odd at 93k miles.

So I'm weighting my options and a few of them look appealing atm:
1: Get a refurbished crank and pistons and rods and rebuild it.
2: Ls2 or ls3 block with a 3.622 stroke to keep it happy at high rpm.
3: Ls2 or ls3 block, ls3/l92 head, stroker kit to 416

The main reason I'm not going with the 3rd option right this second is that I will eventually upgrade to a c6 z06 due to the aluminum frame being lighter and this upgrade would postpone that upgrade.
They are vastly different options and I know that my question is vague but I just wanted some input from you some road racing guys.

DietCoke

iTrader: (18)

Accusump? Even a stock ls motor will starve of oil on a road course without oil mods.

david_12121

Reviewing my video, I was not losing oil pressure.
I've talked to several c5 owners on track and never heard that oil starvation is an issue. Is it?

Edit:
I read a bit about the oil starvation and it seems to happen on high G left hand sweepers. I was on Buttonwillow 13CW and it does not have any.

.boB

iTrader: (1)

Low mileage LS1's are practically falling our of trees. Cruise through your local bone yard, CR, or e-bay and see what you can come across. Swap out the parts you need, and get back to it. That way, you're right back where you started, with minimal investment in time and money.

When you're ready for your upgrade, you can do it at your convenience. Going to a 416 now is going to be a bigger project than you think it is - time and money both (it always is). It's spring, and you'll miss out on a lot of track and street time.

A C6 is so much better in so many ways, you'll probably decide to do that anyway, so you'll end up saving a boatload of time and money on the C5.

PS- Don't forget the Accusump this time.

DietCoke

iTrader: (18)

This time maybe.

If you're relying on your stock sending unit/dash to tell you, you're also doing that wrong - it's way too slow to be useful in this case. Accusump is a must for any type of road race, period. I'd also recommend the improved racing batwing baffle.

redtan

iTrader: (5)

Unless you address the oiling issues, this will keep happening...don't ask me how I know.

Also stick with the LS6 engine, those have better oil control than the Gen IV (especially the LS3 heads).

What you need is reliability, so get some Gen IV rods (or budget forged rods), ARP bolts, some nice basic forged pistons and top it off with some LS6 heads. Oil pan baffle and accusump with a ported Melling and hope it holds lol.

david_12121

I feel like starting with a partially worn engine is not as effective a method as rebuilding with better parts. I was making nearly 50% more power than a stock LS1 makes, and putting my speed parts on it will get me back to where I was.
Also what makes you say the c6 is a better platform? Same suspension, so I'd be maintaining my pfadt coilovers and hotchkiss sways, I'll also be putting on my AP racing calipers on it. It's just marginally lighter to my knowledge.


I've heard about the low response time of the stock units. I will look into a quicker response gauge and an accusump.
What do you guys think is the best way to address the oiling without breaking the bank on a dry sump system?

DietCoke

iTrader: (18)

accusump, scraper, pan baffles.

260DET

With the electric valve Accusump a indicator light showing when it is operating ie the valve is open, can be wired to the valve switch. Get a big bright red one where it can be easily seen when driving and if it comes on you know that the oil pump is starving.

gnx7

iTrader: (28)

If you keep shift points around 6500rpm and only rev it out to 7000rpm to avoid up shifting into the next corner.... then run as many cubic inches as you can for the added torque. That will last for many many seasons.

If you plan to rev it much above 7000rpm then you need a better oiling system (dry sump) to prevent cavitation of the oil pump.... and a better intake manifold to take advantage of the RPMs. Most polymer intake manifolds hit a flow wall around 6600-7000rpm.... For longevity and bang for the buck... keep the RPM's under 7000rpm. Your valvetrain will be happier as well.

A new LS2 block from Summit is $1133 delivered... LS3 is $1519.
Running a 4" stroke crank that is 402ci vs. 416 which is about 20rwtq all across the board.

david_12121

My rev limiter was at 6800 and I wasn't shifting over 6k.

Current plan is rebuilding the LS1 if it's healthy enough. OEM rotating assembly, melling 10296, drilled trays, 3qt accusump(with a bright light inside), and speed pro 3/4 groove bearings and 8-7100CH rod bearings.
I already have an engine oil cooler and will install a trans and diff cooler as well.

Any other recommendations are welcome.

beach cruiser

iTrader: (1)

Get the Improved Racing baffles for the pan for sure, accusump as well. I'm running an LS6 platform in my racecar. I usually drill the lifter trays with a hole half way down to aid in oil drainback into the pan. If you forgo the accusump, you should at least run a half quart or so past full.
I'm in the process of building a LS2 402 CID with LS3 heads and intake. it will take you longer to put all those pieces together and cost more too. I'm taking my time since my LS6 is still running.

david_12121

Added to the list.

I also read that 3/4 groove bearings are not as good as 1/2, due to oil film thickness dropping a good bit lower than the 1/2.

Anybody have any insight into bearings?

bigmackloud

I'm in the same boat. 01 C5 coupe, street/HPDE car. LS1. ringlands on the #7 piston broke.

Personally I'm planning on forged rods and pistons simply because they can take a bit more heat abuse. Plus forged rods will come with ARP rod bolts, which are a common failure point.

If you have significant damage to the bottom end, buying a built short block might be more economical. Schwanke engines seems to have decent prices.

A few other things to consider during your build...

The #7 cylinder is a known failure point. One possible contributing factor is that when they went to the LS6 intake (01+), they removed the steam vent lines from the back of the heads. I'm planning to add these back. Trickflow sells a kit. other options too.

Now's a good time to do the rocker trunnion upgrade. the Straub bushing kit gets too reviews.

Adding a timing chain damper is also good insurance for a road race motor. If you have an early LS block that isn't already drilled, Trick Flow makes a bracket that bolts to the cam retainer plate and allows you to add a damper. $50.

TrickFlowTech

As others have said, the trunnion kit, LS2 damper, and steam kit are great ideas. The factory ring gaps are tight and opening up the gap on 7 a bit more than the others is a good idea. Probably .018 on the top and .023 2nd would be a good starting point.

I myself took out #7 on my C5Z, so I feel your pain. The Improved racing parts and running extra oil is good. Finally, not all of us have the $ for a Dailey drysump etc., but shifting up a gear and running through a sweeper at lower rpm is a good preventative measure.

pdxmotorhead

Regularly checking your valve springs is a good idea on a road race V8 ,, I've seen an amazing number of DNF's over the years for that one item... 30 to 40 minutes of road race rpm is hard on them. YMMV

260DET

The #7 problem is not fuel distribution related is it? I'm no engine expert but have always understood that breaking top rings was usually caused by preignition, not enough fuel, too much ignition advance.

bigmackloud

To be clear, for me any ways, it didn't break the rings. It broke the ringlands between the rings.

There are a variety of suggested causes to the #7 cylinder issue. Mine at least, appears to be heat related. The ringlands pinched the rings. I suspect that cylinder got hot... could be partially ignition timing... but that cylinder is also at the back of the block and it's been suggested the coolant doesn't flow around that cylinder as well as the ones at the front. Plus the lack of rear steam vent ports makes matters worse.

Some have also purposed that the design of the intake manifold rams a bit more air into the back cylinders and causes them to run slightly lean. (again, more heat). I can't say if that's actually true or not.

My plan is forged pistons (can simply take more abuse) and I'm adding the TFS steam vent line kit. I also appreciated the above suggestion on the ring gaps for that cylinder.

TrickFlowTech

With the LS, the fuel and the ignition in #7 can be the same as the other cylinders, but the water jackets in the block and heads are a restriction.

Generally, the piston can't dissipate heat quickly enough (through the rings) and the factory spec tight ring end gaps butt. With no room to expand, the top ring bows upwards and pops the top or 2nd ring land.

260DET

That makes sense, uneven coolant flow to back cylinders can be a problem with other engines too. One model straight six engine I know of often has an extra exterior coolant line plumbed into the back of the head.