Engine build for sustained high RPM...

djsanchez2 · 07-17-2008, 12:22 PM

Hello fellas,

I went on my first road course venture yesterday and IT WAS A BLAST!! Thing is we noticed a rod knock at the end of the day. So i am now going to tear it down and build a blueprinted / forged bottom end. I would take this question to the engine section, but they seem to be pre-occupied with drag stuff.

Is there anything i need to take into consideration? A different approach i need to take to ensure it stays together? Keep in mind that i am only looking for a reliable ~380 rwhp.

I was looking at:

SCAT I-beam rods (lighter than H-beams, yet strong)
Mahle flat top pistons
Clevite bearings
Stock polished balanced crank
LS6 Oil pump
Also does anyone know of a good Road Race style pan? I found this but an skeptical, http://www.improvedracing.com/produc...products_id=27

The top end will be:
Patriot 5.3 stage 2, Ti retainers, 918 beehives
LS7 lifters
mid 220's cam
Modded factory rockers

dailydriver · 07-17-2008, 06:15 PM

You'll probably get more responses asking this on the drivetrain forum over at; www.frrax.com

AU N EGL · 07-17-2008, 06:23 PM

Canton makes some find rr pans along with dry sumps pans

roy · 07-19-2008, 12:47 PM

I am pushing about the same hp (400 to the wheels) and still using stock crank and rods. I do run an extremely large oil cooler and have a 9 qt oil capacity, 10qts if I put it 1qt over the full mark. I run this car hard on the rings over here with virtually no problems engine wise. Rpm and temps are killers if not kept in check

djsanchez2 · 07-19-2008, 02:58 PM

I only plan on revving it up to ~6800 once I figure out the power curve and drop off of the H/C package.

It will also be used for Open Road racing down the line as well. I don't know if that makes a difference. And the coolers will come into play as a result of that. I will have oil, trans, diff, P/S coolers, and a larger radiator.

Don't know maybe i am just over reacting because this happened, but that is not necessarily a bad thing, in the hopes that i will never have to worry bout it again once it is built right.

Speedpup · 07-19-2008, 09:02 PM

Accusump or dry sump

bucks69 · 07-19-2008, 09:12 PM

I will be watching this thread close. I am also building a "Road Racing Type Car" and had many of the same Questions and a few of my own. What is ideal CR for sustained WOT? I was not really wanting to do dry-sump but it may be better in the end. I will have a completely forged bottom end and at least 427CI. Not sure about top end yet on mine.

bucks69 · 07-19-2008, 09:15 PM

[quote=djsanchez2;9755146]Hello fellas,

I would take this question to the engine section, but they seem to be pre-occupied with drag stuff.

Not much traffic in here either or so it seems...lol
I have had 2 replies...lol
That Auto-X bit me so I know what you mean about getting bit by the bug.

ae13291 · 07-20-2008, 04:31 AM

Quote:

Originally Posted by djsanchez2

I only plan on revving it up to ~6800 once I figure out the power curve and drop off of the H/C package.

It will also be used for Open Road racing down the line as well. I don't know if that makes a difference. And the coolers will come into play as a result of that. I will have oil, trans, diff, P/S coolers, and a larger radiator.

Don't know maybe i am just over reacting because this happened, but that is not necessarily a bad thing, in the hopes that i will never have to worry bout it again once it is built right.

danial, do they even have coolers for a T56? and diff cooler? ill giv u hand with the power steering cooler if u buy the same one i have

mitchntx · 07-20-2008, 08:24 AM

Quick lap times are mostly about momentum and TQ to get you off the turns.

Reving to the moon is cool, but not typically the fast way around the track.

djsanchez2 · 07-20-2008, 01:15 PM

That's why I am only looking for 380hp and revving to 6800rpm max (for now). The whole reason for this is to OVERbuild it for a closed track, yet be able to run it out on an open road race course. That has ALOT of straight near WOT straight, and the motor has to survive that. That is the main concern with the whole project.

Oh and ARA, yeah i'll let you help. Yes they do make a cooler for a T-56, and for the diff you have to use a lil pump. I'll explain it to you later. I'll wait for the new rear before i go to the rear cooler though.

E.O.D. · 07-21-2008, 10:52 PM

probably not the answer you looking for, but I'd just go with an LS6, bolt ons, with an accusump.

Same weight. 380+ to the wheels. can up the limiter to 6500ish. Or higher if you want to test it.

Matt87GTA · 07-22-2008, 04:37 PM

I just put in one of those pan baffles from Improved Racing... Sure seems like it has to be better than the stock baffle for road course use, but I haven't been on the track yet to see if I have any issues. I was skeptical too, but he sent me all the info on the development work and seeing as the measurements are all pretty much identical to the LS2 pan as far as the baffle wall sizes and oil re-entry channels, it seems well designed to me.

FWIW, I had some bearings spin on me at the track about two months ago and just went through the engine and added the baffle as a precautionary thing. Nobody I talked to, after seeing my toasted #3 and #4 rod bearings ONLY, seemed to know exactly why me engine decided to go. It was my first time on the track after the heads and cam upgrade and it happened pretty much right after I ran the engine to the highest RPMs for some consistent time (about 1 full lap at BIR)... Even the engine rebuilder wasn't entirely sure what happened since all of the other bearings and surfaces looked good. Could have starved for oil or foamed the oil some, could have been too hot, could have been a scuffed bearing surface due to any number of reasons that finally decided to let go...

I used to run the oil level over-filled by about 1/2 quart and the car never dipped oil pressure in corners before I stepped up the power output and RPMs (6700 RPM limiter) with the heads and cam upgrade... I didn't see it drop pressure after the upgrades either. But hopefully now I can run stock levels with the baffle and not smoke so much on decel into the corners.

I am also going to add a Setrab cooler before I hit the track again just in case it was a temp issue. I was running Mobil 1 and it was at about 285* when the engine started to rattle from the lower end, so I don't think it was too hot, but again, I don't want to have to go through the engine again any time soon

. So a cooler is going on too.

OKcruising · 07-23-2008, 08:53 PM

When I was running my car with just stickies, I could get a complete loss of oil pressure every once in a while.

Oil starvation is a real issue with the LSx engines. Get an accusump system as a piece of mind. Going to a full blown dry sump system can be a $$$$pricey$$$$ proposition.

A good option is a crate LS6, boltons and some tuning. higher flow oil pump. Get an overbuilt valvetrain. Accusump. eng oil cooler, and get an upgraded radiator. Smile

djsanchez2 · 07-23-2008, 09:04 PM

Yeah i've been considering all of the many options out there. I will deff check out the Accusump and weigh the benefits. As far as the LS6 crate motor goes, i think i will build my own just for piece of mind, I would rather OVER BUILD it than have to worry about something letting go.

I have changed my mind on the springs though, I'm switching over to the Patriot gold duals.

AU N EGL · 07-24-2008, 08:10 AM

6800 is too bad. My red line is 6750. and pound on the motor 3000 to redline 2-4 times every 2 min for 20 to 40 min at a time. I have 23,000 hard track miles on my engine

Dont dismiss the LS6 create motor too fast. That motor was designed for sustained high rpm use. GM Performance tested the LS6 motor for 100 continuous hours at 6900 rpms. There were no problems.

if you are building your own motor, light wt springs and light wt valves are very important for those high rpm usage.
accu-sump or dry sump is a MUST.

Good Luck on your project

Robert@SPEEDSOUTH · 07-27-2008, 11:27 PM

Many people forget that as they get quicker on track they start wearing out parts quicker and stickier tires will pull more Gs too. In the case of a stock GM pan, a quick driver on race rubber can decrease OP to 0 in a hurry. An accusump(oil reserve) will help in a lot of circumstances, but their shortcoming is in long high G corners, the accusump will run out of reserves again leaving you w/o OP.

Drysumps are expensive from every angle, but if playing on road courses is your deal then why not buy one now, allow your engine to live a long life, and then transfer it to your next build. Sure beats blowing one up due to low OP, having to build another one, and THEN purchasing a dry sump so it doesn't happen again.

Just my $.02

djsanchez2 · 07-28-2008, 01:29 AM

Ok fellas I'm in the process of collecting parts for my motor and am looking at rod/pistons combos. They will be hung on a stock LS1 crank w/ clevite bearings of course.

Mahle forged 346 pistons (stock size replacements)
stock 3.898" bore
stock 3.622 stroke .
stock 6.098" Rod Length
-4cc dome volume
standard .945" wrist pin

Scat forged I-beam rods (Pressed)
6.100 length
2.100" wrist pin, .944" Wrist Pin

OR

Scat Forged I-beam rods (bushed)
6.100 length
2.100” Wrist Pin, .927" Wrist Pin

Main questions:

Which would work better? (Bushed vs. Pressed)
Any clearance issues with the rod being slightly longer? (6.098 vs. 6.100)
Which rod is a better choice for my build?

Tavarez · 09-02-2008, 10:46 PM

How do ls2's do vs ls6's road racing?

kmspruill242 · 09-04-2008, 03:28 PM

I would go with a shorter rod for high rpm use.

I don't like assuming the accusump is going to be your best line of defense. A good baffled pan is really the best way to go. An accusump is only going to put a bandaid over your oil starvation problem. Prevent the starvtion from happening and your not going to need the accusump. The one thing I like accusump for is if something happens to-lets say my oil pump-and I loose oil pressure it might save my motor. Thats the only reason I have it. Volvos have a problem with oil starvation and I've watched quite a few accusmped engines toast bearings. Fix the problem internally.

Just my 2 cents....