SBC and bearings

[ROWDYRENAULT]

The small block Chevy has been around since 1955. The SBC has been raced in every from of speed contest known to man since 1955. Time after time I see posts about main bearing and rod bearing failures. Sprint car teams in the U.S. use maybe two to three motors a season. No, not Steve Kinsler and his peers, but the guys runnin mid pack with a limited budget and quess what the engines aren't failing they get tired and need to be refurbished. The stories go on and on, different classes of racing same story. Take that POS Acusump and toss the thing. Buy a real dry sump with a proper pan and go about your way. These cars make way to much G force to run a wet sump. Further more if you still have bearing problems with a dry sump, your builder is building the thing wrong. Lee

[60mph]

I had the same problem with my audi coupe . When cornering hard , as usual , the oil gauge would read 0 , then the big ends went even though the oil stick showed "full" . On taking off the sump the pickup was 2 inches off the sump bottom ! What the hell was that for . With the Astons I ran , I never had a problem . The oil pickup was 3/8 " off the floor and 4 " wide . The only reason they dry sumped them for Le Mans was to get a shorter engine to obtain a low C/G and also less frontal area to the car .

Is a dry sump really necessary for the Ultima with SBC ?

Frank

[ROWDYRENAULT]

Frank: the position of the LS7 used in the ZO6 Corvette is the same as the LS3 that goes in the standard vette. The reason stated by Chevy for the dry sump system in the ZO6 is to insure proper lubrication during high G periods. The vette will pull .98 Gs on a 200 foot circle the Ultima has recorded 1.17 on street tires I would excpect that to go UP to at least 1.25 on race slicks. Chevy didn't go to the exspense of the dry sump if they didn't need to. Dry sump the thing and quit screwing up bearings.

[k wright]

I have just replaced a set of bearings after a red light on the oil pressure gauge came on. Luckily bearings were all that were needed.

If your building the car now make it easy and specify an LS7 with a dry sump system.

[Boosted LS1]

Has anybody got an experience with the ls7 dry sump system?

[738 driver]

I would agree Lee, dry sump is the way to go .......so long as you know what you are doing and are reasonably interested in the mechanical side of things. Problem is many owners just want to jump in the car and go fast or trackday and when something fails/leaks it's immediately labelled the weak link, word gets around a small community so it's avoided like the plague. People are reluctant to accept the Ultima needs a completely different approach than a production car...Porker etc.

SBC bearing failures I've seen recently have nearly all been contamination, bearings pitted/scraped. Most of this is due to lack of maintainance/abuse or just poor initial housekeeping on the engine builders part...... those accumulators do seem to hoard crap though, for some reason? The other common problem is people buying their engine far too early in their build.....the motor sits hardly touched in a damp garage for months on end, when it is eventually used it suffers premature death due to surface corrosion. One recent failure was due to installation (crank/clutch/adapter compatibility).....its amazing how frequently we see clutch forks riding on covers..... one car (professionally built) had such a bad case of this that about 7-8mm of the steel arm was worn away (and most of the clutch cover too). Obviously oil pi!""ing out of the rear main seal and a knackered rear main/thrust bearing!! I think the mid-engined environment is extra harsh too, careful planning of oil and fuel systems should help here though...far too many 'stick it here because theres space' builds.

[ROWDYRENAULT]

O.K. I am on a little bit of a rant here, but its all for the good. Frank I will gaurentee you that Aston Martin would never never never go to Le Manns without a dry sump system in the car, regardless of the position in the chassis. The point being that once you generate the numbers that an Ultima will, the wet sump systems WILL FAIL sooner than later. Z28 makes a very good point about motors setting around for months on end before install, if the builder is not really carefull to store the motor correctly and pre prime it, before start, you will have a problem. The question about the LS7 and its dry sump is intresting. Gary from ARE Racing who builds the dry sump pan on my LS1 feels that the stock LS7 dry sump pan could be better. he said this at a point after I had bought my system and was not on a sales mission at the time. Further to the question of the LS7, I had my LS1 at Cal Speedway a month ago and data logged every inch of 4 twenty minute sessions on my Motec 800. Review of that data showed no flucuations in oil pressure at all on the oval banks or the road course. Hope all this helps I hate to see guys suffer through these repeated failures when I think the answer is available. Lee

[60mph]

Hi Lee

My motor was built by American Speed in about Dec 2007 . Before I installed it I removed the sump and checked all the torque settings and all were OK . I noticed that the oil pickup was very small , about 2.5" x 2.5" . I did not measure the clearance to the bottom of the sump . I also noticed a system of hinged vertical trapdoors in the bottom of the sump , presumably to keep oil over the pickup whilst in horizontal G . Do you know how effective these are ? My experience with Aston Martin was with 1959 cars[ when they hadn't experienced G ! ] but they did win Le Mans with the motor I had .

Cheers , Frank .

[Rusti Evo]

Fact is the American gurus like Smokey Yunick gave up trying to make wet sumps work many many years ago. End of........

[Boosted LS1]

A lot of cars have to run wet sumps for racing though depending on rules. Group A rovers had a big winged wet sump with a central chamber. Basically the sump was cruciform inside with 4 feeds to the central chamber and a system of one way trap doors. No matter which way the car was loaded under G there was always a door feeding the pickup. The big wings also held plenty of extra oil to. The oil pick up was spring loaded on the tube so was always in contact with the bottom of the sump even if the sump got bashed upwards. Oil entered the pick up through it's gauze sides. It was a very clever system but a ball ache to make. The front and rear drain channels are under cover plates so can't be seen. It looks like this:

Edited by Boosted LS1 on Tuesday 29th September 19:38

[ROWDYRENAULT]

Boasted is correct, lots of cars have run wet sump in racing because thats what the rules required. But as race cars started exceeding 1g in several directions pretty much the requirments to continue to run wet sumps has disappered. My point is I continue to read of bearing failures in SBCs mounted in Ultima's. Call me crazy but I consider the people who own Ultima's as friends who are certified motor heads or they would not own Ultimas for long. As a friend with absoultley no commercail intrest involved, I am suggesting that you dry sump your motor. I hate reading about bad things happening to good people. Notice that we have not seen these failures in LS motors. I will bet that the vast majority of LS owners are running dry sump. Those who aren't have an advantage because one look at an LS pan will tell you that Chevy spent some money optimisibg its wet sump pans. Lee

[Boosted LS1]

The ls pans have a horizontal baffle plate above the pickup and the pickups are low down right near the bottom of the pan. They also have a windage tray running across the main cap undersides.

Early ls pans became quite complex and peaked imo with the split level big wing vette pan. They really are that good inside and probably very expensive to produce. After that they went to a much simpler design found on the ls3 which is a bit of a dissapointment to me. It works but must be the cheapest pan they made.

I can use the big wing or the ls7 dry sump on my engine hance why I was looking for feedback on the ls7 dry sump arrangement. Anybody?