Why the GM LS Engine uses a Cast Oil Pan and Full Circle Bellhousing - Driveline Beaming / Vibration
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- Опубліковано 6 вер 2024
- One thing that is different between the old Small Block Chevrolet and the LS Small Block engines is that the older engine used a stamped steel oil pan and the newer LS series uses a structural cast aluminum oil pan that has attachments for a full circle bell housing and mounting pattern with bolts below the crankshaft centerline.
In the late 1980s, I was involved in a team effort to investigate and improve the vibration characteristics and strength of the connections between the engine and transmission. This work contributed to the LS having a deeper skirt on the block and a cast oil pan combined with a revised bell housing on the transmissions to provide additional bolts for batter structural attachment. This video explains the basics of what we learned and why we revised the designs to improve the bolt pattern for mounting to the engine.
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I can relate to this because back in the 90’s when I would rip the engines out of these older GM vehicles with our SAS Engine Biter attachment every bell housing would break and just the engine would get ripped out.
On GM RWD models from ‘96 on the whole complete powertrain would rip out in one unit due to the full bell housing giving enhanced reinforcement.
Thanks for the explanation always good to hear what the engineers were thinking at that time. To me the LS is not worth all the headaches for this older fella. The old way and blocks were easy to work on, etc. Im enjoying learning the 92 tech on my sb 3.1 litre v6 (189 ci) Camaro RS! Very fun motor with good pep and drivability and probably gas mileage. It has the 4L60 - first year for the 700 changeover to 4L60. My car is the only one at any show with original v6 in it. Crossfire injection ( I noticed the Fieros have these engines too - some 2.8). I appreciate you teaching us about these LS motors though! In a few years, no classic car will be without one at the rate people are installing these computer-heavy tethered engines
As you know, I have an old school SBC in my Camaro and I like it that way. I am not advocating for changing out the old for new, yet some want to make the changes and that's ok, too. You're right, this is in part a help to the LS folks and also some understanding of the advancement of automotive technology.
Back in the 70's and 80's cracked flexplates were pretty common on SBC. Since the LS came out, I have not had a cracked plate. I attributed this to the full circumference of the bell housing. 47 years in GM dealerships, I've seen it all.
I am not familiar with the flexplate issues being common, but the driveline flex could have an influence on the flexplate.
@@bitsofwisdom460 The plate would fracture around the crank mounting area. I bet we did 1 a week at the large dealer I worked at. It was common on all gm makes too. So common we stocked the flex plates.
I never knew any of this. Great subject and class at GMU!
Thanks! Yes, my version is simplified a little, but I'm sure there is internal GMU training in this area.
Great video! Love the tech info
Thank you!
Great explanation and the drawings really help. Thanks for sharing.
You're welcome.
Thanks for the info makes since
It always amazed me how GM made some of the best engines ever built and some of the worst ones built sometimes at the same time! The LS is probably the best small displacement gasoline engine ever built. While the 3100, 3400 v6s are in my opinion the worst. I’ve yet to see a stock one that will last more then a hour or two of hard driving before blowing a head gasket or throwing a rod. Even just running one at 3,000-4,000 rpm for an hour or two will result in a blown head gasket. The only fix is cutting the block for orings and installing head studs. Having to run studs, O rings, and copper gaskets on a stock daily driver is absolutely insane, yet GM built millions of these POS’s without fixing the problems for a long time with zero fucks given. This is the same company that gave us the wonderful EMD 567s, 645s, 710s, the 71 series Detroit diesel, the SBC, BBC, and LS engines.
sbc is way better "structural oil pan" dumb idea lol. As mechanic I can tell you the changes made from the sbc to the LS made it harder to work on. The 2 piece rear main you could change in an hour or two. the one piece rear main takes 4-6 hours because you have to remove the transmission. And why in the world would they design the LS to where when its installed in the vehicle you have to remove the heads to change the cam. I wish they never quit making the sbc.
But every single SBC rear main seal leaks, yet Gen III and up hardly ever leak
@@needleonthevinyl From improper installation! How many people put the two piece rear main together with silicone dry? Because exactly what silicon sticks to oil? That would be zero. Mine never leak, and if 10 years from now it does leak it will be easy to change because I don't have disconnect the engine from the transmission in order to change it. And gen 3 leaks all the time. In fact I have never seen one more than five years old not leak. I've seen two in the past week on two separate vehicles in fact.
@@The0utmode two piece rear main will never leak huh ? 😂
Wonder why *EVERY* manufacturer abandoned them 40 years ago.....
@@jamesgeorge4874 Planned obsolescence. Customer "Oh the leak is coming from my rear main seal and it's 1000 dollars to have it fixed, I will just trade it in then." That's exactly the main reason manufacturers abandoned them. Same reason they make everything else unserviceable too.
@@jamesgeorge4874 Here is how bad your argument sounds. "If transmission dipsticks were so good how come every manufacturer abandoned them years ago."
This must be a big part of the reason the LS mains and Rod bearings, seem to last forever, and can take upgrades to 1000 HP and survive! However, in my limited experience the cam bearings don't survive as well, great engines I've put a lot of miles on 6.0's. If I may, what truth is there to GM bringing in some racing engine builders to assist in the LS designs? Thanks
I don't know specifically about the race engine builders on the LS, but it wouldn't surprise me. I can say that over the years, I have seen engineering teams consult or collaborate with outside organizations such as race teams. There are times where their expertise and experience can be helpful in guiding a design. In my own case, when I was working on manual transmissions long ago, we were supporting a stock class road race team and using the feedback to gain experience and refine our designs. We had a variety of ways to gather knowledge from the field.