kossuth

iTrader: (12)

Just how important is the oil pan in providing block rigidity like gm states in tech manuals etc?

sparkwirez06

iTrader: (18)

I haven't heard of many block failures and there's a lot of ls engines with aftermarket and swap pans. if you run a 4l80e there are no bellhousing to oil pan bolts.

poconojoe

iTrader: (43)

GM had extra paper and a bunch of enginners sitting around doing nothing, so they added that to manuals just for you. Of course its important, but if you were worried about the rigidity of the block, you'd be running a cast iron block. Did you ever notice, GM doesn't put 4L80e's behind aluminum blocks, so you think there might be a reason for that?

G-Body

iTrader: (4)

From what I can tell it looks like the rigidity that they are talking about is that it bolts the engine/trans together more solidly and gets higher noise harshness and vibration ratings. From what I can tell, running without the cast aluminum oil pan doesn`t seem to weaken the motor (just ask my old iron block 5.3, that rod went through the block and the pan) But running a different pan would lead to more noise harshness and vibration.......like any of us care about that stuff

JonCR96Z

iTrader: (33)

They put 6L80s on aluminum blocks.

poconojoe

iTrader: (43)

Do you actually have a point?
A 6l80e isn't a 4L80e, it isn't even close.
They are transmissions for 2 totally differant purposes

bczee

iTrader: (12)

I would say that it is engineered into the the rigidity.. When you consider the span between the motor mount and the distance to the Rear trans mount and fpr a F-Body car that (or even a C5/C6 torgtube) uses a Torque Arm that is bolted to the Trans. Their are a lot of forces and torque between an aluminum Engine and Transmisstion that would have to stay solid.

With a Iron block, you might get away with out the extra pan/trans bolts. But even in the late 80's and 90's SBC trucks (maybe BBC too ?), they started to use braces on each side between the front engine mount and the lower Transmission Bell housing.

IMO, If you can keep them, use them. if not.. it may turn into a problem it may not...Depends !

Kenova

iTrader: (4)

Have you seen a 6l80e!? They are at least 50% bigger and heavier than a 4l80e. GM had to modify the trans hoists on the engine line to accommodate the extra weight of the 6l80e. If the aluminum blocks can handle these transmissions, then 4l80e's are not a problem.

This is also my understanding. The blocks were designed with the deep skirts and crossbolts for strength. The cast aluminum pans are for controlling NVH.
There are plenty of high horsepower aluminum block engines surviving just fine with sheet metal oil pans.

Ken

poconojoe

iTrader: (43)

Sorry but according to these guys the 6l is lighter

Http://www.southernperformancesystem...ecs_4l80e.html

http://www.southernperformancesystem...ecs_6l80e.html

Of course the 4l80e is good for an 18,000 vehicle, the 6l80e is only rated at half that

themachasy

iTrader: (5)

I don't see how the pan would do anything useful for rigidity. Glance up with the windage tray out- you have huge six bolt steel mains going along the block with plenty of webbing. I don't think the oilpan is going to do anything significant.

1quickirocz

the 6L80E also uses bolts all the way around (including the oil pan) unlike the 4L80E. That has to help something with strength.