Oil pan clearance…. How much do you need?

[WPS 73 Bronco]

I have an issue with Oil Pan clearance with the front diff on my engine swap. The corner of the rear pan has a 1” gap between it and the front axle-pumpkin. I need to find a pan that will fit, or one that I can modify.

That brings up the main question. How much clearance do I need between the pan and the axle-pumpkin.

I also have a post on my LS swap thread, but I thought I’d bring this up on a different thread for more eyes.

 

[Yeller]

It can be very close, an aluminum pan needs a little more clearance than a steel pan. For steel literally a sheet of copy paper. For aluminum 1/8-3/16”.

Reason being cast aluminum gets hit it cracks, steel get hit it scuffs and deflects.

 

[WPS 73 Bronco]

Let me clarify. The pan fits and has about a 1” gap between the corner of the pan and the pumpkin. When the suspension is compressed, the pan bottoms out on the pumpkin.

So I’m looking for what the gap should be with the truck at a zero suspension compression?

 

[Yeller]

The bump stops need to dictate that. The axle needs to contact the bump stops 1" before contacting the pan. In a hard hit the bump stops will compress, which they are supposed to. Rough highways are as bad or worse for those impacts than even hard off road unless your running at highway speeds in the dirt.

 

[WPS 73 Bronco]

Here are pics. My bump stops have a clearance of 3 1/2” at rest. I have a 2 1/2 “ suspension lift and a 1” body lift.

The first pic is taken from the front passenger tire, looking back towards the drivers side. The second pic is from the transmission looking forward.

 

[Torkman66]

A steel pan is pretty easy to modify. Depending on the rig, a BAH can get you a couple more inches. But if you want it to look pretty, mark and cut out a flat plane at an angle. Like a “slice” where it hits. Then mig weld on a flat piece of steel, grind down welds, done… custom pan. Or find one pre-made that fits better.

 

[Broncobowsher]

So I’m looking for what the gap should be with the truck at a zero suspension compression?

Wrong way of doing it. Is this a show car that will never move? Doubt it.
You need clearance with the suspension compressed into (not on, but into) the bump stops. That is what happens when you actually drive it.
The front is easy, take the coils out. Put the full weight onto the bump stops. Not touching is a good starting point. Rubber bushings (and even steel frames) will have a little flex in them. 1/8" I would consider as tight. 1/4" would be fairly comfortable.

If you insist on doing it wrong and try to measure at ride height. The needed clearance is the same as the bumpstop to frame clearance. You can confirm on that first huge bump you hit after you are done. Or just take the springs out now and confirm everything actually fits. You may find other issues that need fixing besides just the oil pan to diff. hint: try steering side to side while compressed.

 

[1969miller]

I will be using this pan Yeller recommended, should be very easy to trim and weld up in the garage if need be for your application.

https://www.speedwaymotors.com/LS-S...ofile-Oil-Pan-Kit-OEM-Filter-Zinc,399004.html

 

[ntsqd]

FWIW I don't count on the bump-stops being there. I set clearances at metal to metal because I have blown bump-stops off the truck in the past. But I do occasionally beat on things. If this is going to be a pavement pounder then it's much less of a concern.

 

[WPS 73 Bronco]

I will be using this pan Yeller recommended, should be very easy to trim and weld up in the garage if need be for your application.

https://www.speedwaymotors.com/LS-S...ofile-Oil-Pan-Kit-OEM-Filter-Zinc,399004.html

I went ahead and ordered one of those. I’m sure it will need to me modified, but I can handle that. I’m betting Holley won’t give me a return credit…..TBD.

 

[Dylan_Shaffer]

My steel pan self clearanced on the trail

 

[73azbronco]

yeah I would pull the front springs, then lower it to see how much room you need on zero bump stop, frame to axle