SERVICE BULLITEN

[RonT]

A/S Advance models with the Chevy motors have slightly deeper oil pans than the Ford models and clearance between the oil pan and hull bottom  is critical. If the engine to propshaft alignment is off or not checked annually these motors will settle down and the clearance between the oil pan & hull bottom will be reduced. The results of this condition will cause the normal hull bottom flexing to "beat" the oil drain fitting into the pan, flake off the paint, and allow rust to begin to eat the metal. In time the corrosion will allow oil to begin seeping through the now porous metal and leaking into the bilge. I have repaired (3) of these boats over the last 2 years.
Oil drain fitting on bottom of oil pan should be 1/2" minimum above the hull bottom, you should be able to reach and place your fingers between the drain fitting and bottom.
I am working on modifying some new GM pans and re-locating the bottom drains to side drains, this will enhance & improve the whole fit and clearance issues. Look for these on the parts site soon.
Pictured is a removed pan, the sheetmetal is actually "beat-in" where the drain fitting was.

     

[lcgordon]

Thanks. I have a chevy but Im pretty sure I have plenty of clearance.

[backfoot100]

Interesting that you mention this Ron.
I noticed that the oil drain fitting was dangerously close to one of the tracking fin studs coming through the hull quite a few years ago. By dangerously close I mean it was only .019" clearance!!! I was checking the clearance with a feeler gauge about once a month to make sure that it wasn't causing an issue.

When I rebuilt my engine I knew the clearance needed to be addressed so I started doing some research. I found out that factory SBC marine oil pans were 6 QT. capacity and had the drain plug on the centerline of the pan. Auto pans were normally 5 QT. capacity and had the drain plug on the side of the pan.

Trying to find a suitable replacement pan was quite a bit harder than what you might imagine. I couldn't use a factory pan because a stroker build needs proper clearance of the pan to the crank. Factory pans don't provide that clearance.
Aftermarket marine pans can be huge. Normally 10 to 12 QT. capacities and the dimensions would not even come close to fitting in the bilge. So I was pretty much stuck with an automotive aftermarket pan.

I checked with several pan makers and heard horror stories about fitment issues with anything other than American made craftsmanship. That in itself eliminated several manufacturers. I finally settled on a Milodon street performance unit that was designed to look stock but still provides enough internal clearance for a stroker crank. It was listed as a 5QT. capacity so I lost a QT. of capacity but with a filter would still be six QT's. It also contained a built in windage tray. I also decided to get the matching Milodon oil pump and pickup so there wouldn't be any pump pickup depth issues for the new pan.

You can see the difference between the two pans here. Factory on the left and the Milodon on the right. The factory pan still has the oil drain fitting installed which transferred to the new pan perfectly. It doesn't look like much but 1/2" less depth combined with the side drain leaves plenty of clearance.




Based on the issues that I ran into trying to find a new pan, the fact that Ron is looking into stocking a suitable replacement deserves a huge THANK YOU.

[micahgaston]

Ron,
Thank you for the information.  I have recently noticed oil in my bilge and could not find where it is coming from.  My '89 Advance (Chevy)has less than 1/2 inch between the oil drain tube fitting and the bottom of the hull.  I cannot even slide my finger between them.  I don't notice any visible damage on the oil pan.  For some reason I cannot see any of the photos that were posted with info on this problem.  Do you have any advice on how I should proceed forward in fixing this problem?  Do you recommend replacing the oil pan with a milodon?
Thanks