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Oil Pan to Crossmember Clearance


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When the engine was installed by the machine shop, two Prothane Motor mounts (6-503) were installed to replace the original worn ones from Ford.  According to the machine shop, the Prothane mounts have a slightly lower profile than the Ford originals due to the polyurethane material.  As a result, a clearance of approx 1/8 of an inch was now created between the oil pan outer corners and the cross member.  My question is what should the proper clearance distance be on a 302 engine to the crossmember?

The machine shop would like to install 1/4 inch plates between the motor mounts and the engine block which are shown below (black).  Also below is a photo of the present clearance between the oil pan and the crossmember (1/8 inch) without the plates.  The plates would raise the engine; hence an increase in the clearance would occur.  They are not worried about the drivetrain, but rather any lateral torqueing of the engine during startup and whether or not the oil pan will contact the cross member if the plates are not installed.  Below is the Prothane motor mount and the black 1/4 inch plate.  Numerous phone calls to Prothane have been made where they indicate the mounts are the correct ones.

IMG_20210311_113642667.jpg

IMG_20210215_091620104_HDR.jpg

 

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I can't help much here. I have the Prothane mounts but I have an aftermarket Kevco oil pan with no clearance issues. When I measure the Prothane vs the OEM (Edit: 71 mounts) I considered them the same since the difference is very small and my OEM was not completely flat. This picture I took shows the Prothane slightly lower but it can be deceiving because the ear of the OEM is slightly bent. I am surprised that small of a height difference is making such a large effect on the oil pan clearance. Hopefully someone else can chime in, but maybe there is something else going on.

 

1725280987_20180402_135442(moutnscomparison).thumb.jpg.e627739edcaf7304b9f62c31e34ff05e.jpg

Edited by tony-muscle

20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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Did you think about the frame mounts (supports). Is there a chance they have been changed at some point for the wrong ones for a 302? I'm just grabbing straws there, but that thought occurred to me. I don't have any knowledge of the 302 set-up, but if the frame mounts are lower, then the engine will sit lower regardless of the minor difference in the motor mounts. I would definitely look at the frame mounts.

Geoff.

 I learn something new every day!

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Somebody posted this picture of frame supports years ago.  No measurements but can see difference in height.

71-73-Motor-Mounts.jpg

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Thank you for the comments.  I will need to check the frame supports to see which one is on the Vert and whether or not they are damaged.  The Machine shop did not comment on what they may have found.

 

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The 73 convertible mount looks shorter to me but I don't have both mounts to actually compare. If the Prothane mounts are designed for the 71-72 that may be the reason the clearance is tight since the 73 mount is physically thicker. I don't see an issue with adding the 1/4" spacer to gain back the clearance. It won't affect the driveline angle much. 

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[align=left]Jeff T.

 

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passengers. [/align]

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The frame looks like been bent or something in the pic. The other area of concern will be your fan and fan shroud can tear it up if too close and engine torques over any.

When a man is in the woods and talks and no women are there is he still wrong??:P

David

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