Ok, I admit I've never remounted an oil pan before, but something seems really off. I have a 74 350 sbc block. trying to remount the oil pan with a new gasket. I've bought both the thin and thick once piece Felpro rubber gaskets (part number OS 34509 T and OS 34510 T). Neither of them seem to fit right. Both seem to have huge gaps between the pan and the block in different areas depending on if I use the thin or thick gasket.

I took some pictures:

This first one is of the pan fitted onto the block without a gasket. Fits good, no major gaps except between timing cover and pan - which is small:

Tiny gap between timing cover and pan - without gasket
http://i165.photobucket.com/albums/u61/ccorso2/oilpan001Medium.jpg


Pan sits flat on block surface - without gasket
http://i165.photobucket.com/albums/u61/ccorso2/oilpan002Medium.jpg

Pan fits on rear of block wiith little to no gap - without gasket
http://i165.photobucket.com/albums/u61/ccorso2/oilpan003Medium.jpg


Now here is a picture with the "thin" felpro gasket installed. There is a still a gap betwen the front timing cover and the gasket, enough to put a feller guage through, even if I push down on the pan to compress the gasket, there is no way this gasket is thick enough to seal betweem the timing cover and pan. The rear seal seems to fit perfectly around the pan and creates a good seal with no gaps. There is a very tiny gap on the sides of the pan between the block and the pan. It seems if I really push down on the pan it *might* get close to sealing the sides shut, but would take tightening the bolts pretty good to draw it in. The pan seems to rock back and forth a little on the rear gasket area and the gasket does not allow the pan to go down enough. Maybe this is normal and just require tightening?? The gasket is fully seated onto the block with the rear nubs fully seated in the block. See below:

Font of pan - thin gasket installed, still gap even if I push front of pan down.
http://i165.photobucket.com/albums/u61/ccorso2/oilpan005Medium.jpg

Now I install the "thick" gasket, and it appears to seal the front now between the oil pan and timing chain cover, however it apears too thick to push down to mate the sides of the pan with the block. There is a big gap now on the sides of the pan. I push down with about a 100LBS of force and it still will not take up the gap.

Front of pan at timing cover, showing gap on the sides.
http://i165.photobucket.com/albums/u61/ccorso2/oilpan010Medium.jpg

Any ideas??

Thanks!

- Colby

They both kinda look pretty good to me. You will always have some of this "rocking" action. Once you start tightening the bolts, it draws the pan down. There are a lot of pan bolts, so I'm gonna guess the force applied is a whole lot more than the "100 pounds" you reference.

Which gasket is called for according to the Felpro book????

-

Thanks for the reply, I'll try putting on the bolts and tightening it down and see if it seals.

I do not know specifically what the book says, but from what I read on posts here, the "thin" gasket is used on SBC motors from 74 and before, and the "thick" gasket is for 75 and later. While it appears by the numbers that I have a '74 block, who knows if the pan is original. The timing cover is obviously aftermarket but it has the same gasket area measurements as an original one I have.

I'm going out to the garage now to try tightening the pan down with the thick gasket in place.

Report back shortly. Thanks.

Ok, looks like drawing the pan in with the bolts worked. It took a *ton* of force (all my weight) on the pan to get it to compress enough to get the bolts to thread, especially the longer ones at the corners.

I guess this works though as it seems to be a tight fit with no gaps. I didn't know if it was normal or not to have to use so much pressure to compress the gasket just to get the bolts to thread. Seems like it will work though.

Thanks!

My Moroso pan was the same way. I had to push down on it to get the bolts started.

Mine was the same too. On a BB. It rocked alot. Once I started bolting it down it seemed to slip right into place. Still havent started the motor though.

If you have a gap between the pan and timing cover you better go with the thick gasket to tqke up the space. I know from experience. On my first block I changed the pan gasket with the thin one not knowing that they also made a thick one. Then I noticed a drip of oil at the front of the pan. On my second motor with the engine out it was more evident tome what the problem was. Also use a dab of RTV black in the corners where the little ears of the gasket fit into the block. You should be good to go. You may have to get a little longer pan bolts, but once you get the bolts started you'll get it up there.

Ok, figured out why it was so diffilcult to get the bolts threaded. When I was test fitting the pan I was using the old stock pan bolts. When I went to do the final mounting (just now) I used the bolts that were in the box with the gasket. The bolts ended up being longer and didn't require so much force on the pan to get them started.

- Colby

SB must be different then BB cause I didnt get any bolts with my felpro one piece. Glad you got it going. I talked to their techline about smearing some silicone in the corners. The tech said he would do it, off the record, but the company doesnt want you to. I smeared just a light coating on the corners of the block.

Be careful. I think your front cover gasket has funny little tabs that go in between block and front cover. Just a little, like 3/16 of an inch. This is a headache for sbc. Will leak if your not careful. Take your time, and Do not over torque. Trust me

CC, Do not go by what you have read. Different engines take different front seals. 55-85 according to FelPro can have either a thick or thin front seal. I have a 71 350 and mine uses the thick front seal. I am pretty sure that yours is the same and going by the pictures of the pan and thick front seal gasket, it looks right. I run a Milodon 7qt w/kickouts and it takes the thick front seal. I would use the thick one.

Summit shows listings for both: 55-85 w/thick front seal as well as 55-85 w/thin front seal. If you still have a gao with the thin front seal then it needs the thick seal. Go with what fits, not by what papers may say or the books may say. The last thing you would want is to get the engine together, installed, and then find out the front seal is leaking and have to pull the engine again.

That's another thing. The timing cover needs the corners cut off and you need to put silicone on all four corners. Make sure you trim the corners off the timing cover.

The thick/thin front seal delima is easily solved by measuring the distance from the bottom of the front lip to the rail. Set the pan upside down on a flat surface and measure the height of the front lip. 2 3/8" : thick seal. 2 1/4" : thin seal. This is straight out of the Lingenfieter book. This way you do not need to know what year your pan is. The Fel-Pro one piece silicone gasket fits real tight (duh) so, it can be difficult to get all the bolts started. Just go slow and try to tighten everything evenly by going around the pan several times. A new aftermarket pan may be tougher to install than a OEM used one. After several attempts to stop a front pan leak, I ditched the cheapo GM chrome timing cover (made in Tiawan), got a die cast Edelbrock cover and Fel-Pro gaslet. Problem solved. I've heard that those covers can leak where the lip is spotwelded.

Thanks for the info everyone. I ended up using the thick gasket with the bolts that came with with kit. I RTVed around the 4 seal corners, and tightened the pan down. It seems to have a real nice tight seal with no gaps.

Thanks again.

- Colby