Shelby Block Rear Main Seal Leak

[RICK LAKE]

A98Coupe Stuart As far as shelby motor experience, I have 2 blocks and 1 set of heads. Block # CSX58 and CSX#428, ( inthe works ) #58 was a machining problem with locations and bottom out holes, and the list goes on. A machine shop in Nebs gave me a list to correct problems.
Want to start here, an aluminum motor is a living breathing thing. The expansion rate is about .001" every time it hits operation temps. When cold it contracts the same numbers. Here's the problem, sealing a motor with a .002" expansion rate. This doesnot include movement of the heads, intake manifold, timing cover, waterpump, and oil pan, ( most are steel ) I also have an aluminum one. If your oil pan is aluminum the expansion rate is about the same as the block, No problem. You said you have a windage tray, I bet it's steel. Here's the problem, 2 different expandsion rates. If you where around in the early days of motors that had iron blocks and aluminum heads they all had leaks of coolant and oil over time. In the early days the RTV was used to keep adjusting to the expansions and would loose grip to the 2 parts it seals. We where told to rough up the surfaces with #80 grit sand paper to give better bite and holding properties. It helped some. It took HOnda to come out with the gray rtv the seals and lasts a long, long time with sealing and holding. GM, Jeep, and Ford now use this RTV. Moving on,
Oil leaks on these motors can come from anywear and always leak at the lowest point of the motor. Timing cover leaks go along the oil rail and end up at the back of the oil pan. The 100% way to find ANY leak is with a dye and black light. The kit cost about $45.00 and works on all fluids in a car. Add to fluid and run for 5-15 minutes and look for the leak. You may have the bottom of the motor apart. 1 question is the bellhousing inside full of oil? And the Clutch wet ?? If yes rear main seal. If not but leaking down The block plate on the bell housing it could be gaskets for the windage tray to block and oil pan. I have been through this problem 3 times. Sandwich gaskets that go between block, tray, and pan if the surfaces are not 100% flat will leak over time and push the gaskets around. My 1st set where cork, and they need fluid to keep them sealing and not dry out. I used a spray sealer Hi-tac on all surfaces. It worked for a couple of years and then the leaks started. Found the gaskets pulled and holes where moving and leaks would come from bolt holes. I went to a 484 stroker kit, had to modify windage try to clear rotating parts. I went this time with RTV. It took 1.5 tubes for both sides of the windage tray for sealing. Most people DON'T follow directions for installing RTV. It needs clean surfaces and more important needs to setup up for 3-5 minutes before installing. It then needs 24 hours to seal up. Need to follow torque specs and no adjustments after installing. Rear main seal should be about 10-20 degrees off center and not have the ends even with the cap and block. I add a thin coat to hold the seal in place. I add thin coats the where the main cap goes into the block, both sides and surfaces. I rough up the machine surfaces with a #40 grit paper for small scratches. All surfaces need to be 100% clean. I have done this repair once inside the car and once on the motor stand. 7 years of auto cross and road racing and no leaks. I am not sure how easy it is to pull the pan in your car, ERA with lifting the motor give enough room. I did lose a valve cover gasket at the R&G in NEB. The gasket was 12 years old and thick cork. A small piece popped out and I had an oil fire. No damage to paint or car and it gave the track guys some practice,.
I am thinking the oil level may be causing your leak and you don't have the correct level in the oil pan. Also is the car on flat ground or on a hill of angles drive way? I ran Canton system in my car and over fill the pan 1 quart because of autocross and the poor return of oil to the oil pan and pump. I also use a HVHP oil pump with 100# spring. My whole system has 13 quarts. I have and use a 3 quart accusump for keeping pressure up in long high "G" turns. It also is used for per oiling the motor before starting it. This works for me. At some tracks they will not allow dry sump systems.
Oil level was the check done? You measure from the oil pan bottom with the pan in place to the block skirt, this is with all gaskets and seals installed. Remove pan. measure with windage tray on block to bottom of tray. should be about 1-2" I like the oil level right on the bottom of the windage tray. The measurement is in the middle of the oil pan. Subtract this from the total depth and you have your oil level. I mark the side of the oil pan and fill with water to get the correct amount of oil for this pan setup. If you are running a FE orginial windage tray which is solid steel, drill some 1/4" holes to help with oil draining faster into the pan. Holes be 1" apart at the lowest spot on the tray. Put the clean and dry pan setup back on the motor and fill. Let sit over night and check the oil level on stick. This should be the correct level. Mark and you are done. Sorry for long story, FE forum also has info on this. If you are running a large system of more than 6 quarts, runing dry on turns shouldn't be an issue, less than I would overfill the motor 1 quart. I have been doing this on all my motors for the last 40+ years. I don't worry about a small oil leaks. I don't like them but at $20,000.00+ to build these motors, let them sweat. Good luck with repair. Rick L.

[A98Coupe]

Rick L,

Thank you very much for your comprehensive information & advice. My Aviaid oil pan & windage tray is steel and I am aware about different expansion rates between steel & aluminium and it has crossed my mind that the leak could be due to this. I confirm there is no signs of oil inside the bellhousing or on the back of the flywheel - crank seal side. I also confirm that the leak doesn't show when running on the drive, it only showed after first drive of 18 miles. It could very well be oil leaking past the pan gasket during acceleration. This is a good point for me because it means I can probably fix it without removing the engine - may only have to remove exhausts & hoist engine up enough for pan to clear chassis cross rail.
Anyway, I think that's a winter job and I need to enjoy the car as much as possible over the next few weekends before the British winter sets in and the road salt crews spread that nasty corrosive stuff over the two lane black top!

Thanks again
Stuart

[fordracing65]

I know all FE's leak, do the pond blocks leak as well in the same spots, if not I wonder why, they probably just leak, lol...

[Bernica]

Like my old Jaguars...
If I don't see oil on the floor, something is wrong!

[fordracing65]

Does any body have an FE that does not leak, or seen one that does not leak???

[Barry_R]

Sorry I am sooo late in finding this thread. I assembled the engine in question. It was "dry" on the dyno, but FEs rarely seem to stay dry for long.

The comment on dye is spot on - - I have seen leaks from all over the place get diagnosed as rear seal because that is where it ends up dripping from. Liquids will do an amazing job of following along edges in the castings and gaskets to find the way to the rear. I usually find tiny leaks at the junction of the intake and the cylinder head to be the hardest to trace down.

The Shelby block used should be OK - its not that old and should not have the rear drainback issue - that was from a very long time ago. If I recall correctly it has the complete Aviaid pan and screen kit. I use the TF-31 gray Motorcraft silicone on assembly on all pan & tray surfaces. Still possible for stuff to go wrong there - but the pan gasket is usually OK.

On aluminum blocks it seems that every fastener needs a turn or two after some run time & then they are OK for a long time. The pan gaskets are especially bad since they are sandwiches of gasket, tray, gasket and you cannot really tighten them much with damaging & distorting things.

Check the oil level - and get the dye kit. Fix it when its cold and wet - - enjoy the car and the weather while you can. It was 34 degrees F here in Detroit right now...

[blykins]

FE's are fun.

Seems like I've had more issues with aluminum blocks and Aviaid pans though. I rarely have any issues with the cast iron block combos. Seems like the combos in question are always dry on the dyno as well, but end up seeping weeks/months later. Is it material expansion rates? Possibly. Is it double stacked gaskets? Possibly. Fun stuff, especially when you can't point a finger at anything in particular.

[fordracing65]

It seems like the iron block is the way to go for more hp and less leaks, may be onto something...

[lippy]

I'm gonna try some dye too. I've done my Aviaid pan twice very carefully but I still have a leak that looks like the pan or main seal. Since I've never used dye, any particular type and procedure?

[4pipes]

Lippy, I think I have the dye and a strong black light. PM me if you want me to look for it.

[lippy]

Dave, thanks much but probably not worth your trouble. I found Delco dye and a light/glasses kit for about $20 on Amazon. Should do the trick. Appreciate the offer.

[fordracing65]

Originally Posted by lippy

Dave, thanks much but probably not worth your trouble. I found Delco dye and a light/glasses kit for about $20 on Amazon. Should do the trick. Appreciate the offer.

Please let us know what you find, I'd like to know..

[cobrakiwi]

I have manufactured a few of these now for the Aviaid pans with Alloy blocks,
this will help with the oil leaks from the pan gaskets that seem to be a problem.

These comments are from one of our customers using my oil pan flange support,

(My original iron block had an Aviaid pan on it for 20 years. Multiple rebuilds on that block, and multiple new gaskets. Always leaked.

New Pond aluminum block with new Aviaid pan. There were multiple leaks around the pan, a bit more leaking occurred at the rear of pan.

The photos taken today show the oil pan after driving about 180 miles since the installation of the girdle. 130 of those miles were in Arkansas while cruising through the Ozark Mountains last week. There were quite a few runs above 6,000 rpm. There is zero indication of oil leaking anywhere around the pan. The frame of my car has never been this oil-free. Prior to installing the girdle, a 20 mile drive would leave multiple oil drips on the frame.

I feel the Aviaid pan's flange isn't sufficiently rigid to provide uniform clamping of the pan, 2 gaskets and 1 windage tray.)

Here is the link with pictures of the installed part and the car owners opinions.

601 HP HiTech Mod's

[MOTORHEAD]

KiWi: absolutely this is what is needed ! What is the price?

[cobrakiwi]

Originally Posted by MOTORHEAD

KiWi: absolutely this is what is needed ! What is the price?

PM sent, thanks for your interest.

[lippy]

I'll bet that would solve my problem also. Please LMK the price as well.

Did you also make the aluminum covers for the a Xtreme air cleaner. Interested in one of those too.

Thanks.

[A98Coupe]

Originally Posted by Barry_R

Sorry I am sooo late in finding this thread. I assembled the engine in question. It was "dry" on the dyno, but FEs rarely seem to stay dry for long.

The comment on dye is spot on - - I have seen leaks from all over the place get diagnosed as rear seal because that is where it ends up dripping from. Liquids will do an amazing job of following along edges in the castings and gaskets to find the way to the rear. I usually find tiny leaks at the junction of the intake and the cylinder head to be the hardest to trace down.

The Shelby block used should be OK - its not that old and should not have the rear drainback issue - that was from a very long time ago. If I recall correctly it has the complete Aviaid pan and screen kit. I use the TF-31 gray Motorcraft silicone on assembly on all pan & tray surfaces. Still possible for stuff to go wrong there - but the pan gasket is usually OK.

On aluminum blocks it seems that every fastener needs a turn or two after some run time & then they are OK for a long time. The pan gaskets are especially bad since they are sandwiches of gasket, tray, gasket and you cannot really tighten them much with damaging & distorting things.

Check the oil level - and get the dye kit. Fix it when its cold and wet - - enjoy the car and the weather while you can. It was 34 degrees F here in Detroit right now...

Barry,
Thanks for the comments. Still haven't had chance to set timing & idle mixture yet due to work, but today I got right up close to the pan gasket and checked all around either directly or using a mirror. The passenger side from front to rear is actually wet looking and looks worse as it gets further back. I think you are probably correct in diagnosing the pan gasket as the source of the leak. I've nipped the pan nuts up a bit more and will give her a run next weekend if the weather holds out. I'll get a dye kit if the leak persists.

Stuart

[jetblue69]

Originally Posted by A98Coupe

Barry,
Thanks for the comments. Still haven't had chance to set timing & idle mixture yet due to work, but today I got right up close to the pan gasket and checked all around either directly or using a mirror. The passenger side from front to rear is actually wet looking and looks worse as it gets further back. I think you are probably correct in diagnosing the pan gasket as the source of the leak. I've nipped the pan nuts up a bit more and will give her a run next weekend if the weather holds out. I'll get a dye kit if the leak persists.

Stuart

Probably the pan gasket. Before you condemn the rear main don't forget the oil return from the rear bearing/seal is right there. Hopefully you checked to see if the pan rail/tray covers it as I had to grind mine. I had a leak, created several new swear words thinking it was the rear main, tightened the pan fasteners (the Canton came with studs) and bye-bye leak. I even used TA-31, torqued it to factory specs when I installed it and the S.O.B. STILL LEAKED after a few runs on my break-in stand!

[lippy]

Quick question on the dye: if I add an Oz or two of dye into the breather hole on the valve cover, will enough of the dye work itself down to the oil in the pan to be effective?

[4pipes]

Yes, doesn't take much.