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Is it over before it even started....


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I've been posting here and there about my progress with my 408c holley EFI build. Well...yesterday I finally got the tires to the road and other than the tune needing to get right everything seemed awesome. I've got several heat cycles in before her maiden voyage. 

Get her back into the garage and come put an hour later and there it is. She's marking her territory. I mentioned this when it first got built that it wasn't machined for a 1 piece seal against my asking but what's done is done.

Here is what it looks like. I'm not 100% sure it's the rear main but probably is. I noticed to bolts on the pan that have drips so I guess there is a possibility that's its just the lose pan? Was going to try and take the nut off, clean it and RTV around the bolt before putting the nut back on. Not 100% sure of the gasket used but it's a kelvko pan. What torque should I be using?

I took my camera scope and looked as much as I could inside my bell housing and didn't see and fluid inside. The hydraulic throw out bearing is fine. The color is just from collecting dirt on the way to the ground because all of my fluids are new. 

So what do you guys think? How boned am I?

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Posted (edited)

If there isnt any oil in the bellhousing it may not be the rear main. It looks like the pan gasket is leaking slightly. I wouldnt take the bolts out. I would just go around the pan and snug up all the bolts. Dont go crazy but make sure they are snug and compress that gasket a little. To be honest i never really torqued my pan gaskets. Just did it by feel. Usually 1/4" drive ratchet by hand.  Dont use impact or air tools.  Let the motor run alittle bit and get some heat in it, then snug all the pan bolts. Be careful not to burn yourself. Then wipe off the pan with some brakekleen.  Go for a spin and see if the leak stopped.  With just a few heat cycles, the pan may just need snugged up.  If the rear main is leaking, then you will probably need to pull the motor. I am running the standard 2 piece rear main seal in mine and havent had any issues with it. 

Edited by turtle5353

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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16 minutes ago, turtle5353 said:

If there isnt any oil in the bellhousing it may not be the rear main. It looks like the pan gasket is leaking slightly. I wouldnt take the bolts out. I would just go around the pan and snug up all the bolts. Dont go crazy but make sure they are snug and compress that gasket a little. To be honest i never really torqued my pan gaskets. Just did it by feel. Usually 1/4" drive ratchet by hand.  Dont use impact or air tools.  Let the motor run alittle bit and get some heat in it, then snug all the pan bolts. Be careful not to burn yourself. Then wipe off the pan with some brakekleen.  Go for a spin and see if the leak stopped.  With just a few heat cycles, the pan may just need snugged up.  If the rear main is leaking, then you will probably need to pull the motor. I am running the standard 2 piece rear main seal in mine and havent had any issues with it. 

That's somewhat comforting. I'm hopeful on the fact that I can see oil on the two oil threads. Again there is zero signs of anything inside the bell.

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Looks like on picture like a pan leak. the wind pushed the oil on the rear of the pan bellow the crank.

if adding a tad of torque doesn't help, the gasket may have been over torqued already and leaks at the bolts holes and it's too late, especially if it's a cork one. As replacing a pan gasket with engine in the car is a hell, you could once cold, degrease the lip, gasket to block with thinner, using masking tape on block to gasket, on pan, add some gasket paste all around pushing it well with your finger against the gasket. Remove the tape and after 1 hour you should be able to put back a big smile on your face ;) 

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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I remember on my build with an aftermarket pan, the seals that went over the main caps were not a great fit, I was a bit worried if they would seal as they seemed a little big. I used Black RTV somewhat liberally in all the corners and carefully tightened with a 1/4" ratchet as well. Usually when a rear main leaks, it runs out because of crankcase pressure. I too vote that it is a pan gasket problem. Hopefully a little snug is all it needs. Good luck!!

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15 minutes ago, Fabrice said:

Looks like on picture like a pan leak. the wind pushed the oil on the rear of the pan bellow the crank.

if adding a tad of torque doesn't help, the gasket may have been over torqued already and leaks at the bolts holes and it's too late, especially if it's a cork one. As replacing a pan gasket with engine in the car is a hell, you could once cold, degrease the lip, gasket to block with thinner, using masking tape on block to gasket, on pan, add some gasket paste all around pushing it well with your finger against the gasket. Remove the tape and after 1 hour you should be able to put back a big smile on your face ;) 

Appreciate the support. Was pretty disappointed last night thinking about the worst-case scenario...which could still be the case but hey, it's just money and metal.

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1 minute ago, Omie01 said:

I remember on my build with an aftermarket pan, the seals that went over the main caps were not a great fit, I was a bit worried if they would seal as they seemed a little big. I used Black RTV somewhat liberally in all the corners and carefully tightened with a 1/4" ratchet as well. Usually when a rear main leaks, it runs out because of crankcase pressure. I too vote that it is a pan gasket problem. Hopefully a little snug is all it needs. Good luck!!

What's the method to confirm I don't have a crankcase pressure issue?

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My oil pressure is a little on the higher side but I'm not sure if that's because of how new everything is. She idles in the 70's but haven't driven it enough to see cruise pressure 

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I just mean the impulse of the pistons and crank spinning, you would have many other problems if your crankcase pressure was abnormal.

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28 minutes ago, 73' mach 1 said:

it's just money and metal.

That's one way to see it! I usually see it as lots of work :)

I won't overthink it too much before you try first to torque a tad. It's easy to have a leaking pan and often overlooked during install because gaskets are relatively thick and the procedure looks super easy.
I know for my 71, I have checked the pan lip on flat surface, and had to correct the metal due to previous over torque during install to have a uniform pressure all around.

Even if you did all ok, sometimes you have to correct the gaskets you get too. Look here for instance at the fellPro gaskets when I was busy installing mine.
On left of the pict, you can clearly see that the provided gaskets were not matching. The rear gasket was having a square shape to receive and connect to the pan gasket, while the provided gasket was round. You also see I needed to cut a tad of that gasket as it was floating and not properly sealing the groove because of the tiny bits of extra length.

felpro.thumb.jpg.79ccf1315a77bdf602665bbd471c057f.jpg

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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32 minutes ago, Fabrice said:

 

That's one way to see it! I usually see it as lots of work :)

I won't overthink it too much before you try first to torque a tad. It's easy to have a leaking pan and often overlooked during install because gaskets are relatively thick and the procedure looks super easy.
I know for my 71, I have checked the pan lip on flat surface, and had to correct the metal due to previous over torque during install to have a uniform pressure all around.

Even if you did all ok, sometimes you have to correct the gaskets you get too. Look here for instance at the fellPro gaskets when I was busy installing mine.
On left of the pict, you can clearly see that the provided gaskets were not matching. The rear gasket was having a square shape to receive and connect to the pan gasket, while the provided gasket was round. You also see I needed to cut a tad of that gasket as it was floating and not properly sealing the groove because of the tiny bits of extra length.

felpro.thumb.jpg.79ccf1315a77bdf602665bbd471c057f.jpg

Fair enough.  Start with the simple stuff I can see. Not that I really want to live with any leaks but primarily as long as it's not the rear main I can deal with the rest. I don't want to lose my clutch!

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Just go tight these bolts now otherwise you won't have a good night rest! :D

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73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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13 minutes ago, Fabrice said:

Just go tight these bolts now otherwise you won't have a good night rest! :D

Lol, it's like you know me! Thanks man

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I'm leaning towards the pan gasket as well. Torque to spec and see what happens. Brake clean and a blow gun will make it all better. 

I'm one of those crazy guys that torques everything. If it has a torque spec, I follow it. People way smarter than me came up with those specs for a reason, so I'll run with it. 

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16 minutes ago, Hemikiller said:

I'm leaning towards the pan gasket as well. Torque to spec and see what happens. Brake clean and a blow gun will make it all better. 

I'm one of those crazy guys that torques everything. If it has a torque spec, I follow it. People way smarter than me came up with those specs for a reason, so I'll run with it. 

I agree. Unfortunately I can't find any specs. One thing I saw was 12ft/lbs. Not sure if it has more to do with the pan or gasket used?

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Posted (edited)

If you don't find them, use a short, say 3 inches wrench and tight them up with one hand so you're sure you won't over torque that gasket.
Assuming here that you're not a bodybuilder! :D and that a bolt is not loose either. A small extra increment on the bolt rotation using that short wrench will do just fine. You will feel the force required unlike with a ratchet. The idea is to sandwich the gasket evenly, not trying to flatten it. As it leaks, try also, even if it's easy to say when your nose is not touching the pan, to jump one bolt and not tight 2 next to each other in one go. Alternating sides in a cross fashion even better.

Again, don't over think it, that little extra will probably do just fine.

1 hour ago, 73' mach 1 said:

Lol, it's like you know me! Thanks man

We're all the same :D

Edited by Fabrice

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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What Hemikiller said on torque. 5/16" torque to 11-13 ft/lb, 1/4" torque to 7-9 ft/lb. Good luck. Chuck

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I'm with Hemikiller on torque specs. Overtightening and under-tightening nuts and bolts have destroyed a lot of components on cars. If I can't find a torque spec on something I use the generic torque tables for the size and grade of bolt.

The oil pan specs are 11-13 ft.lbs. on 5/16" bolts and 7-9 ft.lbs. on 1/4" bolts. Do not attempt these torque specs with even a 3/8" drive torque wrench, they likely won't be accurate at these low values. Use a 1/4" torque wrench and multiply the foot-pound values by 12 to get inch-pound values.

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“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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Thanks for the heads up. Buddy at work lent me his 1/4" in/lb torque wrench. Ill report back by the end of the weekend. 

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11 hours ago, Don C said:

I'm with Hemikiller on torque specs. Overtightening and under-tightening nuts and bolts have destroyed a lot of components on cars. If I can't find a torque spec on something I use the generic torque tables for the size and grade of bolt.

The oil pan specs are 11-13 ft.lbs. on 5/16" bolts and 7-9 ft.lbs. on 1/4" bolts. Do not attempt these torque specs with even a 3/8" drive torque wrench, they likely won't be accurate at these low values. Use a 1/4" torque wrench and multiply the foot-pound values by 12 to get inch-pound values.

Dang DON.........you from this world? How you know all this stuff? We are blessed to have your knowledge on here for sure.

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