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Camaro Research Group Discussion => Maintenance => Topic started by: 69Z28-RS on December 03, 2013, 05:00:03 PM

Title: Oil Pan leaks... ugh..
Post by: 69Z28-RS on December 03, 2013, 05:00:03 PM
Do any of you fellas have a 'surefire' method of preventing oil leaks with Chevy small blocks?  I'm buttoning up a 283 for my '60 Corvette and I really don't want another chevy that 'drips' oil on my floor..  :).    Generally I use a very thin coating of silicone sealer on each side of the cork gasket at install, make sure that the pan rails are 'straight', and only torque to the specified level.. but sooner or later, all of them seem to leak.  Is it because the screws back out?  I've even put locktite on the threads the last few engines I've done....   :(
I'd welcome any suggestions anyone can make to have a DRY engine.   Do I have to use gorilla snot to do that (ie. yellow 3M super weatherstrip sealer...  which I REaLLY hate to use ..)..

Is a different pan gasket or frt/rear seals called for (as opposed to the std ones which come in the Felpro kits)?
Title: Re: Oil Pan leaks... ugh..
Post by: cook_dw on December 03, 2013, 06:06:17 PM
I assume its still on the stand..?..  If so flip the engine over and place the front rubber seal and rear seal in place along with the gaskets.  Sit the pan in place .  Go around to all the corners and see if the pan rocks at all.  if so you might have to shave the rubber seal down so the pan will lay flat.  You can also have a small light or pen light inside the pan (just tape it do a journal) to help with seeing if there are any gaps.  Just like any bolts over time they will need to be torqued down again.  But the loctite should have taken care of it if it was used.  Also start your tightening sequence from the center area and work outwards (which Im sure you already do)..   Felpro makes a one piece gasket.  It has rubber o-ring seals in the bolt holes that work well.

(http://images.oreillyauto.com/parts/img/medium/fel/os34509t_p04_top.jpg)


http://www.oreillyauto.com/site/c/detail/FEL0/OS34509T/02296.oap?year=1969&make=Chevrolet&model=Camaro&vi=1034738&ck=Search_oil+pan+gasket+set_1034738_-1&keyword=oil+pan+gasket+set (http://www.oreillyauto.com/site/c/detail/FEL0/OS34509T/02296.oap?year=1969&make=Chevrolet&model=Camaro&vi=1034738&ck=Search_oil+pan+gasket+set_1034738_-1&keyword=oil+pan+gasket+set)

Regardless of which gasket set you go with you still have to make sure the pan is sitting flush.
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 03, 2013, 06:24:52 PM
Beat me to the punch again ! I've had great success with Felpro 1 piece gaskets. Also the impregnated valve cover gaskets perform wonderful. Need no Permatex.   we run high oil pressure in the race engine plus a stepped out Milodon drag pan--lots of oil flowing through with no leaks.
Title: Re: Oil Pan leaks... ugh..
Post by: cook_dw on December 03, 2013, 06:33:40 PM
 ;D

You know what they say..  Great minds...
Title: Re: Oil Pan leaks... ugh..
Post by: 69Z28-RS on December 03, 2013, 06:37:06 PM
Thanks Fellas..  the 'one piece' gasket sounds like a great idea...   and the local O'reilly's (2 miles away) has one for 29.99...  I'll buy one today.   With this gasket, I'd think if it's all rubber, one doesn't need any other sealers?.. 
Title: Re: Oil Pan leaks... ugh..
Post by: CNorton on December 03, 2013, 06:49:46 PM
With this gasket, I'd think if it's all rubber, one doesn't need any other sealers?.. 

The instructions in the Felpro gasket package suggest a light film of silicone at the four corners.  I also put a small bead of silicone between both the gasket and the pan and between the gasket and the timing cover/rear seal housings.  Some of this might be redundant or even unnecessary but when it comes to leakers, it's better to take a few extra steps than to omit one and regret it later.
Title: Re: Oil Pan leaks... ugh..
Post by: cook_dw on December 03, 2013, 06:53:28 PM
With this gasket, I'd think if it's all rubber, one doesn't need any other sealers?.. 

The instructions in the Felpro gasket package suggest a light film of silicone at the four corners.  I also put a small bead of silicone between both the gasket and the pan and between the gasket and the timing cover/rear seal housings.  Some of this might be redundant or even unnecessary but when it comes to leakers, it's better to take a few extra steps than to omit one and regret it later.

Ditto that.. 

Still remember to check the corners for gaps like in my first post..
Title: Re: Oil Pan leaks... ugh..
Post by: Fred Mertz on December 03, 2013, 07:22:33 PM
Good Luck!  The Fel-Pro one-piece gasket leaks just as bad.  Mine has leaked for the last 4 years.   Leaks at the front and at the back.  Not a drip but a seeping leak.  I usually wipe the oil pan down with a rag before the leak gets to the floor.
Title: Re: Oil Pan leaks... ugh..
Post by: jdv69z on December 03, 2013, 07:42:14 PM
I've always seemed to have the drip at the rear main seal, not with oil pan itself.  Drips between the back of the oil pan and the bell housing/clutch cover. Thought that's why Chevy went to the 1 piece in 86? Any sure fire way to prevent this one?
Title: Re: Oil Pan leaks... ugh..
Post by: cook_dw on December 03, 2013, 08:14:49 PM
I've always seemed to have the drip at the rear main seal, not with oil pan itself.  Drips between the back of the oil pan and the bell housing/clutch cover. Thought that's why Chevy went to the 1 piece in 86? Any sure fire way to prevent this one?


Same scenario along with lots of luck, prayers & silicone.     :D
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 03, 2013, 09:10:26 PM
Sure you built a motor or 2 Gary, follow your procedure for tightening oil pan fasteners : crossing inner to outer , 2 step. I use a 1/4 inch drive and just have a feel when tight. Follow the supplied directions as not to crush the washers.  Of course a lite skim of form a gasket won't hurt. However I was always taught to only apply appliance side and allow gasket to work on engine side. We have not had the pan off in 2 years---bone dry. We also run an engine diaper--no sign of oil on the pad. Results may vary but I've by far had the best luck with the one piece. Only mist I get is from the breather on the trans, automatic ,as should be expected.
Title: Re: Oil Pan leaks... ugh..
Post by: 69Z28-RS on December 04, 2013, 04:48:40 AM
Thanks Jano..  I'm going to follow your suggestion.. 

and yes, I've built a dozen or so over about 38 yrs, but the one I've got dripping on my floor now is one I rebuilt about 10 or 12 yrs ago.. and I thought my old procedure was good, using the cork gaskets, but applying a thin film of silicone on both sides, letting that almost dry, before setting the gasket/pan.. and torqueing..

I bought the one piece rubber Felpro gasket today .. and will follow the included instructions.. and *might* do as someone suggested with a light film of gasket cement on the pan side.   thanks for the suggestions.. but it seems there's no '100% magical cure all' for the old 2 piece main seals.  I'm using an NOS 'trap door' style oil pan from the early 60's (I finally found the correct NOS pickup for use with that pan) and the fits flat and perfect.  This is an .080 overbore 283, '67 Z28 crank and rods, 10:1 pistons, all machined surfaces ground, rotating assembly balanced, and semi blueprinted during assembly with a hydraulic 350 hp cam and rebuilt '60 Corvette heads, intake, and carb.  2.5" rams horn exhausts..  it should run good.. and I don't want it to leak. :) 

and I agree with the poster that the rear main seal is the worst area..  probably the joint between the two pieces, and we still have that  issue even with the one piece seal...
Title: Re: Oil Pan leaks... ugh..
Post by: JohnZ on December 06, 2013, 04:13:00 PM
You certainly want to make sure you buy the correct gasket with the front seal thickness that matches whatever oil pan you have.

Not everyone is aware that Chevrolet changed the front seal radius on the small-block pan in 1975. All production pans prior to 1975 had a 2-1/4" seal radius, and used the "thin" (0.22") front seal. In 1975, the production pan seal radius changed to 2-3/8", and they used the "thick" (0.41") front seal. At the same time, ALL Service replacement pans manufactured after 1975, regardless of their intended application, got the 2-3/8" front seal radius and require the "thick" front seal. Fel-Pro (and others) who make the molded one-piece pan gasket have two part numbers - one with the "thin" front seal, and one with the "thick" front seal. If you use the gasket with the "thin" front seal on a pan that requires the "thick" front seal, it'll leak oil like gangbusters, and you can't stop it. Measure the pan before buying the gasket so you get the right one, per the photo below - you can't take a used one back.

Another great source for front leaks are the cheapo chrome Taiwan timing covers with the front seal flange spot-welded on; the production covers had the flange roller-welded on for a perfect seal, but the Taiwan geniuses didn't know why, so they took the cheap route and spot-welded it. Result? Leaks.
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 06, 2013, 05:11:19 PM
Which surfaces a question I have on the "new" re-makes of Z oil pans. Un fortunately mine lost it's way at the speedshop a few decades ago. My Milodon does not leak nor did I ever have issues with a low profile Moroso I've had for years---and I changed that one on my back. Are you trading quality for "correct" or are these quality pieces ? Price does not always dictate. I'll go with a gold pan under the car vs. one that is out of tolerance. Goes for fasteners too, what you don't see may or may not be ARP.
Title: Re: Oil Pan leaks... ugh..
Post by: 69Z28-RS on December 06, 2013, 06:47:51 PM
You certainly want to make sure you buy the correct gasket with the front seal thickness that matches whatever oil pan you have.

Not everyone is aware that Chevrolet changed the front seal radius on the small-block pan in 1975. All production pans prior to 1975 had a 2-1/4" seal radius, and used the "thin" (0.22") front seal. In 1975, the production pan seal radius changed to 2-3/8", and they used the "thick" (0.41") front seal. At the same time, ALL Service replacement pans manufactured after 1975, regardless of their intended application, got the 2-3/8" front seal radius and require the "thick" front seal. Fel-Pro (and others) who make the molded one-piece pan gasket have two part numbers - one with the "thin" front seal, and one with the "thick" front seal. If you use the gasket with the "thin" front seal on a pan that requires the "thick" front seal, it'll leak oil like gangbusters, and you can't stop it. Measure the pan before buying the gasket so you get the right one, per the photo below - you can't take a used one back.

Another great source for front leaks are the cheapo chrome Taiwan timing covers with the front seal flange spot-welded on; the production covers had the flange roller-welded on for a perfect seal, but the Taiwan geniuses didn't know why, so they took the cheap route and spot-welded it. Result? Leaks.
No worries there John.. :)    I don't buy Japanese *anything* as long as there's a choice, and buying a 'modernized Felrpo' oil pan gasket is about as far away from genuine GM as I am willing to go!   and engines built after '72 are on my 'trade off' rather than rebuild list!  :)  The newest engine I've ever rebuilt is for a '72 Corvette 350..  other than that they all lie between '55 and '71 Chevy.. and only one big block in that mix.. :)   My oil pan is NOS (bought from Chevy for the early Corvette Hipo engines about 40 yrs ago, and in the box since, and the timing chain cover is also good GM.. :)      (And I agree with the skepticism you express over most 'aftermarket' items, from foreign countries especially).

Gary
Title: Re: Oil Pan leaks... ugh..
Post by: Stingr69 on December 10, 2013, 08:22:34 PM
The Z/28 service replacement pan is still available from Chevrolet.  It now comes with the later "thick" style front seal surface in the front now but otherwise it is a direct replacement.  About $130 bucks or probably a little more these days.

-Mark.
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 10, 2013, 08:30:21 PM
Thanks for the input Mark , I've seen them out there...just wanted some feedback on quality--not just looks-I've read nothing to suggest substandard, figured somebody on this site is using one.
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 13, 2013, 09:01:00 PM
How did that one piece gasket work for you ? BTY you have a lot of goodies Gary, got any old traction bars ? Going Day 2 on the Z and looking for a set to rehab-shooting to have the car out for points 2015. My buddy is really stoked  to see how we can rate nationally. Reading rules yesterday stated parts period correct ,no more than 3 years from build date. Matching VIN ,right up my alley!  Leaving no stone unturned---let me know via personal message---steve

Tying the frame and ladder bars were superior--but keeping it in the 60's ,was told ladder bars out ? sub frame connectors I understand.
Title: Re: Oil Pan leaks... ugh..
Post by: Stingr69 on December 19, 2013, 07:55:25 PM
The GM pan is a quality piece.  It's basically as good in quality as the originals with the slight exception of the one I bought a few years ago was "Made in Canada".  It came with a heavy tough black paint coating on it.  I would buy one again without question for any build that could use it.

-Mark.
Title: Re: Oil Pan leaks... ugh..
Post by: janobyte on December 19, 2013, 08:55:52 PM
Thanks Mark, I'll plan on it then.