Front oil pan seal on Small Block Chevys - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-23-2004, 08:51 AM
gearhead77's Avatar
Member
 

Last journal entry: brakes, tranny & distributor
Last photo:
Join Date: Jun 2003
Location: Southern Indiana
Posts: 31
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Front oil pan seal on Small Block Chevys

I had to drop the pan to remove a broken dipstick (this is another sad story in a long chain), but I had some trouble sealing the pan. It is a Small Block 400 Chevy with 4-bolt mains, EIN 3951511. (I know, I counted when the pan was off, what else can you do when you'r scrp). The 40 Hudson truck is titled as a '74, I thought to match the engine, but my refernces show that this engine was only in '71-'73 pickups.

At any rate, I got a CarQuest gasket set for a '74 SBC Oil pan with a Driver's side dipstick. The whole set looked flimsy and when I compared the front seal to the one that came off the pan, it was a lot thinner.

I then got a fel-pro set for a '75 and later SBC that looked a lot better (not as flimsy). When I compaed the front seal to the one that came off the pan, they were about the same thickness, but I noticed that the one that came off the pan was pretty distorted from compression. I started to wonder if the guy before me put the thicker seal on and forced it down. When I put the thicker front seal on the pan, the ends stuck up about 1/4" on both ends, so it looked like the thicker seal did not fit the pan.

I was left with a decision and I think I made the wrong one. I went with the smaller seal that is supposed to fit '74 and earlier blocks.

I fired the engine and set the timing and carb (this is the first time the car has run long enough to do this since I replace the carb, intake (twice) and entire electrical system). When I shut it down, I check for leaks. Everything looked perfect, except the front seal on the pan. I have a leak that is about a drop every 30 seconds that comes right out of the middle of that front pan seal.

Did I choose the wrong seal (are there 4 bolt main 400s with that EIN that came out after 1975 and use the thicker seal)? Could it be the wrong pan for the block? Could it just be installation error (the rest of the pan looks good)? Should I try gasket set and use the thicker seal? Is there a better way to seal a pan? ANY help would be appreciated.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-23-2004, 09:10 AM
Member
 
Join Date: Feb 2003
Location: Enumclaw WA
Age: 29
Posts: 61
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Did you use silicone?
If so did you let it set up first and get a little tacky ?
or mabey use to much ?
also you might have pushed it in with the timing chain cover
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-23-2004, 09:12 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
gasket

The size of the seal you need is determined by the pan. Measure from the mounting surface where it bolts to the block down to the deepest part of the seal diameter.

2 1/4" = thin seal
2 3/8" = thick seal

From what you are saying i think you did pick the wrong seal
If memory serves all the 400 pans took the thick seal.

Keith

royce you out typed me on that one!!!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-23-2004, 09:12 AM
camaroman7d's Avatar
Member
 
Last photo:
Join Date: Dec 2003
Location: Vacaville, California
Age: 47
Posts: 2,245
Wiki Edits: 0

Thanks: 3
Thanked 9 Times in 9 Posts
Well, you have one thing a little "backwards" it is the pan that dictates which seal you need, not the block. The older pans use the thinner seal (I think it is pre-70 or so).

Now he may have put a old style pan of the engine, no big deal. I bet you have the correct gasket because if you didn't, it would be leaking a LOT more than you describe.

I bet the previous owner used a thick front seal with an old style (thin seal) pan and forced it in (which is why the seal you removed was so compressed), when he did this it distorted the pan so now the new correct (thin) seal will no longer do the job.

You could take a bull nose punch and try to gov the pan a few taps to see if you can stop the leak. If I were in your shoes I think I would buy a new pan so you "know" for sure what you have. If you take it out for a drive and step on the brakes and the oil gushes out I would say you might need the thick seal. The only way to know for sure is to pull the pan and lay it upside down on a flat surface, measure front the top of the front lip to the flat surface, this will tell you which style pan you have

Royce
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-23-2004, 09:25 AM
gearhead77's Avatar
Member
 

Last journal entry: brakes, tranny & distributor
Last photo:
Join Date: Jun 2003
Location: Southern Indiana
Posts: 31
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally posted by Mr. Green
Did you use silicone?
If so did you let it set up first and get a little tacky ?
or mabey use to much ?
also you might have pushed it in with the timing chain cover
Yes, I smeared a thin bead of silicone on the pan and the block and let it set for about 5 mins. I placed the gaskets and the rubber seals on the pan and put a blob of silicone in the corners where the seals and gaskets meet, top and bottom and put some silicone on the lip of the seals where they meet the block, waited about 10 mins, and put the pan on the block. I can see the front seal is seat when I look at the front of the pan (I didn't take the truck off the stands because I wanted to check for leaks). It looks uniform, not like it is pushed in or out. There isn't any silicone pushed out of the sides of the gaskets, so I don't think I used too much.

The rest of the pan sealed so well that I think it may just be a problem with the front, but it just seems weird that an early block would want the thicker seal (it poked up so far from the top of the pan, when I test-fitted the thicker seal, that it just looked wrong). Any other ideas?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-23-2004, 09:32 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
seal

i know it looks worng but that is they way they are when assembling.....

keith
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-23-2004, 09:35 AM
gearhead77's Avatar
Member
 

Last journal entry: brakes, tranny & distributor
Last photo:
Join Date: Jun 2003
Location: Southern Indiana
Posts: 31
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Wow, you guys are fast at advice!! I'll try the tap method to try to get it to stop. If it doesn't, I guess it is time to drop the pan & measure it to see what is going on. You probably are right about the pan distortion form the wrong seal, so a new pan may be in order, but that will mean another month of Ramen for lunch. Thanks again for the quick responses.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 04-23-2004, 09:42 AM
killerformula's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 34
Posts: 3,485
Wiki Edits: 3

Thanks: 13
Thanked 27 Times in 18 Posts
if it drips a little while its idling, i'll bet it leaks like hell when you're going 70 on the highway. I hate chevy pans and timing cover gaskets. Those timing covers are horrible... that stamped steel crap just doesn't cut it. Come to think of it, the rear main seals suck too. The only way to do it and not drive yourself nuts is to yank the motor out, clean all the surfaces, check and double check your pan, use the best quality seals and silicone you can and torque to absolute spec. Clean everything, work slow, pray to any god you can think of because chevy's will find any excuse to leak, and there is nothing more annoying than having a leaky motor in a nice car, and having to check the damned oil every 8 minutes.

K
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 04-23-2004, 10:39 AM
Member
 
Join Date: Oct 2003
Location: mn
Age: 34
Posts: 344
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ramen noodles

I think i would let it leak before I ate ramen noodles ick
Jesse
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 04-23-2004, 10:58 AM
killerformula's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 34
Posts: 3,485
Wiki Edits: 3

Thanks: 13
Thanked 27 Times in 18 Posts
Hey! What's wrong with ramen noodles?!?!?

Comon man, when i was in college, ramen was one of the four food groups-

Ramen
Beer
Pizza/pizza rolls
tuna

without these nutrition staples, i wouldn't be the healthy, well-rounded person I am today.

K
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 04-23-2004, 11:32 AM
Member
 
Join Date: Mar 2004
Location: Ontario
Posts: 120
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have seen the thick seal used in place of the thin one and yes it does distort seriously but I think it would be awfully hard to actually warp the pan in that place. My bet is that it is an aftermarket made in taiwan pan. Those things are the curse of engine builders. And by the sounds of it our friend above has had some experience with them too! So yes go out and buy a new pan. Make sure to get a chrome cheapy so that you can have the privilege of doing it all over every six months. lol
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 04-23-2004, 01:58 PM
gearhead77's Avatar
Member
 

Last journal entry: brakes, tranny & distributor
Last photo:
Join Date: Jun 2003
Location: Southern Indiana
Posts: 31
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I Just ordered a decent steel pan from my local speed shop (it turns out I only have to eat Ramen for a week to cover it), so I should be ready to go by Monday. They recommended just using the stock Fel-Pro cork and rubber gasket set. It did seem to do a good job.

I guess I can spend the frre time this weekend putting the garage in order. It seems like I spend more time looking for my tools than turning them.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 04-23-2004, 03:39 PM
Member
 
Join Date: Oct 2003
Location: mn
Age: 34
Posts: 344
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
wow

otherwie you could always go to a junk yard and have them pull a pan off an engine as it is getting torn apart and before it goes in a seperate sprap container. have it tomarrow with a little paine(chevy orange) you;ll have it going again??
then you wouldn't have to eat ramen noodles at all.
Jesse
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 04-23-2004, 05:36 PM
camaroman7d's Avatar
Member
 
Last photo:
Join Date: Dec 2003
Location: Vacaville, California
Age: 47
Posts: 2,245
Wiki Edits: 0

Thanks: 3
Thanked 9 Times in 9 Posts
gearhead77,
Do yourself a HUGE favor and don't use the cork/rubber four piece set. Spend a few extra bucks and get a one piece oil pan gasket. I have had EXCELLENT luck with them from both Fel-Pro and Detroit (I think they are under another name now). This will make sealing than pan much easier and ONLY put silicon in the four corners (when I say corners I mean the corners of the timing cover and rear main).

Royce
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 04-25-2004, 06:35 AM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 37
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Not that it is needed, but I just wanted to say I think Royce hit the nail on the head. I would be willing to bet a little hammer work would have fixed it, but the new one will also work well. I would bet that the front edges of the pan were pulled down while tighting the thick gasket. Any time you reuse an oil pan it is a good idea to check the edge for straightness. If it is not to bad, they can be straghtened with a hammer and a block of wood.....but I am a cheap skate.

Chris
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 06:46 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.