# Rear Strap Under Oil Pan



## Crybaby (May 11, 2021)

I am reassembling my '65 GTO's 389 (without internals), as I plan to paint the block heads, pan, timing cover, etc. then disassemble and discard the gaskets with painted edges to replace with new set when I do the final assembly of the engine. Anyway, there is a steel strap (1/2" wide) that "I believe" goes under the oil pan beneath the oil pan gasket piece that fits in the groove on the outside (curved) of the rear main bearing. The strap has tabs with holes for the rear-most oil pan bolts (which may also act as stiffers to keep the oil pan edges down at either end of the main cap. Anyway, I have a new oil pan and when I install the strap it doesn't hug the curved oil pan flange - it seems to float about 1/8" above it (larger radius). Is there some other gasket (or piece that I'm forgetting to mount) that goes between this strap and the pan? During disassembly (years ago) I did not take pics of this area, so maybe I'm installing something wrong. I'd appreciate any thoughts or suggestions.


----------



## BLK69JUDGE (Jun 10, 2010)

betcha its the repop oil pan 
I would find an original ,,,


----------



## Crybaby (May 11, 2021)

BLK69JUDGE said:


> betcha its the repop oil pan
> I would find an original ,,,


It's a new Canter. Good baffling, bolts line-up, etc. Just can't figure out why the strap won't snug-down. I still have the original pan (but it's damaged beyond use), so I can compare the rear main cut-out and see if there is a dimensional difference. Thx, though, for the post - much appreciated.


----------



## O52 (Jan 27, 2019)

Later years used two reinforcement tabs at the rear corners of the pan. Bolts at the rear tabs are torqued to 20 ft-lbs rather than the normal 12.
They are available from your favorite vendor but may need slight grinding for a perfect fit.

The BOP one piece pan gasket fits great without all the hassle of lining up the different gaskets.


----------



## O52 (Jan 27, 2019)

You may have issues with that pan and the center link. 






Oil pan center link issue? - PY Online Forums - Bringing the Pontiac Hobby Together


Oil pan center link issue? Pontiac - Street



forums.maxperformanceinc.com


----------



## Crybaby (May 11, 2021)

O52 said:


> Later years used two reinforcement tabs at the rear corners of the pan. Bolts at the rear tabs are torqued to 20 ft-lbs rather than the normal 12.
> They are available from your favorite vendor but may need slight grinding for a perfect fit.
> 
> The BOP one piece pan gasket fits great without all the hassle of lining up the different gaskets.
> ...


----------



## Crybaby (May 11, 2021)

Thx Ed - great post. I recently found-out about the corner braces, and will look into the BOP one-piece gasket. Thx for the inputs.


----------



## Crybaby (May 11, 2021)

O52 said:


> You may have issues with that pan and the center link.
> 
> 
> 
> ...


Yikes! I still have the old pan. It has a major dent in the deep end, like someone set the car down on a jack stand. However, I can (before installing new pan) take a closer look, comparing all aspects of the two designs. I'm glad you told me. I thought Canter was a pretty good name, and the baffling/windage inserts in the pan impressed me. That said, I will now re-assess things ... side-by-side.


----------



## Crybaby (May 11, 2021)

Crybaby said:


> Yikes! I still have the old pan. It has a major dent in the deep end, like someone set the car down on a jack stand. However, I can (before installing new pan) take a closer look, comparing all aspects of the two designs. I'm glad you told me. I thought Canter was a pretty good name, and the baffling/windage inserts in the pan impressed me. That said, I will now re-assess things ... side-by-side.


Sorry - I typed "Canter" and meant "Canton" - regardless, I will do a closer comparison before I go further, I do NOT want to finish the engine only to find that it interfere with the chassis ... so, thanks for the insights.


----------



## Jared (Apr 19, 2013)

Crybaby said:


> Sorry - I typed "Canter" and meant "Canton" - regardless, I will do a closer comparison before I go further, I do NOT want to finish the engine only to find that it interfere with the chassis ... so, thanks for the insights.


This has come up before. I am using a Canton pan on the engine that's going back in mine. To be proactive, I am going to install spacers under the chassis mounts. I'll hopefully know in a couple weeks if they work or not.



https://butlerperformance.com/i-31643312-butler-performance-frame-mount-spacers-1964-72-gto-lemans-tempest-set-bpi-1026-2.html?ref=category:1393554


----------



## Crybaby (May 11, 2021)

Jared said:


> This has come up before. I am using a Canton pan on the engine that's going back in mine. To be proactive, I am going to install spacers under the chassis mounts. I'll hopefully know in a couple weeks if they work or not.
> 
> 
> 
> https://butlerperformance.com/i-31643312-butler-performance-frame-mount-spacers-1964-72-gto-lemans-tempest-set-bpi-1026-2.html?ref=category:1393554


Great reply. I'm still at the stage where I could select another pan, but the spacer option (under chassis mounts) is a good thing to know. Wow - is the potential interference only 3/16"? If so, that will make my pan-to-pan comparison more difficult to determine (if aftermarket will rub or not). Good information, though, so "thank you."


----------



## Jared (Apr 19, 2013)

From what I've gathered, the interference is very minimal, to the point where the engine will fit in the car but the pan will just make contact. So 3/16 should be plenty without causing other issues (hood clearance, geometry, etc). Others have added clearance by denting the oil pan where it's going to hit. I didn't like this idea for me so I'll try the spacers. These aftermarket pans probably fit fine when the cars were much newer but in the 50+ years since they were built, things have spread a bit. Not uncommon to find and old A body that has a slight lean. Mine does and it has never been hit. I corrected that with a very thin spacer over one of the rear springs.

You mentioned about having a sloppy gasket around the back of the pan. Was this just during test fit or after you tightened all the bolts? Mine looked like it would have way too much space when I test fit, but snugged right up once everything was torqued to spec. I'm using the BOP gasket mentioned above. I was really careful to make sure the gasket was in the grove before tightening everything because it didn't seem to want to stay in place.

One more thing that will save you headaches in the near future. Don't go with cheep motor mounts. Buy from a reputable source and not from a discount site. You really get what you pay for. I'm using the ones sold through Butler. They are expensive but come with a 3 year warranty which I never expect to use. My car had the discount ones on it and one was blown out when the engine came out.


----------



## O52 (Jan 27, 2019)

Ames now has the correct engine mounts of which they give a lifetime warranty. Not for 455s at this time.


----------



## Crybaby (May 11, 2021)

Jared said:


> From what I've gathered, the interference is very minimal, to the point where the engine will fit in the car but the pan will just make contact. So 3/16 should be plenty without causing other issues (hood clearance, geometry, etc). Others have added clearance by denting the oil pan where it's going to hit. I didn't like this idea for me so I'll try the spacers. These aftermarket pans probably fit fine when the cars were much newer but in the 50+ years since they were built, things have spread a bit. Not uncommon to find and old A body that has a slight lean. Mine does and it has never been hit. I corrected that with a very thin spacer over one of the rear springs.
> 
> You mentioned about having a sloppy gasket around the back of the pan. Was this just during test fit or after you tightened all the bolts? Mine looked like it would have way too much space when I test fit, but snugged right up once everything was torqued to spec. I'm using the BOP gasket mentioned above. I was really careful to make sure the gasket was in the grove before tightening everything because it didn't seem to want to stay in place.
> 
> One more thing that will save you headaches in the near future. Don't go with cheep motor mounts. Buy from a reputable source and not from a discount site. You really get what you pay for. I'm using the ones sold through Butler. They are expensive but come with a 3 year warranty which I never expect to use. My car had the discount ones on it and one was blown out when the engine came out.


Thx for the reply. The sloppy gasket is actually a sloppy half-round steel strap that seems to go outside of the oil pan, from side to side, fastening (via 2 bolts nearest the rear main cap, through 2 tabs (the ears of this half-round), then through the pan rim, and into the block. I have not seen any other '65 389 pics with this strap (very curious). Anyway, thx for the insights. By the way, I bought my mounts through either Year One or Performance Years, so I hope they're OK. Have a good weekend.


----------



## Crybaby (May 11, 2021)

Crybaby said:


> Thx for the reply. The sloppy gasket is actually a sloppy half-round steel strap that seems to go outside of the oil pan, from side to side, fastening (via 2 bolts nearest the rear main cap, through 2 tabs (the ears of this half-round), then through the pan rim, and into the block. I have not seen any other '65 389 pics with this strap (very curious). Anyway, thx for the insights. By the way, I bought my mounts through either Year One or Performance Years, so I hope they're OK. Have a good weekend.


Maybe I can take and send a pic of the steel strap I'm trying to describe.


----------



## Jared (Apr 19, 2013)

Crybaby said:


> Maybe I can take and send a pic of the steel strap I'm trying to describe.


Please do. I may not know what it is but others might. My car was a mongrel when I got it. You came to a great place for advice. There are some really great resources on here.


----------



## Crybaby (May 11, 2021)

From the four pics attached, hopefully you will see the strap (outside of the pan, outside of the cork gasket, outside of the rear main cap). Hopefully, you'll also see the gap between the strap and the pan. I don't know what originally filled this gap, or if - with the new pan - it is just not snugging-up.


----------



## O52 (Jan 27, 2019)

Does it fit your old pan? I looked through my parts manual and there's no mention of or any diagrams of a reinforcement strap. I faintly recall a strap similar to that but it wasn't on a Pontiac. Maybe it's an old Chevy piece you had laying around.


----------



## Crybaby (May 11, 2021)

O52 said:


> Does it fit your old pan? I looked through my parts manual and there's no mention of or any diagrams of a reinforcement strap. I faintly recall a strap similar to that but it wasn't on a Pontiac. Maybe it's an old Chevy piece you had laying around.


Ed - the odd thing is I don't remember taking it off the engine during disassembly. I do have the old pan; it is unusable but I can at least check if it used to fit-up. I had that strap in my container with all of the oil pan bolts. Is there another spot it could have been bolted along the underside (e.g., part of lower baffle? part of dipstick arrangement? part of oil pump config?). It is honestly a mystery to me. Well, maybe I should just not use it (esp. if not parts manuals show it) and just buy the aftermarket corner braces (which were not on my original pan), to help spread the load on the rear corners of the pan rail. Head scratcher.


----------



## Crybaby (May 11, 2021)

The attached pic has the oil pan bolts the the "strap" - I tried to lay things out as they came off the engine.


----------



## Jared (Apr 19, 2013)

I know mine didn't have a strap across the back. It may not belong but I doubt its causing your issue. I'm guessing someone put that on there because they had a leak at the rear of the pan. That being said, it almost looks like your gasket isn't sitting all the way in the groove. Mine has a slight gap between the pan and the rear cap but the gap is constant, if that makes sense. You can see gasket which is why that section is so thick.


----------



## BearGFR (Aug 25, 2008)

Has the block been align-honed? More than once perhaps? That can cause fitment problems like what your photos show.

I too had a very similar 'sloppy fit' problem with a Milodon pan. It fit tight on the sides of the rear main cap but was very loose/slopping in the center. My engine is out right now, waiting for me to have the time/motivation to get it going again. I'll be replacing that Milodon pan with a Canton pan this go round.

Bear


----------



## Crybaby (May 11, 2021)

OK - update on the rear strap (and I'll attach a few pics)

Based upon all of your collective inputs, I think I have three options and just need to pick the best for long-term: (1) bang-out the deep-end dent in the original pan, but not sure how much damage (or cracking) this may cause, (2) pursue Canton about another new pan (refund, replace, or find new aftermarket pan), since I have now verified that the shallow end his about 1/4"+ deeper than original and will likely interfere with cross member, or (3) use the new Canton pan with the Butler spacers (only 3/16") under the engine mount bases on the frame.

The pics show original pan, with radial dimple ridge and the seal is next to it (this is the seal that would go in the groove on the outside of the rear main cap, and seal against the pan (you can see the ridge indentation. Another pic shows the same, but also has the "mystery strap" which maybe helped to hug the pan against the seal (not sure). The final pic shows the new pan (no dimple ridge), but to the points made earlier - maybe I just need to rely upon the new gaskets and some RTV placed in strategic locations (add also order the new corner braces the help to distribute load under the rear-most 4-6 pan bolts.

I'm open to any other thoughts on the matter. I didn't think oil pan fit-up was going to be this big of an issue, but I'd rather spend more time considering it now, then find an immediate oil leak once the engine is reinstalled.


----------



## O52 (Jan 27, 2019)

I would use the Canton pan, buy the spacers, BOP one piece gasket and corner braces


----------



## Crybaby (May 11, 2021)

O52 said:


> I would use the Canton pan, buy the spacers, BOP one piece gasket and corner braces


Ed - that sounds like a good option (including all of your recommendations). One lingering question would be about the spacers under the motor/engine mounts. Even though they are only 3/16" (will that be enough, should I get two for each side?) is that going to potentially lead to other misalignments later (e.g., throttle, clutch linkage, exhaust line-up, hood clearance, tranny or bell housing to underside of body, etc.)? Probably not, but thought I'd ask the question.


----------



## Baaad65 (Aug 29, 2019)

I had the center link rubbing too with a '72 block in my '65, it's a Butler motor with whatever 6 qt. pan they use, found some 1/4" spacers on Ebay for 35.00....good thing you're doing before the motor is installed because that job sucked....actually had to superglue a couple of nuts to the tip of my finger to hold them in place through the control arm while I started the bolt 🤦‍♂️


----------



## Crybaby (May 11, 2021)

Crybaby said:


> Ed - that sounds like a good option (including all of your recommendations). One lingering question would be about the spacers under the motor/engine mounts. Even though they are only 3/16" (will that be enough, should I get two for each side?) is that going to potentially lead to other misalignments later (e.g., throttle, clutch linkage, exhaust line-up, hood clearance, tranny or bell housing to underside of body, etc.)? Probably not, but thought I'd ask the question.


I wonder if anyone has had any luck going back to Canton to tell them their '65 GTO pan does not fit a '65 GTO. I wonder if they offer any remedy (e.g., refund pan, apply credit for spacers, etc). Maybe not - mostly curious - perhaps worth my trying.


----------



## Crybaby (May 11, 2021)

Baaad65 said:


> I had the center link rubbing too with a '72 block in my '65, it's a Butler motor with whatever 6 qt. pan they use, found some 1/4" spacers on Ebay for 35.00....good thing you're doing before the motor is installed because that job sucked....actually had to superglue a couple of nuts to the tip of my finger to hold them in place through the control arm while I started the bolt 🤦‍♂️
> View attachment 142734
> View attachment 142735


Good to know - but now I'm concerned about adequate spacer thickness. I see Butler has a 3/16" design, but it seems you needed 1/4". Per my other concern, this this lead to misalignment elsewhere? e.g., throttle, clutch, exhaust, bell hsg or tranny (vs. underside of body), etc?


----------



## O52 (Jan 27, 2019)

Go too much then hood clearance becomes an issue.

I think the advantages of the Canton pan outweigh the possibility of interference. Especially if you're aware of it ahead of time. Also, the wrong transmission mount (to tall) can cause oil pan interference. I had that issue with my El Camino. It seems that the majority of part store mounts are too tall. I found a slightly shorter one (TH400 version) that not only gave me more oil pan clearance but reduced driveline vibration.


----------



## Crybaby (May 11, 2021)

O52 said:


> Go too much then hood clearance becomes an issue.
> 
> I think the advantages of the Canton pan outweigh the possibility of interference. Especially if you're aware of it ahead of time. Also, the wrong transmission mount (to tall) can cause oil pan interference. I had that issue with my El Camino. It seems that the majority of part store mounts are too tall. I found a slightly shorter one (TH400 version) that not only gave me more oil pan clearance but reduced driveline vibration.


I bought my new engine and transmission mounts from either Performance Years or Year One or Ames, so I hope I've received decent (to spec height) mounts.

Why do you like the Canton pan (re. advantages)? I do believe if looks like a good pan, and had good windage baffling (then again, the engine has the windage baffle that bolts to the mains, so "frothing" should not be an issue). I'd like to use the new pan, but these dimensional concerns have me thinking about trying to straighten the original ... hmmm.


----------



## O52 (Jan 27, 2019)

I was comparing the Canton to your original pan
If you had an original in good condition, I would have picked that over the canton. 
To add more fuel to the discussion, the later (70s) factory pans came with a baffle.


----------



## Baaad65 (Aug 29, 2019)

The shop doing the alignment first noticed the rubbing center link so he took the spacer out of my poly trans mount but it wasn't enough, haven't noticed anything else weird with it spaced up and I have a Edelbrock Performer RPM with a 1/2" carb spacer and custom air cleaner with a billet hold down nut and I still have a 1/4" of clearance...thank goodness for the gto hood scoop bulge 👍


----------



## Crybaby (May 11, 2021)

O52 said:


> I was comparing the Canton to your original pan
> If you had an original in good condition, I would have picked that over the canton.
> To add more fuel to the discussion, the later (70s) factory pans came with a baffle.


That makes it a tougher call. The original has no baffle (windage plate), the Canton does. That said, '65 389's don't "truly" need the pan to have windage plates, since there was a windage baffle plate bolted directly to the underside of the main bearing caps. Anyway, your point is well taken - and I'm still debating between the two options (bang-out the dent under the original, or buy spacers, etc. to use the Canton). This forum provides a lot of good info, so thx again (to all of you)!


----------



## Crybaby (May 11, 2021)

Baaad65 said:


> The shop doing the alignment first noticed the rubbing center link so he took the spacer out of my poly trans mount but it wasn't enough, haven't noticed anything else weird with it spaced up and I have a Edelbrock Performer RPM with a 1/2" carb spacer and custom air cleaner with a billet hold down nut and I still have a 1/4" of clearance...thank goodness for the gto hood scoop bulge 👍
> View attachment 142746


wow - beautiful intake !!


----------



## Crybaby (May 11, 2021)

O52 said:


> I was comparing the Canton to your original pan
> If you had an original in good condition, I would have picked that over the canton.
> To add more fuel to the discussion, the later (70s) factory pans came with a baffle.


I'm beginning to lean towards trying to "press out" the shallow dent, and reuse the original. It probably makes sense for me to purchase the new-tech one-piece BOP gasket, and maybe by the corner shim / brackets.


----------



## PontiacJim (Dec 29, 2012)

Crybaby said:


> I'm beginning to lean towards trying to "press out" the shallow dent, and reuse the original. It probably makes sense for me to purchase the new-tech one-piece BOP gasket, and maybe by the corner shim / brackets.


Don't over think it. So the original pan has a dent, beat it out as long as it is not on the pan rail where it could cause a sealing problem. My 455 pan was dented pretty good. People run up/over stuff with the oil pan. I just beat the dents out as flat as I could and called it a day.

That strap is something someone probably added in an attempt to cure a problem like a leaking rear pan seal. Might have been just a quick cheap fix. The engine may have not had enough breathers and at higher RPM's internal engine pressures were pushing oil out the seal. Who knows, but ditch it.

Use the cork seal, but make sure it fits well and is not bulged up because the ends need some slight trimming to get it to lay flat. You may want to use a good sealant - one that will not be affected by oil. I am a little partial to Indian Shellac that comes in a small bottle and you paint it on with the supplied applicator in the bottle good for cork gaskets. It is sticky stuff and seals well. If you look it up on the internet, you will of course see all the negative reviews and what sealants are better, etc.. Yep, its old school, and yep, it has always worked for me.

If you use a rubber gasket, it is possible that when you clamp down on it, it will squeeze out or slip out of place. My machinist/engine builder uses and recommends putting some of the 3M Yellow gasket adhesive on one side of the rubber gasket to hold it in place. Just follow the directions. I have used this myself after having the front oil pan seal squish/slip out on a Mopar 360 engine and lost a lot of the oil, but caught it in time.

I used Permatex RTV Gear Oil Gasket Maker, #81182, on an old International rear axle cover as I did not have a gasket available. This may be something that could be used as well seeing its purpose if for items having gear oil/oil use.

I would also use the small pan corner tabs as has been pointed out. 

Just take your time, fit the cork seal if you use it, and test fit everything. One of our members, *BaerGFR*, likes to hang his motors by the engine hoist at a high angle with the pan pointing down and adds oil and lets it sit like that for a couple days. This is his procedure for testing for rear pan or rear main oil leaks. Saves some time of putting the engine in the car only to find it leaks oil and you have to pull it again.


----------



## Crybaby (May 11, 2021)

PontiacJim said:


> Don't over think it. So the original pan has a dent, beat it out as long as it is not on the pan rail where it could cause a sealing problem. My 455 pan was dented pretty good. People run up/over stuff with the oil pan. I just beat the dents out as flat as I could and called it a day.
> 
> That strap is something someone probably added in an attempt to cure a problem like a leaking rear pan seal. Might have been just a quick cheap fix. The engine may have not had enough breathers and at higher RPM's internal engine pressures were pushing oil out the seal. Who knows, but ditch it.
> 
> ...


Great reply, thx Pontiac Jim!


----------

