Holley oil pan blues

[cornerstone]

I’ve already installed a aluminum Holley 302-20 oil pan on my L83 and the drain plug that was with the kit is too small, it is an M12x1.75.

I called Holley to find out what size bolt the drain hole was tappped for, and the tech guy didn’t have a clue. He offered to exchange the whole oil pan kit but I really don’t feel like taking it off of the engine repackaging everything and going through the hassle of sending it back. I just want to buy a drain plug that will fit. It appears to be an M14x1.75 or M14x2.0 and neither of these are available.

I found the closest SAE version...a 1/2”x13 tpi bolt and added a Teflon washer. It was a bit loose but seemed like it would hold a seal...
I added the oil and noticed a drip, so I gave the brain bolt a little more torque and this bolt is still to small, as it will not grab enough material to hunker down.

So.... my next idea is to drill and tap a larger size and move forward, but something in me cringes when I have to modify a brand new $325 part.
If I do drill and tap new threads I’m thinking that would go to a 9/16 bolt. Should I go with a fine thread (20 tpi) or a coarse thread (12 tpi)? I have both taps already.

Any idea where I can get an M14 flange bolt with a 1.75 or 2.0 pitch?
Any suggestions before I cut new threads in this BRAND NEW oil pan?!!

The plug on the right is what they provided, and the one in the left is a 1/2”x 13 tpi bolt. Both are too small.

[95 S_Trucker]

Putting SAE bolts where metric bolts go is a bad idea. It never ends well. Now the threads in the oil pan are damaged.

My suggestion is to do what holley is offering. They are standing by their product by exchanging it for another one. Ask them to email a shipping label so you don't have to pay for shipping.

Make sure the drain plug fits before you install the new pan.

[cornerstone]

Definitely the best advice S_Trucker, thanks. I'll most likely do that if I can't locate the correct bolt. I believe the damage to the threads in the pan are minimal and the proper fitting bolt will still work just fine.

Do any of you kind folks out there know who might have an M14 x 1.75 or 2.0 pitch bolt?

[sweetk30]

yet another lack luster product and service from holley .......


and as said find the thread it is and get that bolt and be done with it .

also side note : i was looking for oil pans for my ls swap when i am ready and the holley pans cost more than a gm original new pan of the same basic setup .

[Captainfab]

Have you checked your local Napa for an oil pan drain plug? Last winter I found a drain plug there that I thought I was not going to be able to find. And yes it was metric.

[Ironangel]

Why not take the bolt to a hardware store and verify what you have with one of these? https://www.amazon.com/Horizontal-Ga...24938757&psc=1 Thread pitch gauges are cheap enough and handy to have around...

[cornerstone]

I’ve already installed a aluminum Holley 302-20 oil pan on my L83 and the drain plug that was with the kit is too small, it is an M12x1.75.

I called Holley to find out what size bolt the drain hole was tappped for, and the tech guy didn’t have a clue. He offered to exchange the whole oil pan kit but I really don’t feel like taking it off of the engine repackaging everything and going through the hassle of sending it back. I just want to buy a drain plug that will fit. It appears to be an M14x1.75 or M14x2.0 and neither of these are available.

I found the closest SAE version...a 1/2”x13 tpi bolt and added a Teflon washer. It was a bit loose but seemed like it would hold a seal...
I added the oil and noticed a drip, so I gave the brain bolt a little more torque and this bolt is still to small, as it will not grab enough material to hunker down.

So.... my next idea is to drill and tap a larger size and move forward, but something in me cringes when I have to modify a brand new $325 part.
If I do drill and tap new threads I’m thinking that would go to a 9/16 bolt. Should I go with a fine thread (20 tpi) or a coarse thread (12 tpi)? I have both taps already.

Any idea where I can get an M14 flange bolt with a 1.75 or 2.0 pitch?
Any suggestions before I cut new threads in this BRAND NEW oil pan?!!

The plug on the right is what they provided, and the one in the left is a 1/2”x 13 tpi bolt. Both are too small.

I also posted this in the Engine & Drivetrain forum.

[LockDoc]

-
I would think you would have better luck with this in the LSx Swaps forum. There are some very knowledgeable people over there. I will move it there for you.

LockDoc

[cornerstone]

OK. Thanks Leon!

[Grumpy old man]

This should help

https://www.boltdepot.com/Metric_fla...m_x_2.0mm.aspx

[dozerbill72]

Try an oil change shop, they have "repair" plugs in various sizes. Some of them are cut similar to a tap on the end to cut new threads as they go in.

[truckdude239]

Sounds to me like you got a pan that wasn't drilled properly oil plug should be a 12x 1.75 which is stock next up from that is a 14x 1.50 I f it was me i'd let holly swap the pans out as your going to end up runnign into issuses down the road

[truckdude239]

also i megred your 2 threads together please remenber per form rules

XIV. Multiple Posting - It is simply not acceptable to post your question more than once, or to post it in more than one forum. Choose the forum that your question or post best fits in, and place it there and only there. If, after posting, you feel it should be in another forum, private message the forum Moderator and ask if they would move it for you.

[cornerstone]

Originally Posted by Captainfab

Have you checked your local Napa for an oil pan drain plug? Last winter I found a drain plug there that I thought I was not going to be able to find. And yes it was metric.

I did not check NAPA, but I did go to AutoZone and O'Riely and of course searched the Internet.

Originally Posted by Ironangel

Why not take the bolt to a hardware store and verify what you have with one of these? https://www.amazon.com/Horizontal-Ga...24938757&psc=1 Thread pitch gauges are cheap enough and handy to have around...

I did go to the usuals like Lowes and Home Depot and several good independently owned stores that are known for having a great assortment of hardware, but nothing with a 2.0 pitch. All of the thread pitch gauges were too small, they only went up to M12. Those thread pitch gauges are super handy for sure, I've got one on my list of wants.

Originally Posted by truckdude239

Sounds to me like you got a pan that wasn't drilled properly oil plug should be a 12x 1.75 which is stock next up from that is a 14x 1.50 I f it was me i'd let holly swap the pans out as your going to end up runnign into issuses down the road

That's what I'm thinking too, perhaps it was just a mistake made on only one pan. When I spoke to the Holley tech guy I was assuming he had definitely heard of this before and would be ready and willing to send a new drain plug out, but he told me that there were no other mentions of this problem in the notes section for that part number. Apparently I'm the only lucky one... What other possible future issues am I overlooking?

Originally Posted by truckdude239

also i megred your 2 threads together please remenber per form rules

XIV. Multiple Posting - It is simply not acceptable to post your question more than once, or to post it in more than one forum. Choose the forum that your question or post best fits in, and place it there and only there. If, after posting, you feel it should be in another forum, private message the forum Moderator and ask if they would move it for you.

My apologies truckdude, I won't do it again. Truthfully, I've don't believe I have ever read through the rules.

Thank you all for the responses, the 2 (I ordered a spare) M14x2.0 bolts are to arrive this Tuesday from Bolt Depot... I'll update after I try it out.

[truckdude239]

Future issuse if you dont get right thread or drill and tap it out it could end up striped out wrost and no lo g have holly support

[cornerstone]

Good grief....

The good news is the 2 M14 bolts with a 2.0 thread pitch from Bolt Depot arrived early. The bad news is they don't fit either. They only got 1 full thread in before it was obviously not going to work. At least it was only a 9$ mistake, the shipping cost twice as much as the bolts did.

I'd like to blame it on the parts counter guy at O'Reilly, but that'd be a partial truth. It was an M14 x 1.50 all along. I'm guessing the first one I tried was not really the right one, perhaps incorrectly packaged?

I stopped by the parts house again and picked up a different version of the same size drain plug and it perfectly sealed up tight with no thread damage. Thank the Lord.

I don't know how my brain wasn't able to logically figure this out, which led me to ask you guys for help, but what a pain in the backside. I'm gonna call this my first official senior moment. Sorry to waste every ones time.

Carry on.

[87chevy.com]

Is there a heli coil installed? Sounds like it's missing. Easy to check

[cornerstone]

No helicoil... just threads cut into the aluminum pan itself.

[87chevy.com]

Originally Posted by cornerstone

No helicoil... just threads cut into the aluminum pan itself.

That's the problem, ask them to buy you the heli coil kit. Or refund the cost. If you just simply install the heli coil part and you'll be able to use the factory bolt. Not sure why the do that from the get go... heli coil it..
Clint

[cornerstone]

Originally Posted by 87chevy.com

That's the problem, ask them to buy you the heli coil kit. Or refund the cost. If you just simply install the heli coil part and you'll be able to use the factory bolt. Not sure why the do that from the get go... heli coil it..
Clint

I'm missing something here Clint. The threads in the new Holley pan are exactly an M14 X 1.50 pitch. From what I've learned there are 2 common size oil drain plug sizes, an M12x1.25 and an M14x1.5. I think they just loaded the box with the smaller plug. The M14x1.5 plug fits perfect.

Why would a new oil pan have a heli coil in it? I always thought they are used to repair stripped threads.

Brian

[87chevy.com]

Mis read it. Thought the drain plugs were 12mm x 1.5.
Clint