383 Oil Pickup Thread Help

TPG2112 · May 30, 2021

Looks like whoever had this engine before me cross threaded or damaged the threads bad.
Can't quite figure out what threads this is using. I've seen 3/8 NPT and I've seen 3/8 NPSM.
Anyone ever have this problem? Suggestions and advice appreciated. This was the LAST thing I needed to get this motor back together and now I could be looking at a costly repair and delay if I have to take this thing to the machine shop.
I'd like to try chasing the threads with a tap and see if I can get a pickup to seat. Thanks in advance.

1 Wild R/T · May 31, 2021

Stock is 3/8-NPT. Thing is the hole is angled and easy to cross thread, especially since the pick-up has a few bends.... Might try screwing a standard 3/8 pipe nipple into the hole just to see if the block threads might be Okay & only the pick-up tube threads are the problem...

TPG2112 · May 31, 2021

1 Wild R/T said:
Stock is 3/8-NPT. Thing is the hole is angled and easy to cross thread, especially since the pick-up has a few bends.... Might try screwing a standard 3/8 pipe nipple into the hole just to see if the block threads might be Okay & only the pick-up tube threads are the problem...

I'll pick one up tomorrow when I get a tap too just in case. Pretty sure though based up what I'm seeing in there, its garbage. Second my new oil pickup tube bit, I got half a turn in and stopped because I saw how cocked it was catching at. I've done a few of these and never had a problem, and those threads look good and twisted at the top at least. Good idea, thanks.

JG71B · May 31, 2021

I just went through this with a 400 but the tube itself (440source 402 tube). Went most of the way then was tough. Made the factory tube hard to get all the way back on also. Chased it with a piece of pipe slowly in and out over and over and kept hosing with WD40. Finally MADE it work but, scary!

TPG2112 · May 31, 2021

JG71B said:
I just went through this with a 400 but the tube itself (440source 402 tube). Went most of the way then was tough. Made the factory tube hard to get all the way back on also. Chased it with a piece of pipe slowly in and out over and over and kept hosing with WD40. Finally MADE it work but, scary!

I was taking a look at it again, yeah, I'm getting all sorts of bad feelings on this. Literally had just finished new rings, pistons, bearings, hone, paint, etc.
This was the LAST thing before throwing on an oil pan, bolting a trans up, and doing a compression test.

Only thing I'm going to try is to get a tap on it to clean and chase the threads. Ordered 2 new oil pickups and maybe with a little luck I can get one to seal and fit.
If not well, looks like my challenger is going to sit for another year. So much for dirt cheap basic rebuild.

Wondering if worst comes to worst since it looks like its only the top threads if I can could try drilling those out a bit and chase it what a tap and get it to seat just with a little less engagement.

1 Wild R/T · May 31, 2021

There are a number of fixes if you wind up taking it back apart.. Back in the day it was common to open the pick up to 1/2 NPT so thats a pretty easy option... Pick up tubes are available...

Another option is an external pick up, lot of $$ that shouldn't be needed...

TPG2112 · May 31, 2021

1 Wild R/T said:
There are a number of fixes if you wind up taking it back apart.. Back in the day it was common to open the pick up to 1/2 NPT so thats a pretty easy option... Pick up tubes are available...

Another option is an external pick up, lot of $$ that shouldn't be needed...

I did see the 1/2 inch option. I just don't know if I have the skill to fully drill and tap that. Never would have attempted such a feat plus with metal it's kind of a one shot deal. What I'd probably have to do is take it all down again and put it in storage since I'm getting ready to move back to California and I've got a camper truck that needs money put into it right now. Kind of a drag since I was slamming this together and hoping to drive and have fun with it in the next year. Have a machine shop take a look at it when I get another tax return or something.

Is there any potential for oil pressure loss with a bigger tube? Considering that's the suction end, I could only see that being better on volume. Would I need a different pan?

1 Wild R/T · May 31, 2021

Same pan, no loss of suction, just a loss of restriction (thats good). I wouldn't try drilling & tapping free hand, I'd set it up in a mill... Not really a big job just gotta tear the engine apart to do it....

I would tell you not to move to California but your already in California's Northern Freak Show.. Well actually Spokane is better than Seattle or Portland.... You might wanna stay where you are...

TPG2112 · May 31, 2021

1 Wild R/T said:
Same pan, no loss of suction, just a loss of restriction (thats good). I wouldn't try drilling & tapping free hand, I'd set it up in a mill... Not really a big job just gotta tear the engine apart to do it....

I would tell you not to move to California but your already in California's Northern Freak Show.. Well actually Spokane is better than Seattle or Portland.... You might wanna stay where you are...

I'm a California native and have a ranch up near Tehachapi. Plus, I'm a surfer. Been up here about a year and I'm really not digging the vibe. But I get what you mean about some of newer California. Home is home though, and no waves to be had really up here. (What is it with the Northwest and no good beach cities??)

Yeah, by hand would be a nogo for sure and I don't really have any way to mill something that big. So it'll probably be off to the shop in the future if this doesnt work.
May be trying to get that junk 360 thats sitting in the Challenger slapped back together with bearings and rings earlier than I thought.

1 Wild R/T · May 31, 2021

Biggest thing is getting the angle right... I'd make an extended driver for the tap or use an extended tap so any change of the tap angle would require the end of the driver move quite a bit.... then If you have access to a big block with a good oil pick up hole you can verify the correct angle before attempting to repair the damaged threads...

This would work.... It's NPTF which is slightly different from NPT but the angles, pitch & thread count are the same, Plenty of guys have & continue to use NPTF on oil pick ups

https://www.ebay.com/itm/2334335529...kSBO3CHQ%2Fol1g45HHG|ampid:PL_CLK|clp:2047675

TPG2112 · May 31, 2021

1 Wild R/T said:
Biggest thing is getting the angle right... I'd make an extended driver for the tap or use an extended tap so any change of the tap angle would require the end of the driver move quite a bit.... then If you have access to a big block with a good oil pick up hole you can verify the correct angle before attempting to repair the damaged threads...

This would work.... It's NPTF which is slightly different from NPT but the angles, pitch & thread count are the same, Plenty of guys have & continue to use NPTF on oil pick ups

https://www.ebay.com/itm/233433552991?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20200818143132&meid=f3861dc5f1184dd0a983c6ee9384b845&pid=101198&rk=2&rkt=12&sd=142031169309&itm=233433552991&pmt=1&noa=0&pg=2047675&algv=SimplAMLCvipPairwiseWebWithBBEV2bDemotion&_trksid=p2047675.c101198.m1985&amdata=cksum:233433552991f3861dc5f1184dd0a983c6ee9384b845|enc:AQAFAAACAMP%2F0458p79hJUCOXbgc6Q0bA6wpsYW%2ByRxiNyB11EfRvnZVkCiVa8U0QjshoHe4qQKqFOL83A8uCk4youmMJZq5WEgaiVpM9c9GRlxStrDXstT7GtZXJ%2BIwdBVpJZKKv33tDS8nKz3QreLykHEdXYGWSaBx3WvL71h%2Fwu8P3x4cTO3onymoS6ymPylgnV375WHL55E889XRFXh1OGZOKG%2FKIi73%2FERcCLop2EMQc6C1ahRpM0tArbZSg5DuXmkABNcGt79tiEDil4TcaEJCEkV%2F5HICiboc5ZZYMY836f0PmQh9HhTsbiLnYl4hqWAV%2B5i0lZhNg1AEfxo07Q0oFe%2Blytwr%2BtY0ZAJVYnY%2FSvHi1Yb3WGeEAK4319LOiPC%2Ffyv3YKzrrArh9c5A4khQT1nLQTKfs29c4cnwFek9Dp6s5DvJkGKy7sMdaIB4vq60ARLbnRQ3YOx9M%2FP%2BOZ0Oy8Dsll13nu9DVz9PUqGSW%2FquJAvqSaeMjHJhHwFzBZnWTudpsFnir8CyTsSyXJe6tXzaGgVPv5Ae7UXdGj2ym9K3VW6GhiroUz94mP8Dlhou3xpmVWz4jsmuh96qClzuhFdoE3uDffR5rMcPJ6NkpzwSYTQXh2Ahs0tfvUPLoxV1q66jw2A3Nmd6J0dt0t1IcYH6SqkSBO3CHQ%2Fol1g45HHG|ampidL_CLK|clp:2047675

Another great idea, thanks. I'll mull it over tonight and probably go with the driver for sure. Wondering if theres some way to fabricate a mag base/angle read to the block. Concocted a lot weirder stuff than that for home made alignment since there doesn't seem to be a single shop on the West Coast that knows how to work with Cam bolts.

Demonic · May 31, 2021

If you run a 3/8 pipe tap in it to clean it up, be careful not to go too far, Pipe thread needs some taper to seal well, especially the suction side of the pump.

TPG2112 · May 31, 2021

Demonic said:
If you run a 3/8 pipe tap in it to clean it up, be careful not to go too far, Pipe thread needs some taper to seal well, especially the suction side of the pump.

Thanks, I'm pretty sure its just on the first 1/8th of an inch leading in or so. Threads below it look good.

BSB67 · May 31, 2021

The threads on the factory pick-up are NPSM. In the block it's NPT.

You are correct to be very cautious.

Installing a 1/2" pick up is only for the very skilled, IMO. There is no shortage of stories about busting the pick-up boss. And breaking the boss can happen during the drilling, thread cutting, AND installation of the 1/2" pick-up.

TPG2112 · May 31, 2021

BSB67 said:
The threads on the factory pick-up are NPSM. In the block it's NPT.

You are correct to be very cautious.

Installing a 1/2" pick up is only for the very skilled, IMO. There is no shortage of stories about busting the pick-up boss. And breaking the boss can happen during the drilling, thread cutting, AND installation of the 1/2" pick-up.

Plus for what I'm doing, I'd rather not spend the time, effort money making that work.
Thanks for clarifying that threads as well. I've seen it all back and forth but makes sense. Added to the quirks folder in the noggin you only get with fiddlin.
I'll be picking up a 3/8 NPT tap today at Ace and will update. Im gonna try some very light chasing to see if I can get those upper threads to catch and clean up.
I was debating getting a brass fitting of some kind to test it before going to the oil pump pickup which is still 2 days out. Thoughts?

Dave6T4 · May 31, 2021

Don't Hemi engines have a larger oil pick-up tube? I thought big block guys sometimes upgraded their oiling system by enlarging this hole and using Hemi tube?

TPG2112 · May 31, 2021

Dave6T4 said:
Don't Hemi engines have a larger oil pick-up tube? I thought big block guys sometimes upgraded their oiling system by enlarging this hole and using Hemi tube?

It's 3/8 stock still in this engine.

66Satellite47 · May 31, 2021

Slow, careful effort with the tap can work well. Trick is to get the tap lined up correctly and don't try to force the tap. I had one that I had to play with quite a bit to get the tap to line up. Patience is a must.
Edit: Never went to the larger pickup on any of my bracket motors, never had oil pressure issues.

TPG2112 · May 31, 2021

66Satellite47 said:
Slow, careful effort with the tap can work well. Trick is to get the tap lined up correctly and don't try to force the tap. I had one that I had to play with quite a bit to get the tap to line up. Patience is a must.

I'm hoping the fact I'm using an NPT tap with that slight taper may get me settled just deep enough since the damage seems to be right on the top two thread rows.

BSB67 · May 31, 2021

Dave6T4 said:
Don't Hemi engines have a larger oil pick-up tube? I thought big block guys sometimes upgraded their oiling system by enlarging this hole and using Hemi tube?

Correct

383 Oil Pickup Thread Help

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