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LCOX Samba Member
Joined: December 21, 2009 Posts: 56 Location: Pinnacle
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Posted: Fri Dec 01, 2017 7:38 am Post subject: oil pressure switch threads in case stripped need advice |
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The threads in the engine case where the oil pressure swicth screws into on my type 4 engine are stripped badly and the switch won't tighten down at all.
-I bought a new oil switch and the info on the box it came in stated that the thread size of the switch are 10mmx1.0 pipe thread.
-I can't find this size in a heli coil kit here locally. Does any one know the correct size tap, drill, and insert size to repair this properly. Can a standard 1/4inch or 1/8 inch pipe thread tap be used. The hole appears to be too big to use a 1/8 pipe thread tap. As a last resort can it be glued in? Don't want to do this if possible. Any advice appreciated. Thanx L |
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Busstom Samba Member
Joined: November 23, 2014 Posts: 3853 Location: San Jose, CA
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Posted: Fri Dec 01, 2017 7:56 am Post subject: Re: oil pressure switch threads in case stripped need advice |
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You could evaluate these options. It seems the missing element from these options is "pipe" thread (which in the US implies "tapered"). However, BSP (British Standard Pipe) is NOT tapered, which in my experience is useless for making a tight seal, but I do believe your oil pressure switch threads ARE tapered, so these items below may not be appropriate, but a quick search turned them up.
https://www.amazon.com/Thread-repair-helicoil-damaged-thread/dp/B01MCZHOX7
I know a hundred bucks is pricy, but... https://www.mechanicstoolsandbits.com/time-sert-1010-m10-x-1-0mm-metric-thread-repair-kit.html
Edit: Thinking outside of the box...you know, some guys run a remote line to this sender, so that the engine vibration isn't shaking the crap out of it. I'd guess one alternative solution is to tap the case with an oversize "pipe" thread, then reduce that somewhere along the remote line connection before it gets to the sender, if you were to go this route. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21519 Location: Oklahoma City
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Posted: Fri Dec 01, 2017 8:24 am Post subject: Re: oil pressure switch threads in case stripped need advice |
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Busstom wrote: |
You could evaluate these options. It seems the missing element from these options is "pipe" thread (which in the US implies "tapered"). However, BSP (British Standard Pipe) is NOT tapered, which in my experience is useless for making a tight seal, but I do believe your oil pressure switch threads ARE tapered, so these items below may not be appropriate, but a quick search turned them up.
https://www.amazon.com/Thread-repair-helicoil-damaged-thread/dp/B01MCZHOX7
I know a hundred bucks is pricy, but... https://www.mechanicstoolsandbits.com/time-sert-1010-m10-x-1-0mm-metric-thread-repair-kit.html
Edit: Thinking outside of the box...you know, some guys run a remote line to this sender, so that the engine vibration isn't shaking the crap out of it. I'd guess one alternative solution is to tap the case with an oversize "pipe" thread, then reduce that somewhere along the remote line connection before it gets to the sender, if you were to go this route. |
Its not necessary to spend $100 on the time-sert "kit".....for installing the time-sert insert....in this application. I. This case.....you can notch the top of the insert ....simply apply lock-tite and recess the insert by about 1/2 thread below flush and then lightly peen the case material into the notch. You can install it with a bolt.
This is a lightly loaded thread. The inner swage lip can be done without if need be. Ray |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50351
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Posted: Fri Dec 01, 2017 9:21 am Post subject: Re: oil pressure switch threads in case stripped need advice |
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This is a dangerous repair as even the smallest chip of metal is going to destroy the main bearings should it fall into the hole. I would fill the bottom of the hole with a thick grease and then use grease on the drill and on the tap. When done you need to carefully scoop out the grease being 100% sure that no metal is left down in the hole.
1/8 pipe and 10x1mm are very close to being the same diameter and tread pitch. People frequently use senders that are mismatched to the threads and mostly get away with it.
This might be a good place to use something like Loctite's thread repair compound. Have no experience with this product myself. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Fri Dec 01, 2017 12:05 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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You might try this to help keep crap out of your oil system.
You are going to need to cut new threads into the case. Off hand I don't know what size that would be though. Trying to glue something in place is just asking for trouble. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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surfbus23 Samba Member
Joined: July 21, 2016 Posts: 383
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Posted: Fri Dec 01, 2017 2:36 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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What is "this"?
aeromech wrote: |
You might try this to help keep crap out of your oil system.
You are going to need to cut new threads into the case. Off hand I don't know what size that would be though. Trying to glue something in place is just asking for trouble. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76938 Location: Sneaking up behind you
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Posted: Fri Dec 01, 2017 2:50 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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surfbus23 wrote: |
What is "this"? |
It pressurizes the oil passages so any debris is blown out. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Fri Dec 01, 2017 2:52 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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He's suggesting you find a way to keep filings out of your oil passages so they don't end up in your bearings. He is using compressed air. Some folks use a glob of grease, other folks take the engine apart and don't risk it at all. Some mechanics who do it for others gamble that the owner will never know that the bearing failure 5,000 miles later is due to the filings that ended up in the oil passage then the bearings when tapping that hole for new threads. I don't know what I would do if that stripped thread thing happened to me. It is not a happy full of joy moment. Probably I would look to see if the threads went deeper in the case and I could use a small extension and hose to a sender - otherwise I would be one of the folks who pulled the engine and split the case to fix it. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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surfbus23 Samba Member
Joined: July 21, 2016 Posts: 383
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Posted: Fri Dec 01, 2017 3:02 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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You mention a bearing failure but after some amount of time. Say you were to get a shaving down this thread. Would an oil change not be helpful in removing it? |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76938 Location: Sneaking up behind you
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Posted: Fri Dec 01, 2017 3:08 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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surfbus23 wrote: |
You mention a bearing failure but after some amount of time. Say you were to get a shaving down this thread. Would an oil change not be helpful in removing it? |
No, since dumping the oil doesn't mean you flushed out all the passages.
20 years ago I have a valve spring break and the chromoly pushrod chewed up the aluminum rocker ark. I dumped the oil and the oil filter and found metal shavings in the inlet side of the filter and none on the outlet. The oil looked clean. I then replaced the oil filter and filled the engine with kerosene. I ran it for a few seconds and then dumped the kerosene and the filter. I found some aluminum on the inlet and none on the outlet. I did it again and found a little more on the inlet. On the 3rd time I put oil in and drove it for 50 miles and dumped it again. I found no aluminum in the filter. I put in fresh oil and drove the car doing regular 3000 mile oil changes.
20,000 miles later, the engine failed do to a seized valve guide. I did a post mortem, and the bearings and journals looked OK. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50351
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Posted: Fri Dec 01, 2017 4:50 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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surfbus23 wrote: |
You mention a bearing failure but after some amount of time. Say you were to get a shaving down this thread. Would an oil change not be helpful in removing it? |
The oil sender location is post filter so that anything that goes down the hole is going to end up passing through the main bearings. |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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Posted: Fri Dec 01, 2017 6:15 pm Post subject: Re: oil pressure switch threads in case stripped need advice |
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It is just a tricky fix. Do what it takes to keep the shavings out of the bearings/oil passages (air pressure in the oil filter and filling below the tap with grease and a couple of oil changes) and you should be OK. Then keep an eye on it. Drive it. |
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