What's the best way to fix aluminum intake threaded hole for temp gauge sending unit?

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gtgto

gtgto

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I made a purchase of an Edelbrock LD340 intake before I went to Carlisle and saw I did pretty good on the price I paid compared to what they were asking at Carlisle. The one I bought was advertised as unmodified and it pretty much isn't. What is modified is the threaded hole for the temp sending unit. There is pretty much no threads let to grip and any force tightening the sender just spins. What is the best option to fix this once and once only . The intake is on the car and I would rather not take it off. I've thought about Heli coiling it or maybe putting a reducer fitting in 1/2 male to 3/8 female after drilling out to 1/2 inch and tapping the hole. Half assing it with thread tape and sealer did not seal it up.
 
You will need to oversize the hole and install the proper threaded pipe bushing or send it off to a machine shop and have the hole tig welded, drilled, and retapped.
 
Figure out what size hole it is now, and that will tell you what Threaded inserts are available.. I recommend Timesert they are a solid threaded insert unlike helicoil with the spring.
 
Pipe thread, no?
You'll need to drill and tap to the next bigger size pipe thread and get a reducer. Find the reducer first.
I don't know of a helicoil for a pipe thread. Maybe there is a time sert.
Either way, your drilling and tapping a bigger hole.
 
Big.J.007 said:
Figure out what size hole it is now, and that will tell you what Threaded inserts are available.. I recommend Timesert they are a solid threaded insert unlike helicoil with the spring.
Click to expand...


It doesn’t mean they don’t exist but I’ve never seen a helicoil for pipe thread.
 
The end of the sensor must be in the flowing hot water, in order for the gauge to read right.
If you install that temp sender into a stand-off pipe, the water in the pipe will be cooled by the surface-area of the pipe, and read cooler than the water passing by at the bottom of the pipe. and so, your gauge will read erroneously, all the time.
 
Whatever you end up doing don't use a standard Helicoil. Having a round aluminum slug made, bored and tapped to the proper size would be a really good repair. The manifold would obviously have to be bored to insert and weld the slug, it would be a great repair. It is a shame how many aluminum bolt holes and coolant holes are damaged because installers don't go the extra step to properly coat the pieces before they are installed.
 
I started typing out a suggestion but first could you post up a picture of the hole you are dealing with so we can lay out the best plan. Nice pictures and several of them.
 
https://www.grainger.com/product/60...p.ds&msclkid=63dd3e1009cc140df1f15887daa036ad You could use a simple coupler like this one with the correct thread for your slug. As AJ mentioned you should trim it to the correct length so the sensor is at the correct depth. Bore the manifold to the correct size and drop in your slug and weld. Pittsburgracer makes a great point on how much real estate you have for these ideas.
 
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AJ/FormS said:
The end of the sensor must be in the flowing hot water, in order for the gauge to read right.
If you install that temp sender into a stand-off pipe, the water in the pipe will be cooled by the surface-area of the pipe, and read cooler than the water passing by at the bottom of the pipe. and so, your gauge will read erroneously, all the time.
Click to expand...
Stand off pipe? Did I miss something?
 
gtgto, Not to change the subject but the Duster in your avatar is identical to mine back in 1974.
Basic 340 3 speed rubber floor mat.Plain Jane. Thanks for the memories !
 
toolmanmike said:
Stand off pipe? Did I miss something?
Click to expand...
Some guys will install two or more adapter bushings, into a coolant port on the intake, to make their aftermarket parts fit together. This raises the sensor well out of the coolant's flow-path and is the equivalent of a short pipe.
With the sensor thus in stagnant water, inside a pipe that is radiating it's heat into the surrounding air, it does not properly indicate the temp of the water that is flowing just an inch or so away. The difference can be dramatic.

Add to that, say, a brass, or iron plumbing bushing, in an alloy manifold, and there's another variable to deal with.
And then there's grounding.....
IMO, weld up the hole like you and others have suggested.
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I have this other opinion, namely; trying to tune an engine in the which the coolant temp is ever-changing, like say with electric fans, is an exercise in frustration. I imagine, tuning an engine to an erroneous coolant temperature, might also be frustrating.

Plus, let's say your coolant is at 210, but the gauge is reading 190. You might be lulled into thinking that everything is ok. But, you have no temperature headroom, if for some reason the coolant-temp actually rises 10 or 20 degrees.

Or how about, when your fuel starts to boil on a hot day, what's the first thing you do? IDK about you, but Ima checking my temp gauge. If it's telling me 190, Ima thinking that's fine and I start dissecting the fuel system, maybe wasting hours on that, until I recheck the daymn coolant temp. and the liquid is actually much hotter.
How do I charge my customer for the hours I wasted?
I don't, I learned my lesson;
Put the sensor into the moving water, and verify the gauge with an IR gun. Then make sure the gauge is reliably consistent.
------------------------------------------------
One of my pet peeves is that guys(streeters) will spend outrageous amounts of time and energy
1) trynta run 20 degrees of idle-timing, or
2) the last two degrees of Power-timing, or
3) looking for 1psi of fuel pressure, and
4) their engine is inhaling hot underhood air,
5) yet, they don't spend hardly any time studying their coolant temp. until the engine overheats and pukes it out.
end rant.
 
AJ/FormS said:
Some guys will install two or more adapter bushings, into a coolant port on the intake, to make their aftermarket parts fit together. This raises the sensor well out of the coolant's flow-path and is the equivalent of a short pipe.
With the sensor thus in stagnant water, inside a pipe that is radiating it's heat into the surrounding air, it does not properly indicate the temp of the water that is flowing just an inch or so away. The difference can be dramatic.

Add to that, say, a brass, or iron plumbing bushing, in an alloy manifold, and there's another variable to deal with.
And then there's grounding.....
IMO, weld up the hole like you and others have suggested.
--------------------------------------------
I have this other opinion, namely; trying to tune an engine in the which the coolant temp is ever-changing, like say with electric fans, is an exercise in frustration. I imagine, tuning an engine to an erroneous coolant temperature, might also be frustrating.

Plus, let's say your coolant is at 210, but the gauge is reading 190. You might be lulled into thinking that everything is ok. But, you have no temperature headroom, if for some reason the coolant-temp actually rises 10 or 20 degrees.

Or how about, when your fuel starts to boil on a hot day, what's the first thing you do? IDK about you, but Ima checking my temp gauge. If it's telling me 190, Ima thinking that's fine and I start dissecting the fuel system, maybe wasting hours on that, until I recheck the daymn coolant temp. and the liquid is actually much hotter.
How do I charge my customer for the hours I wasted?
I don't, I learned my lesson;
Put the sensor into the moving water, and verify the gauge with an IR gun. Then make sure the gauge is reliably consistent.
------------------------------------------------
One of my pet peeves is that guys(streeters) will spend outrageous amounts of time and energy
1) trynta run 20 degrees of idle-timing, or
2) the last two degrees of Power-timing, or
3) looking for 1psi of fuel pressure, and
4) their engine is inhaling hot underhood air,
5) yet, they don't spend hardly any time studying their coolant temp. until the engine overheats and pukes it out.
end rant.
Click to expand...


I just read the part that starts with “I have this other opinion” part.

Ya nailed it. HARD. With a sky scraper sized hammer.

Engine coolant temp is important but like you said, it changes your tune up. A lot.

Good post old man!
 
I would NEVER go buy the really really thick grey teflon tape and wrap it like ten times when you're only supposed to go five....
 
Grounding? My bad. I assumed a mechanical gauge, not electric. Probably cause I have never used an aftermarket electric water temp gauge.
But I agree, the temp sender has to be in the coolant to read right.
 
Drill the taper out, machine a larger brass bushing to a press fit and tap in after Loctite.

Pontiac does this with their heater hose barbs and your freeze plugs or frost plugs work the same.
 
There is a pipe thread dope called expando. “ The problem solver”
It is in a powder form you mix up a little bit with water and apply to threads and assemble. No need to tighten.
Let it set up 24 hours
It’s impressive stuff.
 
The factory senders are 1/8" pipe thread. You may be able to chase it with an 1/8" NPT tap. Expando, maybe red Gasola - the old varnish type will seal it. Lampwick is hard to do with 1/8 NPT. I would tap it to 1/4" pipe thread - 1/4 NPT and run a brass bushing with Expando or Red Gasola.
 
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