Pyrometer/Thermocouple Fitment

[crash-harris]

Got my Stewart Warner thermocouple in this week. Waiting on the gauge (in back order) and the extension (shipping directly from SW). But I have a concern if it's going to fit or not. When looking at the probe and my drivers side exhaust manifold, I'm wondering if the probe is too long. I planned on drilling straight up from under the truck if I can, but I'm worried about it.

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Probe looks to be 3 1/16" from the nut. I know that since it's NPT it won't make it in that far, but is 2 3/4"-3" to long for the IDI exhaust manifold? I'm planning on doing the install while I have the front clip of the truck to replace the damaged body panels from the accident.

 

[Clb]

Darn good question
I can't recall measuring any I installed, seems like 2 1/2-3" is what I'd of said....call s-w yet?
I think the id is a good 3" back there at 8????

 

[sjwelds]

Hmmm. On mine there were two pieces. Let me see if I can explain.

So you drill and tap the manifold. Then there's a fitting that screws to it. Then the probe itself slides through the fitting and you tighten a nut on fitting to hold the probe at whatever depth you desire. It's like a compression nut, similar to a die grinder mandrel, that holds the probe itself in place.

So, if you're looking at a picture online, they may have assembled it for you to where it looks like it's all in one piece, but in reality is adjustable. Don't know though, different brands may be different.....

Also, I would doubt that the manifold is 3" ID anywhere in the system....

Edit: crash, I can't see your pic because my web filter blocks photobucket. So the pic is probably worth the proverbial 1000 words...

 

[IDIoit]

mine was about that long, but it had a AN style nut, with a fitting to go to NPT.
VDO gauge.
so minus about 3/4"

if you have a turbo, i suggest you take the manifold off.
or atleast take the cross over off and start it up for a second to blow any metal shavings out.

 

[crash-harris]

Engine is N/A.

Sherwin, the SW one that I have is one piece with no jam nut or anything of the like. The probe itself measures about 2.5" from the base of the threaded fitting and the threads are just under another 1/2".

I guess I could get another stainless NPT female/male fitting of the correct size to use as a spacer?

 

[crash-harris]

Small update. It does indeed have a 2 piece fitting on it, but when tightened it can only sit in one spot, so the problem remains.

Also turns out that I wasted money on a 1/8 NPT tap and bit since the threads or much larger than 1/8 NPT. Maybe more like 1/4-3/8 NPT. Guess I will be calling then tomorrow to let them know since they don't list any useful information on their site other than the lead wires are 17" long. This is already turning until a PITA and I haven't even begun to start the project.

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[riotwarrior]

Could see about shorter probe abd exchange it. Send it all back for refund or inquire if there is a way to bend probe with a wide radius 45 or so sweep???

 

[crash-harris]

SW only makes one thermocouple. Would adding another NPT adapter between the thermocouple threads and the manifold work out (same size female to same size male)? I'm guessinv it's made of stainless steel, but could be chrome plated brass. I'm new to thermocouples in general.

 

[riotwarrior]

Could you MARK the placement on manifold then remove manifold and have some tpe of machined deeper bung TIG welded to the manifold?

Stacking adapters could work...but finding a pyro with much shorter probe sounds like best bet and sell that one to someone who wants to weld a bung into a down pipe on a turbo engine....

JM7.3CW

 

[crash-harris]

I'm actively trying to avoid removing the manifold, or anything else that has a gasket. If I do that I'll end up tearing the entire thing down.

Been thinking about possibly getting another t/c, but it seems that all the ones I can find connect differently than the Stewart Warner t/c and guage. Wouldn't having it bent damage the probe internally?

I did find a listing on another site stating that the threads are 1/4 NPT. I'll verify with SW tomorrow.

 

[riotwarrior]

Do oil cooler now btw....

 

[crash-harris]

Luckily it was done just before I bought the truck in April, else I would

Only leak the truck had was from the front main. After the main seal additive thread I posted, I put some in when changing oil/filter a few months ago and no more leaks

If I had a cooler from a turbo 7.3L I'd do it when the clip comes off, but I need to do injectors, pump and return lines first. If not for getting hit last month and laid off in the same week I'd be collecting those.

 

[fsmyth]

If the fitting is 1/4" NPT, get a 3/8" brass adapter. install it.
That will take about 1/2" off. 1/2" to 3/8" should take off a bit more.
The probe tip SHOULD be in the center of the exhaust flow, but I
have found that there is not a great deal of difference. As long as
it is in, the probe itself will heat the tip. Just slows response a bit.

 

[crash-harris]

I was thinking about a 1/4 to 3/8 adapter, but I did find stainless 1/4 to 1/4 npt fittings. Thinking about getting 2 of those, just in case. Still going to call Stewart Warner today and get some specifics and see if they have an spacer fitting for it or if putting it in a tube bender would damage the filament. I could totally hit it with a brake line bender. Now my question is, what is everyone else's fittings made of?

Stainless, brass, or chrome plated brass?

 

[DaveBen]

Don't bend the sensor. You will damage it. I put mine in the 2 & 3 cylinder port. I don't think my sensor was as long as yours.

Dave