What thread size?

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What thread size?

Postby BoostedSunbird78 » Fri Mar 31, 2017 11:56 am

Does anyone know the thread size for the oil pressure sender that is on late 70's gm engines? Is it npt or is it bspt? (P.s. I got a 1978 pontiac sunbird with the 2.5 iron duke... a low budget turbo project.)
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Re: What thread size?

Postby spencerforhire » Fri Mar 31, 2017 3:44 pm

1/8" NPT
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.45@146.19)(6.01@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Re: What thread size?

Postby Monza Harry » Fri Mar 31, 2017 3:58 pm

Welcome aboard Boosted! Sorry I some how missed this thread. I don't know for sure, but as I recall it should be easily visible [if yours isn't the cross flow head] on the passenger side of the engine near the lifter cover. But all of these at that time would have been NPT on that engine [based off of the "Chevy II" which is a short Inline 6] and I remember those as 1/8NPT. 1/8NPT tap drill is "Q" about 21/64 so the outside of the switch will measure about 3/8" dia. or slightly larger. 1/4NPT tap drill is 7/16" so its' outside dia. will be just over 1/2" Sorry I cant give you an exact as the switch isn't usually made from pipe and will have a rolled thread so it could be made to a number of sizes. Harry
Harry Bitched wrote: Damn it Spencer you Treed me again! :censored: :cuss: :bang:
I'm not a hoarder I'm a preservationist 78 Monza Spyder (Soon To Be 2+2 with Spoilers)
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Re: What thread size?

Postby BoostedSunbird78 » Fri Mar 31, 2017 4:25 pm

I'm having problems sealing the fitting going into the block. How should I seal it properly?
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Re: What thread size?

Postby spencerforhire » Fri Mar 31, 2017 6:34 pm

How to seal the sender has an "it depends" answer. If it's the standard h-body 3 wire fuel pump control one, go ahead and use the sealant of your choice; liquid pipe sealant, teflon tape, or even rtv. Ditto for a mechanical gauge line adapter. But if it's a single wire "idiot light" sender, they are designed to be installed dry so there is a good ground connection to the block.
Whatever it is, it has to be TIGHT.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.45@146.19)(6.01@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2356
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback


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