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"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 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(ish +/- I guess) 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"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 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: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback


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