anthonyP

Did 1970 W-31's have TVS solenoids from the factory? Were they installed in automatic or stick equipped W-31's?

If no W-31's were equipped with a TVS solenoid, what type of plug was installed at the factory in the aluminum intake manifold?

BlackGold

Neither the automatic nor manual W-31 in 1970 had a TVS. In fact, the only A-body Olds with a 350 that got a TVS in 1970 were those with air conditioning (an option which was not available with the W-31).

Engines without TVS received a hole plug at that location. It was part number 103880. It has pipe (tapered) threads and a square head.

anthonyP

Thanks again Brian for your help. My friend with an automatic '70 W-31 could not determine if his car should have a TVS solenoid.

My brother's Rallye has air conditioning and came with a W-31 intake that was installed by the previous owner. Oddly, the intake has a square recessed head plug instead of a square head plug fitting.

Since the plug might have been there since manufactured, and does not want to come out, any suggestions how to remove it without damaging the intake so a TVS solenoid can be installed.

BlackGold

You can try some penetrants. Otherwise, heat will probably help remove the plug. But I'm not an expert on such things.

For the record, the TVS is a switch, and the TCS is a solenoid.

joe_padavano

Beat me to it, Brian.

A solenoid is electrically operated. That's the Transmission Controlled Spark solenoid valve, for example. The Thermal Vacuum Switch is a mechanically-operated vacuum switch with no electrical connections. I do realize this is a little confusing, especially since the two units were combined into one housing for the 1971 model year, so you do have both a Thermal Vacuum Switch and a Transmission Controlled Spark solenoid in one housing.

anthonyP

Thanks Brian and Joe.

Always did confuse the switch and solenoid definitions.

Tried the penetrates, but no luck. Hopefully, applying heat will help coax the plug out.

jensenracing77

Try to heat mostly the aluminum and not the plug. They will both get hot but the aluminum should be hotter.

anthonyP

Thanks for the tip Eric.

mownhoj

Thanks for that clarification you guys. Joe knows I had trouble with the name of 'the F-shaped thing" (TVS).

Someone must have decided not to use this system when they put the Edelbrock carb and manifold on the car I now own. I have all the pieces except the TCS in order to get the system going again, do you guys know where I can get a TCS? I can't find one.

Thanks!

BlackGold

A used original will cost a pretty penny, probably well over $100. If you're lucky that will include the bracket. Probably not.

Why do you want a TCS? For the sake of originality? Fine, then you'll have to pay up. But there's no other reason to want a TCS. It removes spark advance in every gear except high. It exists for improved emissions, not performance and not cooling.

oldspackrat

Anthony,
I found one today but did not get a picture of it. I'll shoot for tomorrow.

anthonyP

Thanks Scott. No rush, whenever it is convenient for you.

Anthony

mownhoj

That is really good to know, thank you. I think I have learned from this post, my really long post called Can't Take the Heat, and another post I put up asking about gauges, that I might be obsessing a little too much over my temperature gauge. I was interested in hooking up the TVS since I have the switch installed and I figured it might help a little with the cooling. The car has ac (not working, so I don't even have a belt on it at the moment), and I understand that the TVS should give full advance to the distributor when the ac is turned on. I would like to get the ac going next summer also so that was another reason for wanting to hook up the TVS.

So, if I understand you guys then, the TCS is not related to the TVS then? I thought one of the hoses from the TVS went to the TCS, is that incorrect?

joe_padavano

One more time...

Transmission Controlled Spark is an early emissions control system that disables vacuum advance in lower gears to reduce NOx emissions.

The Thermal Vacuum Switch is designed to switch the distributor from a ported vacuum source to straight manifold vacuum if the temp gets too high. If you are running straight manifold vacuum to the distributor already, you DO NOT NEED the TVS.

TVS is related to TCS only in that if the TCS causes overheating at low speeds due to no vacuum advance, the TVS will bypass it if overheating starts.

On the 1970 cars, these were two different devices. On the 1971-72 cars they were integrated into a single device.

mownhoj

I'm not running straight manifold vaccum

kennethlaw442

anyone know where you can find the one for the 71-72 olds ? the 2 combinded

briane

Is the pipe plug for the TVS hole brass or plated steel? Is the square head machined or as cast?
Thanks.

70Post

briane - original plug would be steel, not brass. I assume they were plated but not sure if the typical "silver" finish or the yellow/gold finish. I suspect they were in the "silver" type color/finish.

As far as the square head on the plug....that area is all smooth but it wasn't a machined finish (no machining marks) but a smooth finish on whatever tooling was used to make the plugs and thus the smooth finish on the plug.

I'll try to post a pic of an original still in the intake.

EDIT AND ADD: Pic attached showing original '70 version. The darker area at the bottom of the plug isn't anything to be concerned with...it's just some old penetrant sitting on there. Note the slight "circle" head marking on the square portion.

It's hard to tell but the squared off area is what I consider smooth.....not a rough cast finish like you may have seen on iron pipe plugs at Lowe's, HDepot, etc.

briane

Thank you for the quick response, the photo is extremely helpful. Now I'll have to locate a plug at close to that as possible. Apparently I don't need these NOS TVS units I collected!

70Post

You would think Inline Tube would have/sell this plug as focused as they are on these smaller "detail" items but I don't see it in their paper catalog.

You might check with them and/or check online in their "new parts" area.
Could be they sell it on ebay under their Motorcity Muscle name (not sure on the exact name they use on there).

AMK Products sells the plug (AMK PN B-10661 - package of 2 plugs for $3 - they typically have a $30 minimum order but you can probably get to that fairly easily) BUT theirs is finished in yellow zinc (ie gold) finish and has a red sealer already applied to the threads. The sealer can be removed with a solvent and you may be able to remove the yellow tint or have it replated if you want a different color/finish. Their plug does have a sort of "circle" head marking but on their plug it's more of a slight circular depression (PIC of AMK-sourced plugs below).

briane

Thank you for the additional information. I'm wondering if I can find one in 304 of 316 stainless with the appropriate contouring of the square head and it's transition into the cylindrical threaded portion. Looks like they all the stainless plugs come from one of perhaps two places in China.

70Post

I may do some "digging" since you mention stainless. Not exactly the same coloring/appearance but that option would be nice since there would be no deterioration in the surface/color, etc over time compared to a plated part.

I "made" my own stainless heater hose fitting for the back of the '70 non-AC car intake a few years ago.....took some doing but it's not a bad option and I was thinking the same thing as you when I made it.

briane

This is a possible stainless steel TVS plug alternative I found, purchased on Amazon. Seems to match well the original in 70Post's photo above, with regards to the square head width to height aspect ratio. Also the contour from the threaded portion to the square head is mostly correct. Some of the others I looked at had a too tall of a square head or a flat transition from the threaded area to the square head.

This one, however, is too smooth compared to the cast looking original (maybe it could be roughened up by blasting?). Interesting this one is from Japan, not China.