stevengerard

what is this vent for and is it correct for a 1970 W30 Auto with AC? I have one with this vent and one without it. Never noticed it was on my car in the first place..... very interesting.

joe_padavano

If you are asking about the hard plastic elbow at the opening of the snorkel, that was the fresh air feed for the evaporative cannister. The evap system was phased in during the 1970 model year, primarily for California cars, which is why you have one with and one without.

stevengerard

OK, thanks Joe, my car does not have the evaporate canister, mine was sold originally in Oklahoma so my guess is it did not come with it. I'll keep the one with out it and put this one on ebay as a 1 of 1 rare California emissions only original low-mileage dealer installed non-Lansing OAI base with the special addition plastic elbow starting bid $99,000, maybe the 442 convertible for 169k could use this.

BlackGold

Just to be clear, many 1970 air cleaner bases (OAI or not) have the 1/2" hole in the end of the snorkle. But only those cars with the NA9 emissions option (ie, California cars) got the elbow, hoses, and other equipment (which included not only the vapor canister under the hood but also a multi-port contraption back by the gas tank).

stevengerard

thanks I was looking through the assembly manual today and noticed that it looked like the air cleaner bases were the same part number for W30s and as you mentioned the clip and hose adapter was added if the car had NA9. I also was very confused over the 3 port vacuum switch as it shows it in the engine assembly manual but not in the assembly manual (or the other way around) then I noticed in section 6-1 page 87 a chart that shows what parts are changed when adding AC to a W30 automatic car. The note states you need the vacuum port for a 455 W/AC - chart is titled "to convert 455 AT W30 ENGINE (TT) to C60" very cool, never noticed it before.

bil

Steve-it already has it,being in California! What is the number on the flapper door inside? Are the numbers the same on both bases? Thanks. ---bil

stevengerard

yes as the flapper is a separate assembly piece, according to the manual there are a few bases - i.e. one for 442s with OAI and another base for W30s.

BlackGold

Yup, this is a conundrum for those of us with a '70 W-30 with A/C.

The deal is, for every other engine type, Olds assigned a different 2-letter code if it was going in a car with A/C. But for the W-30, it was type TT regardless of whether or not the car was to get A/C. This means that the engine assembly plant had no idea if the TT engine they were building was going in an A/C car or not.

Why does it matter? Because for every other engine type Olds installed a TVS (the 3-port vacuum switch) if the car had A/C. For all those other engine types, the engine assembly plant could build the engine correctly, with TVS installed. But for the TT W-30 engines, they couldn't possible know. Thus, it was up to the final assembly plant to remove the plug and install a TVS for any TT engine destined for an A/C car. This was probably done in the "engine dress" area of final assembly, not after the engine was installed in the chassis.

So, the big question is: did the final assembly plant really go to this trouble of installing the TVS? If so, were they consistent? I'd love to get information from original owners (or sunsequent owners of unmolested cars) of A/C W-30s who have TVS. If it's not there, it might have been removed by a mechanic when it failed, so that doesnn't prove much. But if TVS is there, that probably means the factory installed it.