C-3 & K66

[Donald O.]

In looking throuh a 71 AIM I don't see the K66, or transistorized ignition, listed. I thought that it was available through 1971. Am I wrong? When did tis option end.

Don

[Terry M.]

Re: C-3 & K66

There was no K66 after 1969. K66 is the add-on transistor ignition system. After 1969 transistor ignition was a part of the LT1 engine option in 1970 and 1971 and a part of the LS6 engine option in 1971.
So while it is correct to say that the last year for the transistor ignition system in Corvette was 1971, the last year for K66 was 1969.
Always splitting hairs. :-)

[Donald O.]

Re: C-3 & K66

Sooooooooooo Terry,

Then in 72 all engines were point/condensor type until the HEI began in 75? And the HEI continued until the distributorless in the C5?

Don

PS
When did the hot watwer shut stop getting installed at the factory? It isn't shown in the 71 AIM either.

As always, thanks in advance

[Terry M.]

Re: C-3 & K66

Yes Donald, all 1972 Corvette engines used the points/condenser (Kettering system) ignition. I am not sure when HEI started, so I can't address that part of your question, but all Corvettes used the Kettering system from 1972 until HEI was installed.

Water shut-off depends not only on the year of the car, but whether C60 (air conditioning) was installed, and I think the engine size as well. My best recollection is that when I looked for the install of that valve in the AIM, I found it in the C60 section. Others will have to address that issue, however. It might be worth starting another thread exclusively for that subject.

[Craig S.]

Re: C-3 & K66

I think the HEI started in the 75 model, I know my 74 still had the Kettering points system....Craig

[Duke W.]

Re: C-3 & K66

The first year for HEI was 1975 and the primary motivation was emissions and to keep a misfiring Kettering ignition from overheating the converter. I think it was used across the board in all GM engines from that point, even though a couple of 1975 engines did not have catalysts.

It's interesting that the TI was not available after 1972 with any Corvette engine, either bundled with the engine option or as a stand alone option. The system was used on the ill-fated 1974 Cosworth Vega engine. The amp and harness part numbers were the same as early seventies Corvettes, but it had an special four pole mag pulse distributor.

This configuration failed the 50K mile EPA durability test due to burned exhaust valves, so Chevrolet abandoned bringing the CV to market in 1974. Emission control was primarily with ignition timing. The dist. had what looked like a vacuum advance can, but it actually RETARDED the timing. No wonder the valves burned!

Chevrolet re-engineered the entire emission control system for '75, and since a catalyst was added the HEI had a more conventional igntion map, which was just a centrifugal advance - no vacuum advance or retard. The engine was the cleanest ever certified by EPA at that time, and it didn't burn valves.

Duke

[Terry M.]

[Jim T.]

Re: C-3 & K66

You are correct, 1975 was the first year of HEI ignition for the Corvette. In 1975 and later Corvettes electronic tacks replaced the mechanical, no more tach gear failures.