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I removed the Crane breakerless ignition system from my '66 small block, along with the 1111069 distributor. The previous owner had it installed and had the distributor recurved for the engine. I removed it and put the original 1111156 distributor in, with the original vacuum advance and set the timing as it was before. The car starts quicker, but is not nearly as quick now, and "pings" going up hill. As much as I like originality, I'm going to put the Crane system back in. If I left the original one in and had a good speed shop recurve this one, could I expect the car to run as good as it did with the Crane system?
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Re: '66 350HP DISTRIBUTOR
Rob,
Short answer: yes, you can get it to run just as well with a properly set up stock system.
I would highly recommend going through the archives and reading up on timing, but I'd map out the car's vacuum characteristics and then make sure the vacuum canister will be approprite for your car. Make sure your current canister actually is functioning. Then when that's done, check the advance curve as best you can. Once you have that info, bring the distributor to a speed shop with a distributor machine and have it curved.
PatrickVice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code. -
Re: '66 350HP DISTRIBUTOR
Pinging has nothing to do with the type of ignition and everything to do with the advance map. If you're happy with the "recurved" distributor simply transfer the weights, springs, and vacuum can the the OE distributor.
What is the number on the on the respective vacuum cans?
DukeComment
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Re: '66 350HP DISTRIBUTOR
Duke,
I was just going to post a message asking if I could do just what you mentioned....good idea...Thanks...Comment
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Re: '66 350HP DISTRIBUTOR
Anyone thought of just changing the ID band? If you are happy with the characteristics of the 069 distributor, why not just switch bands and leave it in the car? I am not familar with the 069 distributor but the only visable differences in all the 63-74 distributors was the addition of the relief hole opposite of the tach coupling.Dick WhittingtonComment
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Re: '66 350HP DISTRIBUTOR
The 069 distributor is '64-'65 365HP, which has the most aggressive OE centrifugal curve ever installed in a Corvette engine. The L-79 curve is slower. But being as how this 069 distributor has been recurved, who knows what the map is. My suggestion would be to test both with a dial back light to see what the centrifugal curve is. Also, test the vacuum advance curve. The numbers on the vacuum cans should cross reference to their specifications. Without understanding the advance map that each distributor provides, you are just bumping around blind in the dark.
L-79s use an 8" vacuum can as did the 30-30 cam engines, but it's more aggressive than necessary.
For L-79 owners who have part throttle or transient detonation when opening the throttle I recommend the NAPA/Echlin VC 1765 can, which is 12". Being as how a properly setup L-79 should pull about 14-15" at 750-800 idle speed with about 25 degrees of total idle timing, a 12" can is sufficient.
Anecdotal evidence indicates that a lot of vacuum cans are defective. Nobody ever pays any attention to them. They could be leaky, sticky, or stuck. They are easy to check with a Mighty Vac or vacuum gage and oral vacuum.
DukeComment
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Re: '66 350HP DISTRIBUTOR
Dick,
I thought of that. I'd have to remove the Crane breakerless module and reinstall the normal point setup from the original distributor...certainly an option. Thanks...Comment
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Re: '66 350HP DISTRIBUTOR
Duke,
Switched the weights, springs and vacuum advance to the original distributor and it runs strong again. The difference between the two vacuum advances was night and day. Thanks...Comment
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Re: '66 350HP DISTRIBUTOR
Can you test the two centrifugal and vacuum curves or at least give me the numbers off the vacuum cans?
It may be useful to all not only that the problem was fixed but how it was fixed.
DukeComment
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Re: '66 350HP DISTRIBUTOR
Duke,
The vacuum advance that was on the 1111156 is 236 16, which I believe is correct for it. The one on the ..69 distributor was recently replaced by the previous owner, and the work invoice shows part#BWEV375.Comment
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Re: '66 350HP DISTRIBUTOR
The '236 16" is the OE vacuum can used on L-79. Does the Borg-Warner V375 have numbers stamped on the bracket? You may have to lift up the dist. cap to see them.
DukeComment
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Re: '66 350HP DISTRIBUTOR
Duke,
I'll look for the numbers when I get in there again.Comment
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Re: '66 350HP DISTRIBUTOR
Duke,
This may be a stupid question but.... I have been restoring my 66 L79 for a few years now and I read these posts constantly and copy the ones that I feel will benefit me in the future.....So in Oct 2003 to Kenny Hancock, you said that an L79 should get an Echlin vc-1810 if not the original GM one.,so I copied it and put it in with the distributor for future reference..Now this post says the vc-1765 ....Is this a newer version ,or a different situation or what.... I am Not trying to be a wise guy !! I am just trying to determine which one I should get. Your "word" is my "law " and so far ,I probably have ten of your posts tucked away in various places, but now I have two different #s For the same application.Which one do I need?
Thanks in advance
JimComment
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Re: '66 350HP DISTRIBUTOR
The basic rule for vacuum can selection is that it should provide full vacuum advance at no less that 2" below typical idle vacuum with the proper amount of total idle timing, which is in the range of 20-26 degrees for medium performance engines and 26-32 for SHP/FI.
Since the 30-30 cam engines only pull about 10" they must use the 8" can. L-79s also used the 8" can as OE, but since they pull about 14" at idle, it's more aggresive than necessary, and could cause part throttle detonation or transient detonation - a short period of detonation when throttle setting is increased.
If the above situation occurs, then the VC1765 12" can can be used as an alternative. There is sufficient vacuum to keep it pulled to the limit at idle, but it should mitigate a part throttle detonation on L-79, if part throttle detonation is a problem.
That's why I'm trying to figure out the two spark advance maps on Rob's engine.
BTW, during judging, a non-OE vacuum can does not appear to loose any points since the JGs don't say anything about the stamped numbers. You can see the numbers on an OE vacuum can, but on the current replacements, the number code appears to be stamped farther down the bracket and are covered by the dist. cap.
Current replacements have the same phyical appearance, so the only way to check if a can is OE or a correct OE replacement is to look at the numbers, but since the JGs don't say anything about the numbers, they are not judged.
DukeComment
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Got it ! *NM*
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