Did a complete tune-up on my recent purchase of a '64 C10 that has a '70 250 six cylinder. Replaced plug wires, plugs, points, and cap. Forgot what it was like to set points at a .019" gap. What a PITA. Kinda reminds me of mortar fire... on the 3rd attempt you dial it in. I used a dwell meter to check my work. Specs call for 34* dwell. After 4 attempts, the closest I got was 32* dwell. My other rides have Pertronix or MSD. GM 1960's V8's had a window to adjust the dwell with an allen wrench on the dizzy. Why doesn't the 6 cyl. Is it because the cap is too small? Summit doesn't offer an electronic/pointless dizzy. Just grin and bear it and look at it has a labor of love? I'd love to convert to something else. Got any ideas?
http://www.amazon.com/PerTronix-91162A-Ignitor-Adaptive-Cylinder/dp/B000JUXGEI PerTronix 91162A Ignitor II Adaptive Dwell Control for Delco 6 Cylinder with Vacuum Advance Thats for a 70 250
http://www.summitracing.com/parts/dui-61720bk/overview/ http://www.summitracing.com/search/make/chevrolet/engine-size/4-1l-250/engine-family/gm-inline-6-cylinder/department/ignitions-electrical/part-type/distributors/year/1970
Check your distributor shaft for excessive side play. Older 6 Cyl. distributors tended to have two bushings, one at the top and one at the bottom of the housing. Yours is new enough that it might have just a single bushing in the center. These tended to wear in an hourgl*** shape and could get quite sloppy. As a result the dwell can be all over the place and the timing gets erratic depending on RPMs. Get a new housing if possible or maybe Bubba can re-bush the one you've got. http://www.jalopyjournal.com/forum/member.php?u=15923 Then your tune-ups will be easier and last longer too.
Thanks Gimpy, I must have not done the search properly. Appreciate the available options. I'm at a crossroads. This engine is suppose to have only 5,000 miles on a rebuild. If the PO lied to me I'm, thinking about a 327. I am driving roundtrip to Los Angeles, this weekend. I will know when I get back what the plan of performance improvement will be.
I'd just get the distributor, and some matching wires. You already own it, and it is already in there. If the compression is good, and it is not full of sludge, run it.
How do you check a distributor shaft for excessive side play? The dwell meter holds at a steady 32* while engine running. Anything I should check for?
Yes. I've picked them up at swap meets for $5.00....it's not for a V8, so how can it be worth anything? I would suggest using an adjustable vacuum advance with any H.E.I., as they had way too much from the factory for an older engine.
...And it might be more evident with the distruibutor pulled and chucked up in a vice. This will disengage the dist. gear from the cam.
Good news. Distributor is fine. No wobble or side play. Dwell holds steady. Bustedwrench you got me thinking about installing a HEI. There is this GM 1977 HEI for $29.95, locally for a 250 or 292 6 cyl. Summit does not advertise an adjustable vacuum adv canister for a inline six. Where do I get one?
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