Hi Tom,
Yikes, you mean total advance should be 31 BTDC?? I could of sworn
that it was 35BTDC....in your dist FAQ... That number is the total advance
regardless of type of car? My Solex carb/cam non-smog dist 69 2000
seems to be running pretty good with about 21 deg at idle and 33 at max
advance.
Daniel 69 2000
At 1:52 PM -0500 6/11/00, Thomas Walter wrote:
>Rob,
>
>Stick with the 16BTDC at idle.
>
>Confirm you do not have more than 31 BTDC at 4,000 rpm
>with vacuum disconnected.
>
>TWO ADDITIONAL COMMENTS:
>
>Tom - How does 16 + 7.5 = 31?
>
> Uh good point. 16 degrees is at the CRANKSHAFT.
> The distributor rotates only ONCE for every two
> crankshaft rotations, so the distributor advance
> cam is in "distributor degrees, so you have to
> double it to change is to crankshaft degrees"
> So 16 + (7.5 * 2+ = 16 + 15 = 31
>
>Tom - If I set my "smog distributor" with a 17.5 cam to
> a maximum of 30 degrees at 4,000.... doesn't that
> mean my idle setting would be around 5 degrees
> ATDC (AFTER TOP DEAD CENTER) and not at TDC?
>
> Correct! This will also cause the engine to run
> much hotter in stop and go traffic... I'd recommend
> changing to the "early" cam, weights, and springs.
>
> Problem with setting it to TDC, and having worn slots
> is the distributor may actually advance a total of 40
> degrees. Running that much advance while charging up
> hills may do some damage.
>
>It is NOT UNCOMMON to find all sorts of problems in the
>older distributors. Hence putting a dial back light to
>good use.
>
>Cheers,
>
>Tom
>
>>
>> Thanks for the in depth info. I know I have a
>> "non-smog" 7.5 distributor however I will also be
>> installing a Pertronix unit. Should I look to do
>> anything different or just stick with the 16 BTDC?
>>
>> Rob
|