1965 riviera pertronix install question

[Chefcg1]

I just did a lobe sensor pertronix installation on my 65 riviera and have a couple questions. My dwell now reads 24? Also what kinda manifold vacuum are you guys seeing? I'm only seeing 10-15 with timing set to 10 degrees. If I drop down to 2 degrees I'm only seeing a vacuum of 10? Seems really low?

 

thanks!

Edited May 1, 2016 by Chefcg1 (see edit history)

[Seafoam65]

                   Why are you checking the  dwell on a Pertronix?  There's no need to check dwell, if it has spark you are done.

All you need to check is the timing. Normal vacuum is 17 to 20 inches at idle.

[Chefcg1]

Checked out of curiosity.unfortunatly while timing everything I noticed that what was a very small drip of coolant from what I thought was a leaking heater hose that I replaced while doing the pertronix install turned into a full fledged river out the heater core. Some days I hate my luck. Guess I'll be pulling the interior and doing the heater core finally repairing my center console and redoing my window alignment and  window motors while I have it apart.  A lot of work ahead, but luckily it's a hobby not a daily driver. I was initially hopping to have her running this month so I had it to drive to work while I put my supercharger on my c7 corvette, but I guess that is out for now....

[Chefcg1]

I'm guessing my lower vacuum is probably due to ported heads, intake manifold and headers.

[telriv]

What has been done should NOT cause low vacuum it should make it BETTER not WORSE. Suspect maybe the intake gaskets are installed wrong or a vacuum leak.

[Seafoam65]

                I still have the original heater core in my car and it doesn't leak, but if it ever does I'm going to enlarge

the opening in the firewall to where it can be removed from the engine compartment.....no way I'm tearing into my totally

unmolested dash board. 

[EmTee]

15 hours ago, telriv said:

What has been done should NOT cause low vacuum it should make it BETTER not WORSE. Suspect maybe the intake gaskets are installed wrong or a vacuum leak.

I'm with 'telriv' on this -- I think it's time to check for an intake vacuum leak.  You don't mention a camshaft change, which could result in lower than stock idle manifold vacuum.  As far as the heater core leak is concerned, if you only drive the car in nice (i.e., warm) weather, you could postpone the heater core repair and still enjoy the car by temporarily bypassing the heater core...

[Chefcg1]

I'll check for vacuumed leaks when I get my heater core leak figured out. Can't think of how I could have installed the intake gaskets incorrectly.

[EmTee]

Check hoses first, then spritz some carb cleaner where the intake manifold and heads meet moving from cylinder to cylinder listening for a change in the idle.  Don't ask me how, but gaskets seem to take any opportunity to shift as you're lowering the intake into position.  I don't know what sort of manifold you have, but is it possible there's an open or improperly plugged vacuum port somewhere?  You could also try grounding one sparkplug at a time and note the drop in RPM.  If you find one that doesn't seem to be pulling its weight, that would narrow the search.  Have you measured the cylinder compression?

[Chefcg1]

I need to pick bypass the heater core and then I'll hunt down if I have any vacuum links. I'm running the stock manifold that has been ported. I port matched the heads at the same time last winter. I did do a compression test 2 years ago and everything was fine, I know 2 years seems like a long time ago , but that's only 50 miles of driving. Plugs and wires are all new. When I was timing it it got right at 15 vacuum at 10deg timing which the car seemed to run best at. Full advance to 31degrees at 3200 rpm with distributed vacuum disconnected.