slade69

Oldsmobile diesel engines have the vacuum pump where the gasoline models have the distributor. If i convert my gasoline engine to crank trigger type of ignition and thus don't need the distributor, could I just bolt the diesel vacuum pump in place of dist and have plenty of vacuum for brakes?

joe_padavano

Only if your crank trigger ignition is coil-on-plug. If you only have one coil, you still need a distributor to act as a rotary switch. In any case, you need SOMETHING there to drive the oil pump. FYI, some diesels used a belt-driven vacuum pump.

slade69

Yes, I'm considering fully programmable multi coil wasted spark system, so I would not need distributor at all. My engine does not make great vacuum numbers causing the brakes are not exellent. What I really wanted to know does this vacuum pump bolt on in place of my distributor?

https://www.carid.com/cardone/remanu...6&url=11825756

joe_padavano

Yes, it does, and yes it also drives the oil pump. Don't you still need a cam position sensor? Or will your waste spark system fire 1-6, 8-5, 4-7, 3-2 so the crank sensor is all you need?

Inline

How about using MSD programmable ignition and locking your points distributor, and using one of those alternators with vacuum pump? If you want programmable ignition. I quess it would be easier to fabricate some new hangers and maybe new wheel for belt?

slade69

No cam sensor needed. I think you are right how it fires the cylinder pairs. There are not too many distributorless stand alone programmable ignitions on the market, but this is the one I have been looking for.

https://motorsport-electronics.co.uk...ems/nodiz-pro/

Joe, do you know what was the purpose of 5,7 diesel vacuum pump in my link in previous post? Was it for brakes or air ventilation only? Or both? This is not clear to me, because I remember there was hydraulic brake boosters in diesel engined cars, working with power steering pump.

slade69

I would love the idea to get completely rid of distributor, and the signal from cranck sensor would be much more accurate (no cam gear play). I would also like the idea of mechanical vac source in place of distributor. Only need to know if this kind of cam driven spherical pump creates enough vacuum for brakes.

What is your plan with ignition?

Inline

Ah. Then that rules out my whole suggestion.

I bought back then whole MSD-set, one thing was that HEI wont fit with dual-quads. Other reason was ease. Probillet distributor, programmable 6al2 digital and vacuum sensor ( which is also adjustable, vacuum advance, i mean) along with external coil. Plug & pray. Not actually cheap, but nothing is with these so..

joe_padavano

The primary purpose was to supply vacuum to the transmission, believe it or not. The diesel cars used the TH350, which still had a vacuum modulator. The diesel throttle control on the injector pump also had a device called a Vacuum Regulator Valve. This device basically mimiced the vacuum vs. throttle position characteristics of a gasoline engine (ie, high vacuum at closed throttle, low at W.O.T.) so the vacuum modulator on the trans would work properly and the trans would shift. Keep in mind that the vacuum modulator is essentially an engine load sensor, and on a gas engine manifold vacuum is a reasonable indicator of engine load. Of course this was all a kluge, which is why newer GM transmissions (700R4 and 200-4R, for example) used a throttle valve cable instead of a vacuum modulator. Turbo cars like the GN have that same problem, by the way.

Of course, the HVAC system also requires engine vacuum to operate the flapper doors, so the vacuum pump provided that vacuum as well. The brakes on diesel cars were hydroboost, so no vacuum required. I don't know if the output of that pump would be adequate for brakes and trans and HVAC.