Itinerant Air-Cooled

Bleyseng wrote:
Scatter can also be a worn distributor housing and the shaft flops around in it.

Only with breaker points. When I put in a Pertronix in the Road Warrior, expecting a lovely precise timing mark, you can imagine how devastated I was to find it just going all over the place. When you look at the physics of a loose distributor shaft, it can't give you the scattershot strobes we see, it can play with your timing however, as the shaft movement causes the points to open a little sooner or a little later as the gap is increased/decreased depending on the position of the shaft in the loose bore.

But look at how dramatically the brass gear can advance or retard the distributor drive gear as the crankshaft moves back and forth, try it statically during an engine rebuild, a 5* arc of the distributor driveshaft translates to a good 10* shift in timing at the scale.

That is what I discovered with the Road Warrior, a sloppy .008" endplay. Then the BobD opened up its endplay to some gross .0074" by 80,000 miles, and the timing marks went all slipshod, both with the Pertronix I inherited, and with the points now installed.
Colin

I agree but this is a rebuild engine so I would think the endplay is close but you are right in that it could be a worn brass gear or bad end play.
These are all the little details in engine rebuilding/maintenance that can "be a pain in the ass" if overlooked.

I am waiting to see what ends up being his problem.

Bleyseng wrote:I agree but this is a rebuild engine so I would think the endplay is close but you are right in that it could be a worn brass gear or bad end play.
These are all the little details in engine rebuilding/maintenance that can "be a pain in the ass" if overlooked.

I am waiting to see what ends up being his problem.

You mean it wont go away if I just close my eyes

Hey there folks. I am having a similar problem as WaterDawg did. I have a 1978 2.0 FI bus. It smells like it is running pretty rich, doesn't idle great, sometimes dies, seems like there is a vacuum leak (as it idles inconsistently). What is the best way to test for a vacuum leak? I read people used Gumout to determine a leak, but also read 'bus on fire', so I don't want to just go in blazin' or gout out blazin'! I am due for a valve adjustment, my driver push rods and my valves on same side are leaking. UGG. I could go on probably. I did replace my rear shocks and replace the copper ring in the passenger side exhaust manifold (that sucked), but successful, so I got that going for me. I realize this is all of the map, but I am a little overwhelmed and figured I would reach out to the knowledgeable ones! Thanks in advance. Kris

WaterDawg wrote:

tristessa wrote:Hope I'm not stating the obvious, but .. vacuum leak? Check where the two hoses connect into the side of the "S" boot, they're rather notorious for Not Quite Sealing But Looking Connected...

I'm new so nothing is too obvious. I'll be tackling this in the AM with light. If I can't figure it out, I have someone 2 hours away that will help me. Neither of us are mechanics, but two heads and four hands are better =D>

So please keep the suggestions coming in.

khargis wrote:Hey there folks. I am having a similar problem as WaterDawg did. I have a 1978 2.0 FI bus. It smells like it is running pretty rich, doesn't idle great, sometimes dies, seems like there is a vacuum leak (as it idles inconsistently).

What is your elevation?
Rich is rich, it is on the other side of the diagnostic spectrum from "vacuum leak" (too lean).
To investigate "rich", start your investigation by idling your warm engine. Pump the brakes rapidly and lightly. Does idle speed go up? Lean out your fuel mixture.
See AFM article in Fuel Delivery.
Colin

Elevation is 2,730'. I will do the brake check when I return home later and in the meantime, I will read the AFM article in fuel delivery. Kris