[T2] Timing type 4 motor

[Sami Dakhlia]

Hi Richard,
I agree with Greg. I would also add that your jumpy timing is a sign
that the distributor is worn out.
Besides, you did not tell us what kind of distributor you have, does
it have vacuum advance and retard? The story with timing at high rpm
with 38 deg total advance is eyebrow-raising; I'm not so sure that's
necessarily correct if you have vacuum advance. Maybe others can
confirm or reject that statement.
Good luck,
Sami

On 23 avr. 2014, at 21:23, Greg Potts <greg at pottsfamily.ca> wrote:

Hi Richard,

There's a lot to consider from what you have told us thus far.

If the engine/exhaust heat melted the cooling fan guard then you have a
problem. If the air going into the fan is hot enough to
melt plastic it's not going to be doing a very good job of cooling the
engine.

Is the engine tin and foam seal installed correctly between the
engine and the body?  Missing tin or a missing seal will damage your
engine as the exhaust heat gets recycled endlessly through the cooling
system.

With a stock type4 engine and a single-vac distributor I'd recommend
running at 7.5 BTDC, and check the total advance to make sure it
doesn't get any higher than 40-44 degrees.

I usually set all my valves at 0.006" and use a non-adjustable timing
light without problems. I can't see a reason to retorque the heads
from what you've told us but a basic compression test or a leak-down
test would provide more insight as to what is going on inside the
engine.

Happy Trails,

Greg Potts
Toronto, Ontario Canada
197x Westfakia "Bob the Tomato"
www.pottsfamily.ca
www.busesofthecorn.ca


> On 4/23/2014 6:38 AM, Richard J wrote:
> Question about the timing on my 1974 type 4 motor. It has stock dual
> carbs, with a single vac. Advance distributor with points.
>
> My question stems from my road trip this weekend. My bus ran great
> until my second stop for fuel. It had trouble starting and staying
> running. I threw a timing light on it and when it was running rough
> at idle it was jumping from 8 to 12 advanced. If I revved it a few
> times I could get it run a little betterat 4 to 6 advanced. It jumps
> around some.
>
> So I emailed the guy and he said, "Glad the bus treating you well. I
> rebuilt the motor while I was working at danny's volks stuff, the
> summer before you bought it. New pistons and cylinders, new cam and
> SOLID lifters, all new bearings, ect. I used solid lifters because I
> hate the hydraulics. Set the valves like a beetle .006. I didn't do
> anything to the distributor, just installed the pertronix type points
> set up and made sure it maxed out at 38degrees total advance. The
> only way to set the timing is total advance, you don't really care
> what it's doing at an idle. You need an adjustable timing light and
> an accurate timing mark. Did you ever get a new timing tab? if not
> get one from bus boys." (I did get a timing tab)
>
> So, I replaced the petronix with points cause it went out after the
> first month I had the bus. Second I reset the valves at .006 intake
> and .008 exhaust. Now, ever once in awhile I get a pop when I start
> the bus that blows the small boot below the right hand carb, off.
> It'll start but runs rough. Once I push it back on it runs fine.
>
> So, the kicker is I ran the bus home pretty hard(lots of head wind).
> It ran great after I got it started, with advanced timing I talked
> about earlier. (I didn't think it ran too hot cause I could touch the
> dipstick and it was cool, and the distributor was cool enough I could
> hold my hand on it) After arriving home, I guess the exhaust or
> engine or combined melted the lower part if the plastic fan guard.
> Then before I noticed I started the bus(which started fine while once
> cool), and sucked in the guard parts into the fan.
>
> I can pull the motor and clean all those pieces out, but what about
> the timing? Valves? Torque the heads? I need a little help, please!
>
> Thanks for any advice!
>
> Richard Jack 1974 westy Lubbock, TX
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>

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