Date: Thu, 9 Apr 2020 09:35:42 -0400
Reply-To: Geoffrey Toye <geoffreytoye@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Geoffrey Toye <geoffreytoye@GMAIL.COM>
Subject: Re: 81 Vanagon Type 4 Motor Timing
In-Reply-To: <SN6PR10MB28944445924FD4F7547AD865A0C10@SN6PR10MB2894.namprd10.prod.outlook.com>
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Thanks Dennis. I have no parts of the EGR system on my engine apart from
the unused arm on the throttle linkage. Looks like it will stay that way.
The van likes 50-55 mph and that's where we will probably be most of the
time. It does have an oil pressure and temperature gauge (VDO) but they
are not hooked up. Wires go down into the spare wheel clamshell and head
rearwards but don't turn up in the engine compartment or underneath. I see
no sensors either. Probably when the engine was replaced the sensors were
not carried over. May need a rewire and new sensors. I've seen an adapter
for sale that goes between the oil filter and the engine, maybe I could add
the sensors there. A CHT would also be nice to have (and a rev counter).
I see a gauge project coming in my future.
It did seem to idle better at 7.5 deg BTDC (higher RPM) but it's ok at 4
ATDC and the bus runs well. I will try the spec setting without the vacuum
advance next time I look at the ignition and see how the van drives. For
now, if it ain't broke ......
Any advice on removing/reinstalling the dizzy drive shaft?
On Wed, Apr 8, 2020 at 10:32 PM Dennis Haynes <d23haynes57@hotmail.com>
wrote:
> The ignition point contacts are hard coated-plated. Once damaged filing is
> something you do just to get home. Often they burn up due to insufficient
> gap or a bad condenser. If I recall the proper setting is .016”
>
> It will probably be difficult to replace the EGR system. If you have the
> valve and linkage you can make up the rest. Off the muffler one of the
> parts is a filter-cooler box. As the EGR should be closed at full or closed
> throttle it doesn’t help for performance there. The critical point for your
> engine is to avoid detonation and sudden death melting piston syndrome. If
> you plan to drive long distances and like to go over 55 oil and head temp
> gauges are a must. They’ll let you know when you need to lift your foot.
> For some customers I set the base timing at spec for good idle and low
> speed response and disconnect the vacuum advance to limit the overall
> advance. Back in the Beetle days it was common for us to use a 009 or 050
> centrifugal advance distributor. The 050 was my choice as it had 28 degrees
> total advance.
>
>
>
> Dennis
>
>
>
> *From:* Geoffrey Toye [mailto:geoffreytoye@gmail.com]
> *Sent:* Wednesday, April 8, 2020 9:37 AM
> *To:* Vanagon Mailing List <vanagon@gerry.vanagon.com>; Dennis Haynes <
> d23haynes57@hotmail.com>
> *Subject:* 81 Vanagon Type 4 Motor Timing
>
>
>
> As a followup to this discussion, I swapped out the points and
> condenser for a new Bosch set. Put the points gap at 18 thou which gave me
> a dwell of 46 deg. This moved the dizzy away from the cold start valve to
> give me room for future adjustments as the points rubbing block wears. All
> good news.
>
> The points I removed were pitted but probably serviceable if filed but the
> rubbing block was notably worn compared to the new set. I lubed the cam and
> centre felt. If I do this once a year I probably will never have this
> problem again, unless I take out the dizzy drive gear and rotate it a tooth.
>
> I set the timing at 7.5 deg BTDC to see what it would give me at 3000
> RPM. The advance introduced by the SVDA dizzy was way ahead of the target
> 35 deg so I backed it off to give me 35 deg BTDC at 3000 RPM. This
> resulted in 4 deg ATDC at idle. Originally it was 6 deg ATDC so pretty
> close to being back where I started timing wise which is good since the bus
> ran well at that setting.
>
> So now two more thoughts come to mind. Would installing an EGR valve as
> originally designed and putting the timing to 7.5 deg BTDC give me any
> performance improvement? Also, how do you take the distributor drive shaft
> out? The Bently does it with a special tool, Tom Wilsons book pushes it
> out with the cases split, the Haynes manual says use a tapered dowl pin but
> leaves it there.
>
> Any thoughts are welcome.
> Geoffrey Toye <geoffreytoye@gmail.com>
>
> Mon, Mar 23, 5:47 PM
>
> to Vanagon
>
> I bought an air-cooled vanagon last year and decided to take a look at the
> points/dwell/timing situation while it was laid up for the winter. The
> points are pitted (bad) and the dwell is 60 deg (hard on the coil). I
> found the timing mark on the fan pulley by using Ratwell's information and
> the sticker inside the engine compartment says the static/idle timing
> should be 7.5 Deg BTDC.
>
>
>
> On checking the static/idle timing I found it to be 6 Deg ATDC and that it
> advances to 34 Deg BTDC at 3,000 RPM. The van starts and runs great. No
> issues with power.
>
>
>
> I would like to replace the points and advance the timing. The problem is
> that I cannot advance the timing because the vacuum can on the SVDA
> distributor is up tight against the cold start valve and I need to turn the
> distributor in that direction. (I can find no markings on the distributor
> to determine it's heritage).
>
>
>
> Looking at other Type 4 engine layouts I see the vacuum can is near the
> shaft that connects the air flaps and not near the cold start valve.
>
>
>
> I have consulted the Bently and Haynes manuals and awaiting Tom Wilson's
> book for more research. I have looked through the Vanagon threads and The
> Samba discussion too.
>
>
>
> I know the engine was rebuilt 25,000 kms ago. The PO was not an engine
> guy so don't think he ever did the timing. Looking at the service records
> I see it was done by others.
>
>
>
> So two questions. Why does the van run so well with the timing so far
> off? Is the incorrect positioning of the distributor due to the drive gear
> being mis-oriented during the rebuild? Or am I missing something obvious
> here.
>
>
>
> Thanks in advance for any thoughts people might have on this issue.
>
>
> Dennis Haynes
>
> Mon, Mar 23, 6:52 PM
>
> to me, vanagon@GERRY.VANAGON.COM
>
> It is most likely the distributor drive gear is off by at tooth limiting
> the adjustment. However, the timing is directly affected by point gap,
> dwell. It is normal for the rubbing block on the pointe to wear which
> reduces the gap, increases the dwell and retards the timing. So, replace
> the points and condenser set, set the gap and the timing will be more
> advanced.
>
> As for timing, since most likely you are missing the EGR system you want
> to run retarded as compared to stock settings. Waterboxers run ~35 BTDC at
> 3,000 rpm so I usually put the air-cooled engines without EGR there also.
> The death kneel of these engines is unheard pre-ignition and thermal run
> away of the heads and pistons. They can go from perfectly running to a
> melted mess in a few minutes.
>
> Dennis
> Geoffrey Toye <geoffreytoye@gmail.com>
>
> Mon, Mar 23, 7:00 PM
>
> to Dennis
>
> Thanks Dennis. Great insight.
>
>
>
> Yes, the EGR system is missing.
>
>
>
> Since the van has been running for 25,000 Kim’s I assume all is well, it’s
> just not right?
>
>
>
> Will put in new points/condenser and see where that puts me.
>
>
>
> Thanks again.
>
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