<VV> Utravan 4.11's? was PG rebuild

[Dan & Synde]

Hi Matt,

Well, I think the 4:11's have worked out nice.  That's what was in it when
we bought it but at the time didn't know it.  Originally, most came with
3.55's and they came with 7.5 x 14 tires (approx 195R14) which are about
26.6" diameter.  I went up to a 205R14 in the rear which are about 27.2"
diameter using 4.11 gearing.  For comparison, I've calculated what the
engine rpm & ground speed would look like with either setup @ 2800 rpm and @
1600.  2800 is the sweet spot because of the 889 cam and the 4 degree cam
retard.  Should be around the torque peak.  1600 is the point at which the
torque converter stalls.

Gearing:  3.55	Tire Size:  195R14 (26.6")	RPM: 2800	MPH: 57.9
1.08 x	        3.55 = 3.83 to 1  (Assuming 8 % torque converter slip in
high)
								MPH: 31.8
1.08 x 1.82 x 3.55 = 6.98 to 1  (Assuming 8 % torque converter slip in low)
						RPM 1600	MPH: 7.7
2.6 x 1.82 x 3.55 = 16.80 to 1  (Assuming max 2.6 torque multiplication)

Gearing:  3.89	Tire Size:  205R14 (27.2")	RPM: 2800	MPH: 54.0
1.08 x           3.89 = 4.20 to 1  (Assuming 8 % torque converter slip in
high)
								MPH: 29.6
1.08 x 1.82 x 3.89 = 7.65 to 1  (Assuming 8 % torque converter slip in low)
						RPM 1600	MPH: 7
2.6 x 1.82 x 3.89 = 18.40 to 1  (Assuming max 2.6 torque multiplication)

Gearing:  4.11	Tire Size:  205R14 (27.2")	RPM: 2800	MPH: 51.1
1.08 x           4.11 = 4.44 to 1  (Assuming 8 % torque converter slip in
high)
								MPH: 28.1
1.08 x 1.82 x 4.11 = 8.08 to 1  (Assuming 8 % torque converter slip in low)

						RPM: 1600	MPH: 6.7
2.6 x 1.82 x 4.11 = 19.46 to 1  (Assuming max 2.6 torque multiplication)

Hopefully, I didn't screw any of the calculations up.  I remember pouring
through it when I was picking the engine, gearing and tire size and the
numbers above, at least for our gearing are just about spot on.  The above
is my understanding of how it should work.

Initially, when we bought the Ultra, I was thinking I had a 3.55 and that I
might like to upgrade to a 3.89.  That would have let me run larger tires
than stock but also retain and enhance it's hill climbing ability.  Well, as
it turned out, we actually had the 4.11 gears which aren't all that much
different than the 3.89's.  Saved me some dough.  I definitely think there
is an advantage to using the 3.89 or 4.11 gearing instead of the 3.55 for
people with the original displacement engines.  You can run larger tires in
back which increases the load handling and road handling.  It also gives you
a little more ground clearance and a bit more power on hills once the engine
rpms are up above 2400.  I think if I were upgrading from the 3.55's I'd
just go to the 3.89's that GM made.  I've heard that some of the early 4.11
were brittle.  Since the 4.11's were there, I decided to give them a try.

It has worked out well for us so far.  Our average speed driving 400 miles
home from Ventura to the Bay Area was 58 mph and we weren't pushing it.
Before the trip, the engine had about 500 miles on it.  Now we have about
1300.  We were bucking a head wind for part of the journey too.  Mileage was
15 mpg.

Time will tell if the 4.11's will survive but they've been in there since
around 1994 already.

Dan Kling

1961 Greenbrier Deluxe, 4spd, 3.89  On the Road Again,  yeehaw :)
1963 Spyder, restored   4spd Saginaw
1967 Ultravan #299  Newest of the herd!! Almost killed me already!!


http://www.flickr.com/photos/81412237@N00/sets/
A few pictures of the Greenbrier, UltraVan, engine and tranny tear down with
more to come! 




Matt said

>So Dan,  are you telling us that you've decided your Ultra can use the  
>4.11's?