
Type
4 Connecting Rods
This page was last updated
Tuesday, September 15, 2009
The connecting rod is a key component in
the air cooled VW engine. Let's look take an indepth look at it and see
how it compares/contrasts with the Type 1.
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This connecting rod is from a 1.7L
Type 4 engine. The 1.8L are almost identical to this,
but have a slightly larger block on top of the small
end (wrist pin end). One word has been used to describe
the 1.7/1.8 rod: beefy. It's quite a large and hefty
component, but it shares a common weakness with all
of VW's connecting rods in the Type 1 and Type 4: weak
rod bolts. The rod bolts are known to break under severe
use. |
Above us is a 2.0 L connecting rod.
It is similar to the 1.7/1.8L rod, but does have the
balancing pad (block) on the small end. It also features
a smaller diameter "big end". The 1.7/1.8s use 55mm
diameter rod journals, whereas the 2.0s used 50mm. The
extra 5mm went to increase the stroke of the crankshaft
(66mm to 71mm). These rods are quite expensive, even
as cores. The desirability of increased displacement,
coupled with the relative scarcity of the 2.0 engine
(especially the VW/Porsche 914) has made the price exorbitant
at times. A resourceful junkyard scavenger should be
able to find a Transporter 2.0 for a reasonable price.
The rods are identical regardless whether it was in
a Bus or a 914. |
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Compare the Type 4 rods with the Type
1 1600cc rod above. The Type 1 rod looks rather fragile
in comparision. The Type 1 1600cc rod features a 53mm
diameter big end, 22mm diameter small end and the same
inherent weakness with the rod bolts. |
Here we see all of three of the rods
laid out side by side. Obvious from this photo is the
longer center-to-center length of the Type 1 rod. The
shorter rods of the Type 4 moves the RPM band farther
down and makes the engine better suited for the heavy
411/412 and the boxy Transporter. These two vehicles
need more bottom end grunt to get going and to keep
accelerating up hills. |
The photos are courtesy of Rolf
Christensen.
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