Every day digging through my late model Beetle introduces me to something new and different from most prior years. The tear down of the FI Cylinder Heads for rebuild has introduced me to even more new things.
The years 1975-1979 saw the US import models shift from the early 70’s carbureted system to the successor Fuel Injection that the Type III’s had used since the late 60’s.
The Bosch L-Jetronic system was a substantial change from the D-Jetronic system found in Type III’s in prior years.
For the US FI vehicles, Volkswagen supplied their engines with a new modified cylinder head. While still based on predecessor molds, the new 043 head changed up the valves to work better with the differences of the FI system, as well as the hotter temperatures that the system generated.
The 043 heads (043.101.375H / 043.101.375R) in the case of my 79) was introduced in 1974 and had 35.5mm intake valves and 32mm exhaust valves.
In 75, for the US market cars, the head was modified, stepping the valves down in size, changing the stem width of the exhaust valve, and adding a boss to the right side of the heads that would be tapped for the FI systems Cylinder Head Temperature (CHT) sensor for heads used on the 3/4 side. The 75-79 heads had 33mm intake valves with the typical 8mm stem width and 30mm exhaust valves with a 9mm width stem. The exhaust head also is sodium-filled. This allows for a greater transfer and shedding of heat. (1) (2) (3)’
VW has not made these heads in decades, but there are both similar new heads available to purchase, as well as replacement parts.
New Complete Heads
Aircooled.net – 043-101-065 $249.95/head
30mm Exhaust Valves (9mm stem)
CIP1 – VWC-043-109-611-A4 $59.99/set of 4
Aircooled.net – 043-109-611A $29.95/valve
AutohausAZ – 043109611A JP Group Dansk $12.95/valve
FCPEuro – 041109611 $7.00/valve
Mofoco – 113-109-612 $10.90/valve
33mm Intake Valves
8mm Valve Seal
AutohausAZ – CRP Valve Stem Seal $0.11/each
Cylinder Head Temperature Sensor (3/4 head only)
Info Around The Net
Various things I found on the net related to these heads and valves.
Why is the exhaust valve on FI Head Smaller? (shoptalkforums.com)
VGM / Sat May 28, 2005 2:55 pm – A bigger exhaust valve will” over scavenge” the combustion chamber.Fuel injection was more efficient and did not require the larger size valves used for the earlier carberated systems. But I think the intakes are smaller as well on the FI heads so the balance is maintained between intake and exhaust flow.
raygreenwood / Sat May 28, 2005 7:47pm – Thats all true, but the biggest reason had to do with keeping correct runner diameters…so they could keep correct runner volumes versus the length they had to reach to the plenum.What does that have to do with valve diameter? Because its best to have the runner diameter (in cross section) and the open cross section the valve creates at full lift…as close as possible. Too large of a valve opening will change the velocity in the runners. That in turn would necessitate changes to the plenum…and the TB to meter it all. Bear in mind that velocity and vacuum signature… even on L-jet and especially on D-jet …were critical to metering. The exhaust valve was also kept small ..to balance the overall flow…as suggested in the last post.
PJMS / Tue Jun 14, 2005 8:19 pm – Just to make it even more interesting: Three months after VW started production of the L-jet Type 1 unit, with 33mm intake and 30 mm exhaust valves, they started fitting the small exhaust valve to the 1600 carb engines in Europe. Less than two years later, they then reduced the intake down to the 33mm, which is how all German and Mexican produced heads have come since then (also as replacement heads for all 1600 engines back to 1971). Brazil finally changed to the smaller valves in 1984, although the familiar Brazilian heads we see are of the pre-84 type with the larger 35/32mm valves. Apparently, the period of 35/30mm valve heads saw an increase in engine failures due to over-heating.