Why VW engines sound so terrible in a ST4!
VW Engines have noisy Valves. On it's own this wouldn't be much of a problem, but when one adds on the Heat Exchangers for the Vehicle Heat and Defrost systems this all changes.
All manner of engine noise comes thru the heat system. It was a problem with the VW Cars, but not near as much as an ST4. In later years of VW production they add a sort of muffler to reduce the sound. The hoses that connect from the heater boxes to the tubes on the chasis are filled with a sound absorbing material. They really help. Unfortunately they won't fit in an ST4. So the noise from the engine comes screaming right up the defroster vents and is reflected right off the windshield. The "Fix" is 3 fold. Initially get rid of engine noise by having the engine balanced. Generally this only applies when building a new engine or having one re-built. .
Second, you can line the engine compartment with this heavy lead/rubber sound deadening stuff that is adhesive. It really helps. I did it to several machines. Hood, and side walls. Available from Eastwood.(Car restorer mail order outfit) >
The last and certainly one of the more effective ways is to obtain some of the After 1965 heater tube muffelers and modify them so that they will fit in the engine compartment. They are made of plastic, and will come apart. They just screw together. You unscrew one end, shorted it up and screw the end back on. Shortened up they can be made to fit into the engine compartment.
Also take the linkage bars that actualte the heater controls out and replace them with conventional aftermarked choke/throttle cables. It's a real no brainer and cost only a couple bucks. The vibration from the heaterboxex comes right up these which are right on the firewall. I'm not sure this part is even shown in the ST4 manuals, but it's that 20" long piece of flat bar that comes thru a small slot right below the dash. Some models have 2, early ones only had one. You can mount the new choke cables right in the slot where the notched piece of flat bar was.
VW Engines have noisy Valves. On it's own this wouldn't be much of a problem, but when one adds on the Heat Exchangers for the Vehicle Heat and Defrost systems this all changes.
All manner of engine noise comes thru the heat system. It was a problem with the VW Cars, but not near as much as an ST4. In later years of VW production they add a sort of muffler to reduce the sound. The hoses that connect from the heater boxes to the tubes on the chasis are filled with a sound absorbing material. They really help. Unfortunately they won't fit in an ST4. So the noise from the engine comes screaming right up the defroster vents and is reflected right off the windshield. The "Fix" is 3 fold. Initially get rid of engine noise by having the engine balanced. Generally this only applies when building a new engine or having one re-built. .
Second, you can line the engine compartment with this heavy lead/rubber sound deadening stuff that is adhesive. It really helps. I did it to several machines. Hood, and side walls. Available from Eastwood.(Car restorer mail order outfit) >
The last and certainly one of the more effective ways is to obtain some of the After 1965 heater tube muffelers and modify them so that they will fit in the engine compartment. They are made of plastic, and will come apart. They just screw together. You unscrew one end, shorted it up and screw the end back on. Shortened up they can be made to fit into the engine compartment.
Also take the linkage bars that actualte the heater controls out and replace them with conventional aftermarked choke/throttle cables. It's a real no brainer and cost only a couple bucks. The vibration from the heaterboxex comes right up these which are right on the firewall. I'm not sure this part is even shown in the ST4 manuals, but it's that 20" long piece of flat bar that comes thru a small slot right below the dash. Some models have 2, early ones only had one. You can mount the new choke cables right in the slot where the notched piece of flat bar was.
