Intro and One Question on Engine Pop

[Bristol]

Hello, I just purchased a ’72 914/4 and wanted to introduce myself and ask a question. Here are a few photos of the car:











This is Porsche #3 for me right now. I also have a 2000 Gemballa Boxster S and a 2003 TechArt Carrera 4S. Both are like the 914, highly modified with body kits, wheels, suspension, etc. Obviously there is a trend here with the kind of car I like. I’m a technical car guy, so hopefully I’ll have some good input here once I delve more into the world of air cooled Porsches. I’m also active on 986forum and 6speed under the user name “Kirk”.

The question I have is regarding the way my engine runs. When I test drove it, the engine wouldn’t exactly backfire, but it would make random “pffttt, pffttt” sounds or pops which I assumed was from a valve not completely closing. The engine was rebuilt by AVP (a California VW engine rebuilding company) and installed in 2004. The previous owner claimed only 2,000 miles on the engine and said that it needed a valve adjustment. I did the valve adjustment last night and the valves were really tight, but it didn’t really help to eliminate the noise. The car has plenty of power and runs smooth at highway speeds without these little pops. The FI has been removed and replaced with dual Weber carbs.
I have lots of little issues with this car that I need to sort out, but this one is more pressing to me as I don’t want to harm the engine when driving it. I don’t think it’s really an issue and maybe just a characteristic of the car, but I don’t recall this noise with the ’68 aircooled VW I had years ago.

I’m assuming that since it’s mostly happening at low revs and idle that it’s simply a mixture issue with the carbs that needs to be sorted out. Sound about right? Do I need to worry about still driving the car?

Thanks in advance!

Kirk