I am working on a mid 74 (Dec) and came across this head temp sensor modification. I think I remember reading something about this set up but I have never seen one before in 25 years of playing with 914's. It is a hollow bolt with the temp sensor screwed into a engine tin screw hole next to the #4 cylinder. The temp sensor is 0280130003 and has 450 stamped on the side. The temp sensor is listed on Anders site as being for the 1.7 and VW type 3 not the 2.0. All the fuel injection set up is stock other wise.

I'd say it's a PO mod and the proper location is stripped out or the head was replaced at one point with a head that has no sensor hole tapped.
Every factory location I've ever seen, type 1 and 4, was in the head casting itself.

double post

So this cht sensor is not in the head but in the space between the tin & head??? If so, please describe the performance after start up from dead cold and from a restart after it is warmed up.

I'm not saying yours is a Vanagon head, but that's where the CHT is on a Vanagon head.

It is a bone stock 74 2.0L. I went to the Anders site and re-read the info there. It said some people used the type3/1.7L head temp sensor to help with cold start. I can't tell you what difference it makes until I get the car going. In the middle of replacing all the stuff required from setting 10+ yrs in a barn in West Texas. Needs a new fuel pump too.

Maybe, Brad from 914 LTD can chime in because he sells the hollow spacer for the cylinder head temp sensor.

I was just going to say that Brad Mayeur's shop sells those spacers, & I thought it had something to do with getting the readings right on the 2L in the stock location IIRC.

I have one, but I need the 017 CHT for early 73 2L - if I ever find an NOS one for back-up (mine original/replacement CHT is still in the engine & functional AFAIK).

well, does it work?

The CHT will enrich the mixture until it gets hot.
Its almost a binary deal...its either hot or cold.

I played around with it for a while and it is a pretty binary setup, but its three different maps (so its not really binary)

Cold cold
Kinda cold
Hot.

If what you have works, what is the benefit?

rich

The spacer on the CHT delays the warm up of the CHT so the cold mix (richer) helps the car to run better cold "IF" it needs it.
The location is the later Bus location too but I don't know if it helps or screws up the Djet cold running doing this.

L-jet busses had the CHT sensor mounted in place of the shroud screw next to the #3 runner, not the #4 site as shown. They didn't use the spacer as shown. That was a T3 part, and maybe T1 as well. 914s never used this setup, but I doubt it would present a problem. BTW, busses have been known to have issues with the sensor coming loose. When you install one there, you MUST assure the tin is clearanced for the sensor so it sits flat against the head.

The Cap'n

Ok, so this is a home made set up. The factory one used the spacer in the factory cylinder head location. Some one probably got the IDEA from what they saw on a bus head and thought it would work on the 914. So I will be removing it and putting the correct one in the cylinder head without the spacer. Not many mornings in South Texas that would require extra time for a cold start.