late models run hotter?
 

I ran across this in browsing today, in the PP tech section Q&A

"The later cars (75 & 76) were tuned to run hotter and release less emissions. As a result, the engines generally did not last as long.

This is not good! How is this done, in the ECU? Dizzy? can i "untune" it out?

Is this only on 1.8's I hope?

I've looked at the ECU and MPS settings (injection duration vs. load and engine speed) and I can't see much of a difference between the '75-'76 and '74-'73 2.0L (they all use the same MPS except for the '73, different ECU's for 73, 74, and 75-76). However, the later cars used a different injector, which MAY have a slightly lower flow rate - but nobody knows, because I've never seen any flow rate numbers on the later injectors. If true, you could richen the mixture by going with the early injectors. But this is all conjecture.

It's next to impossible to tell how hot a car is running from the stock guage also. The stock temp guage is really only useful in a "if it's pegged at the max, something's probably wrong" sense. My '76 2.0 has been backdated to '73/'74 specs by a PO (well, partially backdated, he never filled the holes in the head when he disconnected the air pump) and the guage indicates the engine's in the upper 1/4 of the temp range all the time. Never gets into the red zone though.

My personal thoughts are that the engines ran hotter because of the different exaust design and the extra emissions equipment. I think that if you remove the emissions and effectively backdate your 1.8's exhaust/emissions to earlier 1.7 specs, you'll get it to run a little cooler.

Aaron

Not only was the exhaust more restrictive due to the design, they also ran a cat. converter to further impede flow.

I wouldn't worry about it too much...it's not like you just bought it brand new and have to worry that it'll fail right after the warrenty expires :)

my 76 has neither air holes nor cat. converter, (score 1 for Texas) and I have the decel valve removed . I have an earlier style exhaust, If it flows better I'll put it on.

In my spare parts I have 3- 038 injectors and 3- 019's, I think I'll flow test them to see if there's a consistent difference.

I guess if it's lean mixture related heating, I can tune that out when I get an analyzer or o2 sensor setup working.

My son's kidding me now, calls me 1 injector short of a set ;-) I'll get him for that lol

PD

The Rule of Thumb has always been, If it pegs in the red zone and stays there! pull it over immediately& pray