Is there any concensus out there on whether the Harlan or the Summit RPM switch is any better than the other in terms of problems?
Let me know which you have and whether you like it or not. I'll keep a tally posted (below):

Brand/Like/Dislike
Harlan/1/1
Summit/2/0

 

Several people have had trouble with the Harlan switch, although I and a few others have had no problems whatsoever. I can't recall anybody having problems with the Summit switch (except for one person who didn't set the rpm properly). I have installed both in different people's cars and there is really no difference in difficulty of installation.

One possible advantage of the Summit switch is that it has a wire that provides a ground once the set rpm has been reached (which is what you would use to open a variable intake, for instance), and another wire that provides a ground up until the set rpm. The second wire may be useful in some applications. The Harlan switch only provides a ground after the set rpm has been reached.

 

Myself, like many others, had problems with the harlan. It worked fine for a while then radomly flaked out. The bad thing about it is that when it flakes out and does not activate the solenoid it won't work again till the car is shut off and restarted. So you would be driving and it would be working fine, then all of the sudden it would stop working and you would have to pull over and turn the car off.

Eventually the harlan switch hardly ever worked. I trouble shooted for a long time with this problem. Re wired everything, changed vacuum canisters, etc....finally just got the summit switch and had no problems since.

 

In my mind there is absolutely no comparison between the two. Summit is the far superior switch. I had nothing but problems with the Harlan. Total waste of money.

 

I went throught 2 Harlans before I wised up and got a Summit, been in there for about 2 years, and no problems yet ...

 

That was me, I didn't realize it was made for a V8 but once someone told me what I should set it on I had no problems.

 

That is the only disadvantage of the Summit switch. It is set up for a V8 so the RPM increments are not correct. I know the MSD has a correction for it. Besides that it is a good switch from what I hear.

 

Harlan was a POS and messed up alot, got a summit and not one problem yet in 2+ years.

 

+1 for the Summit. It's nice having the extra output type too.. (normally open vs normally grounded).

 

I've had no problems with my Harlan, but I seem to be in the minority.

 

Maybe not. People that have had problems are the most likely to give an opinion. But I have two of them with no problems, and I know of another person who had four of them operating different devices with no problems. It's probably an installation issue.