65 Wildcat - Cruising RPM's?? Switch-Pitch.

[Guest 1965cat]

I have a stock 65 wildcat conv, rebuilt with less than 2K miles. I took the tranny to a local shop for a bench job that included a new torque converter. Well, I notice now that the car seems to be pushing high-rpm's in 3rd gear at cruising speed.. (50mph = 2K rpm, 80mph sounds like 3K+ rpm's - my test tach only goes to 2K rpm's). I could have sworn I could cruise at 75-80mph around 1800-2000rpm before the rebuild.... The car launches fine, idles perfect, switched gears with no problems... Would the wrong torque converter cause this problem (I assume the rpm's are too high for mph's)?? If I need to purchase a new switch-pitch convertor, any suggestions on a reputable place? I have a used switch-pitch from another 65 I can use as a core.<P>Thanks,<P>Mark<BR>BCA# 372362

[Wildcat-65]

The factory Tacho in my 65 Wilcat reads<BR>around 2000rpm @50mph and 2200rpm @60mph.<BR>I think that at 80mph the 3000rpm you quoted sounds about right but I can't recall exactly.<BR>I should as we have just completed a 1,500 mile rally following our National Meet here in Australia and I was looking at the tacho for over 3 weeks.<P>We had a ball...........if you want to read about it go to our website <A HREF="http://www.buickclub.wiredup.com" TARGET=_blank>Buick Car Club of Australia</A><BR>Brian Flynn buickclub@wiredup.com

[NTX5467]

Tha main differences in converters (i.e., stall speed specs) will take place outside of the cruise condition orientation. Provided the stall speed isn't around 3000 rpm (i.e., "loose"), the different converter should not make a significant difference in cruise rpm.<P>Was there a significant reason you needed another torque converter to be installed? Did they put all of the switch pitch stuff back in the trans? Just curious as the switch pitch converter requires a particular front pump and some difference electrical wires to make it work.<P>Could there be some exhaust leaks from where they might have taken the pipes loose and didn't get them put back tightly enough?<P>Enjoy!<BR>NTX5467

[NTX5467]

If you give a known switch pitch converter out as a core on another converter, make sure you get a switch pitch converter back. I would suspect that unless there is some operational problem with an existing switch pitch converter, that a good flushing on a converter flushing machine should be sufficient to get the converter ready to use instead of taking a chance on a rebuilt unit--unless it was from someone that was well versed with "switch pitch ology" as that's somewhat unusual in current times--and offers some kind of warranty on the refurbished converter.<P>There might be some good aspects of getting the converter cut open and checked out, but it seems like they did not usually cause any operational problems anyway. Unlike a modern lockup converter, there are no friction materials or clutches in the switch pitch converter to fail. Usually, the only reason people replaced a switch pitch configuration with a regular configuration was parts availability and not durability issues (from what I remember).<P>Just some additional thoughts . . .<BR>NTX5467

[Guest 1965cat]

The only reason I put a new converter on was out of ignorance.. I assumed since I was having the tranny rebuilt and did not know where it had been, I should have a new/rebuilt converter installed. They said the pump was good and the solenoids checked out... From the reply's I have recieved, it looks as though the RPM's are where they should be at the speeds I am cruising... What originally brought this to my attention was the amount of noise the fan was making at cruising speed.. that is why I put a tach on there to see if it was too high of an RPM for cruising... It's a thermo fan and it makes quite a racket at 1800+ RPM's, it sounds like it is not working when it gets warm, i.e. it's stuck like it was bolted directly to the water pump.. is there an easy way to check this or is this how its supposed to function? I am going to search the other posts to see if there is info out there.<BR> Thanks for everyones help, This is my first ever rebuild and diagnosis of problems... what a learning experience!! Can't wait for the next Buick project!!<P>Thanks,<P>Mark <BR>BCA 372362

[NTX5467]

If the fan clutch is working correctly, it should freewheel as vehicle speed increases. If you got a fan clutch that is smooth on the front, it will kick out only with rotational rpm as there is no thermostatic spring to help it come in as needed. The factory OEM clutches will have the thermostatic spring on the front that are heat sensitive. They will still spin with the water pump, but will tighten up as the heat coming through the radiator gets above their design "activation" point. <P>In the summer, we used to get some customers come in with their 454 C30s complaining of a transmission problem while towing. They thought it was downshifting or slipping due to the fan noise. What it was was the fan clutch cycling in and out as needed and not the transmission.<P>Just some additional thoughts . . <BR>NTX5467

[Ted "Wildcat65" Nagel]

Check the fan clutch by seeing if it will spin with the engine off. If it has failed it will not spin. If its good, it should spin a bit but not freely. they make lots of noise when they are stuck!