can someone send me a pic of a correct 70 fan clutch? i have 2 and they are completely different. mgreene@crawford.com
thanks
thanks
-
-
1970 fan clutch. Which engine? AC? *NM*
Terry -
Re: 1970 fan clutch. Which engine? AC?
70 lt-1Comment
-
Re: 1970 fan clutch. Which engine? AC?
Don't know about 1970, but on midyears, both clutch designs (Eaton with the coil thermo element and Schwitzer with the flat plate thermo element) were used optionally/interchangeably throughout production.Comment
-
Re: 1970 fan clutch. Which engine? AC?
Send me a PM, and when I get home, and that will not be until after the Florida Regional, I can see if I can get you a picture of the one on the car -- much as one can see while it is on the car.
Maybe someone else can fulfill your request sooner.
Just as a hint you need the flat bar on the front -- that won't show in the picture. It also has straight fins -- curved fins is a later replacement. No slots for the mounting bolts -- another indication of a later replacement. The date code is usually on the edge (circumference) of the mounting flange. A straight up date MM - DD - YY SC. SC = Switcher Clutch I think I spelled that right. If new, or near new, there will be a small green spritz of paint on a few (1 to 3) of the fins which face the engine compartment.
Remember: Life is a beach.TerryComment
-
Addendum
It also will have the smaller bolt hole circle. 1971 began a larger bolt hole circle to accomodate a larger water pump shaft and bearing. No, I don't know what size smaller and larger is, but others who frequent here on normal days (non-holidays) will. I can tell the proper diameter by eye based on how close the nuts are to the flange shaft, but I have been doing this for far too long.TerryComment
-
Nah...Forget It!...
"I can tell the proper diameter by eye based on how close the nuts are to the flange shaft, but I have been doing this for far too long."
I know what you're thinking while you're down there in sunny Florida, but beach bumming would drive you nuts after two weeks.Comment
-
Re: Nah...Forget It!...
Florida?? You wish. There are lots of nice beaches even farther south.
Prospero Ano Nuevo
North and east to Florida next week. And life IS a beach.TerryComment
-
Re: Addendum
Terry------
Pre-1971 used a fan clutch hub bolt circle of 1-3/4"; 1971 and later use a fan clutch bolt circle of 2-1/8". This applies to BOTH big blocks and small blocks.In Appreciation of John HinckleyComment
-
Re: Addendum
Thanks Joe, I knew you woulld know the answer without references. I just didn't want to put you on the spot. Thanks. I'm sure the OP will appreciate that information also.TerryComment
-
Re: Addendum
Terry------
By the way, I should have mentioned that there's also a difference in the fan blade-to-fan clutch bolt pattern for pre-1971 and 1971+. The pre-71 used a 3" bolt circle with a 2-3/8" center hole; 1971+ used a 3-1/4" bolt circle with a 2-5/8" center hole.
The above information applies to CORVETTES. It's also GENERALLY true for other Chevrolets, but there are "exceptions to the rule" for other Chevrolet models. It's also POSSIBLE that some early 1971 small blocks used the pre-71 configuration for both the fan clutch hub and the fan-to-fan clutch. However, I've never been able to confirm that with any degree of certainty.In Appreciation of John HinckleyComment
-
More Addendum since we are there
And there is also a difference in the water pump shaft diameter from 1970 + .TerryComment
-
Re: More Addendum since we are there
Terry-----
Yes, there's a difference in shaft diameter for small blocks. However, there are 3 different places that shaft diameter can be measured and this is what confuses a lot of folks. Here's the deal FOR CORVETTE WATERPUMPS:
"pilot diameter" represents that portion of the shaft exposed outward of the flange;
"through-the-bearing" ("TTB") represents that portion of the shaft that is directly supported by ball and/or roller bearings and including the portion of the shaft to which the flange is an interference fit;
"impeller shaft" represents that portion of the shaft inward of the bearing and to which the pump impeller is an interference fit;
PRE-1971
small blocks:
pilot diameter= 5/8" OD
TTB= 5/8" OD
impeller shaft= 5/8" OD
big blocks:
pilot diameter= 5/8" OD
TTB= 3/4" OD
impeller shaft= 5/8" OD
1971 AND LATER
small blocks:
pilot= 3/4" OD
TTB= 3/4" OD
impeller shaft= 5/8" OD
big blocks:
pilot= 3/4"
TTB= 3/4"
impeller shaft= 5/8"In Appreciation of John HinckleyComment
-
Si!...Muchas Gracias Y Prospero Ano! *NM*
Comment
-
Re: More Addendum since we are there
Sorry Joe, I should have been more clear. Pilot was what I was thinking of since the OP asked about the fan clutch. I knew that a 1970 and earlier fan clutch has a different diameter locating or pilot hole than those used in later applications. Sorry I didn't remember the actual size. I hope he is still with us.
Thanks agina for your detailed information.TerryComment
Comment