with the formula in the link , you should be able calculate what resisters to add in parallel to get full sweep .  easier than disecting a sending unit me thinks??

34 ohm   60 psi

26 ohm   50 psi

21 ohm   40 psi

16 ohm   30 psi

11 ohm   20 psi

 8 ohm   10 psi

 

I find the generator is not extremely accurate. The dial has numbers on a "clock" face and I tested it first with my digital meter. Then I noted the values and adjusted the numbers so that the numbers shown above are accurate. Depending where you are on the scale, the generator is about 6 ohms lower than acutal.

Yes, I'm using the 1's scale. As soon as I get past 35 ohms it's pegged. NOBODY makes a sender like that! I'll be building one.

I've been through all the buyers guides etc that the jobbers have. I searched columns and columns for all makes. I found one that is not bad, I think it was 45 ohms @ 60 psi but that is still way too much. If I'm going to rewire the little resistor plate anyway, I don't think it matters if I start with an 100 ohm or 60 ohm anyway. I just unravel the wire, find where 35 ohms is on the wire and then re-wrap it around the plate with only that length wire instead of the much longer wire.

I'll try to post pictures once it's done.

A resistor will add base resistance through the entire scale so you could make it exactly correct at one point but it would be off at points away from that mark.
ie. starting with a 0-25 sender... adding a 10 ohm resistor would net a 10-35 ohm performance. so instead of 0 you still have the resistor in the circuit. The gauge would then start at 17-18 psi (10 ohms) and end correctly at 60.

Gut one of your slot car controllers for parts !!

Carl Stevenson wrote:

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I wasn't sure but I kinda figured it would work out that way.

I think I have figured out how to rewire an existing sender that will make it accurate. I just need to find really thin sheets of plastic for the block to wind the resistor wire on.

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Got you covered on the plastic, I'll bring you some on Saturday.

 TodayI bought myself a nice ratcheting crimper for doing the factory style wire ends.

The cluster is ready to put in now, all connections done. It's a plug and play now. All tested except the oil gauge because I haven't installed the correct sending unit yet.

Just can't put it in yet. First have to put in the tach, reverb switch, power antenna switch and AM/FM.

 

 

As simple as plug in, put cluster in position, install 2 bolts and 2 nuts that hold it in, and "Bob's your uncle".

Now  I really want one of those! Some day....

Like!

-- Edited by Muddawg on Saturday 11th of May 2013 08:27:06 AM

Hey Carl just for info's sake since i've got mine hooked up and running quite a bit I've been finding the oil pressure works great and seems pretty accurate as compared to the old aftermarket one that was in there.  However the temp gauge goes up to the hot end very quickly even though the engine used to run at a nice 180-190 with the aftermarket one.

Could it be the wrong sending unit?

I want to read this through when I get a chance. Looks very interesting.

www.lbfun.com/warehouse/tech_info/gauges%20&%20instruments/Temp-Sending-Unit-and-GaugeCF-Thread.pdf">www.lbfun.com/warehouse/tech_info/gauges%20&%20instruments/Temp-Sending-Unit-and-GaugeCF-Thread.pdf