I dropped a sbc into a 38 chevy pu.now im about to mate the 38 mechanical gauge to the motor.its the original gauge with a longer capilliary tube fitted.if you have done something similar lets see how you did it,how you routed it,how is it working out.thankswhat are the pitfalls of the copper tube ?
No tricks to this. Just make sure you have a match between the engine water hole threads and the capillary tube threads. Buy a brass fitting to mate the two if they are different.
the threads are good and the same.my issue is the tube is way longer than it needs to be..i was thinking of coiling the excess under the dash.what diameter pipe is ideal to wrap the excess around to create the coil and what about the 90 degree bends near the gauge and sender what size pipe /tube is ideal to create the bend thanx I have a pipe bender but be easier to wrap around a piece of tube/pipe
Just coil the excess up under the dash and don't make any sharp bends. Protect it from vibration and rubbing on anything and don't let it short out on any electrics.
On my sedan I have the extra coiled up under the dash, with tight wire ties holding it out of the way of electrical stuff. If you don't get it tight it will shake and make springy sounds. As Double said, DO NOT MAKE SHARP BENDS. Gentle bends prevent kinking, see the sender behind the oil filter canister.