Autometer gauge question..attn Mr Baxter

[Whaler]

Hi
I have the autometer Cobra replicas..a set of seven
replaced the clock with an oil temp

I have one question for anyone who has done the mechanical pressure gauges ( 2 1/8") It says to use nothing else BUT a SS braided signal line to this gauge from the engine?? AN 4

Why can't I use the old copper 1/8 capillary tube with the approprate ferrules and nuts

My hole set is mechanaical as was the original Smiths

The autometer classics will come in either.

Also For my temperature gauges what size is the hole to be drilled in the firewall/footbox for this grommet....

Tim

[Cobranut]

Whaler,

Two reasons:
First, the gauge response will be VERY slow with 1/8" tubing.

Second, and more importantly, safety. Copper tube will work harden from vibration and eventually break, spraying hot oil all over your very sensitive area.

Also, if you use a fuel press gauge, use an isolater in the engine compartment. You don't want to trust even braided line piping fuel into the cockpit.

Later,

[Whaler]

Cobranut

Thanks for the advice, I guess I have to buy the SS braided signal line now...AN4

I only have the oil pressure gage (model 201006) to worry about, no fuel pressure gage

I found both the 90 elbow at the gage and the AN 4 braided is available as accessories. What length do you guys suggest??
Choices are 3,4 and 6 ft.

BY the way AN4 is 3/16" ID

Tim

[Horse]

yes use the 90 and the SS- thats what we do- as for lenght- what ever is the best for you- I say this because I cant remember what length it is!

[JEwalt]

It sounds as if you are going to run the SS line from the engine, through the firewall, to the gauge. You might want to use an AN bulkhead fitting at the firewall then run one line from the engine to the fitting and another from the fitting to the guage.
Jeff

[Whaler]

Yes Jeff
Thats the plan. I would prefer not to have another two connections to worry about ( ie a bulkhead fitting)
I am uneasy with more connection and the customness of multipes line and there corresponding differing lengths ( a pain)

I will just buzz thru using the rubber grommet

As for length I guess I will have to measure it out...watching for the headers will be the challange as I plan to run down to the 427 style remote oil filter adapter and tap off that 1/8 NPT female post.

Will the autometer line kit use the appropriate an4 to 1/8 "pipe connector, is it included??

If so I guess an elbow or a straight is the big question...at the motor side



Tim

[Whaler]

Screw it I am using 1/8 copper line as planned....its what I work with day in and day out at my mill and I seldom see that stuff break. We use it on fire detectors ( filled thermal systems) to trigger sprinkler systems..you should see the rough service and heat that line gets. Its in a papermill dryer...

I priced out the 6 ft an 4 line from autometer...guess what...115 CDN....Thats more than the gauge was...LOL

So I will use the copper line I had planned on initially....It will make a better run anyway.

I have friends with 70's muscle cars using the same thing...no problems.

Tim