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Mechanical Oil Pressure Gauge- is it OK to mount inside?

11K views 31 replies 19 participants last post by  sm96mustang 
#1 ·
Probably the dumbest question you will read today- Is it OK to mount a mechanical oil pressure gauge inside. It will be mounted on the pillar. Its an Autometer.

I know you can't mount a mechanical fuel pressure inside, that is the only reason I ask.
 
#2 ·
Yes, it's fine, but I recommend springing the coin for the braided stainless feed line.
 
#4 ·
Yes you can, it will be fine if you use an autometer 6' steel braided line. That is not going to be fun trying to run up through the A-pillar though.
 
#5 ·
It's not that bad, I fished mine up there no problem. Gotta take the A-pillar trim off to cut a hole in it for the gauge pod anyway, so the tough part is fishing it up in the cranny between the dash and the A-pillar. Still no biggie if you tie a length of electrical wire around the end of it, stick the electrical wire up first, then use it to pull the braided line up. And I ran it through a slit I cut in the big steering column grommet to get it through the firewall.
 
#6 ·
i know most people go for mechanical gauges to save money, but by the time you factor in 10 or so feet of steel braided hose, and a mechanical gauge.. im pretty sure the elec will be similar in price.. and less chance of horrid mess, and easier to install.. just my .02
 
#7 ·
The install is easier on the electrical but if you're trying to do it cheap, you'd have to find it used.

Autometer full sweep mechanical oil pressure gauge: $50
Autometer 6-foot braided line $61...and I'm pretty sure the $50 4-footer is all that's required for an A-pillar install
Miscellaneous adapters $5
Total: $105-116

Autometer electrical full sweep oil pressure gauge: $200+
 
#8 ·
The question is simple - do you want the potential for hot oil inside the car? If your answer is no - go electrical. If you're ok with that risk - go for the mechanical with the upgraded line as suggested by MFE.

With the quality electrical gauges and senders that are available today - I wouldn't run a mechanical that required liquid to pass through the firewall. But that's just me.
 
#11 ·
Me too on the mech. oil pressure. Had an Autometer electric and sender was a problem from pretty close to the beginnning. Any dip in voltage and the thing would read erraticly. Had to restart the car and then it would read correctly again for a few minutes and then back again to BS. Now that I have the mech installed, I see that I have great oil pressure for a 150k engine. Once hot, idle pressure is 35-40 psi, cruising around it follows the revs very well. I put in the plastic line for now and plan to use it to pull the braided line in place very soon. Dont like the idea of oil in a plastic line in my interior either. Used some 3/8" fuel line to protect it from the engine heat when I ran it from the firewall to the oil press. tap. too close to the header for plastic,teflon or whatever.....haha.
 
#12 ·
Use 1/8" copper line w/comp fittings from sender to gauge. It's soft & w/bends easily. Further won't explode like the plastic line. The easiest way to get wires & lines to "A Pillar" is use a coat hanger w/the hook cut off. U simply straighten it out, run it down thru the dash(NOT UP THRU)..I bend a small U & hook the line/wires onto it w/elect tape. The tape holds it in place & prevents them from getting caught on shyt while fishing them down thru & out the firewall..Works for me & I install a lot of gauges!!!
 
#18 ·
Someone needs to read reher morrisons page on oil pressure gauges and senders. I used to use the 1/8 crap on my cars. I read what David Reher had to say about it, I use -4 stainless line if the pressure fluctuates any at all I know it right then. 1/8 inch line is not accurate. I proved this to myself I went out and made a pass in my car and at the end when I let off I saw some drop in pressure more so than with 1/8 inch copper or plastic tubbing ever showed.
 
#13 ·
I had a mechanical oil pressure gauge leak inside the car once, made a mess and ruined the carpet. Luckily it shot down into the floor instead of up at me. This wasn't a line leaking, it was the gauge it's self leaking internally. The oil came out the light bulb socket. Never again.
 
#14 ·
All cars before 1985 were all mechanical gauges with most of the time plastic tubing. The copper tubing is good and so is the braided line. Just make sure you route it good around headers etc. Do not be afraid of mechanical, they have less probs than the electrical, also more accurate, Sending units go bad or are slow to react at times.
 
#16 · (Edited)
"All cars before 1985 were all mechanical gauges....."

Someone knows not of what they speak. Circa 1982 - Volvo - all factory VDO electric gauges....in fact, it's been a long time since any cars came from the factory with mechanical gauges other than the speedo -- and even those stopped being mechanical for the most part over the last 15-20 years.

 
#17 ·
Michael do you have a website? I've always wanted to see lots of pics of the 5.volvo.
 
#23 ·
Thread back from the dead, I just did this tonight with braided stainless steel line and when I started the car up oil sprayed all over the inside of my console above the heater controls and all over my carpet and floor mat on driver side. I have essentially destroyed my carpet. I am WAY too pissed right now to see if the line sprung a leak or if I connected the line to the gauge wrong.:curses:

Obviously, my vote is don't put it inside the car.

Scott
 
#24 ·
Dammit man! That sucks bad and my heart goes out to ya for sure. Can anyone say worst case scenario? I am tryin to figure out how it could have been operator error in any way, no offence. Using braided line you think it would have been blatantly obvious if any cross-threading was taking place when you were cinchin it up. Over-tightening the fitting is a possibility tho but I am gonna be positive on your behalf and put my money on a defective gauge. At least that way you arent kickin yourself while your steam-cleanin......Good Luck!
 
#25 ·
the other question is did you use teflon on the connections? Right adaptors? I had 1/8 before, but somehow I kinked it and had a drip going down my a pillar so I bought autometer stainless line, never ever had a problems with it. Mechanical gauges are nice, more precise I think, meaning it displays actul readings instead of a sending unit has to translate it to signial they gauge can read.
 
#26 · (Edited)
The only thing I'm really pissed about was that I put the gauge pod back in and tightened everything up and started the car when really I should have left the gauge dangling out to check the connections in case this happened, then I would have seen it before it got messy.

I did use teflon and am pretty sure I didn't overtighten, but it just seemed odd that no other fitting needed to go in between the line and the gauge like I have on the other end where the line meets the block in front of the oil filter. So, last night I reconnected to the gauge but put one of these in between-



And now it doesn't leak and holds pressure. The small copper line I had in before this had little ferrules at both ends to prevent leaking, but the braided line just has -4 fittings at both ends so I was not sure if you can just screw them on or if some sort of adapter like above is needed.

I still have a pretty soaked carpet under my pedals with 3 rolls or bounty towels soaking it up. I may just spring for a new carpet anyway. So yeah, it seems it was pretty much operator error, at the very least for not leaving the gauge out to check it before buttoning everything up.:crying:

Scott
 
#27 ·
You can't just screw the braided steel AN line into the back of the guage, you need an adapter
 
#31 ·
For a street car mostly stock application Electric is probably fine. I prefer mechanical gauges whenever I have a choice. As far as using the 1/8 line (either plastic,not NHRA legal or copper), the engine could piss most of the oil out before you knew from the gauge reading. On my car the autometer mech oil gauge took about 3 seconds to drop to zero after shutting the engine off. A lot can happen in 3 seconds at 6500-7000 rpm. With a 1/4 line I can see the holes in the crank go past the bearings... Well that might be exaggerated ;) But it is very responsive. With the old setup I never saw a sudden drop in oil pressure in the shutdown. I discovered that if I run 5 quarts in the seven quart pan it drops to 20 lbs on the shutdown. 5 & 1/2 quarts, it drops to about 40-50. I would have never known without going to the -4 braided stainless line
 
#32 ·
I like the responsiveness (and price difference) of mechanical over electric gauges, but that's just me. I've had a mech. fuel pressure gauge in my car - with an isolator - for over 10 years (used to have a supercharged 4.6). With my 351 swap, I now have a mech. oil pressure gauge which has been in for over a year. Both with no problems.

I wouldn't run either of them without braided steel lines. The clear plastic lines that come with the gauges are way to easy to break (I only ever used it for my vacuum/boost gauge), and the copper is too easy to kink, pinch or break. Do what you're comfortable with, but with proper fittings and lines (and an isolator in the case of fuel), it's no big deal to run those gauges in the car.
 
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