16 replies to this topic

[D Jaws II]

Attempted unsuccessfully to install an afermarket oil pressure gauge last week.

First for those who do not know, this sensor is located directly above the oil filter. DO NOT RUN ENGINE PRIOR TO DOING THIS!!!! IT GETS REAL HOT!!!!

IT was time after three nights of racing to change the oil anyway, so I drained the oil and removed the filter to make access somewhat easier (not). Removed stock sensor and attempted installing a "T" with a very short extension. Didn't work, too much stuff in the way and no easy way to access the space (with the damn thing hot). Back to hardware store (as a side note, my first rule of plumbing applies to cars as well, Step one, fill car with gas. You'll be making multiple trips to said hardware store) to find a longer extension to fit the brass "T". Picked up a 1" 2" 3" brass extension. Chose to use the 3" because it was easier to hold while installing. Finally got my paws in there and after putting teflon tape on all joints to prevent leaking, installed back into block. Hooked everything up, and everything seemed fine, worked like a champ. That is until I got to the track, after the first set of hot laps, on the cool down lap, smoke appeared coming from the engine bay. Crawled under the car and sure enough it was leaking a small amount of oil from the freshly installed fitting. Removed the oil filter, and touched the brass and it fell off in my hand. Leaving about 1/4" of brass threads still in the bung for the sensor. After wrangling, getting that out without damage to threads, unhooked what I installed and put the stock sensor back in. The cause of the breaking must have been vibration of the engine. I really don't know and now I am stumpted as to how to get this thing installed without any further worries or problems.

87 CRX SI D15A3 strictly stock, for now.

Any advice? I'll all eyes.


Thanks,


Donnie

[jsgprod]

Donnie, sorry to hear about the problems, I would’ve warned you about the possibility of that long extension cracking/breaking beforehand. Not that I had the same thing happen but I did do that very thing back when I first installed an O.P. gauge in my first CRX a looong time ago, with a tee also. Then I went back after thinking about it and took it out before I raced it and mounted the tee at an angle that would work up close to the block. Ran it like that for years with no problems, until I no longer needed the original sending unit.

Here’s a drawing of how I ended up getting it to work with 1/8” NPT stuff. There's enough room to mount the original sending unit on the side or on the end, I mounted mine on the side FWIW.




Jay

[King D]

I really don't know and now I am stumpted as to how to get this thing installed without any further worries or problems.

Honda oil pressure sending units are BSP thread. you need a BSP -> NPT converter, or re-tap your block NPT. Personally, i won't run a T / T on a brass extension right off the block. Not uncommon to crack/break off a portion of the block casting hanging off a large sending unit. Use a short 2-2.5' length of braided line to a T, and connect your sending units.

OR... why even use a T to begin with... just use the aftermarket sending unit.

[EPcivic]

I just went through this as well a few weeks ago, except mine is even tighter than normal. Since I'm running the AWD block with an Si oil cooler, things were REALLY tight around the pressure sender. I've heard of people having problems with the brass fittings. What I did was to run a 1/8BSP to -4AN adapter, then a -4AN braided line to the firewall, and a -4AN to 1/8NPT adapter for the sensor. I didn't reuse the factory sender.

-Chris

[D Jaws II]

Well, looks I am not alone in having this problem. Dang, I just didn't think through the issue when I installed the damn thing. Kept fighting it knowing I should have quit long before I did. LOL

Jay, the right side illustration is what I ended up doing, except...too long of an extension, duh. If there are not any following issues with the ECU, I would rather just eliminate the stock unit. That would be my preference. Also, I sent you a PM earlier about some other possible changes in the making.

King, I didn't realize there was a difference in threads. I "assumed" (my bad) that they were something else, don't work that way, huh?

Chris, I have to agree with all of you, braided line with -an fitting is the way I will go. One question though, why not use a fitting to put the oil line tube into (don't know the name of it) the block and run that to a "T" mounted on the firewall with enough slack that it would not stress the line? Braided would be even better i guess, huh? Are those fitting numbers exactly what is needed? If so, that was a home run!!!! Kudo's (Glad I filled up with gas, even at $3.29 Track gas is currently $7.50 gal ) Off to the hardware store and speed shop.

I hope to be putting on a new head/intake in a couple of weeks, I believe I'll wait and eliminate that headache all over again.

I appreciate all the input. This type of issue when I was growing up, just had to be worked out in one's own mind, there was no internet way back when. Greater appreciation for technology now'a days.


Donnie

[DEIVIONCRX]

My biggest problem with using a T fitting, would be the added weight on the block could break off if you hit a good bump.
It would make it alot eazyer and worry free IMO to use a SS line and do it like this.

[D Jaws II]

Deivioncrx,

Grand slam, man. WOW, that, too will help, great idea about the ground.

Thank to all, this is going to get fixed right, finally.

Someone needs to sticky Deivioncrx's drawing to a DIY for future reference.


Thanks again,


Donnie

[kakabox]

My biggest problem with using a T fitting, would be the added weight on the block could break off if you hit a good bump.
It would make it alot eazyer and worry free IMO to use a SS line and do it like this.

Nice...great tech.

[EPcivic]

Nice diagram. That's pretty much what I did, except I don't have the stock warning light for two reasons. First, I don't have the factory gauge cluster, and I didn't want to add an idiot light. Second, the pressure that sets off the light is so low, it isn't going to help in a racing environment. If the oil pressure drops low enough to set off the light while I'm racing, it's already too late.

There shouldn't be any problem with using nylon tubing and compression fittings - this is typical for gauge installations. I just couldn't bring myself to use one - it just seems too fragile. I'd sure hate to loose a race motor to something silly like an oil gauge line.

Also, as shown on the diagram it is critical that you ground the sender - it won't work right if it isn't grounded.

-Chris

[D Jaws II]

Nice diagram. That's pretty much what I did, except I don't have the stock warning light for two reasons. First, I don't have the factory gauge cluster, and I didn't want to add an idiot light. Second, the pressure that sets off the light is so low, it isn't going to help in a racing environment. If the oil pressure drops low enough to set off the light while I'm racing, it's already too late.

There shouldn't be any problem with using nylon tubing and compression fittings - this is typical for gauge installations. I just couldn't bring myself to use one - it just seems too fragile. I'd sure hate to loose a race motor to something silly like an oil gauge line.

Also, as shown on the diagram it is critical that you ground the sender - it won't work right if it isn't grounded.

-Chris

Good point on the idiot lights presets that are set too low to actually prevent damage.

You are absolutely correct about the fragile nature of the nylon tubing. Something to consider when doing this. As a alternative, what should be used? Recommendations?

Leaks at the track are not fun, aggravating and could lead to a costly outcome.


Thanks


Donnie

[jsgprod]

As far as what to get for the oil line, this price is hard to beat. I’ve been telling myself I need to order one for the better part of a year now. Oil line

I know these are available elsewhere also (like Pegasus) but since I already listed their oil line… Pressure & Temp sending units

Jay

[Greg Gauper]

Keep in mind, some sanctioning bodies don't allow the clear plastic tubing in the cockpit area. You have to use braided steel like Jay indicated. That is a good price.

They do make aftermarket oil pressure switches designed for racing with higher settings. Most people wire them to a big honking red light on the dash. The reason? Sometimes the red mist takes over when you are racing and you can forget to look at the gauges. A big red light gets your attention.

[D Jaws II]

Thanks guys. Very good info for those of us who haven't done this before. Or for us who didn't think through the issues before installing one the first time.

Donnie

[DEIVIONCRX]

I was going to say i bet you could figure out how the sensor works, and modify the signal to make it come on sooner. I know it changes resistance based on PSI so maybe throw in a small resistor so it would trip at 15-20psi insted of the 5psi or whatever stock it is.

[Greg Gauper]

I'm pretty sure the stock sensor is nothing more than a switch and not a variable resistance device, based on the wiring diagram....

Nothing you can really modify.

Edited by Greg Gauper, 16 May 2007 - 08:23 PM.