• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

What are you doing to your rig - the continuing saga

I dood this:



It's still a tired engine with bad compression on two cylinders, blows oil, and needs a rear main seal, but the T-body does make it run stronger. It also seems to run smoother, aided by losing a vacuum leak, and fixing the exhaust.

So Fred, did you bore it out yourself? If so how did you make the throttle plate? My mill is down at the moment, but I have been wanting to do this or make an adapter and run the later model throttle body.
 
I had it done by Lehigh machine. I'm the farthest thing from a machinist. I'd do the adapter, the biggest a Renix can be bored is 60 mm, and you have a stroker. You need a big! t-body. :)
 
Changed the rear main seal and oil pan gasket. Not too bad of a job, everyone makes it seem harder than it was. Next on the list is the valve cover gasket, oil filter adapter o-ring and distributor o-ring.

Also installed my new winch on my new bumper!
 
Forgot to mention this:

STOCK
Voltage at Battery, 12.16 Vdc.
Voltage at Headlight 8.5 Vdc at Passenger side.

WITH RELAYS
Voltage at Battery, 12.16 Vdc.
Voltage at Headlight 12.09 Vdc at Passenger side.

When deciding on how to handle the grounds, I measured the resistance of the stock connector location to the battery post. It read 0.04 Ohms. So, rather than run discrete ground wires, I used the stock connector via a 1/4" spade on the new connectors ground location.

It should be noted that this value was at the Driver's side (worst case) connector, the Passenger side value was 0 Ohms... At least Chryco got something right........

The wiring is done as follows:
1) A 10 gauge wire from the battery to the fuse block.
2) 14 gauge wire from fuse block to relays.
3) 16 gauge wire from relays to headlight connector.

Now before anyone jumps up and says that the wires are too small, the circuits carry less than 10 Amps and the run is less than 10 foot. The PDC holds a single 10 Amp fuse for the stock wiring and that has a considerably longer run...

I installed discrete fuses for the low/high beams. Once I get around to measuring the actual beam currents, appropriately sized fuses will be installed. Plus, once the LED headlights go in the fuses will need be changed again...

And yes, my battery is down from it not being driven much. Will toss it on the charger.

Did you use 2 relays total (one for low beams, one for high beams) to run both head lights or 4 relays (2 relays per head light)?
 
Good info there... are those headlight voltages measured from chassis ground to bulb positive pin, across the bulb pins, or from bulb positive pin to battery negative? If it isn't across the bulb pins, those are some excellent gains but I would bet you have around another 0.4V to gain yet!
 
To Summarize the project:

After reading all the posts, here on NAXJA, on just how lousy the headlight voltage really is, I decided to take measurements with my Fluke Model 87 III digital multimeter and those values recorded were verified with my Fluke Model 8021 B digital multimeter. Both meters have been through their calibration cycles within the last year so, I have faith in the accuracy of the values reported.

All of the voltage readings were taken as follows:
Both bulbs were removed from their respective buckets and left dangling on the factory harness. The meters were then connected across the terminals of the bulbs and the voltages recorded. The engine was off, the key was off. I regarded this as the "worst case scenario" for the voltage.

After verifying the length of the wire run, I made the decision to use 16 gauge wire as the current draw is less than 10 amps and the run length is less than 10 feet. Direct Current wiring is susceptible to line loss to a much greater degree than is Alternating Current so wire size is important. On the other hand, utilizing wire in a gauge larger than is required is just a waste of monies. It does not buy anything is the way of performance.

The feed line (42" plus the 6" jumper between the blocks) from the battery to the fuse blocks (There are now two of them on the firewall...) is 10 gauge with each headlight relay being fed by a dedicated (one 6", one 7") 14 gauge wire.

There are two relays, one for each "beam". These relays sit in a box on the firewall. For those that remember what my firewall looks like, the single relay that was there has been relocated into the relay box along with the two new relays for the headlights. This was done to tidy the firewall....

The 16 gauge wires that run to the headlight connectors are not solderless. In fact, every connection made was soldered as I have a "thing" about solderless connections.... Personal thing, have seen too many of them fail in the field.

To quantify the ground situation, I disconnected the headlights from the harness and Ohmed the connector pin to the battery ground post. I found 0.04 Ohms resistance. My leads have 0.02 Ohms resistance in and of themselves so the actual displayed value was 0.06 Ohms.

Side note: To eliminate a variable, the same leads were used with both meters. A small point to be sure but..... I do tend to strain at gnats...

Beginning Voltage:
Battery = 12.16Vdc
Headlight = 8.5Vdc.

This is an initial voltage loss of 30.09% an improvement should be rather easy.

Ending Voltage:
Battery = 12.16Vdc
Headlight = 12.09Vdc.

This is a final voltage loss of 0.57% an improvement to be sure.

Wire gauge selection was assisted by this calculator:
http://www.bulkwire.com/wireresistance.asp

To be sure, I had already selected the wire size based upon experience but, I never trust my experience, I always double check. Very Old Habit from when I was a working Engineer....

BTW, me being me, I polished the pins at the headlights to improve connectivity. As it turned out, it was a somewhat wasted effort as the performance did not improve. But then again, these bulbs are only 5 years old...

Once the LED headlights go in the beam dedicated fuses will be replaced. The factory headlight fuse (10 Amp) has been replaced with a 5 amp fuse as all it is now protecting is the relay coil wiring and the relay coils themselves.

As for attempting to improve this result, I fail to see how it can be done. The total system loss at the headlights is now a whopping 0.07 Vdc... For all intents and purposes, there is no loss.

I did not purchase a harness, I built mine. Again, a personal thing as I just hate to buy what I can build myself. Was it less expensive than the commercial harness? No, it was not. It cost way more but I feel the investment is justified fro not other reason than it forced me to think it out and build it. At my age/health condition any sort of build event that I can pull off has value...............................................
 
Yeah, makes sense. Just wasn't sure if you were including ground return wiring loss in your measurement or not. You are, so all's good as far as I'm concerned.

To add to what you said, halogen bulbs use the halogen cycle to rejuvenate the filament during operation, but it only works when the bulb is up to temperature. The halogen cycle allows them to operate the tungsten filament at a much higher temperature than a regular incandescent, which is what requires the special quartz glass bulb and installation/handling requirements. The much higher temperature is what makes halogen bulbs so much whiter and brighter than regular ones. And the effect is exponential - wikipedia says it's a cubic function.

lightoutputcurve.jpg


Bulb life degrades significantly if undervolted more than a little, because the temperature doesn't get high enough to make the halogen cycle work.

With (some) LED lighting, it's nowhere near as important, as they have a buck/boost converter built in that drives the LEDs at the recommended voltage and pulse width no matter what voltage (within reason) you feed them. Cheaper units sometimes don't have this benefit, it depends on the design.
 
I should have mentioned hat there is a set of Sylvania Silerstars installed. I have used these for years and, whilst not the very best bulb on the market, they have a reputation for longevity...

kastein,
Not too terribly surprisingly, I quite agree about bulb life versus bulb operating voltage. All bulbs have a "sweet spot" that allows for both longevity and output. I am actually surprised that these have lasted as long as they have given that they were operating at such a low voltage.

I take your comments very seriously as you are one of the very few on this site that knows what you are on about.

It is a certainty that I endeavored to be thorough in the project. What else do I have to do but be anal retentive in my installations? If I have failed to impart the knowledge gained by this project, that fault is mine to own and I apologize for that. I freely admit that I have difficulty writing...
 
With the help of Led, Crispy, Fred, Joe F. and Flores we got the old rig stripped down last weekend. Got the hood swapped onto the new rig as well -didn't feel like cutting in the hood vents again so swapping the hood was easier. Cody did my window tint last week :thumbup::thumbup:. Yesterday I got the control arm bushings & races replaced with new ones and got the cage, steering links, track bar, front bumper, rock sliders and axle housings repainted. Next weekend is build the new rig.

So Long Black Jeep, you served me well. :wave1:

 
Follow up on the headlight rewire project:
On '97+ XJs, there are four 10 Amp fuses (F3, F4, F5, F18) associated with the headlights. One Fuse Per Filament.....

I took current readings today and found this:
Low Beam (two filaments) = 8.75 Amps
High Beam (two filaments) = 10.34 Amps

Based upon these readings, I have replaced the 10 Amp fuse I had in the high beam with a 15 Amp. If there were a 12 Amp available...

Essentially, this rewire project has cut the current draw in half.

In theory.... The lower current draw will reduce the load on the Alternator unloading some of the parasitic power loss from the engine.

Means, more available for the road wheels...
 
Back
Top