BritishV8 Forum

Using them like daytime running lights and forget to turn them off.  Any reason not to use power that's only hot when the ignition is on?

And, while I'm at it, my fan is wired to a temp probe so it switches on & of automagicly.  The relay has constant power so the fan stays on even after I turn the car off (until the engine cools).  Should I switch it to ignition power too?

I don't see why you can't use switched power for headlights. As for the fan, I think it is a good idea to have it run after shutdown to cool the engine down and prevent after boil. I will have an electric water pump on mine and I have a switch provision for running both after the ignition is off to cool the engine down if it is really hot.

Hey Rob,
By all means use a switched power for your headlights.
You might even want to use a dropping resistor like a lot of the OEMs.
This lets the lights run at a reduced intensity during the day.
Or a nifty idea that some use is a relay to connect the high beams in series when the ign is on.
This gives a reduced power output and uses the often unused high beam element to even out the bulb life.
I generally use a relay switched by the alternator indicator or the oil pressure switch.
This avoids the battery drain when the engine isn't actually running.
As far as the rad fan, it's your call.
They get wired up both ways.
I prefer to have it run after the engine is shut down to help with heat soak.
Hope thats helpfull.
Cheers
Fred

...another possible solution comes in the form of inexpensive DRL conversion kits on the market.

Example added:
http://www.automotiveelectronicaccessories.com/aeapn480hd.htm

Rob, to reduce current load on the switch, just take off a switched power source and use that to engergize a relay for the lights. Run it off the accessory circuit and you can turn the lights on in an emergency without having the ignition on the run position and having the extra current draw on the battery of the ignition circuit.

Already have relays running the headlights.  They're wired the way Fred helped me figure out earlier this year or late last where the power is all outside of the cockpit & the switches control the ground connection.

Think I'm going to change them to use switched power.  The oil pressure switch idea is interesting, but I think I'm going to use an ignition controlled source so I don't lose lights in the event the engine dies unexpectedly.

I guess I'll leave the fan as is for now.  Seems anomolisticly loud when the engine's off but maybe I'll get used to it.

Taking the car to my son's high school car show this weekend; will try to get some current pics.

Another topic - anyone remember that post about a tool borrow/trade web site?  My motor didn't have a timing pointer so I used a screwdriver to find TDC (while manually turning the crank.  Not satisfied I got it right; would love to look with a bore scope.

Rob

The way to accurately find top dead center is to use a positive stop screwed into the spark plug hole. You can make one out of an old spark plug by removing the side and center electrodes along with the ceramic and welding in a piece of rod that extends far enough down to stop the piston before it reaches the top. You then turn the engine (by hand) until it contacts the stop and mark the balancer. Then turn the opposite direction until it stops and mark the balancer. TDC is halfway in between the marks - very accurate. Don't forget to remove your stop before you start the engine.

Looking forward to the pics at your son's car show.

Dagnamit... So close and so far.  I have a thing that screwed into the spark plug hole that has a threaded rod thru the middle.  I tried to use it to find TDC by slowly adjusting the center rod till the piston barely touched it.  Decided I was more accurate with the screwdriver.  Never occurred to me to let the tool split the difference.  I decided it just wasn't a very effective tool...  Proves the saying "it's a poor craftsman who blames his tools"!

I inherited a bunch of tools from an amazing guy who had a machine shop back when I was in college.  I've managed to learn how to use most of them but there are a few like this one that still mystify me.

It amazes me to see people building engines on TV that use a dial indicator on the piston to find TDC instead of a positive stop. If you use the dial indicator method there are several degrees of rotation where the piston just sits at TDC before you can detect any movement. The positive stop method is the only accurate way to locate the true TDC.

Now you can show off your fancy tool for your friends when they come over. What are some of the others that you haven't been able to figure out?

I'm there with you Jim.
The positive stop method is the only way to go.
The dial indicator doesn't "load" the components and on a loose engine you could easily be 4 or 5 degrees off.
Regarding the TV experts, I especially like the ones that tig weld with goggles a T shirt and sandals.
Cheers
Fred