distributor cap zapped me a couple days ago and just turned 280,000 on the odometer so thinking its time to do some maintenance. Going through the local toyota dealership was a royal PITA last time, so was going to give rockauto a shot since it's been recommended to me before and they have denso wires and plugs cheaper than any aftermarket wire set at the local stores but they don't have denso distributor caps so was looking at the standard motor parts cap with brass components vs all the others which have aluminum.

 

idk which one would be better (i would just go with aluminum personally, its a better conductor), but i LOVE Rockauto. If i know i need to work on something in advance, i try to order most of my parts from there, i usually save about 20-30% over what i would going to napa or somewhere. Returns are super easy as well if you have to return something.

 

Brass has a much higher melting point, and is a much harder metal. So I would think that it should last a lot longer than aluminum when used as an electrical contact. I can't really see how electrical conductivity is even a factor worth considering, in this instance(such a short path). I'm sure both conduct electricity sufficiently enough to more than get the job done there.

Not sure what Denso is using in their distributor caps these days, but the OEM distributor cap on my 88 3VZ-E has brass contacts. So I'd tend to stick with that myself.

Brass is also ~3x the price of aluminum, pound for pound. Which says something in itself.

 

kickass, looks like I'm going with brass, its funny cuz brass was also the cheaper one. I've also got the 3vze, I was really hating it most of this last late summer/winter season because it was dogging so bad in the hills and suddenly mileage dropped from 18~20mpg to about 12mpg, then I checked my spark plugs and well... the .72 wire on my gapper passed right through them, so lesson learned, nobody touches my 'yota unless they are also a fanatic and stoked about working on it. instantly no misfiring, mileage jumped back up to 16~18mpg (down to 15 now) and POWER

 

always always always use brass over aluminum for conductivity of any electrical current... aluminum does have conductivity bus brass has alot more. I know this because Im an electrician amoung other things hehe

 

Well...YOU'RE WRONG!!!

There are few things that conduct electricity better than aluminum. BRASS IS NOT ONE OF THEM. Gold, Copper, and Silver are. I know this because I work on electronics frequently.

Study the charts in the following link for proof.
http://www.tibtech.com/conductivity.php

 

lol ill be honest i get the two missed up i meant copper not brass... been a long day head not on straight lol.. i never see brass or aluminum as conductors in my field.. i always see copper everywhere I work of course I work on RV and mobile homes so nothing by siding is aluminum in my industry...unless you count all the heat sheilds hidden throughout an rv... but yea mud you got me on that one I just fluked up in my thinking and got brass confused with copper... hey come to think of it they have any caps with any of those??

 

If brass and aluminum are the choices, Then go brass.
Brass does not burn away as much as aluminum from arcing.
The dull coating that builds up on aluminum is aluminum oxide, which is a protective skin and is non-conductive, This builds thicker as arcing accurs and lowers spark power and chance.
Brass does not expand and contract from temperature change which can cause arcing at the wire plugs or loose terminals.

 

My experience with both aluminum and brass distributor caps in a 86 2WD SR5 22RE engine 5-speed manual with a 20 years with a MSD Master Blastert II coil sending 45,000 volts vs. stock of 12,000 to 15,000 volts.

They both idle as smooth and accelerate as fast.
They both return the same gas mileage of 32 MPG doing 65 MPH.

They difference is the internal posts on the Aluminum create a horizontal scar line with a layer of oxidation/crude that looks like a 'scab'. With a small fat blade screw driver you can lightly scrap the scab off and that's when you see the scaring. Need to do this once a year during the Spring tune-up. Afterwards you do feel some better throttle response. Might be the higher voltage causing the aluminum to corrode quicker. Had less scaring and scab on the OEM coil.

Where as the brass does not scar or scab. It still needs a light touch of sand paper to bring back the shine, but then almost like new.

I am running the brass now and at 33 years of daily driving since bought new and 469,000 miles it idles smoothly even though it's a 22RE .

I would highly recommend an upgrade to a MSD Master Blaster II coil as it make the throttle response time quicker and higher RPM power doesn;t seem to drop quite as much. Mine is 20 years plus old and never had one issue. For ~$55 it's a great upgrade. Running stock OEM Toyota plug wires is no problem and the best to use. I tried many others and back to OEM.

 

Please only use OEM cap and rotor. (edit: and coil)
Or don't, and chase random issues (weird idle, misfires, jumping around light while trying to hit 5° TDC) until you buy them anyways.

At least I have never had luck from aftermarket cap and rotors on one of our 4runner (2x 22RE, 2x6slow)

 

I put an aftermarket rotor and cap on my 88 one time, and the rotor button exploded while I was driving down the highway. I ˟˟˟˟˟ you not, sounded like a gun shot under the hood. I only go oem now and never look back. don't have to go to a dealer, use one of the many oem parts websites now. I get wires, plugs, cap, and button all from Toyota. the wires even come with the handy little plastic keepers still.

 

Hint: Toyota does not make their own rotors and caps. If you buy cheap aftermarket, you can tell from how the rotor is made, you may have issues. There is pure junk out of there and there is quality. Never had an issue with the rotor, caps, and coil in 33 years.