I found this site a blessing and wealth of information... been reading topics for the last few days... found out new things each day.

Now for a brief vehicle history... my baby is a '89 Toyota 4Runner, V6 3.0L VZE EFI Engine, it has about 165,000 mi. It resides here in the Northeast (New England... Brrrrrrrr)

I am due for a tune up (well quite over due), and was wondering if Iridium plugs would be worth the extra money to replace the older plugs. They state that with the Iridium plugs less voltage is needed for spark and would help start on these cold winter days. (my feeling... and it may be misunderstood but less voltage would mean less stress on the whole ignition system, than the older plugs that are currently installed.)

Also, same thing for Syntheic oil, would it be in my best interest to use synthetic oil for my Senior Citizen vehicle and what would be the opinion of the best type for my needs? The truck spends most of the time on road, although there are the times in the summer i do stretch its so called legs and play a little off road.


Thanks
Mark

 

Yes and yes.

Iridium plugs last longer and fire better than other plugs, resulting in less maintenance and better ignition.

Synthetic oils....can't believe you are not using these already, in every engine, tranny, transfer case and differential you own. Longer life, lower friction means less maintenance and improved fuel economy.

For example:
I use M1 in the engine, changing oil once a year whether it needs it or not. With dinosaur juice, I would change oil 3 or 4 times a year. Priced out in just cost of oil, filter and labor, and I come out ahead. A few extra MPG is just icing IMO.

And as a point for reference, my 87 4Runner 22RE had the same once a year synthetic oil change schedule since I owned it from 43K miles to 190K miles over 13 years. Disassembled the motor after a high water crossing bent a connecting rod. The factory cross hatching was still on the cylinder walls and all the main and connecting rod bearings (except the bearing associated with the bent rod) measured well within tolerance.

 

I thought using synthetic oil in a high mileage vehicle can result in leaks? I would read up on it more, thats the reason I didnt switch to syn (120k miles)

 

i wouldn't waste my money on iridium plugs if your engine doesn't call for them. if you want extended replacement intervals, platinum plugs will last 30k easily. not to mention $2.50 each vs $12 for iridium plugs.

 

Engine doesn't call for synthetic oil either.....



NGK Iridiums from this Ebayer. He's worked well for me.

 

what have you noticed with thoes plugs?

 

On my 99 4Runner, I replaced the factory plugs at 33K miles with NGK Iridiums. Immediately noticed smoother running. Now has 83K miles and still runs quite smooth, at least when the MAF isn't acting stupid.

On my 95 NSX, Iridiums replaced the factory NGK Platinums at 25K miles. It also immediately ran smoother and continues to do so at 55K miles.

Also use Iridiums on a Spec Miata. Runs great.

Less maintenance, smoother running, $7 a plug shipped to me.

 

If the rubber is not vulcanized, as I was told. Also, told that synth cleans carbon deposits and can create a leak by removing deposits from an aged seal. I have and '86 4rnr with 193k on it and have used synth since 125k. It leaked a little, switched from 10w40 to 20w50, and leak slowed way down. Ran Auto Rx twice this past year, fixed the main seal, and still use synth. No leaky-poo! Just $.2!!!

 

The idea that using a full synthetic motor oil will cause leaks in a high mileage vehicle is hogwash. It's another myth perpetuated to keep the aftermarket repair industry in business with the help of the (outdated) 3000 mile oil change interval.
Very important, when using a synth motor oil (which actually is a petroleum dinosaur product whose desirable characteristics have just been maximized with certain additive packages, detergents, etc) USE A HIGH QUALITY FILTER! You need a filter that has the contaminant capacity to avoid becoming clogged at 5k, 7k, even 10k miles. So it doesn't matter whether you like those $12 K&N oil filters, or the $20 Mobil oil filters, or the $8 Wix filters, they're all premium filters. Just don't use PurFlow, Champ, Fram, etc.

 

i cannot comment on how good iridium plugs are compared to standard or pt plugs. but i will say that this reason is false. they may be better because they reach self cleaning temp faster, or the metal may not pit or degrade or things like that (i don't know if any of this is true), but the voltage that it takes to arc is only dependant on the pressure and the gap. it doesn't matter what material the electrode are. these two link talk about voltage breakdown of air:

http://www.allaboutcircuits.com/vol_1/chpt_12/8.html
http://home.earthlink.net/~jimlux/hv/paschen.htm

the main points are that air gnerally has a breakdown of about 30kV/cm/atm.

i haven't gapped plugs in a long time, but aren't the gaps about 2mm (.2cm)

assuming a volumetric efficiency of .75 and a compression ratio of 8:1, the pressure in the cylinder is probably around 6atm so the breakdown voltage is about 30*.2*6=36kV which is probably around what the coil puts out. it doesn't depend on the material of the electrodes at all.

sorry for the nerd rant - but i always want people to know what's going on and not listen to the marketing speak that's out there.

 

I've also been thinking about switching to mobile 1 with my next oil change. What would be the recommended change interval and would a toyota filter be good for this?

 

I've had the NGK Iridiums in my 22RE for a while now and I'll never go back to platinum. When I first changed them I had a noticable gain in power, and I don't have it documented, but I assume my MPG was better too. Not to mention the Iridiums last a long time, just take em out and clean em up every once in a while.

 

Toyota filter is fine. With the Mobil 1 you could probably go 7-8k miles or more. I would at least go 5k to get some value out of it. Mobil also makes a very expensive long life oil that will allegedly go 15k miles. I would change the filter halfway through that interval though.
If you're really curious, spend $20 at CARQUEST for their oil analysis kit. It has everything you need to mail in an oil sample and find out how degraded or contaminated your oil is.