Engine TLC specs

[Rezonans]

Hello everyone, I am a new owner of 1986 toyota Itasca 19 ft, I'd like to now few things about the new buy.

The motor home is in OK condition, I got it in Nevada, it was sitting in the desert for 10 years, but it's ok, it has 90 000 miles on it.

The engine is a bit noisy, drives good, I make 300 miles from Las Vegas back to LA with no problem.

Before I make my first trip to LA, I put some Seafoam to engine oil and put a fuel injector cleaner in a fuel tank.

RV is little slow but I can easily get 65 mph on freeway and up the hill from 1000 ft to 5000 ft on I-15 about 40 mph.

I want to do some TLC, fix engine noise looks like valves or chain tensioner or exhaust gasket.

Also I need to prepare truck to pass California smog check.

What kind of engine oil I should  I use

is spark plug gap 0.030 is ok,

what kind diff oil, (regular or synthetic)

how much in rear axle  6 lug

I have PDF service Shop manual for 1988 Toyota hilux truck/ 4runner, can I follow it all the way, or because I have RV, based on Toyota truck the specs is little different.

Thank you.

 

 

 

 

[Derek up North]

I don't think anyone has any 'magic' recipe of specs that work better for a motorhome. The only 'magic' that seems to work is an axle ratio change from 4.10:1 to 4.56:1.

[zero]

Rear axle takes around 2 1/2 quarts of GL5 oil.

The question of so-called "synthetic" over conventional oil is up to you.  Most oil sold as "synthetic" isn't, anyway. The main gain with real synthetic oil is the high-heat tolerance and broad temp range it can run in.  So if you run your engine at 300 degrees F or start your engine when it is 40 below 0 F - true synthetic has advantages.  There is SO much hype written about it - I'm not even going to try to give my "full" opinion.  My suggestion?  Older engines (built before 1990 as ballpark figure) are designed for motor oil with the extra wear-protection that ZDDP gives.   It has been mostly removed in oils for 2010 and newer engines (another ballpark figure).  So if you want the best oil for your engine - regardless if synthetic or conventional - get something made for older engines with a high ZDDP content.  Shell Rotella T has it.  So does Mobil 1 "high mileage" synthetic oil. Most (but not all) diesel rated oils have it. All racing oils have it.  Many "off road or tractor" oils have it.  It's an emissions thing.  The emission systems used in new cars cannot handle the ZDDP.

There are a lot of parts-store oil sellers that have little understanding of the API rating system and thing all of the newest classifications are backwards compatible. They are not.

 

[zero]

.030" spark plug gap will work fine. The figures given by Toyota are "compromise" figures anyway. My 22RE calls for .032".   A narrower gap means you get less max voltage potential and a plug might foul easier. In the real world - it makes little difference. To the converse - if you set the gap too wide - the ignition system is forced, all the time, to make higher voltage then it is really designed for.  This higher voltage can lead to plug wires shorting out if not in perfect condition.  Or the ignition module running too hot, carbon-tracking inside the distributor cap, etc.  Set it to factory specs or close and you'll be fine.  

[Derek up North]

On the subject of plug gaps, there are some (I'm not one of them) who swear that it's absolutely critical to buy them only from a Toyota Dealer because they come pre-gapped at 0.032" and that 0.30" won't work. I don't care where I buy plugs because I always check the gap anyway. If you don't own and know how to use a set of feeler gauges, how do you even know that they need adjusting or replacing anyway?

[Maineah]

The US is the only country that can call oils with a few drops of synthetic oil "Full Synthetic" Europe and Asian countries do not allow it to be called Synthetic Oil unless it is. Just about every thing in the states is a blended oil yes even Mobile One "full Synthetic"  As JD said the conditions have to be extremely harsh to demand synthetic oils in the first place. In the case of the long mileage draining with a syn. oil that's not a real good ideal in some thing that may only see less than a 1000 miles a year. 

[zero]

20 minutes ago, Derek up North said:

On the subject of plug gaps, there are some (I'm not one of them) who swear that it's absolutely critical to buy them only from a Toyota Dealer because they come pre-gapped at 0.032" and that 0.30" won't work. 

Those people are out of their minds (in my humble opinion).  Gap determines max voltage potential which an engine rarely, ever, uses.  It takes about 15,000 volts to fire a clean .032" gapped sparkplug in a compressed air/fuel environment when there is a distributor in the system. Note that it can take an extra 5-7000 volts just to jump from the rotor to the poles inside the cap. Changing that gap to .030" makes little to no difference in normal driving conditions.  If you somehow flood the engine and are then trying to start with fouled plugs - a wider gap gives a slight advantage.   New engines with no spark-plug wires and no distributor and super-wide plug gaps can run at 40,000-50,000 volts.  The reason being that any misfires can cause excess emissions.  Setting a spark-plug gap to within a few thousandths is near impossible anyway. Usually a feeler gauge is not capable. It only "guesses" because the areas of the spark plug being measured are not flat and not perfectly parallel to each other (center electrode and ground electrode).  Spark plug gap measurements are supposed to be done with round-wire, not a flat feeler gauge.  In the end - it matters little.  Any of these Toyotas set from .030" to .035" will run fine.  Start setting it wider and you are calling for too much voltage and a high speed skip will start to show up.  Maybe even premature module failure.

[Rezonans]

Thank you for reply, what is the right oil viscosity for the truck, I am  planning to put something like 10w30 with zddp adative.

Is any cheap way to make 22r engine little more powerful, without putting turbo on it, it look like turbo will cost about 2k in parts only.

 

[zero]

Short answer is "no."  Anything you add on to increase power also decreases reliability.  That assuming the engine is running as designed and not in need of some serious work. Auto engineers do a lot of work to come out with a good compromise for longevity, power, drivability, etc.  Pretty hard to improve unless you happen to buy a poorly designed auto.  Toyota is well designed.  Compare an 80s Toyota engine to something like an 80s Chevy engine - and the Chevy is kind of a dinosaur.  Now adays - things are more equal since most if not all auto makers share technology back and forth.  If you want better performance, changing the rear-axle ratio will give you more gain for the buck.  Or if you have an automatic trans - changing to manual will also give a good gain.

[WME]

OIL food fight time. This is a mind numbingly long post and the author has both supporters and haters. https://540ratblog.wordpress.com/

Basic ratings over 105K psi incredible, 90-105k psi Outstanding, 75-90K psi good, 60-75K psi modest, 60K or below undesirable.

Random 5w-30 oils from the list, Mobile 1 "full syn" 117K, Quaker State Ultimate  113K, Valvoline Max Life High Mileage 108K , Chevron Supreme  100K, Castrol  GTX 95K, O'Reilly House brand 91K, Castrol  GTX High Mileage Syn Blend 91K, Mobile1 "regular syn" High Mileage 88K, Pennzoil Pure Plus 87K, Pennzoil regular 76K, Royal Purple XTR "syn" 74K, Motorcraft "syn" 68K, Toyota regular 68K,

All in all interesting stuff. Synthetic is not all some would have believe.

In many tests additional  "ZPPD additives" reduced the ratings, One additive increased the ratings, but its make up it could cause long term metal damage. So be careful of what you pour into your engine

 

 

Edited February 25, 2016 by WME

[Rezonans]

So the best choice would be 10w30 Shell Rotella T ?

[Maineah]

Here is another long read all though it was written by an oil company there is a lot of good facts here. http://www.synlube.com/synthetic.html

Edited February 25, 2016 by Maineah

[WME]

4 hours ago, Rezonans said:

So the best choice would be 10w30 Shell Rotella T ?

NO, Shell test rating 71K

Best, easy to find, would be the Valvoline Max Life High Mileage (red bottle) or if your pocket book is OK with a few more bucks Mobile 1 full Syn, GM Dexos 1 approved

[zero]

17 hours ago, Rezonans said:

Thank you for reply, what is the right oil viscosity for the truck, I am  planning to put something like 10w30 with zddp adative.

 

Unless you have to start your engine when it is 40 below zero F, 10W30 is fine for an "all weather" oil - as far as viscosity goes.  In reality - I doubt your engine would ever start if it was colder then 20 below F anyway.  Not unless it is fuel injected.   That being said - one morning, years back, temps went down to 32 F below where I was.  My only vehicle was my 1985 Toyota with a carb (not fuel injected).   Nobody's cars or trucks that had been left outside would start where I was unless they had electric block heaters.  That's the "magic" of carbureted engines.  Too cold - no start.  Fuel condenses before it finds its way into the combustion chambers.   My Toyota was indeed sitting outside.  I climbed in and it was so cold the vinyl on the front seat cracked.  I could barely turn the key. When I did the heater blower was on and squawking something awful.  When I tried to turn it off the switch broke off.  Funny how things change when so cold.  To my very big surprise - the engine started.  I had the only vehicle in the area that did.   As far as oil goes - there is no one "short" or "correct" answer.Oil thickness (viscosity) must match whatever temps the engine is started and driven in.   For best longevity - oil needs detergent and also needs anti-wear additives suitable for the vintage of your engine.  30 weight when hot used to be considered the best for wear protection and that's what you get from 10W-30.  Rear axle and trans usually wants 40 weight which in "gear oil" language is called "80 or 90W" just to confuse things.   Newer engines don't need the same types of additives at the same levels.  And yes - when it comes to ZDDP - it has always been known that there is a curve and a peak when it comes to what is best.  Too little promotes wear.   Too much also promotes wear.  There's a range in the middle that is what your engine ought to have.

A few side-notes you may not see in the many "oil sagas" on the Net.   Many newer engines call for light oil. Like 5W-20.  That has little to do with making the engine last longer. It is an example of using the lightest oil the engine will tolerate and get slightly better fuel mileage.

Also - it wasn't long ago when any conventional multi-viscosity oil was frowned on when used in engines used hard.  Why?  Any conventional multi-visc oil uses polymers and they tend to leave deposits on piston rings that can cause sticking.  Straight weight oils do not use polymers.  Also - many synthetic oils do not use them either when formulated as a multi-viscosity.  Now adays - modern engines run so clean with all the computer controls - I guess it's not a concern except it seems, "synthetic" oil is constantly promoted.