Cwaters

My car was sitting for a year or so and now it won't come down from the 1500 RPM idle. I'm suspecting the thermo-wax rod. I haven't realy tested the TPS or the BAC just yet as I've been trying to figure out this thermo wax thing. I do have and have read the section in the FSM but I'm still having trouble figuring this bit out.

The thermo wax rod thing is supposed to extend and thereby push down on the adjustment screw that's touching the bottom, right?

Should I be able to push UP on the rod from the bottom with the one finger I can thread into that area?

Should I be able to push that adjustment screw DOWN?

I can't do either. so I'm having a hard time figureing out how the mechinism is supposed to work.

I guess I'm about to take the throttle-body off, once the car cools down again.

Today I spilled brake fluid at three of the four wheels while I blead and apparently my big torque wrench is broken. Now I have a pair of dead torque wrenches...1/4 and 1/2" drive. So it was almost a total bust in 7-land for me today.

OTOH, we traded the Xterra in on a new one...who's in favor of 80 more HP?

NZConvertible

As per the FSM (page 4A-57), warm up the engine and watch the thermowax rod and linkage. The rod should extend outwards and cause the cam to seperate from the roller. The picture on that page shows what should happen. You can manually simulate this by pushing the thermowax screw away from the rod.

Cwaters

In my FSM, it's a page 4-41.
I don't think my wax rod is extending. Bu then, I can't push that adjustment screw down either.

CW

HAILERS

Lift up on it.

Or remove the throttle body and pour boiling water over the thermowax and watch it.

EDIT: OOPS. Non turbo. No lift. I'd remove the throttle body where you can actually work on it. Pour some boiling water over the thermowax and see if it extends at all. If it does, then use your judgement and turn the screw in the direction for the cam to fall off the roll pin sooner than it does now.

Cwaters

I was wondering if you'd pop-in Hailers.
It's been a while, but I remember you baing prety helpful.
Once the kids get moving, I'm off to the garage. Again.
CW

HAILERS

Tell you what. When I just had a non turbo I tried to screw with the thermowax adjustments and frankly I never could get a screwdriver on the adjusting screws. Even under the car with a three foot long common screwdriver I had no real succcess.

I could only deal with it when I removed the four nuts off the throttle body and actually removed the throttle body from the car. Then I poured boiling water over the thermowax to see if it would move/extend. If it does, then it's up to your own judgement as to how much you need to move the screw to make the cam fall of the roll pin sooner/later/whichever way.

Others are more dexterious than I am and I'm pleased as punch that they can adjust those adjustment screws without removing the throttle body. Just don't write back and tell me how you don't have to remove the throttle body.

Cwaters

yeah, from the looks of the screws, I doubt they'd turn with minimal torque even if I could get a screwdriver in there...TB coming off next.
CW

HAILERS

I"ll stop after this next remark..........you might try blowing thru the water feed/return ports/lines after you have the throttle body off to determine if any water is passing thru the thermowax water passages to heat the thermowax.

Cwaters

Took the TB off. Not as difficult as I imagined but I did manage to brake the little delay valve that is fed from the thermo valve... Guess that shoudln't be expensive, probably just get a new one. And that water hose that comes up fro mthe back and feeds the thermo wax assembly is a bitch.
The fast idle cam is VERY hard to actuate. I'm off to the parts store for some carb cleaner, more Prestone and uh...somethign else I can't remember ATM.

After I celan up the TB (not that gunky) I'm going to try and work some spray lube into the springs on the back side of the TB. maybe that'll loosen-up the fast idle bits.

"this is fun, This is fun, This is fun, this is fun, this is fun, this is fun...

CW

Cwaters

Ok, I quit.
This weekend, every time I go down there I break something.
broke my torque wrench, the bolt that holds the ball joint to the spindle, the delay valve, and now I've stripped one of the screws that holds the thermo wax assembly to the TB.

The high idle cam works ok but when it's in contact with the other pin, it's very sticky. So I got the dremel out and tried to clean off the rusty stuff. All clean and lubricated now it's....wait for it....STICKIER....

WTF?

Not a happy camper.

Cwaters

I got the Thermo wax screw out. Put it in a bowl of boiling water and it extended maybe a 1/4". How much should it extend?

CW

NeCr0mStR

iTrader: (3)

anyone have a pic of the thermo was screw and such... I am confused as to where/what it is.

sorry for the tarded question but it seems to be an issue a lot and I would like to get completely familiar with it.

is it the clearish thing top left of intake just above the white green vacuum doo-hicky... lol such technical terms.

Once again sorry for tarded question

NZConvertible

I'm referring to the 88 FSM available online. You must have a different one. Doesn't matter, the thermowax works basically the same for all FC's.

The thermowax pushes up (or out), so you have to lift it up like I said before.

It's best to do it with the thermowax on the TB. I did what Hailers said before and poured boiling water into the thermowax hose to watch it work. As long as it extends far enough to push the cam off the roller then it's fine.

HAILERS

It's around the green/white check valve (might be a delay valve). The best thing to do is download the FSM and the pages mentioned by NZ and compare your car with the pictues/instructions.

It's easier to work on a turbo car thermowax etc than a non turbo because the throttle bodys are flipped 180* one vs the other. With your engine out you should have a birds eye view. No obstructions etc.

Here's a jpg of the manual that I posted some weeks ago. https://www.rx7club.com/forum/attach...hmentid=124100

How far the thermowax should extend is in the manual somewhere. I don't have one right this minute. Even if the piston does not extend exactly the distance the manual says, you can compensate by turning the screw further or just dicking around with it to make it work as you desire. OR buy another one.

And one last thing: I know on a 86/87 non turbo the valve has no passages to/thru the throttle body, so you should be able to run boiling water thru one passage and out the other to heat the water thermo. Maybe just tap water and turn your water heater thermostat to full Hot to get a good result. Then again, a tea pot of boiling water will do. Pour in one hole and out the other.

Cwaters

The thermowax pushes DOWN in my 86 NA. I guess it's probably different on the turbo TB.

Mine does xetend, probably enough, but the cam sticks on the roller and won't allow it to slide off.

Hey [lightbulb], is that cam supposed be riding on a little ROLLER? Mine certainly isn't rolling...I bet that's why it's sticky even after I cleaned the rust off and oiled it. There's definantly a little groove worn into the "roller" from previous use...

If that pin is supposed to roll, then that's certainly my problem...now, what to do about it?

WOnder if I should just source another TB...

HAILERS

The pin does not roll on mine. But maybe they should roll?????? If you have a flat spot, try to make the pin turn to a round spot and try that. It seems in the picute if you turn the screw IN, that touches the thermowax piston, that the cam will fall off the roll pin sooner

NZConvertible

Yep, the NA's TB is upsidedown compared to the Turbo's. So we'll say the rod pushes outwards. Lifting the linkage on top of the rod (the one with the screw) will simulate the rod extending and should cause the roller to seperate from the cam.

The roller is supposed to roll but in my experience that doesn't stop it moving off the end of the cam if the thermowax rod extends enough. It does make it harder for the linkage to automatically reset itself when the thermowax cools and the rod retracts. You can manually reset it by pushing down on the gas pedal once before starting the engine. Interestingly that's exactly what the owners manual tells you to do...

I used a various tools and some penetrating lube to get the roller rolling again, but it'll never be as good as new. I used a little file to smooth the cam surface, sandpaper to clean up the roller surface and needle-nose pliers to get it turning again.

Mombodogs

Cwaters, just a hair off the subject, but very nice phot of the engine. Nice to get a new perspective. And info on thermowax from all is informative for me. Thanks, and sorry for no real help on your thread.

PEACE THE DOG

HAILERS

I see, said the blind man. There is a sleeve on the *roll pin* that should spin on the *roll pin*. I put some penetrating oil on it and used some duckbills to rotate it. By the way, mine has a bit of a flat spot on it also, BUT even when the sleeve did not roll, the cam would fall off the roll pin at full thermowax piston extension.