ncmn

greetings,

while i was checking out the radiators on the mazdatrix website i came across a claim made by them which i am hoping members here might comment on.

essentially they said that in situations where the air pump/air pump belt was not used the remaining belt would slip on the water pump pulley, particularly at high rpms. thus there would be a great decrease in water circulation and in turn cooling ability.

i found this comment relevant to me as i have previously posted here in regards to some cooling issues i currently have. mazdatrix's statement seemed to EXACTLY describe my situation. when i go above 70 mph/120 km, my temperature gage creeps above half (and threatening more). however it remains safe when i stay below 50 mph, even in situations where i am stop-n-go for over 1/2 hr (i experimented tonite).

i own a 84 gs/12a. my only modifications are k/n drop in filter and racing beat full exhaust. i bought a new fan belt and thermostat from mazda to install this week.

does anyone here have insight in to what mazdatrix claims? i was giving thought to tightening the belt towards the low end of deflection anyways -would this help/hurt? also mazdatrix mentions some dual belt system they have? anyone know what they are talking about or use it?

this info would sure be easy on my pocketbook! i was eventually going to change over the cooling system anyways (electric fan, pump, etc) but i was looking forward to saving for new springs/shocks first!

much appreciation for any insight,
norman ng

duboisr

Garfinkle ran his 81 for 12 years without the air pump with no problems with the belt . He built a 84 and put the double pulley on to be sure no problems would come up because he sold the car. The 81 did not have the double pulley.

Directfreak

iTrader: (2)

they are referring to HI-RPM, freeway cruising at 70mph, does not constitute that.

peejay

i didn't have overheating problems, but the car ate alternator belts like a SOB.

The cure is an electric fan. Not only does the belt live a happy normal life instead of 2-weeks-of-torture, but you get a bit of HP boost as well because the engine doesn't have to turn the fan.

You won't notice the HP gain if your belts are slipping, though

RotorMotorDriver

iTrader: (1)

I have RB exhaust, no air pump, no A/C, and no clutch fan...I fired up my car for the first time today and didnt notice ANY signs of pully slippage. Although I will monitor my temp gauge rather well because I have heard of this problem before...Anyway, I just thought Id let you know my experiance so far .

~T.J.

stinkfist

I used to use the double pully on my car. I had street port 12a, RB road race exhaust, RB light wheight fly wheel, RB Holley intake, direct fire, ect.
I don't think it is needed but it is cool looking. Our race car only uses one stock belt and we never have problems with over heating. Most of the time on the track is spent between 6500 rpm- 8500rpm.

BTW if you want to run a double pulley you can get one for only five bucks. Check this thread out. it's in the second gen forum but it will work on a 1st gen.

https://www.rx7club.com/forum/showth...=double+pulley

Mike

V8kilr

flush your radiator and get an oil change and your temp problem should be fixed,

if not check your rad it might be bad or it could be your water pump,

the temp needle should not go half way at 70

rlking

get a TOP-COG brand belt no slipping

diabolical1

iTrader: (3)

i've run double pulleys for over a decade now, i can't speak on the slipping problem from experience, just what i've "heard" ...

however, change to a Gen II oil cooler!!! cooling should increase noticeably ...

redrx

iTrader: (1)

I have a similar problem, but it only lasts for a little while, and only the first time I drive my car for the day, I think it is the thermostat

SunRedRX7

You may or may not experience slipping. With the electric fan you probably wont. But also realize this, your driving down the road, and SNAP, your only belt just failed. Now not only do you have no alternator, your WATER PUMP no longer is being driven. How long do you have in this situation to get your car shut down and a new belt installed before DOOM, I dont know but I wouldnt want to know.

I bring this up as I lost an alternator belt once that looked fine the week before, and I was in a spot where I couldnt have just stopped and put a new belt on. If it wasnt for the airpump belt that I kept on for such a reason till I got a dual belt pulley, I probably would have lost the engine.

So personally I would run the dual belts for just an added precaution.

Mike

ncmn

greetings,

i was at canadian tire this morning, picking up some coolant flush, some hoses, and a water pump (spur of the moment fix @ $60 can). anyways i will begin to pull off and put on stuff tomorrow. if this doesn't work, i guess i'll look at a new rad next.

as to the dual pulley system...i am intrigued, newly paranoid (thanks SunRed!) but also confused. could someone explain it better (what attaches to what, where, how much!!!).

thanks,
norman ng

Pittdp

my engine was getting hot like that a long time ago, I had to get a new radiator. I tried flushing it first and got a lot of crud uot but it was still overheating till I put the new radiator in.

MIKE-P-28

iTrader: (1)

Yelp, a new belt like every 3 to 4 months was about average

BTW: Never knew mazdatrix to write bullshit, so listen to what they got to say...

Maguire

iTrader: (1)

I have also had a similar problem with my 85 12a. When im just driving around town my temp stays right in the middle. when i get on the expressway it goes up to the 3/4 line. (whats exactly does that line mean anyway?). But when i get up to 80mph it starts to get pretty hot. almost to the high mark. I think its just cause my radiator is old and shitty. The fins have rusted off the backside. But could it be anything else?

REVHED

It's like this. The water pump is normally driven by both the airpump belt and the alternator belt. If you remove the airpump and belt (as many do) it can cause the water pump pulley to slip at high rpm especially if you still have the stock clutch fan.

The solution is to install a dual alternator pulley. This allows you to run dual belts over the water pump and alternator by utilising the grooves vacated by the removal of the airpump belt.

Here's what it looks like on my engine.

Manntis

Slick setup, RevHed.

REVHED

Thanks man.

RotorMotorDriver

iTrader: (1)

I need some kinda dual alternator belt, but that thread just confuses the hell out of me. If anyone knows a specific spot to buy one, that would be great. Or a specific model of car or alternator I can get one from, that would also be great. Thanks.

~T.J.

peejay

Always carry some tools and a spare belt, because of this.

Directfreak

iTrader: (2)

I have to agree RevHead. Everytime I look at your engine bay, I think - "That's how they should all be"

Clean and simple - where form follows function. Nothing unnecessary.

Although I am a wimp and still need air conditioning.

diabolical1

iTrader: (3)

RB or Mazdatrix are the places where you can definitely get them ... but i would imagine other places have 'em by now, too. i think it was, like, 50 or 60 bucks when i bought mine ... don't know what they go for now.


on another note ... i figured it's better to ask here than to get slammed for starting a NEW thread. about 2 days since this thread started, my cooling system took a dump on me! i'm pretty sure it's the radiator ('cause that's the only part that i didn't change when i put this motor in.) however, i've been searching through some old threads on radiators, and i'm a little confused about what to do. if i had a job now, i'd go for an aluminum one for a T2, but i just don't have the cash. so, here's my question ... i know the 81-82 rads are short and thick, and the 83-85 rads are tall and thin, but in terms of internal surface area, is any one of them actually LARGER than the other? i'm thinking of adapting a stock T2 radiator to fit, but i figured i'd ask about the Gen I choices first. i want to get something that will cool at least 200HP for now ...

what do you guys think?

MIKE-P-28

iTrader: (1)

Man we have been through this pulley thing a million times, why the hell doesnt someone archive a thread? Theres a mitsu pulley that is the same exact thing as ours except it is a dual pulley setup and it costs $5 freaking dollars not 50!