So I'm debating buying an EST or doing the delete.
I'm leaning removal, but my brother the mechanic says keep it.
I hate the 50/50 split there seems to be on what to do about this thing HAHA!

I searched a few threads and saw a few people mention delete kits, but I can't seem to find where these come from either cus they mention a person by first name (which means nothing to me still, I don't know anyone) or provide no links.

I was reading an old archived delete thing, and I was thinking of doing what Kevin did?

Suggestions?

 

Ray Crowe at Malloy Mazda supplies the "kit". Essentially it is an OEM 86 filler with pressure cap. 1-888-533-3400

If you decide not to delete, I have a Pettit racing AST with new Stanton cap for sale. PM me.

 

So call that guy and ask for the kit and he should know what it is?
Do you know the cost and time to get it?

Thanks by the way.

 

Delete it, I have done it on over 75 FDs with no issues. It is deleted on my own car, it is just more clutter, headache and possible failure points.

 

Good enough for me! I was already leaning that way, so I don't need much more convincing than that haha!
I'll call tomorrow.

 

Cost: About $40

Time to Get: A couple of days (Please note they are in Virginia so who knows what type of storm related issues they may have had).

Peace of Mind: Priceless.

 

Actually it's the S5 (89-91) filler cap. I second calling Ray Crowe. He's an FD owner himself and familiar with the cars. It'll be price fairly. The kit consists of the S5 filler neck, a new .9 bar pressure cap and a new 'O' ring.
I also deleted mine a couple years ago and got the kit from Ray. Done correctly I have no regrets. Maybe takes me marginally longer to fully purge the system when changing coolant in the spring. But no issues with air iafterward.

 

Did either of you do like Kevin did in the link, or do you still have a bypass hose hooked up?
Having the bypass seems like the main reason anyone wouldn't want to get rid of the AST, yeah?

 

http://www.rx7.org/Robinette/coolant_tank.htm

States its from an 86. I didn't see one on my 90..... S5 has an all plastic neck with no cap.

Either way, Ray will hook you up.

 

My mechanic also wants me to keep the AST. This may also have to do with radiator placement/angle. I have a v-mount setup where the radiator sits low and on an angle. Maybe if it was sitting vertical like in many other cars I'd get rid of the AST. From what I've read Mazda had one on their 787 racecar.

 

Interesting...
I plan on getting the VMIC/Radiator kit eventually...
Still think I'll get rid of it tho.

 

Blue - You know I love you dude but I believe you are incorrect. You might want to double check because I'm 99.9% certain it is the 86 version of the cap...and I've heard the Z31 Cap works as well (should be testing that this week).

Check 1/2 way down the page:
Radiators, Caps, Water Level Sensor

 

I deleted my AST, including removing the AST nipple on the water neck, tapping the hole and putting a plug in it with sealant; no leaks. No problems here, car runs cooler than ever (perhaps the v-mount has something to do with it, heh) and less clutter = success.

Just takes a few extra minutes to burp the coolant when filling, I use that Lisle funnel and it's real easy.

 

Yes, I removed that hose. Leaving it makes no sense since some coolant is allowed to by-pass the radiator completely. Actually I removed that unneeded nipple on the filler neck and plugged it for a cleaner and IMO less leak-prone fit.



Your both right and sorry for misinformation. I may have been thinking of the S5 Thermosensor. Regardless, thanks for the correction.

 

I have the filler neck piece off an FC if you would be interested. 12 bucks shipped. You will need a spring loaded cap you can buy from autozone or wherever youd like. If your interested please pm me.

 

Minutes too late. Called Ray at lunch time.
Thanks tho.

 

So i'll say this just to inform you all. You can make your own decisions. AST stands for air seperator tank. It helps get air bubbles out of coolant. Air bubbles get into the coolant for a couple of reasons. Cavitation can cause this. So can boiling. There is one thing that rotaries are known for doing. That is boiling the coolant around the spark plugs. The further past stock you go on your power levels the more this will happen. Combustion temps and pressures go up when power levels are increased. Which means more air in your coolant. All in all this will lower the overall efficency of your coolant. You have options though. Evans coolant doesnt cavitate, pulls heat better than conventional coolant and has a higher boiling point.

So, not to be pendantic, but if you did this to 75 cars how would you know if it caused a problem? The problem is too esoteric to be able to simply say that since you have done it on 75 cars that its a good thing to do. When each of those 75 cars ended up needing a motor what was the cause? Did they have a bunch of carbon build up around the spark plug from it getting too hot now that that air isnt being removed from the cooling system? Were there cracks in the chrome around the spark plug holes causing damage to the apex seals?

You people can be the judge. Mazda didnt spend money on such a strange part for no reason. Car manufactues literally care about pennies when it comes to the cost of parts and auto production. Hearing that is is on the 787b is no surprise when you know what that part does. Make educated decisions. Dont just jump on internet bandwagons. Its way too easy. I'm positive that i'm going to get a bunch of "i dont care what you say, this is how i have always done things" responses. But remember, the world was once flat, we were once the center of the universe, and cigerettes dont give you cancer.

 

I hear you.
On the reverse tho, car companies don't always make the best vehicle with the best tech or the right decisions. The FD is a clear indication of that. What a great car, but could things have been done better? Absolutely.
The AST is so hotly debated its a bit ridiculous. You have incredibly intelligent and reliable people on both sides of the argument on top of that.
Considering the amount of tinkering that's been going on with these cars, I'm willing to say there are ways to make AST removal safe.
Plus your end quote works for both sides. You're saying we learn from the past, the AST could be the same situation. We thought we needed, maybe we don't.

Honestly I think the AST debate will never end unless some serious studies are done, and that's not likely to happen.

 

^^ I'm sure somewhere in the archive Mazda have folders of info and data on this and so would the Mazda racing team

One side of me wants to get rid of it though.

 

[QUOTE=Alpsta;11281447
One side of me wants to get rid of it though.[/QUOTE]

Me too! Evans coolant might not have been around at the point that mazda was building the 787b. And i totally get why they wouldnt put it in a production car. But if it truly does prevent boiling at those hot spots and doesnt cavitate it could be the best way to justify deleting the ast.

 

Deleting the AST entirely without fitting the filler neck with an appropriate air bleed cap would be asking for trouble. Deleting the AST, utilizing an air bleed cap, and discharge hose into the coolant overflow=No difference! You are simply taking the small 1 pint reservoir out of the engine compartment. The air bleed mechanism is the cap, not the container.
Art

 

I got a Pettit AST but decided not to use it. We are now making a new AST tank from scratch and planning to use a Koyo radiator cap. Is this OK?

 

^This

 

Oops! Totally misunderstood what RTS3GEN said before. Now that I read the whole thing again it kind of makes sense but I'm not an expert on the whole system to be honest. If the air bleed mechanism is the cap then why is there an extra hole in the radiator which goes into the AST. Don't people block the extra hole in the radiator when they remove the AST? So maybe it's not just the cap.

 

Most people plug it or cap that fitting.