Barry Bordes

Jan-Tore, the image was not displayed but from Sven's thread it looks like you have a few issues.

The side seals are falling into the ports and wearing quickly.
Fix- Use less radical ports that fully support the side seals or at least allow them to scissor back over the closing side of the port. ( see Judge ITO's porting post on No-Pistons).

The sparkplug boss is expanding from too much heat and lifting the apex seals.
Fix- You need a better water pump like the Rick Engman design/Mazmart pump. You need to flow more water past the plug area. You need to not bypass water around the radiator (heater core and throttle body hoses should be plugged).

Castor bean is one of the best lubricants available but it will gum up engine parts. I would use another type two stroke oil.

On your new stationary gear bearing that went bad, did you have any transfer of babbit material to the essentric shaft? How long did you break it in?

Barry



This is a Judge ITO template, indexed with dowels, showing the side seal path. The leading edge of the advancing end is captured by the side housing and the trailing end of the previous sideseal is scissoring back onto the side housing surface (this edge should be filed with a fine diamond file and then polished well).
Barry

jantore

Thanks for the reply Barry

I thought so, that that was the problem. Well i cleaned up the rotor housings and they look alot better now tho. But do u think using the stock BUR9EQP plugs did help with the heat build up around the plugs? And im also having some problems with the coils so might be more issues but hey

Im gonna se if im gonna go for some new irons or maybe make a transitions for the seals to go into the 2nd ports. But that's not where it failed, the seals on that side was perfect. Now the bridge on the side that it did fail on was abit smaller then the pri port on the rear rotor. So it would need to be abit bigger.

Where could i get that water pump u are using?

JT

classicauto

iTrader: (3)

www.mazmart.com

The phone number is on the site, can't order through the web...

Must be purchased with the OEM housing now, so the pump and housign will come together - they do not sell the pump only. (ask me how I know )

jantore

okay hmm i don't need that. Im going electrical water pump next year. So that would just be a waste of money. Hmm maybe i need to do it now anyway. Will see what i can afford and have time for. Now that my engine needs a rebuild and a retune as well

JT

Barry Bordes

Yes JT I would think you need colder plugs than the BUR9EQP for over 20 psi, maybe something like R6725-10 or -105 Mazda racing plugs, BR10EIX Iridium plugs or plain non-resistor B10EGV/B11EGV ( if you are not using the HKS twinpower). From Chuck Westbrook's notes.

JT have you seen anything on problems with E85 and platinum/iridium/gold palladium plugs?

Barry

Gorilla RE

iTrader: (1)

Thank you for asking this question, for I was wondering the same thing......

-J

jantore

Well hmmmm, yes and no. I have tested with the NGK 10 and 11 iridium plugs. Where the 10's where in the leading and 11 in the trailing. All worked werry fine the first time we tuned it, no problems what so ever. But when we retuned the car the 2nd time we put in stock 9's in the leading and NGK 10's in the trailing. Then the car started having problems after i overeved the engine, where it would backfire bad. So i thought i might be the stock plugs that died so i tested a few pluggs. I tried the old combo with 10's and 11's and no change. Then i tried with B11EGV plugs when i got home and the car just went lean and would backfire like mad. So i spoke to the person i bought my SM4 from and he said he needed to retune the car if he changed to colder plugs. That E85 was verry sensetive about changing plug range.

Now we got the car to run good on BUR9EQP plugs the third time we dynoed the car, and it needed more fuel. Well i know why now :P since i had 3 broken sideals, 1 stuck sideseal and corner seal. And i was getting way to much E85 in the oil as well.

I think there is no problem running Iridium plugs or colder plugs as long as u have a CDI box with E85. The stok platinum plugs look fantastic after running them on E85. Just don't have a faulty ignition coil like i have had. I messured the resistance in my coils and they had droppen about .060 k ohm on all 4 coils.

So to the no there is no problem running Iridium/platinum plugs as far as i have tested. To the yes do not change heat range of plugs. Have u tuned it once u can't change range. So im gonna run it as cold as possible.

And i might go electrical waterpump since buying the mazmart pump with the water housing is not a viable option for me now. The water housing is quite expensive aint it?

JT

jantore

Wich of these do u think would be the best to use?

R6725-10 , 11 Mazda racing plugs 33,82 USD
BR10EIX Iridium plugs 7,32 USD
B10EGV/B11EGV 5.74 USD

The price is quite diffrent. When it comes to cost on the plugs it's not that important. But still i would get alot more plugs to run the others. But they are shorter so they req a higher base timing to ignite at the same time as the R6725 plugs.

So plugs are a big concern on what to use.

JT

Barry Bordes

JT, I think that the R6725-10 , 11 Mazda racing plugs would be the best.

On another note. Your picture on the NRS thread of the rotor with the stuck seal shows a wide carbon path on it. How did the sequence go? First the over-rev? Then ignition break-up?

Do you have a shift light? I use a G-Tech Pro for my shift light. you can just barely see it on the lower right.

jantore

Yeah first over reving in may then ignition breakup after that. I thought the breakup was due too heat as it would come after a while.

And i got it to work without any breakup after that, by cooling the fuel rails and injectors as they where about 85 degreece from radiant heat from the downpipe and exhaust housing. But i noticed the car needed alot more fuel in higher rpms.

Then i had the car on the dyno again, and it worked like a charm. Got out 530rwhp from it and i was happy. After the last pull the sound of the engine changed like a plug went bad. I thought it was the plugs since they had seen alot of abuse. I stopped it and started it and it started just fine.

Then i went to the track 5 days later and the car worked fine for about 10 laps then started breaking up again. And would do it no matter what. It was ideling fine and would go smooth under vacume, and would suddenlu go like a mad man, then have breakup and then go like a mad man again. So i started suspecting fuel pump or coils. Changed out fuel pump same problem.

So i just said quits for that weekend and took the car home. She starts up straight away when i put here on the trailer and when i got home.

Then i decided to open her up and see how se looked like inside. I even did a compression check on cold engine before i started the tear down. And i had even 60 psi all the way around.

The over reving happend when i kinda miss shifted. I was going from 2nd to 3rd and i put it between 1st and 3rd. And i was gearing quick, so i pressed the throttle verry fast when i was putting it in gear. Im quite quick when it comes to changing gears. But my syncros is feeling the beating now :P

So the car over reved due to it already beeing at 6-7000 rpm when i hit the throttle again, and it could not stop my engine from over reving.

JT

Barry Bordes

JT, I am guessing that you are right in thinking that you have more than one problem going on. 1- The too narrow bridge, 2- The over-rev, and 3- The overheating of the sparkplug boss as evidenced by the carbon stains adjacent to the plugs.

Number 3- is probably I think, the root cause of most of the failures in rotaries at boost. The overheating of the sparkplug boss lifts the apex seal at its center and blows burning gases into the next fresh charge. Usually with stock seal the tip breaks off. This is not likely to happen with NRS one-piece 3mm seals.

It would be great if some of our great engine builders would give us their thoughts.

Barry

eightman1977

okay, so it's 12:40 at night and I was reading all the posts in this thread, and I thought to myself hmmmmm, what if we were to change the direction of travel.

Now we all know that the coolant passages in a rotary engine travel horizontal meaning the coolant travels from front to back. What if there was a way that we could modify the housings or Mazda could redesign the coolant system to travel vertically AROUND the housing. I did a quick doodle in Paint to give you just an idea of what I'm talking about.



If there was a redesign in the rotary engine to have the coolant travel vertically, you could remove a lot more material and stregthen in key points to retain the abilities to produce higher boost levels. This would also allow for each rotor housing to have it's own coolant line running into it and out of it.

also possibly thinking about it now, depending on the tempatures of the engine on each of the 4 sections of the combustion process (intake, compression, combustion, and exhaust) There could be a possibility to avoid cooling the sections that include the intake and compression side for the simple fact that they probably don't see the same tempatures as the combustion and exhaust sides. I don't know exactly what the temps are per section of the rotor housing, but I'm sure they vary a bit.

I'm sure these ideas aren't exactly feasable, but it's something that I had to put out there just for the simple fact that if there is a way to improve the rotary engine, then so be it. Even if people laugh at me.

People constantly ask me why I don't upgrade to a V-8, and my response is "Why fix something that's not broken"

Gorilla RE

iTrader: (1)

I would first ask yourself why? Why did Mazda run the coolant through the engine the way they did? You have to understand that Mazda has engineers that have thought about this through and through..... They my have made some mistakes on the FD's engine layout/accessories but 90% of what they did, they did for a reason. And they accomplished it wonderfully!

On those same lines of thinking though, I would suggest modifying/adding places where the coolant enters and exits the engine, not the flow characteristics.

-J

gn0me

It looks to me from Barry's pics that the apex seal is skipping when it passes over the hole for the trailing spark plug. Couldn't this be prevented by chamfering the opening?

Gorilla RE

iTrader: (1)

If you read the thread it's been talked about in length. Chamfering IS a good idea and Barry and I have been doing this for a long time. But the ROOT of the problem stems from excessive heat in the spark plug boss which causes cracking/swelling of the plug opening. And that my friend is what we are trying to solve.

-J

eightman1977

what if you were to recess the plug opening slight by removing some material? What I'm suggesting is creation a bowl shape for the plug opening. This may reduce material that is prone to cracking or swelling. This may also possibly provide a more efficient burn? I'm no engineer or anything, just including my .02 cents!


Also with my earlier post about the travel of coolant, if Mazda were to redesign the rotor housing and the coolant passages to travel "around" the housing instead of "thru" the housing. You would also have more of a cascading waterfall type effect instead of a journal type effect. This would allow for a much greater surface area to be covered by coolant. You could add to the thickness of the inner section of the rotor housing to prevent coolant leaking into this section. This would allow for more fluid to flow around the spark plugs. I wish I had drawing skills or some type of paint skills or photoshop skills. Seriously if you think about my idea, it sounds like it could work. Because the current issue is the fact that not enough coolant is getting to the spark plugs to do it's job with the journal type coolant system.

Now of course this is just my opinion, obviously if Mazda was wrong and I was right, I'd be a millionaire right now lol. However, as said before, if I can do anything to improve the rotary engine, so be it.

Barry Bordes

Barry

gn0me

Barry what modifications if any had already been made to the rotor housing? Were the coolant passages modified?

Barry Bordes

gn0me, right now I'm running:

-3rd gen housings with the reliefs cut next to the plugs,

-then cut grooves in same area (response #11),

-enlarge passages around the plugs (response #4),

-port the inlet to the sparkplug channels (#58),

-flow water through the tension bolt holes adjacent to the sparkplugs (#27),

-and using a Mazmart pump (#90).

Barry

classicauto

iTrader: (3)

I'm employing a few of these ideas on my current build, I'm thinking to try a few holes through the cooling fins like the shot of the RE housing barry posted at the start of the thread, except locate the holes as close to the plug boss as I can get.

It will retain wall strength to support the housing's surface, but add some area where cooling needs to be.

I'm also contemplating parallel fins with a small end mill on the drill press, but it was mentioned these would reduce strength. I'm curious how they would be any different from the "traditional" cooling fins with respect to strength of the housing?
Some enlightenment would be great

I have also welded my EGR ports in the exhaust sleeves shut as exhaust gases that would normally be used for emissions will still be flowing outside the sleeve and heating the coolant in that area.........not really an issue specific to the plug boss, but if it helps reduce overall coolant temps during high load, it can translate into benefits for the spark plug area given that the coolant (may) be slightly cooler when entering that region.
The "every little bit counts" rule

gn0me

And with these mods the area in question is still getting too hot? Or was this all done after?

gn0me

I ask because I have 5 or 6 spare engines lying around that I can use for testing but I'd like to get some sort of starting point.

Barry Bordes

Everything is running well now. My build-up with the above mods may be able to be inspected through the spark plug holes with a borescope from work. But I haven't anything but drive it so far .

My latest problem is having EGTs over 1000*C from both rotors at 15 psi above 7500 rpm. Think I think my ignition is a little to retarded. Adding a degree at a time. But it rips!

Barry

gxl90rx7

iTrader: (1)

barry, i recently tore down my engine to find very similar housing s to the ones posted earlier:



this was a bruce turrentine rebuild with RA seals/springs.. all seals intact at teardown except for a leaky coolant seal. it was running stock plugs (7's and 9's, too hot?), at low boost (6-10psi)

A previous owner ran synthetic in it for a while, but that was over 20k miles ago, it has been running GTX 10W-30 ever since, stock omp. you would think the marks would have worn off by now. can excessive premix be a cause, or is it indeed overheating at the leading hole?

Barry Bordes

gxl90rx7,
Thanks for the shot of your housing. It seems to follow the normal wear pattern. If you clean the stains with a little scotchbrite and mineral spirits you will notice that it cleans up easily.

The problem is that the spark plug boss is not cooled enough while running hard. It grows with the uneven heating, bowing the housing surface till the apex seals no longer are flat on the surface. This then causes the stains. If this condition is run long enough the apex seals will show "football wear" when you put the two sealing surfaces together face to face.

I would make sure you have the latest 3rd gen reliefs next to the spark plugs and then cut the ribs close to the the bottom of these reliefs.
Barry