Yes and mazmart inspected one of them.

are the tops of the apex seals flat? they shouldn't be. the old engines sometimes warp apex seals if they get too hot

Brett,
Thanks for the info...

As I am reading through, I was going to ask you about Bearing wear, and whether or not you did any mods to the S1 Oil Pump or rear By Pass Valve, like talked about years ago and the Mazmart mod?

Edit: Are you considering 'any' mods to OP.

It was discussed earlier in the thread

do you mean the top where it meets the rotor face, or the top where it runs along the housing?

the sliding surface where it meets the rotor housing. the stock seals are crowned slightly.

Yeap they are round on the edges!

its also crowned lengthwise too. pic is exaggerated, so you can see what i'm talking about

Just to add a little more to the mix, we saw the same wear pattern on the side irons on our N/A race motors.

sub'd
real informative thread!

Yea I've installed a few in my day, atkins seals, RA seals, and factory seals.

can you elaborate on this some more please . Ie was an omp used or premix ? How much use did they get ?Was any porting done in that area ? Was wear as bad as shown on mine ?

In terms of balancing issues, the factory engine is fairly out of balance.

ive included the figures of my engine before and after being balanced

Some slight tidying on the ports but nothing massively extensive, premix was used, wear was similar to yours (~1mm). The nitriding seems fairly thin on '8 side irons so once it gets through the top bit it wears like lightning.

Engines were anywhere from 3k miles down to 200 miles...

Where these engines balanced, new housing and new rotors?

What are the pros and cons of solid corner seals vs standard corner seals on these engines

That's really interesting . It seems to suggest the issue occurs when the engine is run hard enough to generate excess heat in that area rather than anything specifically to do with turbo backpressure .

Did you ever eliminate the issue or find a way to reduce wear ?

No mods on that engine but will do the regulator mod when i get a chance . Although this needs addressing it wasn't the cause of the engine failure .

At high rpm you get shaft wobble if the motor is not balanced

Nah, I ran out of spare engines and money first and sold up :yelrotflm

doesnt excessive back pressure equal heat?
This side port exhaust is restrictive.

did your corner seals look like this?
http://www.pettitracing.com/wp-conte...ESIS-PORT3.jpg


by the way what was that buildup in the rear iron cooling jacket?

that was observent of you . Yes there was a significant buildup of crud . I'm not sure what casued that but suspect it relates back to an earlier time when i ran water wetter with no antifreeze .

Did you still have the tb coolant circulation intact? Or was it capped off?

Yeah . Throttle body was blocked off .

I do wonder if blocking that outlet somehow changes the way the coolant flows in that area?
What do you think?

been a while but I remember someone posting about getting more detonation when the throttle body flow was plugged vs just bypassing the throttle body. Seems that it provides a specific cooling flow to the engine.

Also bypassing the TB isn't necessary, the heat from the coolant doesn't effect intake air temperature dramatically, but it does prevent your throttle body from icing up in the perfect wrong conditions.

No idea - if there is some documented proof that there is an adverse effect ,as Harlan suggests , I guess we should take notice.

Well it is located at the coolest part of the housing...so I don't see how it really would help with detonation control?
I do wonder due to the shape of that area...if its blocked off then maybe a swirl developers and impedes flow somewhat?
Very interesting.

The outlet to the throttle body doesn't have to be blocked at all, just join it back on itself, so water flow is from the pump housing to the back of the block.
Or just run a new piece of pipe from the pump housing to the fitting at the back of the block.

Rotaman

How about ducting air through the TB from the now dormant cooling channels to help cool the TB instead of heating.

i wonder how many people have blocked that spot off?

Brett how built up were the deposits--really cant tell much in the picture.

The deposits were really bad actually . I know my cooling system is not performing the way it used to so i suspect some of that crud is in the rad as well . May have come from the heater radiator as that one keeps blocking up and when i clear it all this rusty water comes out . This is why i suspect the water wetter debacle as the cause , even though i only ran it with the engine previous to this failed one . I know everything went rusty when i did that . Im sure it said on the bottle that it prevented corrosion but ..... no .

Wait, you had the TB circuit blocked instead of just running a hose from the tstat housing to the nipple on the rear iron?

Yes - blocked off both the hose on the tstat and the block

I ran mostly distilled water and some glycol in my last engine and I had a lot of rust and build up for a 30,000 engine that had at least three coolant changes in that time. On this engine I am running 75% straight coolant and 25% distilled water and it is working great along with the secondary radiator. I have my turbo adding heat to the coolant on the throttle body coolant and myself and several other rx8's were sitting in 90F weather in traffic for an hour and I had the lowest coolant temps (never got over 200F) :)

But also the highest intake temps :( Today at lunch I was pushing her pretty hard under boost getting on and off the highway running errands and I got my coolant temps to 210F in traffic. But as soon as I cruise on the highway for a few minutes the temps drop pretty quick unless the engine is totally heat soaked, then it takes longer.

Yeah - i was only running 30% or maybe less antifreeze - maybe it wasn't enough .

Had a real nice drive yesterday = no traffic - windy road for about 1/2 hr ambient temps in high 20s(celcius) . No sign of overheating . Where i am seeing an issue is on a prolonged hillclimb on a windy road on and off the boost the whole way up . Think i need to remove my rad and flush it real good because I never used to have that happen on the same road.

I would think that would be fine.

me too - that's why i did it :)

Try running mostly glycol for a while to clean the system a bit before you flush it. For me too much water was a problem after shutdown, I could feel it boiling in the turbo coolant lines and I was losing a bit to evaporation. With mostly Glycol I don't have the boiling issue and my coolant level is rock steady.

What do you think of this?
https://www.rx8club.com/tech-garage-...licone-238638/

Not as bad as I expected.

you eliminate every issue mentioned by switching to Evans NPG-R waterless coolant, been using it since 2005 ....

Originally Posted by Brettus https://www.rx8club.com/images/buttons/viewpost.gif
Yes - blocked off both the hose on the tstat and the block
I would think that would be fine.

No its not, anywhere you have an area that has stationary water, is where you will have a place for debrie to find a place to sit, and this will be one of the reasons you will have build up of crud and rust.
Best thing to do is thoroughly flush the engine block and heater core using a rust nutralising agent. Then flush again to get all the nutralising agent out, then fill the engine with the best quality

That area will not have stationary water, he just capped the nipples so water will no flow thru those nipples and will just flow thru the engine as normal.

Team---I know Evans prevents or greatly reduces nuculate boiling etc etc. but i havent switched because I wasnt sure about if the little higher temps would make the housing more prone to have protrusion? I guess you havent seen that, but then again you dont put a lot of miles on your engines?
Thoughts?

my thought is that you didn't think that statement through at all

that goes for you too, pull the nipples and install plugs in the hole to eliminate the dead areas

You mean dead areas inside the nipple themselves? You think that would really cause an issue? I don't have them capped, Brettus does. Mine are supplying feed and return for the turbo.

It's like a teaspoon of water at each end ........

well ..... may be over thinking it.
Contrary to some beliefs, waterless cooling does not totally eliminate nucleate boiling. When the metal temp is over 500F it doesnt matter if the coolant temp boiling point is 250F or 375F nucleate boiling is going to occur. What waterless coolant DOES do is eliminate any vapor formation. Vapor and nucleate boiling are two different things....

I think also to get the best out of a waterless coolant-- due to its viscosity and lower heat transfer ability--a bigger tubed radiator and a more robust waterpump is needed?

Some corvette guys here in ga saw a cylinder head temp increase of 150F after converting. They developed more detonation as a result and had to re-tune. Drag strip guys. They are crazy anyway.

Just wondering if you have seen any evidence of brinelling? Corvette guys have not seen that but some older model Mustang guys claimed to have. Whether that would affect us--again IDK.
My point is--waterless coolant may not solve all problems by itself. Like everything else I think it has its place but it does have limitations.
I think in Teams chase it probably works great.

I may be thread jacking here--sorry Brett

Just replace the radiator if it isn't a fancy one.

Umm. I may be missing something, but it appears the nipple on the back of the block is the only path out of that coolant passage. So if you cap it it would cause the entire passage front to back to be stagnant. Not that it has high flow to begin with.

Couldn't find the post about TB bypass I was looking for. Did find a lot of people who capped it and didn't have problems. Regardless I would rather bypass than plug the lines. If I find more I'll post.