The whole thing looks like lack of oil. Think about millions of turns with little oil. It will slowly machine the materials away.

No premix gets down to the side seals that's why Mazda
pointed those oil squirters to the side seals.

I think team is referring to micro pings. The ones that still occur. Small enough that you can't detect it but big enough to cause wear issues.

That would be plausible if ALL the ports were gouged - but they aren't .

not trying to argue with you, we all have ideas and opinions, when it comes to turbo Renesis most of mine come from builders a lot more smarter and experienced than me

Thanks for sharing. Would be interesting to see future breakdowns from other ported engines.

The housing seems to have a lot of wear which is interesting seeing you used a milder seal. the use of second hand parts may skew some of the results.

Running a heavier lubricating oil without increasing the oil pressure bypass limits, will cause a reduction in oil flow (compared to stock). Flow increases directly with rpm until the bypass opens, and from then on is constant. Since increasing the viscosity increases the oil pressure at a given rpm, it results in the stock bypass opening at a lower rpm, giving lower flow than stock above that rpm.

The Mazmart/RX-7 mod allows the volume to increase with rpm pretty much all the way to redline. :rock:

^+1 Just having the same discussion with someone else.

that's all fine & dandy, until you get into the discussion of what the issue is; too little flow or too little viscosity?

further, even if you have extra flow do you really know where it's going? It doesn't necessarily mean it's flowing more everywhere.

the subject is more complex than the typical forum member seems to realize, comparatively speaking a 2-rotor engine doesn't have that many bearings to keep afloat

Brett...

What viscosity of oil did you use?

IMO...a lot of the bearing issues have to do with the shaft balance of the stock motors....If yours was anything like mine before I had it balanced I'm surprised it didn't shake itself to oblivion ;) I noticed a huge difference in the way the engine spun up after it was balanced

0W40 was posted earlier

I didn't consider the balance issue, good catch

Thanks for sharing man.

Yeah that is quite a bit a bearing wear for those miles. Was it balanced when it was put together last time? It really is important, I don't know why some do not think so. Also what type of 5W40 was used? This is why I am leaning towards all new stuff on my next engine rebuild. If I rebuild a Renesis anyway.

so whats for the future?
have you ever conidered putting an rx7 13b with the renesis outer housings?

Stop it. Just stop.

just saying; i know it seems hard but its been pulled off.
The exhaust ports are ideal for boost.

Shady says those exhaust ports were opened up a bit much. We are experimenting with opening the inside a bit more and smoothing that out and leaving the overall size relatively stock.

Anyways I've seen that same wear pattern on the bearings in 4 renesis engines now.

I am sold, factory balancing is not up to par. There is a good chance this is whats been causing engine failures when all seals are intact. Could be a good amount of factors involved though.

As these engines start dropping out of warranty more and more we will start seeing companies and shops jumping in with theories and solutions. Should get interesting here in a few years.

Just stop dude, you don't have a clue what you are talking about.


Yeah and I think team is right about the detonation issues, we have no real way of identifying pinging unless we hear it.

No that engine was not balanced and neither was the one i just put in :( . Think I'll do the oil pressure mod though - on the off chance that may help the situation .
The latest engine had no porting done plus it had practically new parts installed so should last a bit longer .

i see that bearing near pattern on all the non-Rx8 engine's i've torn down, the bearings don't wear evenly, especially on the rear main.

detonation WILL cause extra wear, and it'll be out of round too

Interesting, were those assemblies all balanced at a facility or just weight matched from the factory?

its a mix, most were probably factory assemblies, some are rebuilds, some are just stat gears in a box of stat gears.... we've got lots and lots of torn down engines @ the man cave.

the pic is from the competition prep book from 1979, the Renesis actually has all of the comp specs already, except the oil pressure, but you see that they took steps to keep the rear of the rear main from wearing 34 years ago....

competition book is here, http://foxed.ca/index.php?page=rx7manual#firstgen

I believe the coolant passages don't line up with the newer 13b housings. Unless you go with first gen RX-7 housings. Again, this is if I recall correctly.

sub

Another factor in the bearing wear is that I don't believe the bearings were replaced at the rebuild so they will have a lot more than 60000 kms on them. They may even be the original bearings from the original engine which means 180,000 kms . I assume the builder did inspect them and deem they were serviceable though.

Yeah using parts of varying stages of wear and then not balancing it will just insure that you will be doing this every couple of years :) More time to experiment, :lol:

yeah , I'm regretting not getting this last one balanced now . My engine builder wanted to do it but I actually talked him out of it ...... doh !