Engine teardown - 300+ hp with highish miles
#26
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.
No premix gets down to the side seals that's why Mazda
pointed those oil squirters to the side seals.
#30
rev it up
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.
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.
#31
Registered
iTrader: (2)
The Mazmart/RX-7 mod allows the volume to increase with rpm pretty much all the way to redline.
#33
No respecter of malarkey
iTrader: (25)
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
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
#34
Modulated Moderator
iTrader: (3)
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
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
#36
SARX Legend
iTrader: (46)
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.
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.
#40
WENTGERMAN
iTrader: (6)
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.
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.
#41
SARX Legend
iTrader: (46)
Just stop dude, you don't have a clue what you are talking about.
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.
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.
#42
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 .
The latest engine had no porting done plus it had practically new parts installed so should last a bit longer .
#43
detonation WILL cause extra wear, and it'll be out of round too
#45
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
Last edited by j9fd3s; 03-11-2013 at 02:35 PM.
#48
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.
Last edited by Brettus; 03-11-2013 at 05:19 PM.