[PICS] Pulled apart my blown engine....56K...Maybe
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Joined: Feb 2001
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From: n
Originally Posted by Wankel7
Reted/Overdriven - The run that blew the engine was the first wide open in third gear I had done since I did work to it (RB exhaust, EGT, ported the WG). So, I was more focused on what the boost was after the porting. Should have got the 60MM gauge eh
P/H gauges are your friend when you're drag racing.
Although I tend to ignore the boost gauge and concentrate more on the EGT gauge myself.
It has taken years of driving to force me to watch the EGT gauge!
On that chart that is four seperate runs all from the same night. Where the AFR dips down that is when I got on it. It was from 4000rpm floored thru 7000ish.
I would normally see 12.5 und richer under WOT.
I would normally see 12.5 und richer under WOT.
I would like to see AFR's all under 12.0:1 under boost as absolute limit.
In fact, I would feel safer is it was under 11.5:1 under boost.
Most people will recommend 10.5:1 to 11.0:1 AFR's under boost!
I concur with all the other comments.
The weird apex seal failure could be the exahust ports were not bevelled and / or the exhaust port closing very abruptly.
-Ted
Rotary Enthusiast
Joined: May 2004
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From: SoCal
Originally Posted by Aaron Cake
There doesn't seem to be a spacer missing. That washer sits under the counterweight, and the torrington bearing sits on top of the thrust plate.
The larger chamfer on the the CAS gear goes toward the engine. If you look at each side of the gear where the e-shaft goes through, one will be cut at an angle on the edge. That side toward the engine.
The larger chamfer on the the CAS gear goes toward the engine. If you look at each side of the gear where the e-shaft goes through, one will be cut at an angle on the edge. That side toward the engine.
What will happen if I put that gear on backwards?
I know I put it on backwards in my kinda pre-assembly before I tightened everything down. I told myself several times "Alright, just flip it over before you tighten everything down..." but I cannot for the life of me remember if I did or not. And I could swear in the pictures I have it looks like it's up.
Will the CAS be exactly 180' off if this is in backwards?
--Gary
Joined: Oct 2003
Posts: 11,576
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From: Morristown, TN (east of Knoxville)
Absolutely nothing. The gear itself is made the same from side to side. The bevel is just to help with installation onto the shaft, I suspect. There is no backwards way to install this.
Rotary Enthusiast
Joined: May 2004
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From: SoCal
Originally Posted by RotaryResurrection
Absolutely nothing. The gear itself is made the same from side to side. The bevel is just to help with installation onto the shaft, I suspect. There is no backwards way to install this.
That's one major less worry... I'm still not sure if it's on backwards, but as long as it doesn't matter. =)
--Gary
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From: n
Yep, agreed.
I've seen motors with reversed CAS gear on the front section, and it doesn't seem to have affected everything.
Mazda just "recommends" to install it with the camfer towards the engine.
-Ted
I've seen motors with reversed CAS gear on the front section, and it doesn't seem to have affected everything.
Mazda just "recommends" to install it with the camfer towards the engine.
-Ted
Rotary Enthusiast
Joined: Mar 2004
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From: St Louis
Hey Kevin. Do you lap irons in your rebuilds? Just curious. Sorry to hi-jack the thread. Sorry to see a motor go like that. I've never seen an apex seal break like that one. Mine were always much messier. So, am I safe to assume that detonation causes that?
Joined: Oct 2003
Posts: 11,576
Likes: 27
From: Morristown, TN (east of Knoxville)
No, I never lap irons. The rotorhousing compression surface has the most impact on compression quality after breakin. Even a moderately worn iron can produce a good compression engine with no smoke.
Thread Starter
Haven't we ALL heard this
Joined: Mar 2001
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From: Indiana
Your not hijacking....good question because I was wondering about lapping to.
Is lapping a bad thing?
I know it had been mentioned that lapping could cause the endplay to get to the point where you could not adjust it with the spacers?
James
Is lapping a bad thing?
I know it had been mentioned that lapping could cause the endplay to get to the point where you could not adjust it with the spacers?
James
Joined: Oct 2003
Posts: 11,576
Likes: 27
From: Morristown, TN (east of Knoxville)
Yes, I personally feel that more can be screwed up by lapping housings than by just using originals with normal wear. You face endplay, coolant seal groove depth, and nitriding removal issues when you lap housings.
Thread Starter
Haven't we ALL heard this
Joined: Mar 2001
Posts: 3,948
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From: Indiana
Not a problem man. I will be home in one week and I want to take a peak at the exhaust ports. From what I hear I doubt the porting job retained the stock feature the transion from housing to exhaust port.
James
James
Thread Starter
Haven't we ALL heard this
Joined: Mar 2001
Posts: 3,948
Likes: 1
From: Indiana
I did that
Updated here:
https://www.rx7club.com/showthread.p...=1#post3962744
Also,
Check out this link for some more clues that may have contributed to it...
http://www.atkinsrotary.com/index.php?pag=40-9
James
Updated here:
https://www.rx7club.com/showthread.p...=1#post3962744
Also,
Check out this link for some more clues that may have contributed to it...
http://www.atkinsrotary.com/index.php?pag=40-9
James
Locust of the apocalypse
Joined: Apr 2003
Posts: 2,553
Likes: 2
From: Directly above the center of the earth (York, PA)
Question #1 camfer.... its a small 45 degree angle around the lip on the INSIDE of the gear where the e-shaft passes through it... looks like the flat side is out... as per the FSM
#2... Only one spacer in the motor... Two torrington bearings one of which you have lying in the pic..
That seal looks like it got hit with a massive detonation.... like the trailing fired right on the freakin seal and blew it to shreds......
That port job is about right for a standard street port, but you can see that they took 'em right to the side seal and corner seal marks. the secondary is a bit short IMO, but thats common for a street engine...... just check to make sure that the ports are EXACTLY the same size on the front and rear rotors.... if one rotor has a bigger port job than ther other....... not good.
You heard it knock.... shouldn't ditched the stock system long ago..... A ported motor and a BNR needs a standalone and an FMIC..... but it looks like you've figured that out on your own... just to late!!!!!
I'll bet it was high air charge temps, High AFR and the stock timing that did it... like i said... trailing firing to close to the apex seal under boost.
#2... Only one spacer in the motor... Two torrington bearings one of which you have lying in the pic..
That seal looks like it got hit with a massive detonation.... like the trailing fired right on the freakin seal and blew it to shreds......
That port job is about right for a standard street port, but you can see that they took 'em right to the side seal and corner seal marks. the secondary is a bit short IMO, but thats common for a street engine...... just check to make sure that the ports are EXACTLY the same size on the front and rear rotors.... if one rotor has a bigger port job than ther other....... not good.
You heard it knock.... shouldn't ditched the stock system long ago..... A ported motor and a BNR needs a standalone and an FMIC..... but it looks like you've figured that out on your own... just to late!!!!!
I'll bet it was high air charge temps, High AFR and the stock timing that did it... like i said... trailing firing to close to the apex seal under boost.
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