Questions on Rebuilding Motor
#1
Questions on Rebuilding Motor
So I got the engine apart. This engine is a Malloy reman, almost 6 years old with 29K on it running Evans NPG+ (never been changed either).
Here is the reason for the low compression: Note the lower 2 apex seals. Each has a piece cracked off the end.
Looks like I need a new housing:
Look how clean the coolant passages are:
Another look at the coolant passage:
BACKGROUND: I lifted only the rear rotor housing and rear end plate. I have not removed the front rotor housing or intermediate plate. The front has 95-100 psi of compression on an piston tester before disassembly.
QUESTION: Would it be prudent to leave the front rotor housing, intermediate plate and front plate unassembled and just rebuild the rear section as in new housing, new apex, side seals and corner seals and water o-ring?
Has anyone done something along this line, i.e., a partial rebuild?
Here is the reason for the low compression: Note the lower 2 apex seals. Each has a piece cracked off the end.
Looks like I need a new housing:
Look how clean the coolant passages are:
Another look at the coolant passage:
BACKGROUND: I lifted only the rear rotor housing and rear end plate. I have not removed the front rotor housing or intermediate plate. The front has 95-100 psi of compression on an piston tester before disassembly.
QUESTION: Would it be prudent to leave the front rotor housing, intermediate plate and front plate unassembled and just rebuild the rear section as in new housing, new apex, side seals and corner seals and water o-ring?
Has anyone done something along this line, i.e., a partial rebuild?
#2
Mr. Links
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Could you? Sure. However, you always run the risk of having the cooling passage sealing compromised since the tension has been released with the tension bolts removed. I would in the least replace the coolant seals even if you reuse everything else. You've already removed the engine and that's the hard part. Why take shortcuts now?
#4
Where does this bolt go?
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I would go with new seals all the way. Its easier than pulling the engine again. I have done what your suggesting on an old 4 port 13b NA many years ago, when I had to scrape every last penny to put an engine together. It worked, but that was a low hp NA not a turbo.
#5
Original Gangster/Rotary!
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Definitely disassemble and rebuild the entire engine.
The chipped areas of the apex seals are a common failure point.
The cleanliness of your coolant passages is enough to make me consider using Evans, btw.
The chipped areas of the apex seals are a common failure point.
The cleanliness of your coolant passages is enough to make me consider using Evans, btw.
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#8
Yes.
Background: Engine tuned over a year ago by Steve Kan, running 4X850 injectors, Supra pump, Sard PR. 311 rwhp 268 torque at 12 psi. I put in 10,000 miles on this tune with no problem.
In early August, I put in 8 oz of SeaFoam in the crank to clean out the internals. I was supposed to drain it but forgot and went to work. It was 70F, low humidity, water temp at 86 and I floored it. Got to 12 psi and heard a loud pop.
My guess is that the seafoam, a solvent was injected into the combustion chamber and caused the detonation. Since the rear rotor always run a little leaner than the front, it detonated.
If I had my Aquamist installed, it would have probably saved the motor.
Right now I'm debating with myself whether to rebuild or get a new Malloy.
Background: Engine tuned over a year ago by Steve Kan, running 4X850 injectors, Supra pump, Sard PR. 311 rwhp 268 torque at 12 psi. I put in 10,000 miles on this tune with no problem.
In early August, I put in 8 oz of SeaFoam in the crank to clean out the internals. I was supposed to drain it but forgot and went to work. It was 70F, low humidity, water temp at 86 and I floored it. Got to 12 psi and heard a loud pop.
My guess is that the seafoam, a solvent was injected into the combustion chamber and caused the detonation. Since the rear rotor always run a little leaner than the front, it detonated.
If I had my Aquamist installed, it would have probably saved the motor.
Right now I'm debating with myself whether to rebuild or get a new Malloy.
#11
"Elusive, not deceptive!”
My theory is that the apex seal chips it's tip from snapping across the extended spark plug boss as noted in this image. Note the carbon stains.
Solutions include colder plugs, and improved coolant flow.
Barry
Solutions include colder plugs, and improved coolant flow.
Barry
#12
New QUESTION: has anyone rebuild without taking the front cover off?
That front lock nut for the eccentric shaft is a bitch. I could not move it with my IR700 at 130 psi.
I don't see the point of taking the front cover off when the engine has only 29K on it and no front cover oil leak.
#14
Original Gangster/Rotary!
iTrader: (213)
poman, you don't see the point?
The engine is already out. I think you'd be crazy not to completely disassemble everything. Check, measure, clearance, reseal. If you're hesitating b/c of inexperience, take it to a local reputable builder. Hell, box it all up and mail it to me and I'll take care of it for ya
The engine is already out. I think you'd be crazy not to completely disassemble everything. Check, measure, clearance, reseal. If you're hesitating b/c of inexperience, take it to a local reputable builder. Hell, box it all up and mail it to me and I'll take care of it for ya
#16
Thanks for the offer. I ended up buying gracer-rx7 used motor. I thought about plunking down $5K for a brand new motor but wife 1.0 isn't having any of this. So the most economical and timely way for me to get back on the road is to drop the used motor in while I take my time rebuilding the other.
I don't know about you but I can see a decade of really bad economic time ahead. Money saved is money earned.
I don't know about you but I can see a decade of really bad economic time ahead. Money saved is money earned.
poman, you don't see the point?
The engine is already out. I think you'd be crazy not to completely disassemble everything. Check, measure, clearance, reseal. If you're hesitating b/c of inexperience, take it to a local reputable builder. Hell, box it all up and mail it to me and I'll take care of it for ya
The engine is already out. I think you'd be crazy not to completely disassemble everything. Check, measure, clearance, reseal. If you're hesitating b/c of inexperience, take it to a local reputable builder. Hell, box it all up and mail it to me and I'll take care of it for ya
#17
Turd Ferguson
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sounds like a good solution.
now you can rebuild your engine and take your time doing it.... or just send it to a shop and have them go over it with a comb while the "new" engine gets put to good use.
now you can rebuild your engine and take your time doing it.... or just send it to a shop and have them go over it with a comb while the "new" engine gets put to good use.
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