Losing Compression On Dyno, Any Ideas?

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Mar 28, 2004 | 03:21 PM

#21

j9fd3s

Senior Member

Joined: May 2002

Posts: 22,465

From: California

could maybe be something wired like a bent e shaft?

Mar 28, 2004 | 03:38 PM

#22

93FDGT3540

Thread Starter

Senior Member

Joined: Feb 2003

Posts: 100

From: NewHampshire

Quote:

Originally Posted by j9fd3s' date='Mar 28 2004, 01:21 PM

could maybe be something wired like a bent e shaft?

what would the side effects of that cause? I am looking into any and all possibilities. I have replaced most items that could cause such a failure that i know of. I will ask the engine builder what else to look for but i wanted to get some opinions from here to start me off.

Mar 28, 2004 | 03:59 PM

#23

1Revvin7

Senior Member

Joined: Oct 2001

Posts: 10,906

From: Peoria, AZ

Quote:

Originally Posted by pluto' date='Mar 28 2004, 01:29 PM

The only thing I could really think off is the exhaust port or the shape of the port causing it to run higher EGT than normal.

Sounds like a good suspect

Mar 28, 2004 | 04:15 PM

#24

jspecracer7

Senior Member

Joined: May 2002

Posts: 4,928

From: Okinawa, Japan

Quote:

Originally Posted by j9fd3s' date='Mar 29 2004, 06:21 AM

could maybe be something wired like a bent e shaft?

If his e-shaft was bent, he wouldn't get past 500 miles. You'd know if your motor was blown due to a bent e-shaft. It would sound like a diesel(clunk, ka-clunk, ka-clunk, ka-clunk) and as soon as took the oil pan off...bronze fairy dust everywhere.

Mar 28, 2004 | 04:18 PM

#25

FikseRxSeven

Senior Member

Joined: Jan 2003

Posts: 8,079

From: union, new jersey

im not a rotary engine builder or expert... but for the edge to be sharp as described... something must have been eating it.... so most likely the exhaust port like i stated before

Mar 28, 2004 | 07:12 PM

#26

93FDGT3540

Thread Starter

Senior Member

Joined: Feb 2003

Posts: 100

From: NewHampshire

Quote:

Originally Posted by FikseRxSeven' date='Mar 28 2004, 02:18 PM

im not a rotary engine builder or expert... but for the edge to be sharp as described... something must have been eating it.... so most likely the exhaust port like i stated before

I am no expert either. this motor has been taken apart 3 times and has been inspected for damage, all parts. The engine builder took a real good look this last time and didn't notice any damage. Checked all parts, inspected closely and reassembled with new seals. The car was pulling good vaccum -14 inches as we strapped it too the rollers. I had almost 1k miles on it of very careful driving, no high rpms, no or very little boost. Idled perfectly. Even after closely scutinizing the air/fuels and the timing, fuel pressure and boost levels. the motor slowly started to lose vaccum. we were goin so slow it took us 3 hours on the dyno just to get it up to 13+ psi. There wasn't anything we could see to show why we were losing vaccum at idle. Because this has happened 3x before I knew the signs, I heard the car start to sound like a chopper and the vaccum drop to -10 inches. We stopped there so it would still start and drive until it got sorted out. I had apex seals with me from the previous motors and these are what you see here. I have more pics i took, I hope they show more detail. I have confidence in my engine builder that he will eventually work this out. Sometimes its a slow process. Has anyone ever heard of this happening before?