Engine had turbo compressor wheel for breakfast!!!!!!!!!
04-27-09, 02:38 AM
#1
New Turbo time!
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Engine had turbo compressor wheel for breakfast!!!!!!!!!
Hey Guys,
Had a very interesting Saturday, took my car in for a dyno tune as it was finally run in, was expecting around 250KW. Anyway they ran the car up it was doing well until the decided to push it over a 1 bar boost, thats when the nut on the compressor wheel came off during compressor surge we believe and then got sucked into the turbo and made the mess you see in the picture, it ended up seizing the turbo which is how we found out we thought we have a cooler hose blow off as it was idling a bit funny like a vacuum leak but i think it was being staved air which was the cause i believe.
I have pulled the turbo off as it was a freshly rebuilt S5 factory turbo with bigger compressor wheel and front cover, and was only used during the running in which was no boost till the dyno and was done by one of the best guys in the country who does 1000HP drag cars.
Pulled the turbo and manifold off and the upper intake to clean and did a compression check which just the lower manifold on and only got 25psi on each face on both rotor housings, checked the compression tester in a piston car and it did a 170 on my friends Mazda 6. Looked at the apex seals with a mirror through the exhaust ports and there where no nicks or scratches and they are SCR seals which are very strong 2mm seals. Is there something I'm doing wrong with the compression test? do u need the turbo on to create back pressure? Any advice or help would be great guys as this was a fresh motor and i hope its not stuffed as its gonna be hard getting money out of the guy who rebuilt the turbo.
Thanks
Had a very interesting Saturday, took my car in for a dyno tune as it was finally run in, was expecting around 250KW. Anyway they ran the car up it was doing well until the decided to push it over a 1 bar boost, thats when the nut on the compressor wheel came off during compressor surge we believe and then got sucked into the turbo and made the mess you see in the picture, it ended up seizing the turbo which is how we found out we thought we have a cooler hose blow off as it was idling a bit funny like a vacuum leak but i think it was being staved air which was the cause i believe.
I have pulled the turbo off as it was a freshly rebuilt S5 factory turbo with bigger compressor wheel and front cover, and was only used during the running in which was no boost till the dyno and was done by one of the best guys in the country who does 1000HP drag cars.
Pulled the turbo and manifold off and the upper intake to clean and did a compression check which just the lower manifold on and only got 25psi on each face on both rotor housings, checked the compression tester in a piston car and it did a 170 on my friends Mazda 6. Looked at the apex seals with a mirror through the exhaust ports and there where no nicks or scratches and they are SCR seals which are very strong 2mm seals. Is there something I'm doing wrong with the compression test? do u need the turbo on to create back pressure? Any advice or help would be great guys as this was a fresh motor and i hope its not stuffed as its gonna be hard getting money out of the guy who rebuilt the turbo.
Thanks
04-27-09, 07:04 AM
#2
Try this one.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rotary-compression-tester-734840/
Here is jackhild59's methodology for uniform compression test results on a rotary engines
Fully charge the battery. Slow rotation will yield deceptively low results.
Use the bottom spark plug hole; take both bottom spark plugs out for the duration of the test.
Remove the EGI fuse: you don't want the thing trying to try to run.
The throttle should be held to the floor or the throttle plate tied fully open. Failure to do this will yield very low results.
You will need an assistant to operate the ignition (and throttle) or a remote start switch with the throttle tied open.
Ideally the test should be done while the engine is warm. Cold is ok, but warm numbers are what should count. If you test a cold engine, be aware the what looks like an unacceptably low number may actually turn out to be quite all right. There is no hard fast number that will be the difference from cold to hot. Warm will be consistent, cold may not be. If an engine fails the test cold, it may well pass the test when warm.
Crank the engine for about 10-15 seconds max for each test.
Bump Test:
This verifies that the apex seals are operating properly, ie. not broken or stuck.
Remove the Schroeder valve in the BOTTOM of the compression tester (NOT the side release valve) for the 'look for three uniform bump test'.
Leave the side release valve alone for this test.
Test each chamber front then rear, make notes! Those bumps should be even and somewhere around 60-70 psi minimum.
Compression Test:
This is to test the actual compression in the engine.
Replace the Schroeder valve in the BOTTOM of the compression tester.
Retest each chamber, this time allowing the pressure to pump up to the maximum psi. Write this number down.
PSI should be above 85 psi per the FSM. Lower than this and the engine is in need of a rebuild. This engine will be prone to flood. It may however run for quite sometime, especially if it is NA.
90 psi+ should be enough to run reliably;
95 psi + is great,
100psi+ is excellent.
NOTE: All pressures will tend to be lower with longer hoses and higher with shorter hoses. Experts agree that ideally, the hose should be as short as possible; Best would be if the hose were eliminated and the unit screwed directly into the sparkplug hole essentially with the gauge as closely coupled to the compression chamber as possible.
NOTE 2: In general, Turbo II's will be lower numbers than NA, S4's will be lower than S5's.
NOTE 3: This write up is a compilation from several authors, Reted, Kevin Landers, Aaroncake and others combined, clarified and hammered into one place. The intent is to create consistent documented methodology in one place so that the newbs and accomplished alike can agree on the results.
Here is jackhild59's methodology for uniform compression test results on a rotary engines
Fully charge the battery. Slow rotation will yield deceptively low results.
Use the bottom spark plug hole; take both bottom spark plugs out for the duration of the test.
Remove the EGI fuse: you don't want the thing trying to try to run.
The throttle should be held to the floor or the throttle plate tied fully open. Failure to do this will yield very low results.
You will need an assistant to operate the ignition (and throttle) or a remote start switch with the throttle tied open.
Ideally the test should be done while the engine is warm. Cold is ok, but warm numbers are what should count. If you test a cold engine, be aware the what looks like an unacceptably low number may actually turn out to be quite all right. There is no hard fast number that will be the difference from cold to hot. Warm will be consistent, cold may not be. If an engine fails the test cold, it may well pass the test when warm.
Crank the engine for about 10-15 seconds max for each test.
Bump Test:
This verifies that the apex seals are operating properly, ie. not broken or stuck.
Remove the Schroeder valve in the BOTTOM of the compression tester (NOT the side release valve) for the 'look for three uniform bump test'.
Leave the side release valve alone for this test.
Test each chamber front then rear, make notes! Those bumps should be even and somewhere around 60-70 psi minimum.
Compression Test:
This is to test the actual compression in the engine.
Replace the Schroeder valve in the BOTTOM of the compression tester.
Retest each chamber, this time allowing the pressure to pump up to the maximum psi. Write this number down.
PSI should be above 85 psi per the FSM. Lower than this and the engine is in need of a rebuild. This engine will be prone to flood. It may however run for quite sometime, especially if it is NA.
90 psi+ should be enough to run reliably;
95 psi + is great,
100psi+ is excellent.
NOTE: All pressures will tend to be lower with longer hoses and higher with shorter hoses. Experts agree that ideally, the hose should be as short as possible; Best would be if the hose were eliminated and the unit screwed directly into the sparkplug hole essentially with the gauge as closely coupled to the compression chamber as possible.
NOTE 2: In general, Turbo II's will be lower numbers than NA, S4's will be lower than S5's.
NOTE 3: This write up is a compilation from several authors, Reted, Kevin Landers, Aaroncake and others combined, clarified and hammered into one place. The intent is to create consistent documented methodology in one place so that the newbs and accomplished alike can agree on the results.
04-27-09, 09:26 AM
#3
Engine, Not Motor
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The apex seals my look fine, but the side and corner seals may be toast.
I think TweakGames recently posted some pictures in the single turbo forum that show FOD damage to his engine from a blown intercooler coupler. The apex seals were fine but the corner and side seals were totalled.
I think TweakGames recently posted some pictures in the single turbo forum that show FOD damage to his engine from a blown intercooler coupler. The apex seals were fine but the corner and side seals were totalled.
04-27-09, 05:07 PM
#4
New Turbo time!
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The apex seals my look fine, but the side and corner seals may be toast.
I think TweakGames recently posted some pictures in the single turbo forum that show FOD damage to his engine from a blown intercooler coupler. The apex seals were fine but the corner and side seals were totalled.
I think TweakGames recently posted some pictures in the single turbo forum that show FOD damage to his engine from a blown intercooler coupler. The apex seals were fine but the corner and side seals were totalled.
04-27-09, 09:33 PM
#5
Im gonna get one of those small dentist mirrors and see what else i can view through the exhaust housing, but back to the compression test which im gonna try again, does the exhaust and turbo have to be on? i have put the rest of the intake on so the throttle body is there.
I'd put it all back together and run it.
04-27-09, 10:20 PM
#6
The turbo does not have to be on, reason being that you are measuring pressure on the compression stroke and not the exhaust. Its weird how consistent your numbers are though, maybe you should rent a tester from autozone and check available compression.
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04-28-09, 01:39 AM
#8
New Turbo time!
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Hey Guys,
Thanks for the help, did another compression test put some oil in the housing and it read 125psi on each face on both rotors and then to be sure we tested my mates old RX2 which has 75psi which is pretty got for orginal engine which is tired by now. Im happy and will got get a garrett GT3540 now not touching that old turbo again.
Cheers
Thanks for the help, did another compression test put some oil in the housing and it read 125psi on each face on both rotors and then to be sure we tested my mates old RX2 which has 75psi which is pretty got for orginal engine which is tired by now. Im happy and will got get a garrett GT3540 now not touching that old turbo again.
Cheers
04-28-09, 09:28 AM
#9
04-28-09, 09:11 PM
#10
Hey Guys,
Thanks for the help, did another compression test put some oil in the housing and it read 125psi on each face on both rotors and then to be sure we tested my mates old RX2 which has 75psi which is pretty got for orginal engine which is tired by now. Im happy and will got get a garrett GT3540 now not touching that old turbo again.
Cheers
Thanks for the help, did another compression test put some oil in the housing and it read 125psi on each face on both rotors and then to be sure we tested my mates old RX2 which has 75psi which is pretty got for orginal engine which is tired by now. Im happy and will got get a garrett GT3540 now not touching that old turbo again.
Cheers
Good luck putting it all back together! Post some pics when your done.
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