Timing belt job on a VVT car, now rattle on start up
08-19-2015, 04:22 PM
#71
My bet is the actuator is bad and bleeding down/loosing oil. Thus the noise on startup. Solution would be replace actuator with a new one, good luck finding a used one that's good.
Also worth trying: Unplug the electrical connector that goes to the control valve. This will leave the cam fully retarded at all times. See if the noise is gone with it disconnected. If the noise is still there it's the VVT actuator.
FWIW I've took my VVT actuator apart and put it back together twice now, and it works fine. When you put yours back together, did you keep it perfectly absolutely clean? I can't remember but isn't there a check valve in there? Perhaps it's stuck and letting the system bleed down.
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08-19-2015, 04:26 PM
#72
I run 10-30 in my VVT motor. But 100% that's not your issue with the noise on startup. Running heavier oil might cause the VVT to do weird things in really cold temps though (over or under shoot the target).
My bet is the actuator is bad and bleeding down/loosing oil. Thus the noise on startup. Solution would be replace actuator with a new one, good luck finding a used one that's good.
Also worth trying: Unplug the electrical connector that goes to the control valve. This will leave the cam fully retarded at all times. See if the noise is gone with it disconnected. If the noise is still there it's the VVT actuator.
FWIW I've took my VVT actuator apart and put it back together twice now, and it works fine. When you put yours back together, did you keep it perfectly absolutely clean? I can't remember but isn't there a check valve in there? Perhaps it's stuck and letting the system bleed down.
My bet is the actuator is bad and bleeding down/loosing oil. Thus the noise on startup. Solution would be replace actuator with a new one, good luck finding a used one that's good.
Also worth trying: Unplug the electrical connector that goes to the control valve. This will leave the cam fully retarded at all times. See if the noise is gone with it disconnected. If the noise is still there it's the VVT actuator.
FWIW I've took my VVT actuator apart and put it back together twice now, and it works fine. When you put yours back together, did you keep it perfectly absolutely clean? I can't remember but isn't there a check valve in there? Perhaps it's stuck and letting the system bleed down.
d00d.
I've had 3 different actuators in this thing. Pretty sure it's not the actuator itself at this point.
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08-19-2015, 04:35 PM
#74
I don't know where the 1 way valve is, what it looks like, or what i'm looking for. I don't vvt. For this very reason.
I'm 3 hours away from this car. I'll see if anything changes if he primes it.
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04-10-2018, 09:40 AM
#77
Just VVT things.
I ended up doing the timing belt job again on this thing just on the offchance there was a failing tensioner or bad pulley somewhere. There wasn't.
Then i rebuilt the VVT system with the MR kit. It didn't help.
Car continues to rattle on startup from time to time to this day. Isn't throwing codes, runs fine. Noise sounds like it's coming direct from the actuator. I don't think either of us are interested in continuing to throw actuators at the damn thing. They're expensive and at this point the cumulative cost of a 4th one exceeds that of a new motor if this thing grenades.
I ended up doing the timing belt job again on this thing just on the offchance there was a failing tensioner or bad pulley somewhere. There wasn't.
Then i rebuilt the VVT system with the MR kit. It didn't help.
Car continues to rattle on startup from time to time to this day. Isn't throwing codes, runs fine. Noise sounds like it's coming direct from the actuator. I don't think either of us are interested in continuing to throw actuators at the damn thing. They're expensive and at this point the cumulative cost of a 4th one exceeds that of a new motor if this thing grenades.
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04-10-2018, 01:51 PM
#80
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Ben, have you tried a brand new actuator from Mazda, or just continued to put used ones in it?
As I understand it, inside the actuator there is a spring-loaded pin which locks the actuator in place at start-up. Oil pressure then builds, fills the actuator, and un-locks the actuator once it's got enough oil pressure to operate. My assumption is that the pin is not locking the actuator, which means it's free to flop around until oil pressure builds up.
Acamas has this issue, I've had two used actuators in it so far. I've never had this issue with any other VVT motor (and I've been through a few). I currently have a brand new actuator on the shelf for it but I haven't gotten around to swapping it.
As I understand it, inside the actuator there is a spring-loaded pin which locks the actuator in place at start-up. Oil pressure then builds, fills the actuator, and un-locks the actuator once it's got enough oil pressure to operate. My assumption is that the pin is not locking the actuator, which means it's free to flop around until oil pressure builds up.
Acamas has this issue, I've had two used actuators in it so far. I've never had this issue with any other VVT motor (and I've been through a few). I currently have a brand new actuator on the shelf for it but I haven't gotten around to swapping it.
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