Double roller on an LT4 Motor ???
Thread Starter
Safety Car
Joined: Jul 2001
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From: TurtleCreek Twp Ohio
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Double roller on an LT4 Motor ???
Is anyone aware of a double roller timing chain setup that would work with an optispark ignition system? Cloyes has a heavy duty chain and gearset but what I'm really looking for is something that is guaranteed to hold up to extreme spring pressures. Thanks!
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Joined: Jan 2002
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From: O'Fallon Missouri
Re: Double roller on an LT4 Motor ??? (Aquaman)
To use a double roller timing chain on your LT4, you will have to install an electric water pump. Unfortunately the LT1/4's water pumps are driven by the timing gear. GM does make an extreme duty timing set for the LT4.
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From: Texas
Re: Double roller on an LT4 Motor ??? (Aquaman)
Because of OBD II in '96, you have not only the crank gear on the crank, but a reluctor ring. The reluctor ring is sensed by the cranshaft position sensor (CPS). As a result of this, in order to run a double roller on an LT4 you will have to do one of the following...
- Ditch the '96 PCM and swap in an OBD I PCM. This allows you to also ditch the reluctor ring and the CPS so that the double roller will fit.
- Have a reluctor ring custom machined. This will allow you to retain the '96 PCM and OBD II functionality
You *may* also be able to program the CPS out via LT1 Edit. I can disable the setting of the SES due to misfire this way, and you can also disable P0335 Crank Sensor Failure and P0336 Crank Sensor skew but I've never bothered to look to see if there are other codes associated with the CPS that programming can't address.
Bottom line...it's possible but not a bolt in and depending on the route you take it can be costly.
- Ditch the '96 PCM and swap in an OBD I PCM. This allows you to also ditch the reluctor ring and the CPS so that the double roller will fit.
- Have a reluctor ring custom machined. This will allow you to retain the '96 PCM and OBD II functionality
You *may* also be able to program the CPS out via LT1 Edit. I can disable the setting of the SES due to misfire this way, and you can also disable P0335 Crank Sensor Failure and P0336 Crank Sensor skew but I've never bothered to look to see if there are other codes associated with the CPS that programming can't address.
Bottom line...it's possible but not a bolt in and depending on the route you take it can be costly.
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 3,667
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From: TurtleCreek Twp Ohio
Cruise-In III Veteran
Re: Double roller on an LT4 Motor ??? (96GS#007)
I should clarify a little further.. the car has '93 electronics so it is OBD1.
I hear that a longer dowel pin in the camshaft is what is used to drive the later optisparks? If that is true, I would think that the double roller is not a problem provided the timing cover is also updated.
I hear that a longer dowel pin in the camshaft is what is used to drive the later optisparks? If that is true, I would think that the double roller is not a problem provided the timing cover is also updated.
