QuestionI am working on a Pontiac Super Duty 4 engine (similar to the Iron Duke 151 Cu in engine)
How much movement, if any, should there be on the cam when pulling/pushing on it in and out of the block? Cam is held from coming out of the block by the thrust plate. Cam is prevented from moving into the block by the cam Gear. Should there be any movement here? I am thinking the answer is No, How is this movement limited? Currently I have at least 3/16 inch of movement.
I am currently using the cam spacer that was removed from the engine. (new cam and new gear are being installed) This spacer and thrust plate is of a different design thant the stock duke engine.
This spacer is very thin, perhaps .040 thick. It rides between the big part of the cam and the thrust plate.
The stock spacer is much thicker but it fits INSIDE the hole in the thrust plate. It is about the same thickness as the thrust plate, so this will not provide any additional spacing.
Seems like I should have a really thick (3/16) spacer that goes between cam and the thrust plate, effectively pushing the cam fruther inside the block, and taking up this 'slack' I have now.
I have the Factory Service manual, but only mentions replacement of the spacer/thrust plate if the tolerance of .005 is exceed. Since I have so much more movement than that, and my parts are NOT excessively worn, there must be something else I am missing.
Please help. Happy to email a picture or two if that would help.
AnswerHi Jim:
I have not touched a tech $ engine in 20+ years literally! my online service manual stuff only goes back to 1998. if memory serves me right that 2 piece thrust washer is just to keep the cam from walking out of the block and to make sure the cam and crank gear are aligned. the dummy distributor gear at the other end is also in play on this it's a short stub shaft that is there in place of a distributor when they when to electronic ignition it drives the oil pump off the cam shaft if that gear is work out of the cam that will add to the end play you have 3/16" is a LOT of end play My guess is that gear on the oil pump drive is worn out or the gear machined into the cam chances are it's the gear on the drive more then the cam shaft. good luck :-)
