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Discussion Starter · #1 ·
Hey guys, need a little help. So As some know I’m in the middle of my engine build. Taking my sweet time to make sure everything is perfect. So I noticed when I installed and setup my cam, the cam and crank sprocket didn’t align perfectly. The crank sprocket needed to be pulled out slightly to get the right alignment. The cam could not be pushed back because it was obviously stopped by the rear cam tunnel plug. But I also nothiced that my cam thrust bearing behind the head does not quite touch the block so the cam seems to be sort of floating. Is it common for the cam tunnel plug to be installed too deep( pushing the cam too far forward. Ps this all occurred to me only after I installed everything and put the balancer on and thought, “damn did I just push the crank sprocket back out of alignment” I’m not sure how to get everything to work together
 

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the cam gear must thrust on the block (or the thrust plate).

remove the cam tunnel plug and verify everything is lined up.

the crank gear could be shimmed but the balancer is supposed to hold it against the step on the snout.
 

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Discussion Starter · #5 ·
the cam gear must thrust on the block (or the thrust plate).

remove the cam tunnel plug and verify everything is lined up.

the crank gear could be shimmed but the balancer is supposed to hold it against the step on the snout.
Yeah that’s what I was thinking. So the crank gear has to be seated on the crank snout and the cam thrust bearing should be riding against the block. Problem is that for me to get the cam back far enough to do that the cam tunnel plug has to be removed and put back in or replaced at a shallower depth, but then the next problem is that the cam button is gonna need some serious shimming to get the end play correct
 

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Yeah that’s what I was thinking. So the crank gear has to be seated on the crank snout and the cam thrust bearing should be riding against the block. Problem is that for me to get the cam back far enough to do that the cam tunnel plug has to be removed and put back in or replaced at a shallower depth, but then the next problem is that the cam button is gonna need some serious shimming to get the end play correct
Welcome to the dark side of building a more serious engine, rather than just being a parts assembler. :oops:

I once used the camshaft itself as a driver and pushed a too-deep rear plug back far enough, simply bcause a friend wanted to take the gamble. It worked without a problem....but I always figured if it had been mine it would have leaked for sure, or popped out, such is my luck.
 

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Discussion Starter · #7 ·
Welcome to the dark side of building a more serious engine, rather than just being a parts assembler. :oops:

I once used the camshaft itself as a driver and pushed a too-deep rear plug back far enough, simply bcause a friend wanted to take the gamble. It worked without a problem....but I always figured if it had been mine it would have leaked for sure, or popped out, such is my luck.
While this was my first thought, I don’t like the idea. I’m thinking I will probably pull the cam and do it the right way
 

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Yep you need to fix this if the cam bore plug is stopping the cam it will have to be punched out and replaced. Pushing it backwards might result in an oil leak that cannot be fixed without engine removal so on a risk verses consequences scale it is worth doing this job correctly.

I’m not sure whether you are talking about a flat tappet or OEM roller. In the case of a flat tappet or aftermarket retro roller cam but either of these use the large bolt circle gear with a retainer fitting. This gear is designed to be in contact with a mating surface on the block face. This is the aft movement thrust surface, there being no forward thrust retainer on flat tappet cams. If you are using an aftermarket roller cam then an adjustable thrust button is used between the cam gear center and the timing case cover. Setting this adjustment is a big PIA as it is variable with flex in the cover and the gasket thickness between the cover and block, if you’re doing this please announce such as this is a lengthy paragraph of instruction and caution on its own.

If you are using a factory OEM roller cam the cam’s nose extends about 1/8th inch ahead of the classic gear thrust surface on the block. This is the same location in 3 dimensional space for flat tappet and factory roller blocks. However, where the factory (Original Equipment Manufacturer thus the term OEM) roller cam is used the thrust plate occupies this eighth inch of space. The stepped nose extension of the cam passes through the thrust plate to mount the reduced depth cam gear. The forward thrust of the cam is absorbed by the leading forward edge of the number one cam journal through its clearance to the thrust plate while rearward thrust is absorbed by the timing gear clearance to the thrust plate. This is the same motion as with a flat tappet cam but there the thrust is applied to the block. The OEM roller cam’s gear uses a smaller bolt pattern than the flat tappet/aftermarket (retro) roller cam so these gears do not interchange. The OEM roller also does not and cannot fit the metal bolt retainer of the flat tappet or retro roller cam gear. The factory (OEM) cam gear is retained with pan head, Allen or TORX screws and liquid thread locker for clearance and retention.

So all of this boils down to for either a flat tappet and retro roller or for an OEM roller; the cam gear must properly fit to the block or to the thrust plate as the designs would each require. If the cam will not allow this, you must find out why and correct the situation. The addendum to this is if it is the rear cam bore plug being driven to deeply, it is better to remove the one installed and replace the whole thing after inspecting for cleanliness and damage to the bore as the only fix if this thing leaks oil is to pull the engine back out. Well maybe not the only fix the other is drop the transmission and what ever that uses flex plate or flywheel to gat at the back of the block from underneath, this not being much fun either.

Bogie
 

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Discussion Starter · #9 ·
Yep you need to fix this if the cam bore plug is stopping the cam it will have to be punched out and replaced. Pushing it backwards might result in an oil leak that cannot be fixed without engine removal so on a risk verses consequences scale it is worth doing this job correctly.

I’m not sure whether you are talking about a flat tappet or OEM roller. In the case of a flat tappet or aftermarket retro roller cam but either of these use the large bolt circle gear with a retainer fitting. This gear is designed to be in contact with a mating surface on the block face. This is the aft movement thrust surface, there being no forward thrust retainer on flat tappet cams. If you are using an aftermarket roller cam then an adjustable thrust button is used between the cam gear center and the timing case cover. Setting this adjustment is a big PIA as it is variable with flex in the cover and the gasket thickness between the cover and block, if you’re doing this please announce such as this is a lengthy paragraph of instruction and caution on its own.

If you are using a factory OEM roller cam the cam’s nose extends about 1/8th inch ahead of the classic gear thrust surface on the block. This is the same location in 3 dimensional space for flat tappet and factory roller blocks. However, where the factory (Original Equipment Manufacturer thus the term OEM) roller cam is used the thrust plate occupies this eighth inch of space. The stepped nose extension of the cam passes through the thrust plate to mount the reduced depth cam gear. The forward thrust of the cam is absorbed by the leading forward edge of the number one cam journal through its clearance to the thrust plate while rearward thrust is absorbed by the timing gear clearance to the thrust plate. This is the same motion as with a flat tappet cam but there the thrust is applied to the block. The OEM roller cam’s gear uses a smaller bolt pattern than the flat tappet/aftermarket (retro) roller cam so these gears do not interchange. The OEM roller also does not and cannot fit the metal bolt retainer of the flat tappet or retro roller cam gear. The factory (OEM) cam gear is retained with pan head, Allen or TORX screws and liquid thread locker for clearance and retention.

So all of this boils down to for either a flat tappet and retro roller or for an OEM roller; the cam gear must properly fit to the block or to the thrust plate as the designs would each require. If the cam will not allow this, you must find out why and correct the situation. The addendum to this is if it is the rear cam bore plug being driven to deeply, it is better to remove the one installed and replace the whole thing after inspecting for cleanliness and damage to the bore as the only fix if this thing leaks oil is to pull the engine back out. Well maybe not the only fix the other is drop the transmission and what ever that uses flex plate or flywheel to gat at the back of the block from underneath, this not being much fun either.

Bogie
Yes it’s an aftermarket roller. I do believe the cam tunnel plug was driven to deep. Therefore the the cam cannot slide back far enough for the thrust bearing behind the gear to ride on the thrust surface of the block. In turn the crank gear had to be pulled out to make sure they align. So Im going to have to pull it apart and push the plug out, re install another one to a shallower depth and reassemble. That’s the better option better fix it the right way while it’s on an engine stand rather than later after it’s in the car
 
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