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#1
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Timing chain education
Finally getting around to cam and heads upgrade. I have not changed a cam in 30
years so will need some reminders. First up is timing chain. Does this chain slack look ok or should I replace? https://youtu.be/32vZmd1Sj0k Second for the life of me I can’t get this chain off the motor. Cam sprocket has good play, but cranks sprocket has not budged after me gently prying both. Any tools/tricks to get this thing off? I’ve spent an hour monkeying around with it to no avail. Super qppreciate any thoughts. Thanks guys. I suspect this is probably fairly new timing chain from po. |
#2
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Typical double roller slop, that usually happens soon after install but never seems to get worse. I would probably run it. Cliff likes to use the stock link type chains that don't stretch so much and keep cam timing more precise. YMMV. You can buy or rent a gear puller to get the lower gear off the crank.
__________________
Jeff |
#3
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I have used 2 claw hammers at times to pop a gear free, be it crank or cam.
You also have to walk them off equally, if you get one too far ahead of the other there is no slack left to free the other and it stays wedged there. Be triple sure to pack the nose of the pan with paper towels so if the keyway drops out on removal or install it keeps you out of bad trouble!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#4
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Yes, replace it.
Spotts sells all types. Not all rollers have stretch issues. http://www.spottsperformance.com/Timing%20sets https://www.ebay.com/itm/28404419111...oAAOSwvAhbW0nU |
#5
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Thanks for all the feedback guys. I am going to rent a puller tomorrow and give that a go.
If I were to replace, I assume I would need to know if the crank had been turned/ machined (which I dont)? Or does that not impact choosing a timing chain? |
#6
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Quote:
The undersized chains are to compensate when the main caps have been cut for boring of main journals. |
#7
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I just put a breaker bar on the balancer nut. Can tell by rocking if need a timing chain. If feels slack you do.
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#8
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OP already showed us via video how loose the chain was. It NEEDS to be replaced.
If you want to ACCURATELY see how stretched your timing chain is, pull out all your spark plugs.
Then use that breaker bar to slowly turn the crank CLOCKWISE until the timing mark lines up with 0* on your timing cover. Then disconnect the distributor cap and set it a little to one side so you can see the rotor. Grab that breaker bar and turn the crankshaft back COUNTER-CLOCKWISE just until you see the tip of the rotor move. Stop. Check and see where the timing mark is. That's how many degrees of slop there is in your timing chain. Divide that number in 1/2 and that is how RETARDED your camshaft timing is. Example: The rotor starts to move at the 10* mark. There is 10* of slop in your chain - kinda like the OP's chain - and your camshaft is retarded at least 5*. To get to your original question, Midnight Auto, I'd change out the chain AND gears. As pointed out by geeteeohguy , most double rollers develop a similar amount of slop pretty quickly and then just stay there forever. Maybe that's OK, but slop always bothers me. And, like Cliff Ruggles, I'm a huge fan of the original-style heavy-duty chain and gears. They don't stretch that much in 50k miles. Good luck! |
#9
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When I replaced my chain and gears it was like an extra 20hp. Guess after a few can just feel it.
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#10
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I dont agree that if the chain has 10 degrees of slop, it has retarded 5 degrees. You may lose a couple degrees, but not 5. Has this been verified? or speculation? The slop will be on the slack side, but the crank is always pulling on the chain. I like to put the cam 2 degrees advanced, to make up for chain break in. A new chain may be tight, but gets slack pretty quick. As long as it has less than 1/2" of deflection on the slack side, ship it.
__________________
1968 Firebird 400 RAII M21, 3.31 12 bolt, Mayfair Maize. 1977 Trans Am W72 400, TH350, 3.23 T Top Everyone you will ever meet knows something you don't. Bill Nye. |
#11
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Well after thinking about it a bit, I kind of figure if the patient is open, ~$100 for new chain/gears won’t break me. I’ve been studying the option on degreeing in cam, can someone point me to a link with this alternate chain u guys are talking about vs roller?
I also have been researching options for degreeing in cam- seems it’s either gears with multiple key ways or an offset key? |
#12
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after a few ... beers?
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#13
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Quote:
Jim Hand ran for years with Jim Butler rollers. more pricey than Spotts rollers. https://butlerperformance.com/c-1234...-and-sets.html Last edited by pastry_chef; 07-03-2021 at 11:55 PM. |
#14
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Happy 4th! Puller from local store took care of it. Thanks for that tip. The tear down continues…..
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#15
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Take pictures of how the fuel pump eccentric goes back on for reference.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#16
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Quote:
__________________
Jeff |
#17
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Steve- Lots of pictures for sure for every step of the way, plus marked ziplock bags with every bolt id’d.
I’ll probably get a build thread going to share progress and trials./tribulations |
#18
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Just in case you had some Independence Day beers before disassembly, lol!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#19
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just avoid use during assembly...
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#20
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Good rule on assembly
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