Captain Obvious

F54/P79 Swap Project

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9 hours ago, Captain Obvious said:

@madkaw, another question... What is "a bunch"?

Did you advance it to bring it back to stock timing, or did you go beyond that and advance the timing past the original stock settings?

I was running 8 degrees in advance and wouldn’t have minded some more . Running the ISKY 290 duration put the power band up pretty high. About 4K+ is where she started to really “ come on the cam “! 

 

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5 minutes ago, madkaw said:

I was running 8 degrees in advance and wouldn’t have minded some more . Running the ISKY 290 duration put the power band up pretty high. About 4K+ is where she started to really “ come on the cam “! 

 

Doesn't each hole on the cam sprocket increase advance by 8 degrees?

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1 minute ago, siteunseen said:

Doesn't each hole on the cam sprocket increase advance by 8 degrees?

No - I believe it’s 4 . I was running an adjustable anyway . 

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10 hours ago, grannyknot said:

While there are so many good minds talking about this subject I would like to ask a question about a timing fact/myth I've heard many times. 

Starting with a new chain, by deliberately advancing the cam gear to #2 or #3 you can gain more low down torque. True or false?

Bruce, this is one of those great lines that should be permanently fixed to bottom of each post regardless of whether you are right or wrong:beer:

I would say true. Closing the intake valve earlier will get some low end grunt . 

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10 hours ago, 240260280 said:

For an observer working from the top of the engine like @siteunseen did, moving the sprocket from 1 to 3 while keeping the crank at TDC, it appears that the chain is getting tighter but this illusion is because they can not observe the resultant extra slack hidden inside the timing cover area.  For an observer like @Captain Obvious with the timing cover exposed, they can see they are making more slack and the tensioner is protruding more to correct it.

See it is special relativity and is dependent on the viewer 🙂

I disagree completely. I do not believe it depends on the perspective of the viewer. I say that the tension on the chain is independent on which cam index hole 1-3 is used.

Would you believe me if I took some pics? I'll put the gear in position 1 and take a pic of the tensioner. Then I'll move the gear to position 3 and take another pic of the tensioner. My belief is that the tensioner will look identical in both those pics. I say the plunger will be the same distance out regardless of what hole the cam gear is in..

If I show you, would you believe it then? What say ye?  Haha!!   @240260280   I challenge thee to a geek-off.     :geek:

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2 hours ago, siteunseen said:

Doesn't each hole on the cam sprocket increase advance by 8 degrees?

Nope. What he said. It's four (crank) degrees per position change:
P1150112.JPG

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21 minutes ago, Captain Obvious said:

Would you believe me if I took some pics? I'll put the gear in position 1 and take a pic of the tensioner. Then I'll move the gear to position 3 and take another pic of the tensioner. My belief is that the tensioner will look identical in both those pics. I say the plunger will be the same distance out regardless of what hole the cam gear is in..

Finally! 

1 zip tie.

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1 hour ago, Captain Obvious said:

I disagree completely. I do not believe it depends on the perspective of the viewer. I say that the tension on the chain is independent on which cam index hole 1-3 is used.

Would you believe me if I took some pics? I'll put the gear in position 1 and take a pic of the tensioner. Then I'll move the gear to position 3 and take another pic of the tensioner. My belief is that the tensioner will look identical in both those pics. I say the plunger will be the same distance out regardless of what hole the cam gear is in..

If I show you, would you believe it then? What say ye?  Haha!!   @240260280   I challenge thee to a geek-off.     :geek:

Just think if you could stretch the chain so that only 10 links were between the cam sprocket and the crank sprocket rather than the ~42?  You would have 32 extra links now on the slop side and it would be quite obvious.

I am talking about tension to put sprocket back on when advancing the cam ON THE CAR.  I have done it about 10 times and it "seems" like there is more tension. This is what @siteunseen described.  It is relative and not real. I have also put sprockets on 4 times when rebuilding engines and it is no problem as the tensioner and guides are not in place.

Of course the tension on the chain varies as the engine runs when the valve springs compress and unload but we never discussed this. Our discussion is on advancing the cam timing. When you hand crank at the snout with a 27mm socket, you can feel the variations due to the valve springs.

Edited by 240260280
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Just think if you could stretch the chain so that only 10 links were between the cam sprocket and the crank sprocket rather than the ~42?  You would have 32 extra links now on the slop side and it would be quite obvious.
I am talking about tension to put sprocket back on when advancing the cam ON THE CAR.  I have done it about 10 times and it "seems" like there is more tension. This is what@siteunseen described.  It is relative and not real. I have also put sprockets on 4 times when rebuilding engines and it is no problem as the tensioner and guides are not in place.
Of course the tension on the chain varies as the engine runs when the valve springs compress and unload but we never discussed this. Our discussion is on advancing the cam timing. When you hand crank at the snout with a 27mm socket, you can feel the variations due to the valve springs.
Moving to hole 2 or 3 without moving the crank advances the cam and sprocket 4 or 8 degrees, in essence without moving the chain so that the cam becomes advanced relative to the cam.
But since a chain link is not 4 degrees you'll nearly always end up moving a bit of slack chain to the tight side when you refit the sprocket (also making the Slack side a tad tighter) so then you turn the engine 720 degrees to tdc again to check the cam alignment marks line up as the should.
The tight side will be as tight as it ever was.
The Slack side will be as Slack.

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No one seems to think they're confused, yet everyone seems to say different things

Do you think the cam timing/sprocket position number affects the tensioning of the chain? It absolutely does not.

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I'm not confused at all, and the proof is in the pics.

System with cam gear in position 1:
P1150826.JPG

I rigged up a little wire pointer to indicate TDC. Doesn't have to be exactly dead nuts on TDC as long as it's the same spot each time:
P1150827.JPG

Here's the timing marks in position 1:
P1150830.JPG

Then I used my chain wedge tool (just like if I were doing this in the car). Tool wedged down into place:
P1150834.JPG

Take the cam gear off:
P1150835.JPG

Move the gear to position 3 and take out the wedge tool:
P1150839.JPG

Here's the system in position 3:
P1150840.JPG

Here's the timing marks in position 3. The valve timing has become advanced compared to position 1. Exactly as one would expect:
P1150842.JPG

Now... For the chain tension. I used a feeler gauge to measure how far out the adjuster is. This is position 1:
P1150850.JPG

Measuring the feeler gauge, the tensioner is out about .115 with cam gear in position 1:
P1150851.JPG

Repeating the measurements for position 3:
P1150853.JPG

End result? The adjuster protrudes the same amount regardless of the cam gear position:
P1150854.JPG

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I'm probably over simplifying (or complicating) this but unless the physical distance between the cam gear and the crank gear changes, the slack in the chain remains the same. The slack will change temporarily while adjusting the cam timing unless the cam is rotated a bit.

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1 hour ago, Captain Obvious said:

I'm not confused at all, and the proof is in the pics.

System with cam gear in position 1:
Lo

I rigged up a little wire pointer to indicate TDC. Doesn't have to be exactly dead nuts on TDC as long as it's the same spot each time:
P1150827.JPG

Here's the timing marks in position 1:
P1150830.JPG

Then I used my chain wedge tool (just like if I were doing this in the car). Tool wedged down into place:
P1150834.JPG

Take the cam gear off:
P1150835.JPG

Move the gear to position 3 and take out the wedge tool:
P1150839.JPG

Here's the system in position 3:
P1150840.JPG

Here's the timing marks in position 3. The valve timing has become advanced compared to position 1. Exactly as one would expect:
P1150842.JPG

Now... For the chain tension. I used a feeler gauge to measure how far out the adjuster is. This is position 1:
P1150850.JPG

Measuring the feeler gauge, the tensioner is out about .115 with cam gear in position 1:
P1150851.JPG

Repeating the measurements for position 3:
P1150853.JPG

End result? The adjuster protrudes the same amount regardless of the cam gear position:
P1150854.JPG

I knew it!  You read the National Enquirer when you were young standing in the checkout line.

"Enquiring minds want to know"

Geek Off 2019 was a success.

@240260280 explained it in realative terms as being in the car vs on an engine stand.

@Captain Obvious proved it.

 

Edited by siteunseen

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Well this is settled then! Take a seat in the back row and let professor Obvious move on to the next lesson. Where are we on the shaved head solution now that this is behind us. How are we going to remove the extra slack?
Nice job CO. I was the kid that needed to put my hand on the hot stove. Thanks!


Sent from my iPhone using Tapatalk

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5 hours ago, Av8ferg said:

Well this is settled then! Take a seat in the back row and let professor Obvious move on to the next lesson. Where are we on the shaved head solution now that this is behind us. How are we going to remove the extra slack?
Nice job CO. I was the kid that needed to put my hand on the hot stove. Thanks!


Sent from my iPhone using Tapatalk

ROFLI did it with the cigarette lighter in my dad's Mercury at age 3. I remember it vividly!!! Put a nice big round blister in the palm of my hand :facepalm:

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I tried to take a wall outlet apart with an uninsulated set of pliers at 10yo or so. Nearly blew my shoulder out of socket. I still have that burnt set of pliers around here somewhere...

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Not sure anyone referencing this thread will get anything out of it but confusion.

 

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13 hours ago, madkaw said:

Not sure anyone referencing this thread will get anything out of it but confusion.

Yeah, I'm gonna try just one very last time and then give up....

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