simple valves and timing questions

Joined
Jun 11, 2004
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1,042
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high desert, ca
Keep in mind I am not the most knowledgable with this stuff.
Last weekend I went to adjust my valves because they seemed to have a little bit of excessive noise. They almost seem louder now after adjusting. The #11 valve wasn't even closing all of the way before adjustments. I had a hard time seeing inside of the #1 cylinder to check for TDC, so I used the even harder to find TDC line on the flywhel(covered in rust). Is this line even accurate? It seems like a 36 year old timing chain might stretch a bit. Do most people just use this line for determining TDC, or is there a better way? Also, my old FSM (printed in 1967, so probably for f135, I have an f145) says adjust the intake valves to 0.010", while the tech links say 0.008". Which one, does that 0.002" really make a difference? I used 0.008" for valve lash.

Now for checking timing, my fsm says set the octane adjuster to 0 before checking the timing, but people here say undo the vacuum advance line. So does it matter which one I do for checking the timing? If disconnecting the vac line, do I plug it or check timing with a vac leak?
Thanks, just trying to use the tiny bit of free time I can round up to get the pig running a little better for the 5 hour drive to pismo. Seems to be running a little off from ignition.
 

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Joined
Oct 1, 2003
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MN
.008 intake .014 exhaust...do this with the engine hot.


There is not a timing chain...only gears.


I use the TDC mark on the flywheel...

Plug the vac line..


Good luck!


-Steve
 
Joined
Oct 21, 2005
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10
Location
Rhode island
valve adjustment

not sure which engine you have but I am going to assume stock. On my 350 motor I took the play out of the valves and turn an extra 1/4 turn then lock them down. As for the timing I alway block off my vacumm advance when checking. You stated that the mark may not be visible. Try taping the engine over until your first cylinder is at Top Dead Center. Then you could try and look for a mark that might be rusted over. Not sure if this helps-
 

Pin_Head

 
 
 
Joined
Feb 6, 2002
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OC, CA
Adjusting valves at TDC has the potential for problems because there are two TDC points for every cam rev in a 4 stroke engine. You can only adjsut the valves that are "loose" (cam lifter off of the cam lobe). If you adjust ones that are under tension, they will be way loose afterward.
 
Last edited:
Joined
Jul 18, 2005
Messages
799
Location
Wellington, NZ
snailwagon said:
Keep in mind I am not the most knowledgable with this stuff.
Last weekend I went to adjust my valves because they seemed to have a little bit of excessive noise. They almost seem louder now after adjusting. The #11 valve wasn't even closing all of the way before adjustments. I had a hard time seeing inside of the #1 cylinder to check for TDC, so I used the even harder to find TDC line on the flywhel(covered in rust). Is this line even accurate? It seems like a 36 year old timing chain might stretch a bit. Do most people just use this line for determining TDC, or is there a better way?
Being old school - I dont use TDC to adjust vavles. Instead, use the 'rule of 13'.
Pull spark plugs.
Turn engine until #1 valve fully open - adjust valve #12 (13 - 1).
Turn until next valve fully open - same process.
valves ussually open in pairs.
White paint marker is good to mark 'adjusted' valves to ensure you got them all.
 
Joined
Nov 17, 2003
Messages
257
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South Pierce County, WA
The best tip I got from this board concerning valve adjustment was in determining TDC #1 on compression stroke. I taped a piece of thread over the open spark plug hole. As I cranked the engine over with a large socket and breaker bar I could see the air come out of the #1 spark plug hole as the TDC line came into view. First time I had it 180 out. Not sure of clearances on an F 145, but .008 and .014 are good for 2F's. My old F manual is different but I can't confirm as the book is not with me. I'm sure someone here can confirm settings for your engine.
 
Joined
Jun 11, 2004
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high desert, ca
Thanks, I did adjust it while hot, since I've never tried this before it took me 20 minutes, but it didn't seem to cool down too much during that time. The valves did get set at 0.008" and 0.014", quite easy to tell which is exhaust and intake, it was just one exhaust valve that was reallyl off, but not one of the intakes or exhaust valves had the same lash at first. I forgot their are gears instead of the chains. I guess wear in the teeth would be negligable. I guess if it was a chain, Andrew's method is excellent. I couldn't figure out what the hell the TDC line looked like until I pulled out a spare flywheel and found it one there. After scrubbing I was able to see it.

Now another question. What about setting the vacuum advance? Do you just mess with it until it feels right, or do you actually measure timing for this? If so, what rpm's and what kind of advance. Can I actually do this without a tachometer or a tach light? Or am I confused and the timing curve is dependent on the fuel in use.
Too many midterms,time for a brew.
 
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