My buddy and I were having a conversation in his garage and trying to think outside the box since we were unable to physically move after walking every inch of the Portland, OR swap meet (that is one big dude). He needs to check piston to valve clearance for cam selection purposes. He really doesn't want to pull a head if he doesn't have to. Has anyone ever tried, with motor out and headers off, to look into the sparkplug hole with a flashlight while rotating the motor?? I don't think he is going to go so big that it will be an issue but he'd like to know what he is working with. I think you are supposed to be around .100 min?j Isn't it the exhaust valve that is the issue? It seems like you might be able to see enough but we have never tried it. Just wonder if anyone has or can if they have a complete shortblock laying around. It's a 383 with World Sportsman angle plug heads. Thanks!
Is this an accurate way of check piston to valve clearance?
dubs68camaro
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My buddy and I were having a conversation in his garage and trying to think outside the box since we were unable to physically move after walking every inch of the Portland, OR swap meet (that is one big dude). He needs to check piston to valve clearance for cam selection purposes. He really doesn't want to pull a head if he doesn't have to. Has anyone ever tried, with motor out and headers off, to look into the sparkplug hole with a flashlight while rotating the motor?? I don't think he is going to go so big that it will be an issue but he'd like to know what he is working with. I think you are supposed to be around .100 min?j Isn't it the exhaust valve that is the issue? It seems like you might be able to see enough but we have never tried it. Just wonder if anyone has or can if they have a complete shortblock laying around. It's a 383 with World Sportsman angle plug heads. Thanks!
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well, youll be able to tell if it hits the spark plug or not, lol
I cant think of anyway to check. Could try some math I guess.
I cant think of anyway to check. Could try some math I guess.
If the spark plug is out how do you if it will hit, You can get a acurate reading with a dial indicator and a degree wheel, about 15 before to 15 after get a bar fabricate and push the valve down see wat clearance you have. do both intake and exhaust,
You only want to touch the valve to piston. Using your visual, yoy can't really see the piston, wrong angle
You only want to touch the valve to piston. Using your visual, yoy can't really see the piston, wrong angle
Intersesting...
maybe using some sort of soft plastic strip in thru the spark plug hole, or attached to a wire, placed in the correct postion then turn the motor over by hand..may take several attempts to get in the right position.
Or a plastic or cardboard 'feeler gauge' of known min tollerance or just above and see if can get in the right place and feel it being grabed??
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You're on the right track. Trying to think of how to take a reading without taking off the head, putting on plumbers putty......etc. If a guy had a roll of round material that would dent and hold the dent...then could be fished in through and out the spark plug hole and measured.
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I would be hesitant to do anything but clay the pistons and see for sure. If you are using hydraulic lifters they are not accurate. The best way is the old fashioned solid lifter/putty combo. How long will it take to remove the heads? How long will it take to repair the possible damage from piston/valve contact? It is fairly cheap insurance. What if your "easier" way ends up off? We aren't talking much room for error here.
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And what if the putty gets stuck in the chamber? Or on the valve? It would be teardown time. If you try and fire an engine up with even a little piece of putty in it, it will bend the piston skirts real quick. At best you'd walk away with a nasty piston slap.
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they sell a flex camera from matco tools and others that you can see in through the spark plug hole. there around 400 bux tho.
It's about impossible to measure Piston to Valve Clearance with a Hydraulic Lifter unless the lifter is pumped up. Solids lifters are much easier with lash set a '0' with the heads on. Keep in mind that the Piston is closest to the valve when the Intake Opens and the exhaust Closes. Using a Dial indicator on top of the valve stem with extremely light springs or no springs turn the engine through the TDC sweep in 2 degree increments measuring when both the Intake and Exhaust Valves are closest. Manually move the valve up and down in the guide and measure the stop distance between the seat and touching the piston. It's a time consuming task but it works and is accurate.
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Come on guys.....give me at least a little bit of credit!!! 
We both have fabbed up some lifters just for this...for checking. They are not "solid" lifters but custom welded lifter just with .000000000 lash
Wouldn't use putty and wouldn't use a material that would stick either. There is bound to be something out there that would compress and hold the compression (you could bench test it to be sure!). Maybe this needs to be a new trick of the trade. There is never an easier way to do something until someone figures out an easier way!!!! You guys are always tell me your little tricks to make my life easier. Maybe it's time I figure one out.
This is more than likely something that is impossible but when you are looking at the motor in the car, it makes you think there might be a way. Guess we'll keep you posted.
We both have fabbed up some lifters just for this...for checking. They are not "solid" lifters but custom welded lifter just with .000000000 lash
Wouldn't use putty and wouldn't use a material that would stick either. There is bound to be something out there that would compress and hold the compression (you could bench test it to be sure!). Maybe this needs to be a new trick of the trade. There is never an easier way to do something until someone figures out an easier way!!!! You guys are always tell me your little tricks to make my life easier. Maybe it's time I figure one out.
This is more than likely something that is impossible but when you are looking at the motor in the car, it makes you think there might be a way. Guess we'll keep you posted.
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Checking springs (can be found at a hardware store), dial indicator. Set dial indicator on exhaust rocker arm and at 10* BTDC, push down on rocker and should read no less than .100, intake needs to be measured at 10* ATDC, and no less than .060. Your real springs will add about +.020. This is done on overlap, not compression cycle.
This is about as easy as it gets without removing the head.
This is about as easy as it gets without removing the head.
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Gum wrapped/rolled in paper.
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i'd go with posts 9 and 11...
I also agree with Z15cam... except it would be on the money if you get a tdc tool for your dial indicator that goes into a sparkplug hole. They aren't that much, maybe Summit or Jegs has one? Just a thought for a little extra accuracy for little $$$ >a .004 mistake can be life or death in some cases (my luck) lol
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