I have recently installed and reamed new oversize valves. When running, it starts to make a "Popping" sound after it warms up and runs at higher speed so, Have anyone heard this?
Your adjustment is probably too tight. You need to have AT LEAST .012 cold on the intakes and .015 on the exhausts IMHO. What you are hearing is either a little blowback into the intake or if it more of a "mini exhaust" sound in the exhaust manifold you are getting part of the explosion in the manifold because the valve isn't seating totally.
I used the .015" Reamer and .015" oversize stem Valves. They all look good when cranked by hand. Also, I am not familier with the short meaning for IMHO, can you tell me.
Thanks for the inside, all can help.
IMHO = It's My Honest Opinion
I believe Stan is talking about valve lash, the amount of clearance between the valve stem and the lifter.
IMHO=In my humble opinion. What I am talking about is the clearance between the top of the valve lifter and the bottom of the valve. There needs to be a gap there.
The gap allows for the expansion of the length of the valve stem when the valve heats up during running. The gap should be about 12 thousanths for the intake valves and fifteen thousanths for the exhaust valves. This gap would be measured when the camshaft is turned so the lobe is completely down. The downward movement of the valve is controlled by the depth of the valve seat. The downward movement of the lifter is controlled by the camshaft. New valves are slightly longer than old valves to take up wear etc., and must be sized to each valve seat and lifter by either adjusting the screws on the lifter or grinding the end of the valve stem if you do not have adjustable lifters. The original Ford valve lifters were not adjustable. Modern valve lifters adjust with a screw moving in and out of the lifter. Some require a nut being tightened to lock them in place and some do not. You need a feeler gauge and two thin 3/8ths wrenches to do the adjustments.
If your adjustment is ok---Did you properly lap the new valves to the block?
I heard that noise for a long time. I did four valve jobs with no improvement. Then I checked the coils on a Hand Crank Coil Tester. They were all drawing the correct amps, but one was double sparking. I adjusted the brass piece on top, eliminated the double spark and had a different running Model T.
Evidently that second spark was just enough early or late that the fuel was fired before the valve was fully closed. That is the only logical explanation that I can offer.
>Thanks for all the inside help.
First - to ?, for explaining IMHO.
Second - Stan, I did grind the valves using the KR Wilson Method, but will check "the gap" you suggested. Also I have orginal lifters.
Third - Jerry, I did "lap" the valves in the block.
Forth - James, I never suspected it to be an electrical proplem, but will do so after checking the gaps.
>Also, do any of you or anyone think it could possibly be a leaking Head Gasket. After talking with someone this afternoon, he said it might be but I am confused.
Tom,
The KR wilson method might not get you the clearance you need. It measures the point where the valve opens or closes, but not the clearance. With modern camshafts, you need to measure the clearance. You might be able to compromise, by using the wilson method, and then measure the clearance, and any valve that doesn't have enough clearance will need to be re-adjusted. I didn't have any luck with the Wilson method, so used the clearance and my Ford is like a jackrabbit!
Norm
Tom, The KR Wilson method is only good for an original Ford Cam. It should never be used on a reground cam. I never use it for any cam as the supposed improvement in performance is outweighed by the noise from the mismatch in valve clearance. Just set all of the valves to 0.010-0.015 In clearance and enjoy the car.
A compression test will eliminate a leaking head gasket theory. Go with Glen on the valve settings.
I never believed the coil could be a problem either and was really confused, as I had good compression, good valve settings and a good carb.
Another theory is that a random misfire of a coil will allow raw gas to be dumped into the exhaust manifold, which is then lit with the next hot gas that is dumped into the manifold.
I re-ground 3 of the exhaust valves to .015 in. tappet clearance and this stopped the popping and car is running much better. Thanks for all the advice. Tom