I need to know how to measure the valve gap when using High compression pistons? How do I know the valve is in the right place to measure. Also what does everyone recomend for a gap?
New modern style valve with the original non-adjustable lifters.
When you grind the valves, you measure the gap at the heel of the cam. You can find it by observing the valve when it goes all the way to the top, the heel is 180 degrees. Since the crankshaft turns twice for every turn of the camshaft, the heel would be one complete turn of the crankshaft from the point the valve is all the way open. With the non adjustable lifters, you grind the valve to fit, and then you never have to adjust it again until the next valve job. You would measure according to the instructions of the cam grinder (usually about 12 to 16 thousandths) or use valve timing as shown in the book "engine" The valve timing method only works on a block that has not been decked and with the original Ford camshaft.
The lift of the pistons should make no difference on valve clearances.
I bought a tool to help me know when the valve should be closed by using the piston but it only works on a flat piston. If I get what your saying I need to eyeball it then?
Adjusting valves using the piston position method is the way to go. You do need a dial gauge for this, but it does mean the valves are set to open and close when they should regardless of the condition of the camshaft and what kind of pistons are used.
The actual valve clearances are all over the place when you set them but I'd rather have the valves operating properly than a uniform valve clearance which is really just taking the easy way out.
If you have the standard pistons, measure the difference in height between those and the new pistons and subtract the difference. The piston height method has very little to do with the clearance between the lifter and the valve stem. But you need to be within range at the valve stem when using this method. If it were me, I would set them by the piston height method and then check them again at the heel of the cam for clearance just to be sure they are not too tight. Too loose will be noisy, but if they are set to open and close at the right time, it will run smoothly. But if they are too tight, you will not gave good compression and the valves might burn.
The piston height method has always worked well for me.
What kind of tool do you have, that works on a flat piston?
The alternative method is to set the gap with the cam 180 deg (crankshaft 360 deg or 1 revolution) from the valve being fully open. Typical specs are usually somewhere between .010 and .020. It's more important to have all the intake valves very close to the same and all the exhaust valves very close than the exact clearance. With adjustable lifters you should be able to match the valve clearance within .001 or so.
I copied this from an old post by Glen Chaffin. It worked for me. I have seen dial indicators and magnetic stands at Harbor Freight pretty cheap and should work well for this job. You will find a place on the timing gear cover that is handy to line up the chalk mark on the crankshaft pully.
THE PROCEDURE IS AS FOLLOWS:
Note: This procedure does not require removal of the oil pan inspection cover and was developed to make the job of valve lash adjustment an easy chore.
1. Remove the fan, fan belt, valve cover (s) and head from the engine. You may also want to remove the radiator to make the job easier.
2. Mark the valves number 1 thru 8 with number 1 at the front of the engine and number 8 at the rear. Valves number 1, 4, 5 and 8 are the exhaust valves. Valves number 2, 3, 6 and 7 are the intake valves.
3. Turn the crank handle until number 1 exhaust valve is at top dead center (maximum lift). You may want to use a dial indicator to determine the maximum lift point. The end of the crank pulley pin should now be at approximately 11:00 o’clock. Place a mark on the crankshaft pulley to identify this point as your reference point.
4. Now. using the crank handle, turn the crankshaft exactly 360 degrees. (one full crank revolution). The valve should now be seated and the end of the crankshaft pulley pin should be back at 11:00 o’clock.
5. Now, check the valve clearance of number 1 exhaust valve at this point. If necessary, make adjustments to obtain the proper clearance. After adjustment, recheck the clearance.
6. Repeat this procedure for all four of the exhaust valves, using the appropriate reference point for each valve.
7. Now, turn the crank handle until number 1 intake valve is at top dead center (maximum lift). The end of the crankshaft pulley pin should now be near 1:00 o’clock. Make note of this point as your reference point.
8. Now. using the crank handle, turn the crankshaft exactly 360 degrees. The valve should now be seated and the end of the crankshaft pulley pin should be back at 1:00 o’clock.
9. Check the valve clearance of number 1 intake valve at this point. If necessary, make adjustments to obtain the proper clearance. After adjustment, recheck the clearance.
10. Repeat the procedure above for all four of the intake valves, using the appropriate reference point for each valve.
11. This completes the valve adjustments.
12. Check you’re work carefully and you will be pleased with the results.
Your life will be much simpler if you replace the tappets with the two wrench adjustable lifters. You can do this without removing the engine from the car as the solid lifters have a through hole so they can pinned in the up position so you can remove the camshaft.
I use the "9" method: when valve #1 is at top I adjust valve #8 (8+1 = 9) move on with 2-7, 3-6, 4-5, 5-4, 6-3, 7-2, 8-1.
The piston height tool you mentioned is for a flat top piston and an unmolested block. If you have domed pistons and or a decked block the tool is useless. Do a search on "valve clearance", there are a lot of older threads describing this with the best methods and the recommended gaps. The Ford Service Manual is for old style 2-piece valves, if you have new valves the gaps can be smaller, but the older threads will discuss this.
Valve timing gauge, reproduction of a KRW tool
This topic has been discussed over and over but there are only two important things to remember:
1. If you have a worn out cam with no two lobes the same. then you should use the piston position method to get it to run but only if your block has never been decked and you have flat top pistons. Otherwise simply replace the cam with an accurate one.
2. If you have an accurate old cam or new cam, use a feeler gauge and set them at .010" and .012" so as to use the cam lift that was given to you. Do not throw away lift in order to make tappet noise so as to make folks think you have an old worn out engine.
If you have solid lifters you will have to remove the head in order to stem heighten the valves. Remove material from the seat to decrease the gap and lengthen the lift or from the stem in order to increase the gap and shorten the lift. The piston position method is impossible with an altered engine. You will have all valves in agreement with one another and it will run smoothly but you most likely will lose efficiency.
Note: The adjustable lifter has a 1/4 28 thread and that gives you a thousandth of an inch travel for every 10 degrees wrench rotation. Take the vavle covers off and put a piston at t.d.c. both cam lobes for that or the sister piston will now be on the heel. Crank the lifter down until you do not have any gap and that means zero clearance. Move the wrench a third of a turn and you have your exhaust valve set at .012". Turn the intake tappet wrench 90 degrees and another ten degrees and you have that one set at .010". Life is simple don't go with the pain and suffering boys, enjoy life, it is too short to mess with it by making it complicated. I adjust my valves this way and my car goes like stink !
Frank, thanks for the write-up on valve adj. In your last sentence where you say " Move the wrench a third of a turn and you will have your exhaust valve at .012" I understand this step just fine!! Would you please expand on your next steps beyond this step-----I am not clear on the next steps. Thanks Joe
Joe, you got it right and I will explain it farther in detail for you as you requested. Let us say that you know that the firing order is 1,2 ,4, 3. You start on number one.
Yes you are correct, by going a third of a turn on the exhaust tappet screw you go 120 degrees and so that is .012" give or take a bit. You should then check it with a feeler gauge to be sure and always do this until you get the hang of it or the feel of it as they say. After you do it several times you will just know where you are because that tappet screw is actually a micrometer if you will.
Then to set the intake, your valves are still in the correct position so you simply pull the wrench 90 degrees and a smidge to get it to another ten degrees and you should have .010" on the tappet. Check it with a feeler gauge to be sure that you did it right.
David Cockey states between .010" and .020" and I agree with him that you may go as high as .020" if you have an inaccurate cam and the older valves and that grow more than the new ones do as they heat up. Remember that the block grows too but at a slower rate as it heats up. Old brass Rolls Royces have their valves set at .004" because of the low rate of expansion so I do not like .020" at all and think it not necessary unless you like a lot of clatter and less power. But I would not set a T at .004" because it is not as much of precision engine as a Rolls is.
Once you have set one cylinder's valves you can go on to the next one. Remember the firing order and that number two will come into position at another 180 twist of the crank handle and both valves will be on the heals of the cam lobes ready for adjustment. Adjust number two in the same manner, turn the crank another 180 degrees and do number four. then another 180 and do number three.
Then start up the engine and listen to it. If there is a little noise in any tappet you can listen with a screw driver or one of those $4.00 stethoscopes from Harbor Freight and locate the noisy one. Measure the clearance of the noisy one and adjust it just a bit tighter if it is looser than you thought it to be.
I get lazy and don't like to crank the engine over, so I put it in high gear out on the drive way and push it to the next position when adjusting the valves. I only adjust the valves every five years or so.
Now stem heightening is another thing entirely but I am assuming that you have adjustable lifters.
Frank, thanks for the added info "dau--I think I finally got it Ollie" Ha Ha Joe
Harbor Freight has a dial indicator and magnetic base in their latest flyer for $20 total.