There seems to be some intrest on the subject of cam timing. In another post, I commented that many stock OHC Pintos could very well have retarded cam timing (especially if the head has ever been resurfaced) which leads to poor performance and driveability issues. Even if the engine has never been apart, things like belt stretch and differences in machining tolerances can affect cam timing. Cams are designed to be run "straight up" or zero degrees to the crank. However, advancing or retarding the cam can make a big difference in how the engine runs. Back in my dirt track racing days, by using an adjustable cam pulley, I could "tune" the engine to the track conditions. If the track was tacky and had a lot of grip, I would advance the cam to give it more low end power so it would not bog down off of the corners. If the track was dry and slick, I would retard the cam (taking away low end power) so it would not spin the tires off the corners. That being said, you can see there is a slight trade off with cam timing, but with a stock cammed Pinto, expecially an automatic, I would favor advancing the cam a few degrees to get low end power. Six degrees either way from zero is considered to be the maximum, but I really think that is pushing it. On my wife's stock street driven Pinto, two degrees advanced seemed to work best. Remember, if the cam is already retarded say four degrees, and you set it two degrees advanced, that a grand total of six degrees (but only two degrees past zero) and it is going to make a huge difference! If you can change a timing belt, you can degree your cam. OK, lets get started! ;D
Here are the tools professional engine builders use to set up a cam. (also us backyard performance engine guys!) This is a degree wheel and a dial indicator, and with these you can find absolute top dead center of the crank (TDC) and zero the cam using a spec sheet. We don't need these. I'm going to show you a way that is very close and good enough for what we want to do.
:read:
Here are three different adjustable cam pulleys I have, (these are for a 2.0 as are all of the pics I am going to post, however, the 2.3 is set up the same way.) On the left is a Racer Walsh, center is Esslinger, right is a home made job. Ford motorsport made one for the 2.3 that was a multi-index, it had eight slots for the cam keyway, each was two degrees apart. It worked ok, but in order to change the cam timing you had to loosen the belt, take the pulley off and move it to a different slot. On the three pictured here, you just loosen the three bolts and move the inner section.
Closer pics of the pulleys, the Esslinger has a timing tape on it, the others have dots.
While I agree that there are other ways to Find True TDC, I've always used a thread in plug type Stop in the spark plug hole on #1 cylinder. After using this method with a Esslinger Degree type crank power pulley, I was amazed how far off the Crank Pointer marks were from stock. So I made a New pointer to match up and continued from there. This only was required on a 2.0L motor, I don't know how the 2.3L engine marks on the crank are set up.
In the end, my engine needed less than 2 degrees advance at the Adjustable Esslinger cam pulley.
I used to build Motorcycle engines for racing, Same theory and practice.
Pintosopher
Right you are pintosopher, and to be 100% in time that needs to be done. I don't know an easy way to do it without a degree wheel and with the engine in the car. Maybe someone else can help with that. The 2.3 has a pointer made on the timing belt cover. The 2.0 has a tab made on the lower cover. At this point we will have to hope TDC is at least very close.
OK, here we go!
1. Remove the valve cover. This is a good time to replace that leaky gasket! :o
2.Put the engine on "0" or TDC and line up the cam dot/pointer
3. The front cam lobes should be pointing up and forming a shallow "V"
Note: on the 2.0 you need to remove the oiling tube. Put a rag in the oil return holes (one in front, one in back, see pointer) so the little bolts don't fall down in there and ruin your day! :P
Now we need a few things: a 6" carpenters level and a piece of flat metal. Mine is aluminum, 3-1/2" by 6-1/2"
1. Put the level on the back edge of the head.
2. Jack up the side of the car to get the engine level.
3. Lay the metal across the cam lobes and get it to balance on them. You may need to move it around and side to side a little to get it to balance.
4. Put the level on the metal and get it all to balance.
If the cam is "straight up" the bubble will be centered. Make sure your pointer is still on TDC.
If the cam is retarded, the bubble will be to the right.
If the cam is advanced, the bubble will be to the left.
If you look closely at this pic you can see the cam is retarded, you can even see the metal is leaning a little.
More pics...
By loosening the three bolts on the cam pulley, you can turn the inside part of the pulley and move the cam. The instructions with the pulley say to put a wrench on the cam and turn it but that usually won't work because the tolerances of the pulley make it too tight. I take one of the three bolts out and take a punch and tap it in the slotted area.
Once you have it on 0 the bubble is centered.
Another way is to measure both sides of the metal as it is laying across the cam. When it is the same on both sides it is at 0. Not quite as accurate but it will get you in the ballpark and you don't have to level the engine to do it.
And that, ladies and gents is how it's done! ;D One more thing, if you want to put the timing belt cover back on, you will have to put spacers behind the uppermost bolts because the bolts in the adjustment part of the pulley will hit. If you use the Motorsport index style pulley the cover will fit OK. I just left mine off, I thought it looked cool!! :amazed:
Thanks, that was a great post. Does this procedure work on any type performance cam as long as the lift and duration are equal on both intake and exhaust? Or does that not make a difference?
Kevin
Kevin, it can make a slight difference on a performance cam with different lift and duration profiles. To be 100% accurate you need to use a dial indicator and degree wheel and as pintosopher stated, find absolute TDC. This will get you pretty darn close though.
Thanks for the write up with pics!!! Very nicely done!!!
Kim
+1 to 71pintoracer for the indepth How to
this is the method i used. but as it was stated, it will not get it dead on with a split duration cam. a degree wheel is on my "tool wish list". also dont forget that with hydrolic lifters, a solid lifter is needed, set to 0 lash, to find your exact cam specs. thats just something that could be easily over looked. although, the cam would still be able to be degreed with the hydrolic lifters.
bob
This may be a dumb question, but i need to completely reset my cam timing on my 1975 2.3L and am worried about a valve impacting a piston and maybe bending it while i find TDC on the #1. Its basically an initial set up, so its possible i might have to rotate the crank 180 degrees before i reach TDC and was wondering if there might be some valve interference since the cam wont be turning. If one of the valves were fully open at a cylinder with a TDC piston, would the valve hit the top of the piston? Or am i just making stuff up? Like i said, could be a very dumb question but just would rather be safe than sorry.
Thanks racer, you can also find offset woodruff keys that accomplish the same thing as the adjustable pulleys. I have been fooling around with my Esslinger pulley lately. I found I get a little more top end by retarding my timing a few degrees, and yes advancing gets it off the stop lights better.
Thanks again for the great write up.
Excellent write up!
Quote from: stinsonj on March 09, 2011, 02:49:27 PM
This may be a dumb question, but i need to completely reset my cam timing on my 1975 2.3L and am worried about a valve impacting a piston and maybe bending it while i find TDC on the #1. Its basically an initial set up, so its possible i might have to rotate the crank 180 degrees before i reach TDC and was wondering if there might be some valve interference since the cam wont be turning. If one of the valves were fully open at a cylinder with a TDC piston, would the valve hit the top of the piston? Or am i just making stuff up? Like i said, could be a very dumb question but just would rather be safe than sorry.
Not a dumb question by any means. The stock 2.3 is not an interference engine (nor is the 2.0) so you can turn the engine around and not hit the valves. If you have shaved a lot off of the head and/or are using a performance cam, then yes, they will hit. If that is the case, I put #1 piston down in the cylinder a little bit before installing the head with the cam as close to straight up as possible. Then bring #1 up to TDC.