After much cursing of engineers that think we have 17 elbows per arm, I'm
ready to install a new timing belt on my 88 escort wagon. I replaced the
water pump (original cause of the problem, I suspect, it is in pretty sad
shape - thanks to the engineer that decided this engine should be free
wheeling!). Now all I have to do is find TDC and align the crank and cam
shafts. The cam shaft is sitting nicely at TDC for cylinder 1 compression
stroke as verified by the timing mark on the pully and the position of the
distributor rotor. I'm a bit confused about the crank position - I can get
it so the timing mark on the pulley points to the timing mark on the case,
but I wanted to check something with you all here before proceeding. Since
the crank makes 2 revolutions for each revolution of the cam shaft, is there
a difference as to which of the 2 revolutions I match to the cam shaft? I'm
thinking that it doesn't matter since the crank shaft is the same on each
revolution. Please let me know if I'm wrong :)
Glad you have extra elbows, you'll need them if you don't have a friend to
help. TDC indicates you'll have compression in cylinder one. The crank will
always be pushing the cylinder up when the mark is aligned, but the cam
could have the exhaust valve opened for exhausting the cylinder, rather then
having both closed. Remove the #1 plug, stick your finger in the hole, turn
the engine over by hand. If you don't get air pressure, the cam is not
Well, I didn't really have the extra elbows to begin with, however, my bones
have taken such a beating that my arms now resemble tentacles. Pretty sure
I have the cam in the right alignment, as the distributor rotor is pointing
at the number one position and there does appear to be pressure as indicated
by your method. Now if only I could figure out how to get the belt to go on
without getting out of alignment (as detailed in my response to Bob).
Wrap the belt as tight as possible, opposite the side where the tensioner
is, use a couple of spring clamps on each sprocket to keep it in place, then
release and tighten the tensioner.
You're on the right track. I usually line up the marks, install the belt,
tensioner etc. and turn the engine over twice before rechecking the marks.
If everything looks good put it all back together and away you go.
Sometimes it helps to slightly misalign the marks to start with so they line
up correctly when your done. Try turning the cam clockwise until the mark is
maybe 1/2 a tooth off. Install the belt and tensioner, turn the cam back and
you should see the slack come out of the front of the belt as the marks get
back in line.
======================You should be good to go if your marks are lined up. Because as you said the
2/1 crank/cam the mark will be off on the next round but it will come back
in line the next....
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You're simply making it harder on yourself than it really is.
Fact: You're correct, the camshaft makes only one revolution, for each two
revolutions of the crankshaft.
Deduction: The camshaft will only make one half a revolution for every
revolution of the crankshaft. Therefore, you can line up the crankshaft
(while driving the camshaft sprocket via the belt) twice at it's timing mark,
but only one time will the camshaft sprocket line up with its mark.
Conclusion: Line up both the camshaft sprocket with its mark and the
crankshaft sprocket with its mark, and the valve timing will be set as the
factory intended it.
As for your remarks about the engineers, the Escort was a basic car, sold at a
comparatively cheap price. While it might make servicing a nightmare, it's
cheaper to build a drivetrain for a FWD (like a Ford Escort has) vehicle and
simply drop the body onto it during assembly. It was built in a very
economical assembly process, Ford could produce thousands of them a day, and
good thing, they pretty much sold like hotcakes. The assemblers don't really
give much of a hoot that after many miles past warranty, someone's going to
have to replace the timing belt or water pump. You wish they would, but they
don't answer to you, they answer to the guys that say, "how much is it going
to cost us to build it, and can we build it cheaper than that?" You end up
with a "nightmare" when it comes to servicing it on the passenger side, but
Ford's got their money out of it, they really don't care that it's difficult
or unconventional to someone else service it.
You worked out how to find tdc , to align the cam have both lobes on NO1
just rocking neither will be under spring load , sounds odd but look and
you will see , then slip the belt on , make some marks with white out if
you doubt your ability to hold thing still , this should match the std
its works on every OHC motor Ive worked on over the last few years and
is even better if you have a degree wheel.
Zaphod Beeblebrox wrote:
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