Before engaging in a head replacement (1.3S), I need advise on two questions:
1) regarding camshaft timing, I read the "2.2mm" method, which consists as I understand to release all tappet screws so there is no interference between cams and valves, except for une cylinder (say #1)where play is set at 2.2mm. Then, cams are set unequivocally correctly when intake-side tappet just starts touching intake valve, and outtake-side tappet has just released outtake valve. This should be done at TDC for cylinder 1. Now this may be a silly question, but I presume the TDC is the second one of the cycle, ie. the one when no ignition takes place (distributor finger facing towards #4 instead of #1).
2) it looks to me that I could apply some temporary markings for correct cam timing while head is still off, putting the head on when engine/cranckshaft is at the correct TDC. Does this make sense? And when I strap the timing chain around cranck/camshaft pinions, can the action of tightening the chain tensioner still lead to any misadjustents?
Many thanks for your guidance.
Thomas
camshaft timing
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william
Re: camshaft timing
Thomas, the timing is set when #1 cilinder is in TDC folowing the exhaust stroke. The 2,2 mm is in fact the lift (minus running valve clearance) of both valves when the piston is at the top. So the inlet valve has opened already 2.2mm and the exhaust valve is 2.2mm from completely closed. this is calles the overlap. the reason for it being 2.2mm for you 1,3 S and 1mm for the 1.1, 1.2 and non S 1.3s is that their cams are milder and have less overlap.
There are already coarse markings on the fwd cambearing cap and the sprockets. Close enough for installation. Be aware only to turn the engine in the normal direction. The timing is set with sprockets and chain in place. the tensioner as well.
Good luck. The instructions in the lancia manual are quite easy to follow. For training you can set the timing on the head while it is still on the work bench. No wrong interpretations causing valve damage in this case. take your time.
There are already coarse markings on the fwd cambearing cap and the sprockets. Close enough for installation. Be aware only to turn the engine in the normal direction. The timing is set with sprockets and chain in place. the tensioner as well.
Good luck. The instructions in the lancia manual are quite easy to follow. For training you can set the timing on the head while it is still on the work bench. No wrong interpretations causing valve damage in this case. take your time.
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Huib Geurink
Re: camshaft timing
As William says it is always done on #1. Theoretically you can also use #4. You cannot use #2 nor #3.
It helps to make some tools:
1) turn the head of a spare sprocket wheel bolt till it is round and leaves enough room to play with the dowel pin without removing the bolt. Since you can no longer use a spanner on the now round head, make a slot for a flat screwdriver in the head.
2) take a metal rod of about 10 cm length and 5mm diameter and cut M3 thread on the last 3mm of the rod. The dowel pin has M3 thread inside. This tool is to pull the pin out and push it in. Could be M4 thread BTW. I am sitting in front of my computer.
The sprocket wheel has 11 holes for the pin. The camshaft 12. Or vice versa. Anyway this gives 132 positions. Shifting the pin one position means rotating the camshaft 2.73 degrees or 5.5 crankshaft degrees, just a bit less than 2 teeth on the flywheel. It means that you achieve an accuracy of plus or minus 2.73 crankshaft degrees when timing the camshafts using the dowel pin only. You can accept this. I would then favour the exhaust to close early and the inlet to open late to minimize the risk of intereference with the piston while keeping in mind that the chain will never become shorter but will slowly become longer.
However you can get much better accuracy by also shifting the chain on the sprocket wheel. There are 38 teeth on the camshaft sprocket wheel and thus 19 on the crankshaft. 19 has no common factors with 12 nor 11. Shifting the chain thus gives you 19 times more crankshaft positions. You can achieve plus or minus 0.14 degrees or 8' 15" on the crankshaft by shifting the chain AND using the dowel pin.
I once made a spreadsheet to calculate the number of teeth the chain had to be jumped on the sprocket wheel. It is too complicated in practice. I now look on it as a trial and error / hit or miss operation.
The easiest way to put the tensioner out of the way is to remove the appropriate M6 bolt from the waterpump so you can put a 4.5mm drill bit through the hole to lock the tensioner after having pushed it backward with a large screwdriver from above.
It helps to make some tools:
1) turn the head of a spare sprocket wheel bolt till it is round and leaves enough room to play with the dowel pin without removing the bolt. Since you can no longer use a spanner on the now round head, make a slot for a flat screwdriver in the head.
2) take a metal rod of about 10 cm length and 5mm diameter and cut M3 thread on the last 3mm of the rod. The dowel pin has M3 thread inside. This tool is to pull the pin out and push it in. Could be M4 thread BTW. I am sitting in front of my computer.
The sprocket wheel has 11 holes for the pin. The camshaft 12. Or vice versa. Anyway this gives 132 positions. Shifting the pin one position means rotating the camshaft 2.73 degrees or 5.5 crankshaft degrees, just a bit less than 2 teeth on the flywheel. It means that you achieve an accuracy of plus or minus 2.73 crankshaft degrees when timing the camshafts using the dowel pin only. You can accept this. I would then favour the exhaust to close early and the inlet to open late to minimize the risk of intereference with the piston while keeping in mind that the chain will never become shorter but will slowly become longer.
However you can get much better accuracy by also shifting the chain on the sprocket wheel. There are 38 teeth on the camshaft sprocket wheel and thus 19 on the crankshaft. 19 has no common factors with 12 nor 11. Shifting the chain thus gives you 19 times more crankshaft positions. You can achieve plus or minus 0.14 degrees or 8' 15" on the crankshaft by shifting the chain AND using the dowel pin.
I once made a spreadsheet to calculate the number of teeth the chain had to be jumped on the sprocket wheel. It is too complicated in practice. I now look on it as a trial and error / hit or miss operation.
The easiest way to put the tensioner out of the way is to remove the appropriate M6 bolt from the waterpump so you can put a 4.5mm drill bit through the hole to lock the tensioner after having pushed it backward with a large screwdriver from above.
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Thomas
Re: camshaft timing
William and Huib, many thanks for sharing your expertise.
Interesting suggestion to slide chain over crank pinion to add for possibilities. I presume this can simply be done by lowering the chain, holding both ends, lowering one side and lift to re-engage. Agree that there shall not be a simple solution for the algorithm defining number of crank teeth to shift with given/measured inaccuracy, precisely because 19,11 ans 12 have no common denominators.
I may be eternally stubborn, but I still fail to see why it is not possible to align cams when head is off using the 2,2mm (or Huib's 2,3mm) on #1, releasing all other tappets, clamping camshafts, place head on block while engine at #1 TDC, strap chain around the various gears while sprockets are loose (ie. can be turned without affecting camshafts), find correct dowel hole, tighten everything up, set valve clearance and ignition timing and voila.
Old head comes off this weekend, I'll see where I missed something.
Interesting suggestion to slide chain over crank pinion to add for possibilities. I presume this can simply be done by lowering the chain, holding both ends, lowering one side and lift to re-engage. Agree that there shall not be a simple solution for the algorithm defining number of crank teeth to shift with given/measured inaccuracy, precisely because 19,11 ans 12 have no common denominators.
I may be eternally stubborn, but I still fail to see why it is not possible to align cams when head is off using the 2,2mm (or Huib's 2,3mm) on #1, releasing all other tappets, clamping camshafts, place head on block while engine at #1 TDC, strap chain around the various gears while sprockets are loose (ie. can be turned without affecting camshafts), find correct dowel hole, tighten everything up, set valve clearance and ignition timing and voila.
Old head comes off this weekend, I'll see where I missed something.
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Huib Geurink
Re: camshaft timing
You don't jump a tooth on the crankshaft pinion but on the camshaft pinion which is mathematically equivalent to jumping a tooth on the crankshaft pinion. Doing it on the camshaft pinion is easy. Lock the tensioner. Mark the chain and the pinion, undo the bolt, lower the pinion, put the chain on the desired teeth and put the pinion back on.
Doing the 2.2 mm thing on the camshafts with the head off is pointless as the entire purpose of the exercise is to relate the camshaft to the crankshaft. The head by itself has no TDC, only a complete engine has a TDC.
On camshafts with a vernier adjustment there is a mark on the camshaft which has to be aligned with the mark on the cap of the front bearing for assembly. On later camshafts with a fixed pinion the mark is on the front of the pinion. This mark is not for timing the camshaft but for positioning it during assembly to minimize the risk of bending valves.
Doing the 2.2 mm thing on the camshafts with the head off is pointless as the entire purpose of the exercise is to relate the camshaft to the crankshaft. The head by itself has no TDC, only a complete engine has a TDC.
On camshafts with a vernier adjustment there is a mark on the camshaft which has to be aligned with the mark on the cap of the front bearing for assembly. On later camshafts with a fixed pinion the mark is on the front of the pinion. This mark is not for timing the camshaft but for positioning it during assembly to minimize the risk of bending valves.