Finding TDC with no belt
#1
Instructor
Thread Starter
Finding TDC with no belt
I'm doing some major front end work and I accidentally got ahead of myself while uninstalling components last night.
I removed the timing belt before I installed the flywheel lock. Question is: not knowing where the engine is in relation to the camshaft, do I have to take the cam off to reset everything since I don't know where the pistons are in relation to the valves?
Or, can I still align the camshaft to TDC and crank to TDC safely?
Thanks in advance,
-bp
I removed the timing belt before I installed the flywheel lock. Question is: not knowing where the engine is in relation to the camshaft, do I have to take the cam off to reset everything since I don't know where the pistons are in relation to the valves?
Or, can I still align the camshaft to TDC and crank to TDC safely?
Thanks in advance,
-bp
#2
Rennlist Member
Remove all spark plugs. Then turn the crank so that it is 90 degrees from TDC. This will put the pistons half way down all the cylinders. You can determine this by putting a wooden dowel down cylinder 1 & 2 until the length is equal. Then you can set the cam to the mark, and then finally turn the crank to TDC from the mark at the top of the bellhousing. Done!
Just turn the crank slowly. If you meet resistance, then go the other way.
Just turn the crank slowly. If you meet resistance, then go the other way.
#4
Rennlist Member
if you climb under the car there is a notch at the bottom of the bell housing. There is a corresponding line in the flywheel that lines up at TDC. The cam also has a line and a mark on the cambox.
#5
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Remove all spark plugs. Then turn the crank so that it is 90 degrees from TDC. This will put the pistons half way down all the cylinders. You can determine this by putting a wooden dowel down cylinder 1 & 2 until the length is equal. Then you can set the cam to the mark, and then finally turn the crank to TDC from the mark at the top of the bellhousing. Done!
Just turn the crank slowly. If you meet resistance, then go the other way.
Just turn the crank slowly. If you meet resistance, then go the other way.
#7
Rennlist Member
When the cam is set on the mark, cylinder 4 has just closed the exhaust valve and is about to open the intake valve, so both valves are closed. Cylinder 1 has both valves closed. Cylinder 2 & 3 each have a valve open.
So for the final step when rotating the crank to TDC, you can't have cylinder 2 & 3 pistons getting to the top. That's why I said you might have to go the other way. So if you rotated the crank clockwise 90 degrees to get the pistons half way down the cylinders, then you will have to rotate the crank counter clockwise the 90 degrees to get back to TDC for cylinder 1.
So for the final step when rotating the crank to TDC, you can't have cylinder 2 & 3 pistons getting to the top. That's why I said you might have to go the other way. So if you rotated the crank clockwise 90 degrees to get the pistons half way down the cylinders, then you will have to rotate the crank counter clockwise the 90 degrees to get back to TDC for cylinder 1.
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#8
Burning Brakes
Resurrecting a old thread here. What is the best way for setting the belts when the bottom end has been worked on? In this scenario you have access without the head, cam on a stand so I'm curious what the best method is.
My thoughts are since the engine is on a stand, you don't have the flywheel on with the markers. So then instead set the engine to TDC visually prior to putting the head on (cyl 1 and 4 at top) on the stand, then put on the head, so when you get to the cam you can put it on at the index marker.
My thoughts are since the engine is on a stand, you don't have the flywheel on with the markers. So then instead set the engine to TDC visually prior to putting the head on (cyl 1 and 4 at top) on the stand, then put on the head, so when you get to the cam you can put it on at the index marker.
Last edited by Dave951; 06-19-2016 at 02:20 PM.