Topic: 20/22r ignition and cam timing

[92yota]

I was wondering what is the most optimal range to set the timing on a 20/22r engine it has a mid range cam headers 38 weber and the distributor recurve spring in it i only wana run regular gasoline. Also im thinking about getting an adjustable cam timing gear my new engine that i just built doesnt seem to impressive to me its about the same power as a 22re. whats the easyest way to check and see what degree my cam is at now? Im looking for more bottom end. Any help would be geatly apreciated.

[Zoomschwortz]

For cam timing you will first need to degree the cam and see where you are at. For more bottom end you will need to advance the cam. I bought an LC Engineering adjustable cam gear a couple months ago and really liked it.

As far as ignition timing, Start with an initial timing around 15 degrees and take the truck for a drive. Try flooring the gas in 4th or 5th and see if the engine pings. If it pings back the timing up a couple degrees and go for another test drive. Repeat until no ping.

If there is no ping, advance the timing and go for another test drive. Repeat until a ping is heard, power no longer improves or it starts to run bad and back timing off a couple degrees. 

[92yota [OP]]

do you need a special degree wheel to see where your cam timing is?

[jimbo74]

you can pull the valve cover and look at the sprocket! make sure the peg is up when the crank is at 0* and make sure the bright link is on the dimple in the cam pulley.....

[Zoomschwortz]

do you need a special degree wheel to see where your cam timing is?

If you are going to adjust your cam timing or want to know exactly where your cam timing is, you will need a degree wheel. I bought mine from Summit for $16 or $17.

A new cam can be off a couple degrees. A thicker head gasket, milling the head, or milling the block will all change cam timing on an over head cam engine.

The Comp Cam web site will will tell you how to degree a cam.

To attach the degree wheel to your crank you will need to remove your crank bolt, take it to the hardware store and buy a new bolt that is about 4" long. You will also need a bunch of washers and a couple nuts.

Slip the degree wheel over the bolt (I had to drill out the bushing a little bit) then add washers until some of the threads are covered with washers. Then add a nut and snug up the stack of washers and degree wheel to the point where the degree wheel can still be moved if needed, but won't move if bumped. Add the second nut and jamb it to the 1st nut. Add a couple more washers and install assemby into the end of the crank.

[92yota [OP]]

thanks zoomschworts thats exactly what i wanted to know. I wasnt shure where to purchase a degree wheel. Also jimbo once you startup the engine it is very hard to get the shinny links to line up again but the dowel is in the aproxamatly right spot i just want to try useing a adjustable cam timing gear and see what kind of changes ill get

[jimbo74]

those shiney links should alsways be lined up.... if they deviate, there is another problem.... like a bad tensioner......

mine used to deviate a lot due to broken plastic guides.....

[Zoomschwortz]

I don't know if all timing chains are the same but mine only has 1 shiny link, and the chain is sooooooo long that unlike a Chev or Ford V-8 it takes more than 2 crankshaft rotations to bring the shiny link back to the top. If you keep turning the engine over the shiny link will make it back to the top and it should line up.

One other thing that I just remembered.
When you degree the cam you will need a positive stop for the piston. What it does is stop the piston from reaching top dead center. You turn the engine counter clock wise untill the piston comes in contact with the stop. Mark the degree wheel and then turn the engine clock wise until the piston hits the stop. Mark the degree wheel again. Half way between the 2 marks is your real top dead center.

They sell positive stops that screw into the spark plug hole, problem is, your valves will hit it if you don't remove it when you turn the engine over. When you remove it to turn the engine over, it is hard to get it back to the same depth.

I ended up using a long ratchet extension that fit into the spark plug hole. Before putting the extension into the engine, I slipped a washer over the extension. When the piston contacted the extension, I pushed the washer down until it came in contact with the engine and then marked the washer and extension with a pen. I then removed the extension, and wrapped a bunch of duct tape where the mark was to create a stop for the washer.

This made it a lot easier to put the extension in the same spot after I removed it to rotate the engine.

[92yota [OP]]

thanks for all the pointers