How To Accurately Degree Your Cam With No Special Tools

so a lot of you guys who watch our live engine but Leslie commented on my method of the green camshafts and you wanted to see how it worked so let's do a quick video and show you and I'd like to take credit for this but this is actually the Keith black method of degree in camshafts and the reason why it was developed is because the altering cam timing is one of the tuning elements on a nitro car so you needed a quick easy way between rounds to make those adjustments without having to break out the degree wheel and go through all the motions of that stuff so I'll show you on this 340 here all you need for this is is a straight edge feeler gauge and a way to find top dead center so here's how this works keep all cam timing is based on the concept of split overlap this is where the exhaust valve is closing the intake valve is just starting to open when that for instance when your timing gears are dot-to-dot that's what it is it's the number one cylinder split overlap exhaust valve closing intake valves opening when both the intake and exhaust are open exactly the same amount that's considered to be straight up when the exhaust leads or the exhaust is higher I should say it's considered to be when the intake is higher it's considered to be advanced so the first thing we're going to do is find top dead center and to do that I just you stick a screwdriver in the number one spot phone call them we've already rotated this thing around to where it said basically it's a top dead center of the exhaust stroke so we're going to do is we're going to rotate the motor back and forth watch on the screwdriver so you see coming backwards screwdrivers are going down going forward and screwdrivers topped out and that screwdrivers start to head back down so what we're gonna do here is we're splitting the dwell right the piston is stationary for a ballpark four degrees of crankshaft rotation and that depends on the rod ratio how long that dwell is and what we're doing is we're splitting the dwell and that's your true top debt so and I generally do this three times it's kind of OCD but it's a way that I'm absolutely certain that I've got top dead center and there it is there and there it is and I look at the timing mark here and it's actually right I don't go by the timing marks because they're not always accurate so now we've got top dead center of the exhaust stroke and by the way always make your last move in the direction of engine rotation that takes all of the slack out of the timing chain or gears or whatever situation you've got going there so now we want to check our lifters now on this engine they're just barely above the lifter bores but they're high enough that I can actually lay my straight edge across the lifters right there and I can see that the straightedge makes contact at all four corners so here here here and here the strategy is in contact now if this cam was advanced I would have the intake lifter slightly higher than the exhaust and that's where the feeler gauge comes in the the measurement that we go by is six thousandths of an inch equals two degrees of camshaft of timing so if the intake is up six thousandths of an inch higher than the exhaust and this is how we'd measure this year for six thousands six we would be able to put this feeler gauge between the top of the exhaust lifter and the end the straightedge so this works I've checked this against every method there is I've checked it against known cam specs it's always like right there you might be five thousandths of an inch or maybe 7 thousandths of an inch depending on the camshaft profile but you're not concerned with the textbook end of this you're concerned with your reference point for actually making adjustments tuning adjustments to your camshaft and we'll do a whole separate video on you know cam timing effects and you know when you want to advanced when you want to and so on and so forth also this is a good method to check the trueness of a camshaft they're not always ground exactly perfect what I'll do with something like this is after I've determined my timing at the number one cylinder on an engine on a 180 four three six five seven two engine I'll rotate the crankshaft 360 degrees and then I make my HX at number six and then it'll tell you if the engine is actually true or not now if for some reason you can't get to the lifters and you want to try to employ this method you can do it off of the spring retainers what you'd have to do with this is first make sure that the spring retainers are exactly even right at rest and then decide you can only do this for the Saab lifter engine and get and get set you know actual results accurate results but you take oil and lash out and then using the multiplier effect of the rocker arm you can make that same measurement here off of the spring retainers but 95% of the time it's done right off of the lifters here and also if the lift it doesn't quite clear the top of the board you can stack the lifters and get your measurements out but it takes a little time but you can get it so that's it quick easy simple method of the green camshaft with a feeling age I'll see you tomorrow

Channel: Uncle Tony's Garage

Views: 108,049

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Id: PsZkOpLGtFM

Length: 6min 9sec (369 seconds)

Published: Sun May 10 2020