Measuring for Pushrod Length

[Casey72]

I've measured for pushrod length on the Cleveland, getting a pattern in the dry erase ink on the valve stems after rotating the engine a few times. Did I finally hit the mark or do I need to keep at it for a bit?

Intake

Exhaust

 

[Jeff73Mach1]

Looks perfect to me

 

[Don C]

+1, can't get any closer than that.

 

[Casey72]

Thank you. I was obsessing over very minor variances.

 

[barnett468]

You did not supply enough information . The primary goal is not to get the mark centered over the center of the valve.

 

[Casey72]

You did not supply enough information . The primary goal is not to get the mark centered over the center of the valve.

Being that I'm working from YouTube videos and some online articles, what information am I missing?

 

[barnett468]

You did not supply enough information . The primary goal is not to get the mark centered over the center of the valve.

Being that I'm working from YouTube videos and some online articles, what information am I missing?

Every single one of them you are looking at is wrong if they tell you to center the mark on the valve tip . It's a bit complicated to explain, but there are two different approaches to doing this . The videos below will show both of them . For useful information, you can also Google "valve half lift".

You can set it up so the rocker leaves the narrowest mark possible, however, the difference in the width of the mark can sometimes be maybe .005" which would be very hard to measure.

 

[TommyK]

You did not supply enough information . The primary goal is not to get the mark centered over the center of the valve.

No one seems to understand this.

The goal is to fully and accurately transmit the cam lobe data to the valve while producing the least stress on the valve train components in the process. This is especially important with canted valve heads. A centered pattern often does not accomplish this.

While satisfactory results are usually achieved using the "centered pattern" method, you aren't necessarily getting the most performance or longevity out of your engine.

 

[Casey72]

You did not supply enough information . The primary goal is not to get the mark centered over the center of the valve.

Being that I'm working from YouTube videos and some online articles, what information am I missing?

Every single one of them you are looking at is wrong if they tell you to center the mark on the valve tip . It's a bit complicated to explain, but there are two different approaches to doing this . The videos below will show both of them . For useful information, you can also Google "valve half lift".

You can set it up so the rocker leaves the narrowest mark possible, however, the difference in the width of the mark can sometimes be maybe .005" which would be very hard to measure.

OK, watched both videos, recocked and took another shot. In the end, it looks like two paths to arrive at the same location.

I drew the 90 deg. line on the rocker, installed at 90 deg., turned down the nut, set the pushrod, dialed to 50% lift and had the centerline as close to 90 deg. as it could possibly be. I dialed to max lift (.659/.666) on each vlave and the numbers matched the cam specs. The pushrod was the same length as I had previously established, within a couple thousandths as I measured it. It shot the same pattern on the valve stem.

I'm thinking my length is good at this point. The information was great and it was a good exercise. Is there anything I missed?

 

[MeZapU]

It looks about perfect to me.

 

[barnett468]

OK, watched both videos, recocked and took another shot. In the end, it looks like two paths to arrive at the same location.

I drew the 90 deg. line on the rocker, installed at 90 deg., turned down the nut, set the pushrod, dialed to 50% lift and had the centerline as close to 90 deg. as it could possibly be. I dialed to max lift (.659/.666) on each vlave and the numbers matched the cam specs. The pushrod was the same length as I had previously established, within a couple thousandths as I measured it. It shot the same pattern on the valve stem.

I'm thinking my length is good at this point. The information was great and it was a good exercise. Is there anything I missed?

the methods in two videos actually provide slightly different results and are used for different reasons and some will say one is better than the other, however, either, is far better than just throwing it together without measuring anything, and yours is 100 times better than everyone else that just throws their engine together.

time to start obsessing over beer.

oh, dont forget to check your distributor advance "curve".

 

[Casey72]

the methods in two videos actually provide slightly different results and are used for different reasons and some will say one is better than the other, however, either, is far better than just throwing it together without measuring anything, and yours is 100 times better than everyone else that just throws their engine together.

time to start obsessing over beer.

oh, dont forget to check your distributor advance "curve".

Fair enough, now that I've got (somewhat tight) bearing clearances, piston/valve clearance and valve train geometry, I'll find something else to think about. The direction is appreciated.

ETA: I essentially used the first method, but noted the effects of the second method. It was good to see all the numbers come in. As for timing, that's done through the Atomic handheld, which is just too easy on the presently running Windsor.