Valve Lash Setting

[cobra 53]

As I could learn from several information concerning the procedure to set the valve lash, it always starts with:

"when the EXH valve starts moving, then adjust the INT valve on this cylinder".

Is it possible to set the valve lash when the pistons on the SAME cylinder are on the TDC and FIRING position?,

If this is the POINT where both lifters are off of the LOBE, are there any inconveniences to work with?

Rico

[FWB]

Originally Posted by cobra 53

As I could learn from several information concerning the procedure to set the valve lash, it always starts with:

"when the EXH valve starts moving, then adjust the INT valve on this cylinder".

Is it possible to set the valve lash when the pistons on the SAME cylinder are on the TDC and FIRING position?,

If this is the POINT where both lifters are off of the LOBE, are there any inconveniences to work with?

Rico

here's a chart i found that may make it clear

[Jerry Clayton]

I have always set the valve lash with the cylinder at tdc----been doing it that way for 60+ years--farm tractors,trucks,cars, race cars including top fuelers, funny cars, pro stockers,dirt tracters, sprint cars, indy(Cart) cars-have set held records in every class except Indy cars--------------------

[MOTORHEAD]

FWB: thanks for the chart ! That certainly simplifies the operation!

Jerry: Me too, always tdc until I did this engine (427) with a comp cam and followed the
procedure in their catalog. Had me guessing the whole time if I was doing the correct one at the correct time, still not sure, so I'll do it again using FWB's chart.

I recall someone telling me a while back that the "new" way of doing it related to the modern cam profiles, and that at tdc, the lifter was not necessarily on the "heel" of the cam.

The chart shows setting a cyl at tdc, but not adjusting that cyl's valves, but hopefully the ones on the "heel" with less turning of the crank and without the ambiguity of the " starting to move" or "just before it stops" positioning.

[FWB]

i use a black sharpie and make a hash mark on the rocker after i have set lash. just so when i'm done i can be sure i'm done with glance

[RET_COP]

The chart looks interesting FWB. Can this be verified by other engine builders.
I always used the EO set intake---IC set exhaust-- works flawlessly just takes a little more time

[FWB]

thats really what is happening with the chart, it just cuts down on the amount of times you spin the motor over. when your leaning over the fender and you only weigh 150 lbs, i can't seem to get the right leverage to keep my feet on the ground

[FUNFER2]

Have someone in the car turn over the engine or get a simple remote starter button and you can do it yourself.

[CHANMADD]

The most accurate would be to make a mark on the crank when ...whichever valve is fully open...ie:the spring compressed ,then turn the motor exactly 180 degrees and the lifter will for sure be on the bottom of the lobe.....................................I have mostly also used TDC ........

[Rick Parker]

Flat tappet solid lifter cam.
I get the engine nice and toasty then set the valves on one bank, run it again to get it real warm, then the other bank. They stipulate being set HOT.

[FUNFER2]

You can also just look at the valve lift and you'll see when their closed or open. To find out if the cylinder is on the compression stroke, put your thumb over the spark plug hole. Not as perfect as having tools, just an easy and fast way of lashing. If you do it correctly, you're very close anyway for street driving.

We've done the lash on our sprint car & my Cobra hot and cold, and write down the difference. Both ways work and most engine builders set them cold on the dyno.

[Gaz64]

Originally Posted by Jerry Clayton

I have always set the valve lash with the cylinder at tdc----been doing it that way for 60+ years--farm tractors,trucks,cars, race cars including top fuelers, funny cars, pro stockers,dirt tracters, sprint cars, indy(Cart) cars-have set held records in every class except Indy cars--------------------

I agree. The best way.

Originally Posted by FWB

i use a black sharpie and make a hash mark on the rocker after i have set lash. just so when i'm done i can be sure i'm done with glance

I do similar with a drawing, two rows of 8 circles.

Originally Posted by CHANMADD

The most accurate would be to make a mark on the crank when ...whichever valve is fully open...ie:the spring compressed ,then turn the motor exactly 180 degrees and the lifter will for sure be on the bottom of the lobe.....................................I have mostly also used TDC ........

360 degrees.

Originally Posted by MOTORHEAD

I recall someone telling me a while back that the "new" way of doing it related to the modern cam profiles, and that at tdc, the lifter was not necessarily on the "heel" of the cam.

The chart shows setting a cyl at tdc, but not adjusting that cyl's valves, but hopefully the ones on the "heel" with less turning of the crank and without the ambiguity of the " starting to move" or "just before it stops" positioning.

Never heard of a 4 stroke cam that was "not necessarily on the heel" of the cam at TDC. If that was the case, where would you adjust the valves, and would the engine run at all?

We've been adjusting more than two valves on 4 cylinder engines for donkeys years. No 1 on TDC, adjust both of 1, inlet of 2, exhaust of 3, rotate 360, adjust the rest.

Also, if you can't see where the engine is, there is nothing wrong with EOIC - exhaust opening, inlet closing - exhaust opening adjust inlet, inlet closing adjust exhaust.

[eschaider]

Originally Posted by Jerry Clayton

I have always set the valve lash with the cylinder at tdc----been doing it that way for 60+ years--farm tractors,trucks,cars, race cars including top fuelers, funny cars, pro stockers,dirt tracters, sprint cars, indy(Cart) cars-have set held records in every class except Indy cars--------------------

You guys are making this a whole lot harder than it really is. Jerry is giving you the short way home. Look at a cam chart card. TDC firing is a country mile from the INT closing or the EX opening ramps!

Ed

[Gaz64]

Originally Posted by eschaider

You guys are making this a whole lot harder than it really is. Jerry is giving you the short way home. Look at a cam chart card. TDC firing is a country mile from the INT closing or the EX opening ramps!

Ed

Simply another way, if the exhaust is opening- adjust inlet valve lash; inlet closing - adjust exhaust valve lash. Also quoted in the Comp Cam videos.

There are many ways, but TDC firing and adjust all valves for that cylinder is the easiest for beginners. Do each each cylinder in firing sequence. Too bad if you don't have a degreed balancer. That's when EOIC works.

View here: COMP Cams How to Set a Valve Lash - YouTube

[mdross1]

Never easy answers to these types of questions. I always set my lash on a cold engine. All iron set them a little tighter than recommended all aluminum tighter still, also on everything we own. Been doing it this way for over 50 yrs.When the engines warm up they have that well oiled machine sound.

[eschaider]

Originally Posted by Gaz64

Simply another way, if the exhaust is opening- adjust inlet valve lash; inlet closing - adjust exhaust valve lash. Also quoted in the Comp Cam videos.

There are many ways, but TDC firing and adjust all valves for that cylinder is the easiest for beginners. Do each each cylinder in firing sequence. Too bad if you don't have a degreed balancer. That's when EOIC works.

View here: COMP Cams How to Set a Valve Lash - YouTube

A degreed damper is not required.

Just take a grease pen and mark your damper quadrants 0, 90, 180, 270 and you are good to go.

You can get stunningly close by marking the 180˚ point on the damper first. Then split the difference between it and zero. Those points becomes your 90˚ and 270˚ marks.

Ed

[CHANMADD]

Hey Gaz..........I believe that the cam goes at half speed to the crank......that way if you rotate the crank 360.......then the cam will turn 180..........putting the lobe opposite to where it was..........its not to difficult to visualize......
Corrected info......

[eschaider]

Originally Posted by CHANMADD

Hey Gaz..........I believe that the cam goes at half speed to the crank......that way if you rotate the crank 180.......then the cam will turn 360...........putting the lobe opposite to where it was..........its not to difficult to visualize......

You are right about the half speed relationship Chanmadd.

That means if you rotate the crank 180˚ the cam turns half as many degrees (90˚). The reason for this is because the cam gear is twice the size of the crank gear and therefore requires two turns of the crank to produce one turn of the cam.

Ed

[Gaz64]

Originally Posted by CHANMADD

Hey Gaz..........I believe that the cam goes at half speed to the crank......that way if you rotate the crank 180.......then the cam will turn 360...........putting the lobe opposite to where it was..........its not to difficult to visualize......

It would be difficult to visualize.

Turn the crank 180, cam turns 90 not 360. Cam runs at half engine speed.

Ed has also said this in his post.

[CHANMADD]

Brain fart.........You're right....you're bloody well right......!!!!