[b-man]

Originally Posted by AdamIsAdam

I thought straight up means dot to dot.

It does, sort of.

BUT, you can't be absolutely sure without degreeing the cam.

Production tolerances can sometimes be all over the place on the locations, degree-wise, of the cam key in the cam and in both of the timing chain sprockets.

So you must check so you know where your cam is for sure.

[Steve C.]

I can say some Comp XE sold roller cams come with 4 degrees advance ground in and some have none.


.

[gtofreek]

Originally Posted by Squidward

When you say -1 to +2, would that mean 107 to 110 for spec'd 108 icl?

Sweet work! I thought I heard that dyno pull from afar - spidey sense was tingling and said "something awesome is going down"!

No, if the card says install it at 108 ICL, on a cam that was ground on a 112° LSA, then installing at 108° ICL would be 4° advanced. On a cam with 4° advance ground in, then you would use the zero timing key on the gear, and theoretically, you will be at 108° ICL. When I say -1 to +2, I mean from where the cam card says they want it. In this case, that would be anywhere from 106° - 109°, with 109° being -1° from where the card wanted it.

[gtofreek]

Originally Posted by 72LuxuryLeMansLa.

You have confused me in the past with the fact that most cams do better installed advanced........ And before you say it. yes I can sometimes be confused easily! In my mind when you say straight up I think you are installing the cam at the ICL that is on the cam card. When you say install it advanced I think you mean at an earlier ICL than the cam card states! So in the case where a cam has 4° advance ground in, installing it that way is straight up no? The Stump Puller I have in front of me says install at 107° ICL and that is 5° total advance according to Performance Trends Engine analyzer........ SO in my mind if I install it at 107° ICL it is straight up, no?

Some people consider "straight up" as using the "zero" timing key in the crank gear. That is NOT "straight up" in my book. To me, "straight up" means installing the ICL at the same point as the LSA. So, if a cam was ground on a 112° LSA, then installing the ICL at 112°, would be "straight up". If you use the zero key slot on the crank gear, and it degrees in at 107° ICL, then it is 5° advanced.

"Straight up", or "advanced" or "retarded" are all based off of the cams LSA, nothing else. Installing the ICL at 114°, on this same cam, would be 2° "retarded", regardless of what key slot was used to get that ICL.

Here's a good example. I installed a cam once, using the zero key slot to start with. The cam was ground on a 110° LSA. I wanted it installed on a 106° ICL. That would make it 4° advanced. When I degreed it, the ICL, was 96°! A full 14° advanced! So, I had to use retard key slots to retard it 10° in order to make it 4° advanced! If it wasn't degreed, and just installed with the zero key, he probably would have bent valves.

[Blued and Painted]

Originally Posted by gtofreek

It had a 236/244 Isky cam, but the customer didn't like the idle, he wanted a smooth idle, lots of vacuum, torque,
Lunati VooDoo HFT cam, 227°/233° 110 lsa, RA manifolds.

The voodoo seems to be a contradiction. cant see where it will have more than 11 inches of vacuum, then move to altitude.

[gtofreek]

Originally Posted by Blued and Painted

The voodoo seems to be a contradiction when moving to altitude.

Why would you say that?

[Steve C.]

Voodoo Hydraulic Flat Tappet Cam - Pontiac V8 268/276
https://www.lunatipower.com/Product....d=1776&gid=287

Lunati touts more vacuum with the Voodoo lobes. But then so does Comp..... "Xtreme Energy Cams provide increased torque, vacuum, response, and power while still providing quiet operation of the valve train and the durability required in daily driven vehicles." And also a quiet valvetrain ? ... note how many here will disagree on that about a XE hyd flat tappet lobe


.

[lust4speed]

Seems like many of us have a different definition of "straight up". Not that I can make a case for it, but I consider it to be where the cam manufacturer suggests the cam timing be placed. So if it is cut on a 112 and the card says to install it at 108, then I interpret the 108 is the straight up position since it is what the cam company says to put it.

Continuing on the soap box, I concur that straight up has nothing to do with dot-to-dot alignment since only once in a very rare occasion do these dots have anything to do with reality.

Then again, I've got in trouble with the wife for confusing "this Saturday" for "next Saturday". This usually happens on a Sunday where the closest Saturday is 6 days away. Through enough training sessions I now see the light and know the difference between this and next. So there is probably hope for me on the cam timing issue...

[Motor Daddy]

Originally Posted by lust4speed

Seems like many of us have a different definition of "straight up". Not that I can make a case for it, but I consider it to be where the cam manufacturer suggests the cam timing be placed. So if it is cut on a 112 and the card says to install it at 108, then I interpret the 108 is the straight up position since it is what the cam company says to put it.

Continuing on the soap box, I concur that straight up has nothing to do with dot-to-dot alignment since only once in a very rare occasion do these dots have anything to do with reality.

Then again, I've got in trouble with the wife for confusing "this Saturday" for "next Saturday". This usually happens on a Sunday where the closest Saturday is 6 days away. Through enough training sessions I now see the light and know the difference between this and next. So there is probably hope for me on the cam timing issue...

You made me laugh so I have to reply.

Straight up is when the ICL (the max lift point of the intake lobe) is an equa-distance from TDC as the ECL, (the max lift point of the exhaust lobe), (not real distance, degree distance .)

So imagine the crank at TDC. Leave it there! Now rotate the cam until the ICL and the ECL are an equal number of degree away. Now install the timing set with a true dot to dot that is really dot to dot, in the real world.

If the timing set and crank and cam keyways are machined perfectly, the cam is installed "straight up" at that point, because the crank is at TDC, and if you rotate it you'll find if the cam was a 112 LSA, the cam is installed on a 112 ICL. If the cam is a 110 LSA then it's installed at 110 ICL. If the cam is a 114 LSA then the cam is installed at 114 ICL.

Since the crank is at TDC and the max lift point of the lobes are an equal number of degrees away, TDC is splitting the number of degrees between the two max lift points.

The point is that all the ICL's are different, and the crank never moved, and all the cams are installed "straight up." And yet they all have different LSA and different ICL's and ECL's.

"Straight up" means TDC is centered between the two max lift points.



...and about "this and next..." (that's the part that made me laugh. )

Since the previous Saturday has past (in time) and is now the past (because it has already occurred in time), when you say "this Saturday", you are either saying that when it's Saturday now, or you're making reference to "this coming Saturday", which is the next Saturday in time. In the future...

[grivera]

Originally Posted by Motor Daddy

You made me laugh so I have to reply.

Straight up is when the ICL (the max lift point of the intake lobe) is an equa-distance from TDC as the ECL, (the max lift point of the exhaust lobe), (not real distance, degree distance .)

So imagine the crank at TDC. Leave it there! Now rotate the cam until the ICL and the ECL are an equal number of degree away. Now install the timing set with a true dot to dot that is really dot to dot, in the real world.

If the timing set and crank and cam keyways are machined perfectly, the cam is installed "straight up" at that point, because the crank is at TDC, and if you rotate it you'll find if the cam was a 112 LSA, the cam is installed on a 112 ICL. If the cam is a 110 LSA then it's installed at 110 ICL. If the cam is a 114 LSA then the cam is installed at 114 ICL.

Since the crank is at TDC and the max lift point of the lobes are an equal number of degrees away, TDC is splitting the number of degrees between the two max lift points.

The point is that all the ICL's are different, and the crank never moved, and all the cams are installed "straight up." And yet they all have different LSA and different ICL's and ECL's.

"Straight up" means TDC is centered between the two max lift points.



...and about "this and next..." (that's the part that made me laugh. )

Since the previous Saturday has past (in time) and is now the past (because it has already occurred in time), when you say "this Saturday", you are either saying that when it's Saturday now, or you're making reference to "this coming Saturday", which is the next Saturday in time. In the future...

If one installs a cam according to the cam card (ex. specs based on a 107* icl), and the cam has advance "ground in", one degrees it in at 107*, correct?

BTW, while I agree with the above, I find I'm always on the losing side of the argument regarding "this" and "next"...

[Cliff R]

"Seems like many of us have a different definition of "straight up". Not that I can make a case for it, but I consider it to be where the cam manufacturer suggests the cam timing be placed. So if it is cut on a 112 and the card says to install it at 108, then I interpret the 108 is the straight up position since it is what the cam company says to put it."

+2


"Straight up" is usually interpreted as "dot to dot" on any timing set. If the cam manufacturer has done their job, then the ICL will be at or very close to where they want it on the cam card.

Some say "straight up" is like putting a 110LSA cam in "dot to dot" on the timing set, then finding out that ICL and ECL are both at 110 when you put the degree wheel on it. This happens with the folks grinding the cam didn't grind the desired amount of advance into it.

Almost all "shelf" and stock cams will be where they are supposed to be. Most custom ground cams will say right on them that they ground in 4 degrees (for example) of advance to the get the ICL where it's supposed to be according to their cam card.

None of this really matters in the big scheme of things, ALL cams should be degree'd and put where they are supposed to be or where you want them. I usually find that when using the stock Melling link type timing sets, we don't have to move the cam around much at all compared to aftermarket roller sets, and some that have been supplied here by customers for engine builds have been further off than others.

Yes, there are about two dozen choices for timing sets for these engines in roller varieties, iron gears, billet gears, 3 keyways, 9 keyways, fixed roller chains, true roller chains, really good true roller chains, etc, etc.

For our engines here, I use the Melling stock sets on about 50 percent of them, without exception the only other sets I'll use the high-end true roller stuff with billet sprockets and 9 keyways to move the cam around.......Cliff

[Motor Daddy]

Originally Posted by grivera

If one installs a cam according to the cam card (ex. specs based on a 107* icl), and the cam has advance "ground in", one degrees it in at 107*, correct?

Look at the LSA. Take that number and make it the ICL, that is straight up. So a 110 LSA installed at 110 ICL is straight up. If all is machined properly and nothing ground in, the dots will be perfectly aligned when the cam is installed straight up.

If you install the cam dot to dot, and found the ICL to be 106 on a 110 LSA cam, the cam is advanced 4 degrees (from straight up-110 ICL).

If the cam has 4 ground in it, when you place a 110 LSA cam in the engine dot to dot (perfectly machined) the cam will be installed at 106 when it is dot to dot. That is 4 degrees advanced from straight up of 110 ICL, and the dots are perfect, hence, the cam has 4 degrees ground in it.

[grivera]

The [old] Stump Puller cam card indicates a 112 LSA with 112+5 with specs provided for cam installed on a 107* ICL. So in this case, it gets installed at 107* which is really 112* due to the advance being ground in? Why grind advance in rather than providing instructions that it be installed at 112*?

[gtofreek]

Originally Posted by Motor Daddy

Look at the LSA. Take that number and make it the ICL, that is straight up. So a 110 LSA installed at 110 ICL is straight up. If all is machined properly and nothing ground in, the dots will be perfectly aligned when the cam is installed straight up.

If you install the cam dot to dot, and found the ICL to be 106 on a 110 LSA cam, the cam is advanced 4 degrees (from straight up-110 ICL).

If the cam has 4 ground in it, when you place a 110 LSA cam in the engine dot to dot (perfectly machined) the cam will be installed at 106 when it is dot to dot. That is 4 degrees advanced from straight up of 110 ICL, and the dots are perfect, hence, the cam has 4 degrees ground in it.

Exactly what I explained in post #24.

[gtofreek]

Originally Posted by grivera

The [old] Stump Puller cam card indicates a 112 LSA with 112+5 with specs provided for cam installed on a 107* ICL. So in this case, it gets installed at 107* which is really 112* due to the advance being ground in? Why grind advance in rather than providing instructions that it be installed at 112*?

No, if it gets installed at 107, then it is 107, not 112. 112 is straight up. 107 is advanced 5°, it just had the advance ground into it to make it easier for average Joe to install the cam.

[Motor Daddy]

Originally Posted by grivera

The [old] Stump Puller cam card indicates a 112 LSA with 112+5 with specs provided for cam installed on a 107* ICL. So in this case, it gets installed at 107* which is really 112* due to the advance being ground in? Why grind advance in rather than providing instructions that it be installed at 112*?

No.

If a cam has an LSA of 112, and you install it at 107, it is installed 5 degrees advanced from straight up, which would be 112 ICL.

If you install it dot to dot and it comes out to be 107 ICL, and everything is machined right, the cam has 5 ground in it already. You install it dot to dot and it will be at 107 if everything is right and the cam has 5 ground in.

[grivera]

This makes my heads spin. Dave at SD suggested it be installed at 107*- which ended up being dot-to-dot.

[Motor Daddy]

Originally Posted by grivera

This makes my heads spin. Dave at SD suggested it be installed at 107*- which ended up being dot-to-dot.

Because Dave knows his stuff! He's right, the cam has 5 ground in, hence a 112 LSA cam that has 5 ground in will install at 107 ICL when it is dot to dot. Good job, Dave!!

[grivera]

So the advance is ground in to eliminate the use of cam keys or fancy sets (assuming perfect timing sets)?

[Motor Daddy]

Originally Posted by grivera

So the advance is ground in to eliminate the use of cam keys or fancy sets (assuming perfect timing sets)?

No. That's where the cam grinder recommends the cam to run, at a 107 ICL, so he made it that way so if you install it dot to dot it is where he wants it. If you think you want it somewhere else, then change it, against his recommended 107. At you own risk, obviously.