UDHAROLD i bought your Solid Flat Tappet 288/296 BBC cam on a 112LCA awhile back. I have always heard you say that your cams need to be installed 4/6 degrees advanced. like on the other post; ", this only holds true for running the cam in a 4° to 6° advanced position; cams run straight-up generally accept whatever fuel system you have. They just don't make as much power as the ones that are advanced...... " Now I am confused, Wouldn't you want to install the cam on the Intake centerline that is best for your combo? I don't know a whole lot about this stuff, but i thought that if you have(like me) a 112 lobe seperation and if(like most) cam companies grind it with about a 4 degree advance into the cam core, you end up with a 108 intake centerline. And then if you advance the cam another 4 degrees you would have a 104 intake centerline. Am i right so far? SO it seems that you saying that "all" your cams should be advanced seems kinda odd? I mean shouldn't you put the cam in where it will perform best in your combo? For example lets say you have a cam ground on a 108LCA with the 4 degrees you would have a 104ICA and then advancing it another 4 degrees would leave you with 100ICA isn't that kinda extreme? And couldn't you end up with piston to valve contact? Personally I put my cam in straight up because i wanted a 108ICA to match my DCR and because i have a stick car and was shooting for a little more topend rather than bottom end for longetivy and traction. I understand that the more degrees advanced will build more cylinder compression earlier, but can't that lead to other problems also if the engine isn't blueprinted exactly? Maybe i am just missing something here or just don't know what i am taliking about? But from my perspective it doesnt' make sense to follow those guidelines. I degreed my cam and it came in at 107 which was just fine for me, and my Piston to valve clearance was just acceptable, should i advance it Another 4 degrees and recheck the piston to valve clearance again?(engine is already assembled) thanks again Harold, once again not trying to start an argument i am just honestly curious? graemlins/waving.gif

Cody,
if you have a cam with 112 degrees of seperation it is in "straight up" with the intake lobe at 112 degrees.
If the cam is ground with 4 degrees of advance it will be 4 degrees advanced when you install it on the stock timing marks.
This is 4 degrees advanced from straight up no matter how you get there.
the only difference is you didn't have to change anything to get to the 4 degrees advanced.

Hi Harold graemlins/waving.gif

Well as far as I know the cams have 4 degrees already advance in them so in reality you end up with 108ICA(using my example=112LCA) when installed straight up. I don't know what the Lunati cores have ground into them but most everyone that i see is using 4 degrees. And this is also what I was told about the Ultradyne cams. This would make sense because my cam was ground on a 112, and ended up at 107ICA when installed straight up(I believe +/- 1 degree is acceptable in cam grinding) so if harolds cams already have 4 degrees ground into them then why does he tell everyone to install them advanced "another" 4 degrees?=8 degrees total advanced.

Cody,

When you are told to install a cam 4 degrees advanced it does not matter how you get to this 4 degrees.
If it is ground into the cam you put it in on the marks you are calling "staight up" & if everything is right it will be 4 degrees advanced not straight up in the engine.
In order to put your cam in straight up you would have to retard it 4 degrees from the way it would go in the engine on the marks.
You are talking about two different things. A cam that has 4 degrees ground into the cam is not straight up as far as the engine is concerned it is 4 degrees advanced even though you are putting it in what you are calling "straight up" on the marks as it came aout of the box

Cody,

I don't want them installed ANOTHER 4 to 6 advanced. I just want to make sure they are where they are supposed to be. When cams are installed, there are a number of errors that add and subtract degrees from where the cam should be installed. How the piston manufacter placed the dome and where the piston pin is actually located, how close the crank throws are actually to 90°, and how accurately was the crank key-way cut, how accurately was the timing chain, etc made, dah-de-dah-de-dah......
The only thing important is the relationship between the cam and the piston, none of these other 'errors' are important, as long as the cam is in the correct relationship to the piston. In all the cam-loop testing we have done, from 151 Pontiacs through 555 BBCs, maximum BHP and torque was achieved most often at 6° advanced from straight-up, ie---106 ICL on 112 LSA, 99 ICL on 105 LSA..... Sometimes, depending upon your individual cylinder head, 4° advanced was best. The difference was always only about 4 or 5 BHP, 5 to 8 ftlbs torque.
Lunati grinds all their cams 4° advanced, because all of the core companies, who make the cores, now provide the cores with a 4° advance off the pin........

Sorry about the confusiion....

Mike, Hello, and thanks for your support. It's always nice to have to have friends....
Say hello to the wolves for me....

UDHarold

edited, i posted before i saw UD's post.
Maybe I am just kinda dull, but I think you should let people know exactly what you mean by advancing the cam; you might say to put the marks dot-dot to preserve the 4 degrees advance that the cam comes with, or something along those lines. It might be that I am the only one confused graemlins/clonk.gif But there might be others. Glad i got that cleared up! thanks again.

Personally ..sometimes I wish all these terms were never invented....they often just lead to confusion..

Since you really never know where the cam is in relation to the crank.... until you degree it.... it really doesnt matter.... the important thing is to degree it first to see where you are at.... then if it requires moving something... make the change and recheck it to verify that the change did put the cam into the correct relation with the crank.Once it is where you want it... button it up.. your done graemlins/beers.gif

Exactly, "straight up" means +4 with some grinds. So guys are saying " my cam's in "straight up", but if they've never checked the actual opening with a wheel, or even with Harold's quick and dirty method, they don't really know where the cam is.

Originally posted by cody:
Maybe I am just kinda dull, but I think you should let people know exactly what you mean by advancing the cam; you might say to put the marks dot-dot to preserve the 4 degrees advance that the cam comes with, or something along those lines. It might be that I am the only one confused graemlins/clonk.gif But there might be others. Glad i got that cleared up! thanks again. Cody
I'm glad that you ask that question because I was thinking the same way. The cam needed to be advance 4* after it's align straight up. I bought the Cloyes Timing Chain (9-3100) that has the 4* advance by move it to that keyway position. This post really save me some brain cells that I was burning. Now I can move on to something new about my engine and start clearing the block for the 6" rods.
Excellent Post
Deeboo

Excellent post for dummies like me. I just installed my UD276H10, 110LSA, 104ICL. I put it in at +4 on the crank sprocket and degreed it and came up with about 105 - 105 1/2. Now this is my first cam install and I still don't feel confident I did this right. I assumed the cam had 2 degrees ground into it and you advanced it another 4 by the crank sprocket. After reading these posts about 4 degrees ground into cams I am getting a little more nervous. Mr. Brookshire or others, can you put my feeble mind at ease or straighten me out?

Thanks guys


Jerry

You guys are confusing the marks on the timing set with the location of the ILC in relation to the crank. Straight up means the ICL and the LSA are the same (i.e. a 112º LSA cam is installed at 112º ICL). It doesn't matter where the timing marks are on the timing set. For a cam with 4º advance ground into it, the same timing marks are used to set that cam to 4º advance as are use to set a cam with no advance in it to 0º advance (straight up, as defined above).

When a cam mfg says to install the cam with 4º advance, they mean the ICL is 4º less than the LSA (108 ICL on a 112 LSA). As Mike said, how this is done is immaterial. Whether the advance is ground into the cam or the timing set is adjusted to provide it doesn't matter. Most of the time you can tell how much advance is built into the cam by looking at the cam card. If the specs show the ICL as different than the LSA, the cam has advance built into it (and the timing set is installed in the 0º position to get the 4º). If the ICL is shown as the same as the LSA, the advance is not built into it (and the timing set is installed in the +4º position to get the 4º). No doubt that is a lot of confusion on this. Just another case of the same terms being applied to different but very closely related functions.

So, in short:

If the cam has the advance in it, install the timing set at the "0º" position to get that advance.

If the cam does not have advance in it, install the timing set at the "+4º" to get 4º of advance.

The same applies to any other advance recommended by the mfg, 6º in Harold's case (which might require using offset bushings in some cases)

Again, the ICL spec refers to the location of the ICL in relation to TDC of the crank. The amount of advance is speced in relation to the LSA (+4º or +6º, as the case may be). The marks on the timing set only refer to the amount of change from the stock location of the timing set and not necessarly to the actual location of the ICL of the cam in relation to TDC of the crank.

Pat, if I understand you right in my case for example my cam is 110 LSA and 104 ICL.I assume then the cam has 4 degrees ground into it? I should be installing the cam dot lined up on the 0 degree keyway on the crank sprocket, therefore my cam now is advanced 4 degrees, right? and possibly achieving the other 2 degrees with an offset bushing.I do really appreciate the input and I realize trying to explain something like this to me(and possibly others)can get frustrating.I was assuming the cam manufacturers ground 2 degrees into the cams and then you achieved your advance with the 4 degree increments on the crank sprocket

Jerry

Ok, my turn to take a stab at it...

In your case where your cam has a 110 LSA and you have it installed at a 104 I/C, you have the cam 6* advanced. Regardless of "how" you had to do it, it's 6* advanced.


Mfg's grind most of them with 4* advance built in to "idiot proof" them. Don't take that term wrong....not calling anyone names....just that the Mfg has no idea who is actually installing the cam and whether they will degree it or not. So by grinding it advanvced, they have a pretty good chance that the cam will actually end up in the motor fairly close to the right position. At least it won't end up retarded. As mentioned above, the tolerance stack up of all the interelated parts can easily get things out of whack. And as a timing chain wears it retards the cam naturally, so from day one you are going the other way. "Lining up the Dots" gets you whatever you end up with in YOUR motor with YOUR parts. Most likely it will be a few degrees advanced. Like if you have a 110 LSA cam, it may end up at 106-107 I/C when you first bolt it in. That's where the checking and adjusting come in to get it exactly to say 104* (6* advanced per Harold's recomendations). You use either bushings, gears, keys or whatever to make it perfect.

Since you guys are actually degreeing yours, you are way ahead of the average "line up the dots" guy. You KNOW where your intake centerline is and where the cam is positioned in relation to the piston.


Hope this helps,


JIM

I agree, Degreeing your cam is the very best way, and that is why i did it(even though it took my like three times to get it right!) I still think using the term "installing" is used toooo much. To me "installing" is kinda a verb. SO to install would mean something physical to me, as in actualling positioining the cam differently when advancing it. I think that Harold should definetly state that the cams already have 4 degrees advanced, and NOT that he wants you to additionaly advance the cam. Also where does the term "straight up" come from, I thought it came from using the "dots" which would then mean that by installing the cam straigth up You WOULD have 4 degrees already advanced. I do understand the terminology and the correct way to do this. I was just always confused by what Harold always was saying about advancing his cams. I mean come on, Advancing to me would mean to move foward from what you already have,,, right?? so if you already have 4+ in the cam you would move foward another 4-6+ degrees. Maybe I am getting to techinical but it looks like others were confused too.

Cody,
Quit trying to reinvent the wheel :D
It has been explained by about 5 differnt people in different ways.
The term straight up to any engine builder and almost any good reference book means the intake centerline of the cam is the same as the lobe seperation angle.
IE: a 112 lobe seperation cam is straight up when the intake lobe centerline is at 112 ATDC.
It really is that simple ;)

One more try smile.gif . The timing set mark of "+4" means: 4 more degrees is add to the advance the cam already has ground into it. "0" means the cam timing is not changed from what is built into the cam. "-4" means the cam has 4º subtracted from the advance ground into it.

A cam with 4º built into it if installed with the "0º" timing marks is advanced 4 degrees. With this cam, if you wanted to install it "straight up" (that is, with the LSA and ICL the same) you would use the "-4" mark. The marks on the timing gear either add, subtract, or do nothing to the advance built into the cam.

The main reason for mfgs to built advance into a cam is so a standard factory type chainset (with only one keyway and no adv or retard provisions) can be used and the cam will have the recommended advance.

I understand all of that just fine. It is good information however. I am sure many people will benefit from it. I guess i am getting too techinical with the terms. I am comprehending these terms differently than most others I guess. But my main point was that I think info was being passed on and being interperted wrong, which wouldn't be a big deal, but the info was coming from a "company" so i think it should be explained a little more in depth before being thrown out there. Just to clarify one more thing since you guys interpret the meaning "straight up" differently than me, where did this phrase come from? and what is the exact definition of the actual words? graemlins/clonk.gif

Blumont, when I installed my 276F10 w/ the cloyes set, I got a 110icl with the sprocket in the standard position and 105icl with it at the +2(crank) key way. The triangle. Just like UDharold said on the phone.
The chain had about 700 miles on it. So new, it probably was 104.
Now I did scratch my head a little when I got the 110icl with the card calling for 104. I thought I was in the std slot. But since I couldn't find the chain set box, I just picked a key way and checked it. I found the box later and checked which slot did what.

Pat, I understand what you said in that +4 is adding advance to what the cam already has ground into it and so on. My problem is that I am not completely sure in what advance has been ground into my particular cam (110 lsa, 104icl)At this point now I am assuming 4*

I owe you guys a few cool ones graemlins/beers.gif

I am going to try and degree my again. Timing cover and water pump are all installed but no big deal removing them, engine is still on the stand at this point.When I degreed it initially I came up with about 105* icl and I have used the +4 mark on the crank gear

Thanks

Jerry

Originally posted by cody:
"straight up" differently than me, where did this phrase come from? and what is the exact definition of the actual words? graemlins/clonk.gif Not sure but I believe it would be the opposite of "straight down" :D

Jerry,
If it has a 110 lobe seperation angle & the timing card said 104 ICL then it should have been ground with 6 degrees of advance.
It could also be it was ground with no advance & they wany you to advance it 6 degrees.
All it is telling is this paticular cam was designed to be installed in the engine 6 degrees advanced relitive to TDC in your engine.
Again, how you get there is not relevant. It could be that the pin in the cam has been relocated relative to the lobes or it could be you need to move either the cam or crank gear to get to your 6 degrees of advance
This is why you should degree a cam when you put it in.
Bottom line, when you are done your degree wheel should read 104 ATDC when the intake lobe is centered, or at it's highest lift position.

Just like anything else you do when building an engine, never assume anything & check everything twice ;)

HAS NO ONE ELSE NOTICED,OR DOES THIS GUY HAVE HIS CAPS LOCK ON ???? TURN IT OFF.....

Thanks Mike, I am going to do it again and again till I get this right on. I just thought I was missing something on the cam card that was telling me that the cam had advance ground into it and how much. To me if it did it seems it would be a little easier for the installer to no approx where to start.
Thanks again
Jerry

It would be nice if the cam card explicitly stated how much advance is built into the cam. I know most all of Comp's street cam have 4º (AFAIK, only the 305 Magnum has none). None of the racing cams have any advance built in. They leave it to the builder to install at whatever advance they want.

There are other ways of setting the advance besides the ICL method. Some use the "Split Overlap" method (of which there are a couple variations) while other set the advance using one of the valve timing events, like intake closing or exhaust opening. With highly asymmetrical cams an alternate method to the ICL method might be preferred. On my Comp racing cam I found the intake duration had 3º more degrees than speced, all of it between .050" and .006" on the closing side. Because I wanted a specific intake closing point, I set the IC point where I wanted it and let the ICL fall where it might.

Actually, my cam cards have NEVER said to advance a cam 4°, or 6°. What they tell is what the cam's LSA is, and WHERE to place the Intake CenterLine for BEST overall power. That point is 6° advanced from where the LSA is ground. The catch is core manufacturers changed their pin offset several years ago, and instead of offering cores with a 2° offset, they changed to 4° offset, because most cams liked that better. Because of all the various possible errors, which I mentioned in a previous post, there is no way I can, or any manufacturer, gaurantee that putting a cam in and not checking it means it is exactly where it is supposed to be. We almost all grind the cam with NO advance, the lobes are advanced in relation to the pin. This way we maximize heat-treat on the lobes. To grind extra advance into the cam lobes is to take heat-treated metal off the back side of the lobes......
I told people for years to put cams in using the 4° advance key, because with the 2° pin off-set and the 4° advance, the cam would PROBABLY be around 6° advanced. It is the job of the engine builder to verify that the cam is where the cam manufacturer suggests it to be. Putting a cam with 4° advance pin-offset in 'Dot-to-Dot' means the cam is probably between 3° to 5° advanced, and possibly 2° to 6° advanced. All numbers are possible, and this does not mean that your cam was mis-ground. What it means is that it is your job to make sure the intake CenterLine is as close to the recommended position as you can get it. Almost all cams tolerate a +/- 1° in Intake Centerline position........

Does this make anything clearer?

UDHarold

After reading all this I am a little concerned with my set up. My cam was installed by the previous owner (292H Comp). When I pulled the engine (454/.060 over) and disassembled it the cam was set up dot to dot. I have no cam card or literature for the cam and have looked at the Comp web site. The only thing that I find is that it shows 292/292 duration,244/244 @ .050, lift .550/.550, LSA 110.

When I reassembled the engine I put it back dot to dot. I guess I was assuming that the previous owner knew what he was doing. Is this right???

Thanks,
Billy

If you liked the way it ran, YES....
If you want more bottom-end, you can advance it 2° to 4°. Most Comps now have the 4° advance by pin-offset in them, earlier ones had 2°.....

UDHarold

i can vouge for harolds last statement. all 3 of the ultradyne cams i installed had to be advanced 4 deg to get the desired 103/104 intake centerline. i degreed all 3 and each time i put them in straight up they were 108/109 intake cl . so 4 deg advance (on the triangle) has worked out between 103/104 all three times. (one time i talked to harold on the phone and he clearly stated his cams work best 102/104 intake c/line).
his cams are for the true hot rodder, and his approach is never the "cookie cutter" approach,but every ultradyne cam i have used has "kicked ass"on the street and at the track.
just talk to some crabby tech geeks at comp cams then talk to harold, you can really learn something from this guy. and he dosent try to hurry you off the phone. ray

Ok...now that we have this all sorted out....


Let's really have some fun and check the exhaust lobes too...

And then figure out what the "real" LSA is on YOUR cam.

Then...check each and every lobe and see what you have....

You can really find some strange stuff when you start checking them this close.

And if you use a "cam doctor" tool, you'll get really depressed!

I think it was summed up best above.....if it ran well where it was, then you ahd it where YOUR combo likes it.

I have a friend that does lots of dyno testing on his motor. He found 20+ HP by retarding his 112 LSA cam to 116 I/C. Pretty much just points to the need for a larger cam. A larger cam installed in the correct place would most likely make more overall power than one severely retarded. The general rule I've worked with is to start around 4-6* advanced. If it goes faster at "straight up", then it will be OK, but would probably still be a little faster with a slightly larger cam installed 4-6* advanced again. Same thing holds true if you go the other way...may need a smaller cam.

Unless you do lots of dyno testing and track running to back it up, it's usually best to stick with the proven stuff. Harold says his cams are designed to be installed in a particular spot. Why argue it....he designed it and HAS done the dyno testing to come up with it. On the other hand I have used cams from another mfg. with less aggressive lobes who says he always goes faster when he retards HIS cams. I don't doubt it...different stuff.


Erring to the advanced side of things seldom hurts performance overall.


JIM

Once again thanks to all. I just come in from degreeing my cam all over again. Left the crank gear at +4 where I had initially installed it and was coming up with 105 - 105 1/2 degrees icl. I was extremely careful on everything from setting the dial indicator to using a longer lever to turn the motor over make small movements easier. This time I came up with 59 degrees before full lift and 149 degrees after full lift. Added them both then divided by 2 as per procedure and Voila, 104 degrees ICL. I did it 4 times and came up with 104ICL every time.I feel much more confident now that I have this baby in there right. Am a happy camper today.

Thanks again and HAPPY NEW YEAR

Jerry

Jerry,

Congratulations!
It should run just fine. Let us all know how you like it....

Jim,
Exactly where each cam likes to run is according to how it was designed. Just because some cams are all 300° at .020 and 264° at .050 does not mean they will all run alike. Most of my most popular roller cams have at least 3 distinct LSA at .020, .050, and max lobe lift. The 2 most popular families, the 288/296R and the 310/314R, are 1.5° retarded at .050 from the nose LSA, and 3° retarded at .020,--- ie, 100° ATDC at the nose equals 101.5° ATDC at .050, and 103° ATDC at .020. All these numbers are correct, and this is the reason I tell customers to degree them in off the nose. It's easier to find, and is very accurate. The other numbers are then there automatically.
Symmetrical cams ALWAYS make more top-end power when retarded a few degrees, because the intake opens later, putting in less reversion (Heard this before?), and shuts later, allowing more cylinder filling(Heard this part,too?). I just always designed the retard at low-lift into the design.
Generally speaking, whosever cam you have, follow their general instructions on installing the cam. This is only put you into the ballpark for the ultimate power from that cam. Once you have achieved your best times, playing with the lash will determine whether or not to advance or retard the cam, and that can determine whether or not you need a larger or a smaller cam.
Good Luck, and Happy New Year!

UDHarold

Thanks Harold....that's what I was getting at.

When I really started trying to get deep into cam design stuff, I realized that everytime I learned one new thing, I discovered I had 10 more questions and found out what I didn't know! Watching "similar" lobes on a Cam Doctor or just using a degree wheel produces some pretty wild info from stuff that doesn't look too different on paper.

What was also amazing was that as I read old stuff from WAYYYY back when from old aircraft/military engine design books, some old writings from Isky and others, it was really interesting to see how concepts that were understood and being used 50-60 years ago, still pop up up in "new" stuff with new marketing. It's really almost comical to see. Just as you noted in another post how some of your designs are over 20 years old and still work better. The science of what the engine needs hasn't changed that much, just what folks understand about it. Some of you guys just had it figured out earlier!

Thanks for all your help here, and for sure next time I'm in your neck of the woods I'm buying lunch!


JIM

Well, things are definetly cleared up. Harold, I never really looked at the cam card, so i can't recall what was on it. When i put the cam in, I knew exactly where i wanted it so I just degreed it and put it where i wanted it. All i as was talking about in my original posts, was on your posts here. In the last year I had just always got the sense by reading your posts that your cams always run better 4-6 degrees advanced. Now I guess I just was a little ignorant about what you really meant. I am glad it is all cleared up and hope that this post helps others out to. There is some real good info from you guys here! Harold; do you know where the terminology came from for " straight up" does it refer to the "dots" or something to do with the actual lobe position relative to the crankshaft/piston?

Originally posted by 540Hotrod:
Ok...now that we have this all sorted out....


Let's really have some fun and check the exhaust lobes too...

And then figure out what the "real" LSA is on YOUR cam.

Then...check each and every lobe and see what you have....

You can really find some strange stuff when you start checking them this close.

And if you use a "cam doctor" tool, you'll get really depressed!

JIM Jim,
We use the "Cam Doctor" actually Audies "Cam Pro"
to check all the cams we get.
Actually called & "Bitched" at Harold once because his cam was so far off,,,,,crap man it missed the marks by like 1 degree or something :D :D ,,,,can't have that HEHE.
Anyway the depressing part of the stand measurments is when you put it in the block & degree # 1 intake & everything else is off you start realizing just how far off a block can be & how much it affects cam timing.
I have had customers tell me brand x cam is crap because none of the cylinders timed the same after they checked number one :confused:
They usually quiet down when I put the cam on the stand & show them the lobe timing. ;)

Thanks Pat and Harold for helping to clear up this "mystery". I
If I may borrow a reply from Harolds "Quick and Dirty" method.
Turn #1 cylinder to TDC or dot to dot (straight up). Give it another turn so that the cam dot is now in the 12 oclock position.
Measure the height of the intake retainer from the spring seat and write it down.
Now measure the the exhaust retainer from the spring seat and write it down.
The intake retainer should be .040-.060 CLOSER to the head.
If the exhaust retainer is closer the head, the cam is in wrong.
A common mistake is to line the 4 degree advance keyway up with the dot on the cam gear which retards the cam about 18 degrees and the exhaust retainer will be .150 or more closer to the head.
Just correct it and your in business.
Thanks to all the folks who have helped me through my current engine build.

Have a Happy new year.

Garry graemlins/beers.gif

Originally posted by Wolfplace:
</font><blockquote>quote:</font><hr />Originally posted by 540Hotrod:
Ok...now that we have this all sorted out....


Let's really have some fun and check the exhaust lobes too...

And then figure out what the "real" LSA is on YOUR cam.

Then...check each and every lobe and see what you have....

You can really find some strange stuff when you start checking them this close.

And if you use a "cam doctor" tool, you'll get really depressed!

JIM Jim,
We use the "Cam Doctor" actually Audies "Cam Pro"
to check all the cams we get.
Actually called & "Bitched" at Harold once because his cam was so far off,,,,,crap man it missed the marks by like 1 degree or something :D :D ,,,,can't have that HEHE.
Anyway the depressing part of the stand measurments is when you put it in the block & degree # 1 intake & everything else is off you start realizing just how far off a block can be & how much it affects cam timing.
I have had customers tell me brand x cam is crap because none of the cylinders timed the same after they checked number one :confused:
They usually quiet down when I put the cam on the stand & show them the lobe timing. ;) </font>[/QUOTE]Ya..Bill Jenkins wrote about this nearly 30 years ago in his book.When loaded against the valve springs and measured the rear cylinders were off several degrees from the front...From the 8620 steel core twisting.... led him to chase stuff like non relived cams and such...

Then what really happens when you fire up the engine and bring it up to 8000 RPM and side step the clutch ??!! Where is your cam timing then ?...
Somehow I wouldnt be a bit surprised if it really wasnt exactly where it was when it was degreed on the engine stand.... graemlins/clonk.gif

Yep..have a few lifter bores a little off, lifter mfg, tolerance and it all gets weird. Now for 95% of the stuff out there, it's not too big a deal as most folks combos aren't dialed in to that last 3-5 hp range.

It's pretty common to see a degree or so, nothing to get too excited about in real life. Unless you have a real big degree wheel, it gets pretty tough to see those 1/2 degree differences.

Of course is where all the 55mm cam cores are coming into play. Have you noticed the size of the LS1 core? Lots of meat to play with.

Supposedly there are teams that have cams with varying dimensions down the row to account for twist etc. Makes sense if you have a way to measure it under dynamic conditions.

What about all the old 427 Ford Cammer stories with the one bank about 8* off from the other so that when under running conditions it got in the right range due to chain stretch?

Harold, thanks for the info. That is valuable stuff, since you've already tried it. I figured it was way out there. Roller cams allow us to have the power we want and still be able to cruise around on the street. It just has a price!

Has anyone actually had any experience with the Shubeck stuff? Do you have to run his cams? I know the diesel truck industry is using ceramics on some of it's injector rollers and it seems to help. They will "polish" up a slightly rough looking lobe. Anyone working on ceramic rollers for our stuff? Could needles be eliminated and just stick a ceramic roller on an axle of some sort? Even a ceramic axle? Technolgy does amazing things these days!

JIM

For years I degreed in my cams using one head and the number one cylinder. 1st the intake and than the exhaust. I did this so I could speed clay for clearance and make charges fast. I got wised up a few years ago and started doing the degree with all tappets in play with real springs. You would not believe the difference, :D no matter belt or chain Try it some time... graemlins/waving.gif

A couple years ago I was at the SEMA show when Glen Howard of Crane called me over to show me thier new composite bearing shaft rockers.... He handed it to me and I'll be honest there was ...well there wasnt any friction...grab a roller rocker and hold the trunion and move the rocker and you feel it....these pretty much didnt.... Very free feeling....I asked Glen if you were going to go further with this and use it for roller Tappets..... He simply winked and said " No Comment ".

When I was at PRI this year, I told Mike Allen of Crane, the person I bought my cores from for 15 years or so, the exact same thing. "When are you going to put these in roller lifters and eliminate all those needles?" The only comment, "we're working on it....".

About the Schubeck(SP?) 'Roller' lifters....
The cam masters have to be cut for the larger apparent diameter of his 'wheel'.
When a roller cam model or master is being made, the radius of the base circle and the radius of the roller bearing are CONSTANTS, with the lift curve being added. What we cut out is the path of the AXLE, or center, of the roller bearing as it moves around the cam lobe. Schubecks use a 1.000" radius, most roller lifters have a .375" radius, and some a .405". If you used a Schubeck 'roller' lifter on a normal cam, you would find a completely different cam, with only the lift being the same. Any cam company can take an existing cam profile and convert it to the larger radius wheel---The question is how much do you want to pay?

UDHarold

Does Schubeck make their round nosed solid lifters so they are really rollers held in place by the lifter sides without the axles and just use oil pressure to lube the top half of the roller much like half a main bearing??

I.e., dynamic oiling sort of thing on the top half...

pdq67

pdq, take a look at Schubeck's site (http://www.schubeckracing.com/index2.html).