Degreed My Cam

[psu_Crash]

So i finally got around to degreeing my cam and it wasn't too bad at all. Did it using the centerline method. Degreed it to 112 center as it showed on the cam card from Schneider.

 

Ok so I also just installed the crank pulley with trigger wheel from 101propose.

My only real concern is that when I found TDC using a positive stop (caliper pin) the actual TDC shows about 4 degrees BTDC from where the timing mark on the pulley lines up with the engine timing marks. Is this normal?? I thought it should be pretty much dead on with that mark. I double checked and that is where my TDC is. Guess i should make a new mark on the pulley??

 

Also my centerline was 25 degrees advanced, on the crank, before I touched anything. That could be from installing the cam gear from Pagemo too. After all it is adjustable.

 

Just looking for a little insight.

 

EDIT: Look what I found Starquest Cam Degreeing

Edited November 21, 2008 by psu_Crash

[Edde]

25 is really far off seems to me but I'm no expert that's for sure.

 

As far as TDC goes that is why you go through this in the first place, to find true TDC. Mine was within a half degree. Don't know what others have found at all.

 

I take it you used the resulting TDC as your zero point right?

[psu_Crash]

yep i set zero on the degree wheel to the actual TDC I found. I think a big part of the 25 degrees was simply from the adjustable cam gear just being put on and not set up at all

[pagemo]

So i finally got around to degreeing my cam and it wasn't too bad at all. Did it using the centerline method. Degreed it to 112 center as it showed on the cam card from Schneider.

 

Ok so I also just installed the crank pulley with trigger wheel from 101propose.

My only real concern is that when I found TDC using a positive stop (caliper pin) the actual TDC shows about 4 degrees BTDC from where the timing mark on the pulley lines up with the engine timing marks. Is this normal?? I thought it should be pretty much dead on with that mark. I double checked and that is where my TDC is. Guess i should make a new mark on the pulley??

 

Also my centerline was 25 degrees advanced, on the crank, before I touched anything. That could be from installing the cam gear from Pagemo too. After all it is adjustable.

 

Just looking for a little insight.

 

If you found TDC by using a positive stop and divided the remaining degrees to get 4 deg BTC then yes make a new mark on the crank gear. The installation of the cam gear will in no way affect TDC on the crank. if you measured TDC and the cam gear is off 4 degrees that is a different story, the cam gears are set up at factory 0 (12 oclock on the dowel pin) so if you have a shaved head or depending on chain stretch you could see 3 or 4 degrees difference in the 0 postion on the cam gear. When degreeing the cam note the cam gear spec when set as the new 0 and make adjustments for the power band from there.

Pagemo/Scott

[Shelby]

didn't this adj cam gear have a "0" index mark ?

you can also correct for being one crank tooth off in chain timeing

 

19+4 would make 23 degrees, also i have never found the oem tdc mark to be off by more then 1-2 degrees

Edited November 12, 2008 by Shelby

[Edde]

Yeah we both have pagemo's gear - it has a long 0 line mark - works great. Mine was never out more than 5 either way but late not early. That seems an odd combination of results.

 

Do your test again - it can take quite a bit of time. Your piston stop must not move in any way and should be softer metal than your piston. I blew up a spark plug and solder fitted a bolt thru it because the one I was using before was able to move a bit.

Edited November 12, 2008 by Edde

[Indiana]

TDC isn't where the pin causes the motor to stop turning, not all pins are created equal and none end up causing the crank to be exactly at TDC. You may have just left out the part where you held the tension on the timing chain and ran the motor over counter clockwise and got that number on your degree wheel then took the center of those two points and that's TDC. So is that what you did? If you didn't you have to start all over, finding exact TDC is the basis for everything after...

[psu_Crash]

I made sure to go past the marks and come back clockwise to get the tension on the chain correct. I also tuned it back and forth hitting the positive stop in both directions several times to make sure I was getting the same numbers each time. As I was doing it I was confused that the timing mark was so far from TDC on the timing cover. Going to have to go back and do it again today. The degree wheel is still on there and the radiator is still off so not a big deal.

 

Another thing is that I was only able to go +/- .025 on the valve movement because that is the range of my dial indicator.

 

It is very possible that I jumped a tooth on the crank gear too. The chain was allowed to have a lot of slack in it while pulling the head off for the new gasket. I remember reading in the FAQ a while back about how to correct this. I think I will start there. Either way I think I made a mistake somewhere. The numbers seem too far off to be right.

 

Thanks for the replies! I will update later on

Edited November 12, 2008 by psu_Crash

[Shelby]

you locate absolute TDC with the piston stop not a dial indicator,,

the best range to stop the piston at is aprox 25 btdc

set you degree wheel as close to where tdc is normaly,, turn the crank in normal direction untill the piston contacts the piston stop,, you pointer you made should be some where arround 25 btdc, ,take note of the number the pointer is indicateing,, now turn the engine counter closk wise untill it stops ,, record the number,for example lets say the pointer was at 20btdc turning clock wise,, and 30atdc turning counter clockwise,,take the diff and devide by2,,move the pointer that distance in this case to 25btdc, do this a couple of times untill you read the same numer more the none time,,

once the degree wheel is stoping at the exact same number clock wise and counter clock wise,, TDC is the point exactly in the middle of these two numbers,, move the crank/wheel to tdc made sure from this point on you DO NOT move the pointer , bumping or moveing the pointer after that will require you to redo the entire check

 

the length of you piston stop will depend on what pistons you are useing, stock pistons if i recall it right needs aprox a stop 65-67 mm long to reach 25 btdc , the actual point isn't absolutely cridical but the piston changes speed depending on where it's at and 25 or more btdc makes it easier to find tdc with ,,the closer to tdc you get the harder it is to be precise

[psu_Crash]

I used a caliper pin for the positive stop. Went through everything again tonight and i did find one mistake. Apparently basic algebra wasn't my strong note on the first try

When I find TDC it now lines up almost perfect with timing marks on the crank pulley and timing cover.

Duration also checks out perfect for the cam.

 

I went through the whole procedure a few times just to make sure I have the numbers right. But, I am still way off on centerline.

Currently measuring 152 centerline by measuring the degrees +/- .020 intake lobe max lift. With the cam gear locked on zero. Yes I did get the slack out of the chain when measuring this. I know the closing ramp of the cam grind is much steeper than the opening so that is why I only went .020 thinking it would be more accurate.

My cam card says it should be 112 and I think stock is 107

 

That is a long ways off. Sounds to me like I must have jumped a tooth (or two??) while installing the new gear.

With the crank at TDC my cam dowel is also at about 2 O'clock instead of 12.

Will jumping retarding it back one tooth following Shelby's FAQ be enough??

[Edde]

I used a caliper pin for the positive stop. Went through everything again tonight and i did find one mistake. Apparently basic algebra wasn't my strong note on the first try

When I find TDC it now lines up almost perfect with timing marks on the crank pulley and timing cover.

Duration also checks out perfect for the cam.

 

I went through the whole procedure a few times just to make sure I have the numbers right. But, I am still way off on centerline.

Currently measuring 152 centerline by measuring the degrees +/- .020 intake lobe max lift. With the cam gear locked on zero. Yes I did get the slack out of the chain when measuring this. I know the closing ramp of the cam grind is much steeper than the opening so that is why I only went .020 thinking it would be more accurate.

My cam card says it should be 112 and I think stock is 107

 

That is a long ways off. Sounds to me like I must have jumped a tooth (or two??) while installing the new gear.

With the crank at TDC my cam dowel is also at about 2 O'clock instead of 12.

Will jumping retarding it back one tooth following Shelby's FAQ be enough??

 

Ahh you nailed it. Your cam pin cannot be PAST 12 oclock period. Should be slightly before in almost any case I know of. Do shelby's thing - I've done it. You'll see if one is enough.

[Shelby]

if your useing a stock cam and your open and close points are right on, then you can go by the oem canter line numbers, or if you have an after market cam and the open and close points are right on the center line info on the cam card will be acurate,,

 

as for finding the center line, i have always been told to use .100" lift befor and after max valve lift thats .100" befor max lift point and .100" on the down side ramp , locate the place on the degree wheel each are at ,count the total number between the two marks then devide by 2 to get the center line numbers (example lift point is at 80 and closeing number is 140, the degrees between the two points are 60 devide by 2 = 30, add 30 to the open number and subtract 30 from the closeing and you have 110 center line )

but if your numbers are on, so is the state'd center line , you advance and retard the entire cam not just the center line

oem cam specs are @.001" lift not .020" or .050"

[psu_Crash]

I was told to use .100" before and after too. The only reason I didn't is because my dial indicator only has .025" travel. I will see about "borrowing" one from work with more travel.

 

The only reason I have been going with centerline instead of the open and close degrees on the cam card are because I was having one heck of a time getting zero lash from the hydraulic liters. I think I see what I need to do, so I hope to give it a shot later today but more likely tomorrow.

 

One last question. I know you are supposed to put the dial indicator on the valve and not the rocker, but why not?

Valve lash should be the same on opening and closing right? So why can't I put the indicator right on the rocker over the valve when finding centerline and eliminate and errors coming from the hyd lifters squishing a little differently each time?

[Edde]

If you have hydraulic tappets you use the valve retainer because of the slop bewteen this and the rocker. Zero lash is required to do this - I had difficulties maintaining zero lash myself.

 

First you need to time the cam and crank. 2PM is no good.

[psu_Crash]

My first order of business will be to get the cam and crank in time.

So finding centerline from the rocker is a bad idea?? I am thinking it might be easier.

[Shelby]

this will do you just fine for degreeing your cam

 

http://www.harborfreight.com/cpi/ctaf/disp...?Itemnumber=623

 

heres how i set up my meter and stand

 

http://www.26liter.us/gallery/albums/userpics/10009/Jan08%5E04a.jpg

 

 

to use hyd lifter you have to colapse the lifter and incert some thing under the lifter between it and the valve stem to take up the lash,, a feller gauge will work , place rocker on the cam base circle and add gauge arms untill you have "0" lash in the rocker ,, now it can not change ,, + or - .001" will not have a super amount of change in your findings , meaning if the intake valve starts to open @ 25 btdc and you indicator says it's at 24 or 26 btdc,, it's close enought to not need changeing,, you'l never notice 1 degree in timeing one way or the other ,, but the diff should work out all the way, meaning if you start to open point is 1 degree early/late it should close 1 degree early/late also

 

a reading of 1-3 degrees early with all new chain assy parts is ideal because it will slowly wear in to the correct point , being right on will slowly become later as the chains and gears wear on a street driven engine where you do not want to be messing with it over and over

[Shelby]

you also want the dial indicator to be in line with the valve stem,,and to enable a flat surface to set on, i use'd a fender shim that i magnitize'd so it would hold steady to the retainer

[psu_Crash]

Thanks Shelby! You helped clear up a lot of little questions I had.

 

I shouldn't have a problem getting a different dial indicator from one of the machinists at work. I will grab a bunch of feeler gauges too.

Looks like tomorrow morning will be when I get back at it.

I am confident I will be able to get it right now. Again Your help is VERY much appreciated!

[Shelby]

your welcome i got the dial indicator and the magnetic base mount for less then $20 for both at harbor freight , the mounting plate is a piece of scrap i use'd modify'd a little and drill'd a mounting hole to hold it solid

[psu_Crash]

Here is a pic of my cam card. I set centerline of max intake valve opening on cyclinder 1 at 112 before TDC. Used +/- .050 from max lift as I believe that is what the card is telling me to do. Had to jump 2 cam teeth to get it there. Actually ended up at 110 BTDC. I figure this is fine and allows for the new gear and chain to stretch a little and still be good.

Cam dowel ended up about 10:30. Seems a little early but I checked and rechecked the degrees.

http://img369.imageshack.us/img369/4687/edisandcamcard002pt2.jpg

[Shelby]

some thing is way off here,, no matter if your degreeing the cam or not the cam pin will always be just befor 12:00,,11:50 -11:58, if your at 10:30 some thing is way off your way early on the cam

 

not sure what adj cam gear you have but if it's like Shawn's slot'd gear always start from the "0" seting and set cam to 12:00, then go about checking it's actual timeing , you will not be moveing the cam gear more then an1/8 inch or so no matter how bad the timeing is off , one tooth is 19 degrees crank distance , do not use the adj cam gear to correct for the cam being out of time 1 tooth

 

also any check'd number be it valve opening or closeing or center line,,all numbers must agree , and have the same correction number . due to the ramp being a little diff opening and closeing, i normaly don't bother with checking center line if the cam card gives me the reading, once i have the valve open and valve closeing point exactly known i can figure the center line by those numbers , say if the open and closeing time is off by 2 degrees so is the center line , haveing to find center line is normal for a cam with no card , i know thats the lazy way but the cam can not change any physical dementions so all points must be the same as the were ground

[Edde]

I'm glad you said cause I wanted to - I suppose one could mistake the clock position but it's unlikely you would be off 2 teeth in the first place.

 

My assumption is that centerline whether based on .50 or.75 or whatever is no substitute for opening degree. To me it means disregarding the zero lash requirement and expecting accurate readings. I don't know but it doesn't seem to me that this works in any way without zeroing lash.

 

As I found out (or think I did) unless you can keep oil from being fed into the tappet even in small amounts you cannot maintain zero lash on a hyd setup. I could be wrong I know shelby's done it. I may have spun the engine too fast after numerous tries and getting impatient.

 

But for sure to know you have zero lash you must be able to obtain opening and closing degrees and those MUST add up to your duration for the cam.

[psu_Crash]

Ok .. so I got the dowel pin to line up at 12 O'clock when I am at TDC on the compression stoke. Timing marks on the pulley and cover also line up perfect. Some where I am looking at this all wrong. The cam card is decieving I think. I think the cam card is looking at the cam gear from the windshield side of the engine. That would make a TON more sense as i understand it. It has been VERY difficult to get zero lash and I still don't have it. I have had the head off and I am sure there is no oil left in the lifters so they squish almost to the rocker and I ran out of feeler gauges. These readings are from the rocker movement.

So here is what I have at the moment.

Thanks for bearing with me guys. Not sure what I am missing but I am very confused ...

http://img88.imageshack.us/img88/160/degreewheelmeasurementscd1.jpg

Edited November 15, 2008 by psu_Crash

[Shelby]

not sure if any of this is acurate but going by you valve start to open reading of 53 btdc,,the valve closeing number would be 129 ABDC

to get this you add the opening number 53 btdc to 180 bdc subtract that from 284 and you get 51 , 51 degrees from BDC gives you 129 degrees , for a total duration of 284

 

this is my old 284 cam card specs are the same as yours,, to view the card and understand what your seeing you need to visualize it like you were looking at it from behind,, whom ever made up this cards was not thinking as they made them back wards from what you'd be looking at , if you want take the pic and reverse it and make a copy then add you numbers at their respective points so you can look at what your actualy seeinng , but your open and close numbers will be exactly what the card says for both "0" lift and @.050 lift,, you will have to have 0 lash to obtain eather number in it's proper place,, allthe shims under the hyd lifter does not have to be feeler gauges, you can use a 1/4 piece of metal inplace of all those feeler gauge fingers, use 1/4 metal plate then finesh up with what gauges you need to obtain 0 lash

 

http://www.26liter.us/gallery/albums/userpics/10009/284H_cam_card.jpg

[Shelby]

this is a F or solid lifter cam card

http://www.26liter.us/gallery/albums/userpics/10009/284_solid_cam_card.jpg