Cam degreeing question on my first motor rebuild

[paul25g]

Hi guys,

As the title says, this is my first motor rebuild. It is a 1966 200 CID from a Mustang 3 speed manual. I'm trying to keep things as stock as possible. Cylinders were bored .30 over and I've got an Autolite 1100 carb. Like I said, I'm not wanting to soup this thing up, just a standard rebuild to keep it as close to stock as possible for a weekend driver.

Things have been going really good so far, and now I'm to the point of degreeing the camshaft.

I ordered an engine rebuild kit from Glazier-Nolan which included a new camshaft. The provider of the kit is actually EngineTech. EngineTech doesn't make their own cams, but actually supplies cams made by Clevite, Elgin, Federal Mogul and Melling. The EngineTech website lists the part numbers for each of these companies camshafts.

There was no cam card included with the cam, so I found the cam specs for each companies version of the cam and compared them to what I was getting from my calculations of the centerline method.

The only numbers that were even in the ballpark were for the Clevite camshaft, which calls for an intake lobe center of 111*. After degreeing the cam several times using the centerline method, I'm coming up with 114* centerline. My question is this, is 3* difference enough to worry about for the type of rebuild I'm doing, and if so, what are my options?

I should mention that the rebuild kit also came with a new timing set with only one keyway on the crank gear.

Hope I've provided enough info and bear with a newbie to this process!

Thanks!

Paul

 

[CNC-Dude]

Well since you have no way to alter the cam timing with your current timing set, you could possibly use an offset keyway. Yes 3°can make a big difference, especially since its in the wrong direction(retarded) at 114° instead of 111°.

 

[paul25g]

Thanks for the response!

Is what you're saying that I should take my crank gear into the machine shop and have them cut an additional keyway in the gear to try to hit the 111* centerline? And would I tell them to cut the keyway 3* advanced from the stock keyway? Would the new keyway be clockwise or counterclockwise from the stock keyway?

I've also seen on the internet some Mr. Gasket offset factory gear drive keys for Ford inline 6 cylinders.....987G is supposed to be 2* offset and 988G is supposed to be 4* offset.

Sorry if this is a dumb question.....lots to learn!

Thanks!

 

[170-3tree]

You will want that Mr gasket setup. Most likely the 4* version since Advanced will perform better than retarded. I don't think the machine shop would have the proper tools to make that exact of a cut.

 

[CNC-Dude]

Paul you will be fine just using the Mr. Gasket offset keys. Because of machining tolerances, a 4° keyway may only give you 3°of advance, or it could give you slightly more. It really isn't something that is exact, but you are doing the right thing by at least checking to see where you are at to begin with on the cam timing. Every little bit you can do to improve or tweak the combo will payoff.

 

[170-3tree]

He is exactly right. I wish I had done that with my stock rebuild, because I was in your position when I decided to degree my cam upon tearing it down to make modifications. And who knows hoe much of the fun to drive factor that sacrificed for that first year or more of driving.

 

[paul25g]

Thanks for all your help guys, I'll get one of the 4* offset keys ordered.

So hopefully this will get me from the 114* measured centerline to at least the 111* called for centerline if not even a little advanced of that correct? How far off of the 111* centerline is considered too much.....understanding advanced is better than retarded? Thanks!

 

[MPGmustang]

what I would do is check the center line from the intake, then check the centerline from exhaust, IDK if you did this as I couldn't pick it up... average the 2 numbers, that's your lobe separation. you want your intake to sit at that number and that would be 0*. less and it's advanced, more it's retarded.

post your numbers here so it's easier we can confirm what you find.

find intake open @ .050 lift
find intake close @ .050 lift
(IO + IC) = duration @ .050 then /2 = intake lobe CL

do the same for the exhaust

then take 'intake lobe CL + Exhaust Lobe CL' and divide by 2 and that's your lobe separation. you want the intake to sit at the same number.

I hope I made sense... it sounds like you got a great start and maybe u do know what your doing but maybe someone will stumble accross this thread and want to know what we are talking about.

another simple way would be to get Classic Inlines double roller timing chain set, it has increments of 2* on the keyway itself.

 

[paul25g]

MPG,

I did the centerline for intake only. Now a question about finding open/close @ .050 lift.....would the result I'm looking for be something like the following?

Intake open 24.5* ATC @ .050
Intake close 24* ABC @ .050

Exhaust open XX.X* BBC @ .050
Exhaust close XX.X* BTC @ .050

Not sure if I should record these measurements as degrees ATC, ABC, BBC, BTC or just stick with X degrees clockwise or counter clockwise.

I understand how to get the intake/exhause open @ .050 readings, but as far as intake/exhaust close, do I continue to turn the engine clockwise until the degree wheel returns to zero and then back it up to .050 lift and read the degree wheel?

Thanks again!

 

[MPGmustang]

First watch this video...
http://www.youtube.com/watch?v=zj-GA494 ... re=related

always 'try' to rotate the engine as if it is running,

What I eneded up doing, is going around until is close down to 0 lift again, then reversed up to roughly .100-.130, then went forward again till I reached .050 lift. what this does is take away any chain slack that there might be.

when your looking at the engine from the front, it rotates clockwise when running, so stay that direction if at all possible.

My camshaft degree forum...
viewtopic.php?f=1&t=66005#p505552

 

[MPGmustang]

actually that video is .050 BEFORE max lift, it won't tell u duration.

what you need is .050 after .000 lift, rotating the engine while there is not lift on the intake, when it starts lifting stop @ .050 that's your IVO @ .050 (don't worry about ABC or TDC jsut get the right degree numbers ) then continue on even after maximum lift until it come to .050 lit right before .000 lift on the dial indicator. that is your IVC @ .050. take the 2 numbers together and that's your intake duration @ .050. divide by 2 and thats where your camshaft sits (refrence on wether or not the cam is advanced or retarded)

do the same for the exhaust, then add it to the intake, and divide that by 2 and that's your LOBE SEPARATION.

so if your intake number sits @ 114 and your LOBE SEPARATION number come out to 114 then you're spot on target.

Please ask more questions if your not sure or I didn't clearify it enough. I can rush my explanations (even though they make perfect sense to me lol)

 

[paul25g]

Thanks MPG....didn't get your message till this morning but think I did it correctly.

Assuming this is a Clevite cam (#229-1640), here's the specs that are called for:
.348" lift, 27 degrees of overlap, 178 degrees duration @ .050, int open at 22ATC, INT CLOSE AT 20ABC, EX OPEN AT 11 BBC, CLOSE AT 13BTC. 111 DEGREE LOBE CENTER INT, 102 EXHAUST

Here's what I got measuring last night (all taken on #1 cylinder):

Intake CL = 70.5* + 158.5*= 229/2=114.5
Exhaust CL = 141.5* + 54*=195.5/2=97.75

Intake open @ .050= 24.5 ATC (335.5 CW or 24.5 CCW)
Intake close @ .050= 25 ABC (155 CW or 205 CCW)

Exhaust open @ .050= 7 BBC (187 CW or 173 CCW)
Exhaust close @ .050= 9 BTC (9 CW or 351 CCW)

Hope this makes sense......I wrote down everything (ATC, CW, CCW, etc.) because again, I wasn't sure exactly what you needed to come up with the correct calculations.

So based on all this, what do I need to do? Thanks again for all the help!

Paul

 

[MPGmustang]

watch the video, notice he doesn't worry if it's ATC or BDC or CCW or CW... ur numbers are giving me a head ache try'n to dicipher them.. lol, I'll get back to you after I fumble with the numbers

you need the numbers from TDC all of them, no BDC or ATDC or ABDC, you need them from Top Dead Center related only to the piston position.

then find how many degree's the intake cam lifts .050 inches on the dial indicator when valve is opening. then read the number the degree wheel gives you.
then find how many degree's the intake cam lifts .050 inches on the dial indicator when valve is closing. then read the number the degree wheel gives you.

do the same for the exhaust.

don't 'try' to compare your cam with other cam cards, with the info you give us, we can tell u exactly what your cam is. if it's advanced or retarded... with the 4 numbers. IVO IVC EVO EVC all in relative degree's from where the piston is away from TDC.

the problem with going ADC and TDC and ABDC and ATDC is the fact that they are all different, At Bottom Dead Center is 180* away from TDC so one is 9* @ TDC and other is 7* After Top dead center, it's just more simple for you and everyone to understand when going form Top Dead Center, then there's the before and after fact, some people think this easily but I don't and have to think hard about it... I'm no math major and this confuses me cause it's against the way I think lol.

 

[MPGmustang]

I'm just having a hrad time, it says your cam is 106* lobe separation, and your intake is sitting at 114, you need to advace your cam probably 1 tooth. it's very retarded from what I get.

how about this,
http://www.wallaceracing.com/camcalc.php

plug them numbers in here... it will help you more than ur numbers make sence to me lol

 

[paul25g]

Using that wallaceracing link, it says:

Your cam has an Overlap of -33.50 degrees and has in Intake Duration of 180.50 degrees.
The Exhaust Duration is 178.00 degrees.
The Inlet Cam has an Installed Centerline of 114.75 degrees ATDC.
The exhaust cam has an Installed Centerline of 98.00 degrees BTDC.

I think the degrees you're looking for would be as follows:

Intake CL = 70.5* + 158.5*= 229/2=114.5
Exhaust CL = 141.5* + 54*=195.5/2=97.75

Intake open @ .050= 24.5
Intake close @ .050= 205

Exhaust open @ .050= 173
Exhaust close @ .050= 351

Does this look better?

 

[bubba22349]

Here is another video on install timing chain and Degreeing cam in a 200 six. Maybe it will be helpful.

http://www.youtube.com/watch?v=zj-GA494 ... re=related

 

[MPGmustang]

Your cam has an Overlap of -33.50

that's a problem, u can't have -33* of overlap... thats NO overlap... something is not right here...

 

[paul25g]

Ok,

I've tried to draw some of this out on a degree wheel so I can see what I'm talking about.

Intake open @ .050 occurs at 24.5*
Intake closes @ .050 occurs at 205*
This means that the intake duration is 180.5*

Exhaust open @ .050 occurs at 173*
Exhaust closes @ .050 occurs at 351*
This means that the exhaust duration is 178*

If I'm correct, overlap is the number of degrees where both the intake and exhaust valves are open.
Looking at this on a degree wheel, the span from exhaust opening @ .050 to intake closing @ .050 is 32*.
(From 173* Exhaust open @ .050 to 205* Intake close @ .050)



Aside from calculating using the duration at .050 method, here's what I came up with using the centerline method:

Intake centerline measured :70.5 + 158.5 = 229/2=114.5

Exhaust centerline measured :141.5 + 54 = 195.5/2=97.75

Lobe separation would be 114.5 + 97.75 = 212.25/2=106.125

Intake centerline of 114.5 - Lobe separation of 106.125 means that it is retarded by 8.375*.

Does this make sense using the centerline method?

 

[bubba22349]

Sure maybe 8 degrees retarded are you using an early timing chain set or late model?

 

[MPGmustang]

if you jump one tooth forward, you should be able to bring it advance... which helps more than being retarded in cam timing