First time engine build - Degreeing a cam

[DWinTX]

I have done about just about anything you can do mechanically with a car except rebuild an engine. So I am doing my first one. I am building a 318 poly using a 349 stroker kit. Already gone though some interesting stuff getting the parts machined to work together. Probably should've started with something simpler, but I've never been one to make things easy on myself. :icon_biggrin:

Anyway, I have the short block mostly together and it's time to degree the cam. I read several things on the web and viewed some videos, and I gave it a shot. I tried two methods, the intake centerline method and duration at .050 method. My results seem to be good, but I would appreciate it if some of you experienced engine builders could check it out and tell me if I've done it correctly.

I made three videos, one to establish absolute TDC, one showing degreeing with the IC method, and one showing degreeing with the duration @ .050 method. Could you look at them and tell me if I performed these operations correctly?

Verifying TDC:
https://youtu.be/XoLn6c88eys

Degreeing with IC method:
https://youtu.be/N6es301G_AU

Degreeing with duration @ .050 method:
https://youtu.be/pcCkCSsKiRg

I'm using a Mancini timing set that has multiple crank keyways for +8, +6, +4, +2, 0, -2, -4, -6 and -8 settings. I ended up having to use the -6 setting to get the measurements you see in the videos. That's partly why I'd like to have someone who knows what they are doing tell me if I'm measuring this correctly. I would've thought that having to make this kind of adjustment was uncommon, but maybe it's not.

A couple of things I'm wondering about. The cam card calls for the intake to open at 3 deg. BTDC. I got it to 4 with the -6 keyway. But the intake closing at .050 is 42 deg., rather than the 39 the card call for. If I'm advanced one degree on the opening (4 BTDC vs. 3 BTDC), why am I not advanced one degree on the closing (38 ABDC vs. 42 ABDC)?

The other thing is my lobe lift at .290. The cam card calls for .300. Is it normal for the grind to be off that far? Some of these measurements could be because I'm not using the most sophisticated equipment, but the lift is a pretty easy measurement. Unless the dial indicator is off, I don't see how I could be doing that wrong.
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[lewtot184]

show a pic of the cam card.

 

[DWinTX]

I don't have it with me at the moment. I can post it tomorrow, but if you pause the last video at 2:10, you'll see it.

 

[texas69bee]

First off, I am fairly new at this and just recently finished my first engine build. There are guys on this site like Lewtot and Cranky who are always willing to give some good advice and helped me out a lot. The only question I have is, Are you sure you are interpreting the settings on the timing chain correctly? I bought mine from Hughes and here is a link on how to set there's for the 9 keys.http://www.hughesengines.com/Index/...W50&searchmode=partnumber&page=2&partid=11207

 

[DWinTX]

Mine is a Mancini, but it is very much like the one in your link. And the instructions on the Hughes set are the same as the one I have. So it's definitely set at 6 degrees retarded.

 

[lewtot184]

just use the centerline method and install at 108. if it comes out 107 or 109 i wouldn't get my panties in a knot with that small cam. something i don't do is use a positive stop to find TDC with engine on a stand. i use an indicator and put feeler gauges between the piston and cylinder wall (feelers bottomed against the top ring) to make the sure the piston is square in the bore and true TDC is found. the engine always has to be rotated in the same direction the crank will run, no back-up checks. a cam "degreeing" in perfect is usually not the norm. small variances will occur due to the location of the tappet on the lobe. the lobe has a taper and the bottom of the tappet is slightly convex. if the tappet rides a few thousandths higher on the taper it will show a slight increase in duration and if lower a slight decrease. part of the production tolerances in tappet bore location. the decrease in lift could be base circle machining issues or maybe something else,....? i think your on the right track.

 

[DWinTX]

OK, thanks. I'll use the dial indicator for TDC to verify. Since it's my first build I wanted to make sure I wasn't doing anything stupid.

 

[lewtot184]

OK, thanks. I'll use the dial indicator for TDC to verify. Since it's my first build I wanted to make sure I wasn't doing anything stupid.

your doing fine. is that a solid lifter cam? is it a regrind of an original camshaft and who ground it?

 

[DWinTX]

Yes, it is a solid. Not a regrind that I know of. It's a Schneider cam:

http://schneidercams.com/264Fpolysolid.aspx

It shows regrinds are only available now, but I bought it a couple of years ago. I got it from Gary Pavlovich, who does a lot of poly stroker motors.

 

[Cranky]

Yup, looks lke you're on the right track imo. I do check the cam card specs once I have the center line nailed just to see if it's as advertised or at least close. On checking true TDC, I'll start out using a stop then check using an indicator. My stop is home made and much thicker than the one you're using. Out of curiosity, put a dial indicator on the stop to see if there's any deflection in it. A tip here....I'll stick the cam in when I have just #1 piston in the block. Much easier to turn one piston than all 8 when you are going through the motions of checking and making changes and usually without rings on it. Makes it easier to see how much rock it has too and you can usually place your indicator in the spot that's best for repeatability as I find using feelers to be a pita. Next, I install #8 piston and check the cam on that cylinder. If the cam shows retarded settings, I send it back especially if the engine has a rear distributor. That may sound dumb or **** but that's me but how much does a cam deflect or twist once it's loaded up and running......? One more thing. How stout is your indicator stand? Try to use the biggest and shortest rods you can find to keep deflection to a minimum. A mag base with an indicator mount is about as stout as you can get. It's more of a pita but it's the most accurate way. I also like to use transmission fluid for lube vs 30wt oil or assembly lube. Good luck but when you degree one in, luck isn't in the equation anymore

 

[lewtot184]

Yes, it is a solid. Not a regrind that I know of. It's a Schneider cam:

http://schneidercams.com/264Fpolysolid.aspx

It shows regrinds are only available now, but I bought it a couple of years ago. I got it from Gary Pavlovich, who does a lot of poly stroker motors.

the few extra degrees your seeing on the closing side may be the ramp. that's probably an older profile and may have a longer closing ramp than the opening ramp. i'll bet it's a reground core but that's not a problem in itself. the base circle would have to be reduced a little and that may effect the lower lift readings,....? mopar quit making the engine in '66 so i wouldn't doubt that new cores have dried up years ago.

 

[DWinTX]

Yup, looks lke you're on the right track imo. I do check the cam card specs once I have the center line nailed just to see if it's as advertised or at least close. On checking true TDC, I'll start out using a stop then check using an indicator. My stop is home made and much thicker than the one you're using. Out of curiosity, put a dial indicator on the stop to see if there's any deflection in it. A tip here....I'll stick the cam in when I have just #1 piston in the block. Much easier to turn one piston than all 8 when you are going through the motions of checking and making changes and usually without rings on it. Makes it easier to see how much rock it has too and you can usually place your indicator in the spot that's best for repeatability as I find using feelers to be a pita. Next, I install #8 piston and check the cam on that cylinder. If the cam shows retarded settings, I send it back especially if the engine has a rear distributor. That may sound dumb or **** but that's me but how much does a cam deflect or twist once it's loaded up and running......? One more thing. How stout is your indicator stand? Try to use the biggest and shortest rods you can find to keep deflection to a minimum. A mag base with an indicator mount is about as stout as you can get. It's more of a pita but it's the most accurate way. I also like to use transmission fluid for lube vs 30wt oil or assembly lube. Good luck but when you degree one in, luck isn't in the equation anymore

My stand is a magnetic base. Once I get it locked down, it's pretty solid. I'll check # 8 too and see what I find. Thanks.

- - - Updated - - -

the few extra degrees your seeing on the closing side may be the ramp. that's probably an older profile and may have a longer closing ramp than the opening ramp. i'll bet it's a reground core but that's not a problem in itself. the base circle would have to be reduced a little and that may effect the lower lift readings,....? mopar quit making the engine in '66 so i wouldn't doubt that new cores have dried up years ago.

It's possible that it's reground I guess. I got it through Gary, not directly from Schneider, so maybe they were only doing regrinds back then too and I just didn't realize it.