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360 roller cam - safe to retard a few degrees?
#2639734
04/01/19 03:42 PM
04/01/19 03:42 PM
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Joined: Feb 2003
Posts: 7,982
Scranton, PA
Montclaire
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Hello, I have a stock 1989 LA 360 roller motor. Compression is listed as 8:1, HP is 190@4000, torque is 285@1600. Cam is pn P5249663- hyd roller with 250/264 duration, .385/.401 lift, and 108 CL. Heads are stock 308s. I've read some complaints that these motors could be prone to over scavenging, resulting in cherry-red manifolds. I'm planning to run a cooler plug, would I also be safe retarding the cam a few degrees? Application is a 1973 Charger with a 727 and CR20 converter (roughly 2400-2600 stall behind a 360). Haven't settled on rear gears yet, maybe 3.55s for the 8.25 axle. This is strictly a street build.
Thanks
Last edited by Montclaire; 04/01/19 03:48 PM.
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Re: 360 roller cam - safe to retard a few degrees?
[Re: MR_P_BODY]
#2639849
04/01/19 07:59 PM
04/01/19 07:59 PM
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Joined: Feb 2003
Posts: 7,982
Scranton, PA
Montclaire
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It's a Jasper rebuild out of a B250 van. The seller said it had about 1500 miles on the clock when pulled and the internals were spotless so I believe him. I am guessing Jasper installed the cam straight up for one, and a 73 B-body isn't your mother's Dart. Secondly I thought that retarding it a couple degrees would help minimize any detonation from scavenging and extend my top end on what is really probably a grind for towing.
I don't have the motor in the car but from what I have been reading they top out way before 5k. Torque is peaking at 1600, well before the stall on the converter. So my thought process was to retard it a few degrees and move my top end past 5000 while timing the torque curve to match the converter and avoid the detonation. Am I on the right track?
Last edited by Montclaire; 04/01/19 08:00 PM.
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2639895
04/01/19 08:59 PM
04/01/19 08:59 PM
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Joined: Sep 2014
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Washington
madscientist
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It's a Jasper rebuild out of a B250 van. The seller said it had about 1500 miles on the clock when pulled and the internals were spotless so I believe him. I am guessing Jasper installed the cam straight up for one, and a 73 B-body isn't your mother's Dart. Secondly I thought that retarding it a couple degrees would help minimize any detonation from scavenging and extend my top end on what is really probably a grind for towing.
I don't have the motor in the car but from what I have been reading they top out way before 5k. Torque is peaking at 1600, well before the stall on the converter. So my thought process was to retard it a few degrees and move my top end past 5000 while timing the torque curve to match the converter and avoid the detonation. Am I on the right track? Don't just move the cam. I'd bet everything you have that jasper didn't degree the cam so right now, until YOU degree it, you have no idea where that cams at. It could be 8 degrees retarded already and you want to back it up. You need to degree it yourself and VERIFY where it's at and then make a decision. You need to do it right, not just guess.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2639908
04/01/19 09:39 PM
04/01/19 09:39 PM
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Joined: Sep 2014
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Washington
madscientist
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Yes, that's the plan. I'm just not sure how much I should retard it once I figure out where zero is, or if that will accomplish what I am trying to do. I guess my question is what are you going to do if the cam is already retarded???
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2640110
04/02/19 10:04 AM
04/02/19 10:04 AM
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Posts: 52,972
Romeo MI
MR_P_BODY
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Romeo MI
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You can move the cam but you better know where you are starting at first so degree it first.. with that low of compression it shouldnt be a problem but you will be losing the bottom end torque and that car is heavy so you need it 
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Re: 360 roller cam - safe to retard a few degrees?
[Re: MR_P_BODY]
#2640128
04/02/19 10:46 AM
04/02/19 10:46 AM
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Posts: 7,982
Scranton, PA
Montclaire
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Don't know if this helps any: The specs given for the Magnum 5.9 in the 1995 Dodge FS Manual seem to be incorrect, and actually for the last pre-Magnum V8 in 1992 that did also have a roller cam by then. The 'Magnum Engines' book by author Larry Shepard seems to repeat this mistake because it copies the 1995 FSM word for word.
Those (maybe incorrect) specs are:
Exhaust Valve
Closes ATC 23
Opens BBC 61
Duration 264
Intake Valve
Closes ABC 80
Opens BTC 13
Duration 274
Overlap 36.5
Valve lift 0.410 inches
The major difference is in how late the intake valve closes at 80 degrees After Bottom Center.
The above 264/274 cam is supposedly what was put in the first 360 Magnum 'Crate Engine' from MP according to Al Kirchenbaum in his Hot Rod Magazine article titled 'Magnum Manifesto' in Aug 1998. The Hot Rod article says the cam used was the stock cam from a pre-magnum 1992 model 360 V8 with TBI.
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2640207
04/02/19 01:30 PM
04/02/19 01:30 PM
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Joined: Sep 2014
Posts: 4,457
Washington
madscientist
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I sent an email to Jasper, and to my surprise I got an actual phone call from them. They said on that motor the cam would have been installed on TDC. So it could still be off but at least I know they didn't intentionally retard/advance it. I have no idea what that even means. How do you install the cam on "TDC"?? I've never heard that. I use the intake centerline method and degree the cam at whatever the card calls for and tune from there. That means if the card says install the cam on a 110 intake centerline, the intake valve is at max lift 110 degrees AFTER top dead center. Ain't no way you can install it at TDC as that makes no sense. Call him back and remind him he is out of his gourd. Tell him you either want an intake center line number of where the intake opens at .050 lifter rise. Either will do. Maybe I can make a phone call and get you the number you need.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 360 roller cam - safe to retard a few degrees?
[Re: madscientist]
#2640212
04/02/19 01:33 PM
04/02/19 01:33 PM
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Washington
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Wait wait wait...I just read the OP and you say the cam is ground with a 108 LSA. That means if it's typical Chrysler it installs at 106. You may be able to install it at 104 if you want more bottom end.
I've never seen any DC/MP cam that wanted to be retarded past its LSA. I'm not sure about your cam. It if is ground on a 108 LSA as you say, I'd degree the cam to see where it is. If it's not 106 or 104 I'd put it there and try it. I've seen very few cams that liked to be retarded past the LSA. I've seen a few, but those were oddball combos.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 360 roller cam - safe to retard a few degrees?
[Re: madscientist]
#2640223
04/02/19 02:06 PM
04/02/19 02:06 PM
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Posts: 7,982
Scranton, PA
Montclaire
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I've seen the centerline listed as 108 and 110. I think the 110 comes from the magnum crate literature so take that with a grain of salt (EDIT- from the 2000 mopar catalog). Overlap is 37.
Last edited by Montclaire; 04/02/19 02:15 PM.
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2640235
04/02/19 02:50 PM
04/02/19 02:50 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Romeo MI
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First off.. forget about the overlap.. you have no idea if it will turn your manifolds red or not.. you still have no idea where that cam is installed till YOU check it.. get that data then go from there.. big deal if you read that somewhere.. I havent ever seen a 360 turn red IF it was tuned right and I seen a ton of them at Chrysler and beat on them hard when testing
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Montclaire]
#2640251
04/02/19 03:15 PM
04/02/19 03:15 PM
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Joined: Aug 2003
Posts: 43,157
Bend,OR USA
Cab_Burge
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Bend,OR USA
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SB Mopar motors do not like the cams retarded, NEVER  Any time you retard the ignition timing it will end up burning unburnt fuel in the exhaust turning the manifolds and pipes red   Retarding the cam will open the vales later allowing any unburnt fuel to go into the exhaust with loss of power also  It has been mention and stated by several other posters on here to make sure and check the cam timing before moving it  Do NOT ASSUME that Jasper got the cam timing close, NEVER ASSUME any thing on motor parts, especially cheap rebuilder parts On your deal make sure and check both the intake and exhaust lobe separation angles to make sure exactly what the cam core lobe separation angles are before changing it
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 360 roller cam - safe to retard a few degrees?
[Re: Cab_Burge]
#2640255
04/02/19 03:29 PM
04/02/19 03:29 PM
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Joined: Feb 2003
Posts: 7,982
Scranton, PA
Montclaire
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I at least want to open it to see what kind of timing chain they put on it, I might just throw on a tensioner from a 3.9 and call it a day. The motor ran when it was pulled and it's not a performance build but I figured it wouldn't hurt to make sure the cam was phased properly.
Last edited by Montclaire; 04/02/19 03:31 PM.
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Re: 360 roller cam - safe to retard a few degrees?
[Re: WO23Coronet]
#2640259
04/02/19 03:42 PM
04/02/19 03:42 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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I advance all my SB cams.. I have been from 99* to 108* on some but NEVER retarted... 99* had great torque but ran out of RPMs.. I tend to stay just a couple degrees advanced EDIT When you start talking 114 LSA your getting into blower and turbo stuff and it bleeds off too much pressure for NA stuff
Last edited by MR_P_BODY; 04/02/19 04:47 PM.
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