Slant Six Forum :: Camshaft for stock rebuild

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Camshaft for stock rebuild https://slantsix.org/forum/viewtopic.php?t=62854	Page 1 of 1

Author:	frank79912 [ Thu Sep 20, 2018 1:35 pm ]
Post subject:	Camshaft for stock rebuild
Im finally going to bite the bullet after 40,000 miles of a quart of oil every 400 miles ! I'm planning on complete rebuild closer to blue printing, a little blending at the valve seats and cleaning up the flashing. It is a hydraulic cam with no adjustments , until it goes into the machine shop I wont know anything about deck height or if the head has been cut. The question at hand is to add a little more to the power above 2,000 rpm with out loosing the bottom end.. The factory cam specs are 188@.50 and .373 lift . At 4100 feet of elevation the oil gives it a little more compression - cranking is 125 psi. The gear ratios is 3.08 and a a833 od manual and don't really have too much of a issue in overdrive unless I have a 50 mph head wind . I have found a cam close to the stock solid replacement in hydraulic Intake Duration . Any thoughts or recommendations - keep in mind it sees 9,000 feet at times. Already have free flowing exhaust and GM hei with a BBD from a 318, Intake Duration (.050”): 194 Exhaust Duration (.050”): 204 Intake Valve Lift: .400" Exhaust Valve Lift: .420" Lobe Separation: 112

Author:	emsvitil [ Thu Sep 20, 2018 2:28 pm ]
Post subject:	Re: Camshaft for stock rebuild
Too much lobe seperation

Author:	Dart270 [ Thu Sep 20, 2018 4:27 pm ]
Post subject:	Re: Camshaft for stock rebuild
I have not looked at hydraulic cam profiles, but I would say you need more int duration than exhaust, LSA around 108, degree it at 100-102... Maybe someone has the hydraulic lobe profiles from Oregon Cams?? Lou

Author:	Dart270 [ Thu Sep 20, 2018 4:27 pm ]
Post subject:	Re: Camshaft for stock rebuild
Please tell us what static compression ratio you will run as well. Lou

Author:	frank79912 [ Thu Sep 20, 2018 5:53 pm ]
Post subject:	Re: Camshaft for stock rebuild
Im not planning on adding compression so think the factory ratio - and at this altitude more like 7.5 - 1. Looks as is OCG #640 is next best thing with out custom grinding

Author:	Rick Covalt [ Thu Sep 20, 2018 6:38 pm ]
Post subject:	Re: Camshaft for stock rebuild
Quote: Maybe someone has the hydraulic lobe profiles from Oregon Cams?? They are above in the FAQ with the mechanical ones. Not many with the LSA you would want, but they may be able to adjust that. Generally the longer exhaust duration is not what the slant 6 needs from what everyone says because the Slant 6 exhaust flows pretty well compared to the intake. Why not bump the compression a little? It should help with power and economy.

Author:	frank79912 [ Fri Sep 21, 2018 4:26 am ]
Post subject:	Re: Camshaft for stock rebuild
Both OCG and Schneider will cut 108 lobes,OCG will cut Dutras version of the RV10 on hydraulic profile in either the exact grind of hydraulic equivalent .I worry that the grind is too big for the stock compression at this altitude and I will loose the bottom end torque. For what it is it really doent run too bad - just if Im going thru all that work.

Author:	frank79912 [ Fri Sep 21, 2018 4:40 am ]
Post subject:	Re: Camshaft for stock rebuild
Here is the OCG grind #1461r 212/206 @ .050”, 260/252 adv, .438”/.423” lift, 108 lobe sep Hydraulic lifter grind To cut the head or deck I would have to get custom pushrods made to set the pre load and that's only after its assembled, wasn't looking to make this a long draw out project but down here nothing gets done in a hurry

Author:	Dart270 [ Fri Sep 21, 2018 7:34 am ]
Post subject:	Re: Camshaft for stock rebuild
I would cut the head 0.040-0.060", which should not require custom pushrods. That cam would work very well with a bit more compression and it will be safe with pump gas, especially at high alt. FelPro head gasket is fine, or "Endurotec" from Australia, or almost any composition gasket. They are about twice as thick as a stock gasket, so milling the head at least 0.020" will be needed to get you back to stock CR. Lou

Author:	frank79912 [ Fri Sep 21, 2018 11:45 am ]
Post subject:	Re: Camshaft for stock rebuild
These are net lash hydraulic - no adjusters on the rocker arms and from what I am told by the machine shop this has the thick gasket already - not the steel shim stock.

Author:	Dart270 [ Fri Sep 21, 2018 11:47 am ]
Post subject:	Re: Camshaft for stock rebuild
Oh, right. So, probably you should cut the head 0.020-0.030" and not more. Lou

Author:	frank79912 [ Fri Sep 21, 2018 12:43 pm ]
Post subject:	Re: Camshaft for stock rebuild
The stock cam is 255 advertised duration - 188 @ .050 and .378 of lift - lobe line 108 I 102 e and 45 degree of over lap.For low compression and small cam it will pull from a idle even with that tall gear - from a stop in 2nd and have done in 3rd - direct - with a little slipping of the clutch and dont want to loose that bottom end. From what I remember 200 - 215 degrees classifies as 1 with low rpm and high torque cams. I ran a Isky E4 in a 318 with 216 degrees @ .425 and 108 centers and it drove like the 400 I had. Schneider will cut this one at 108 centers Intake Duration (gross): 256 Exhaust Duration (gross): 256 Intake Duration (.050”): 204 Exhaust Duration (.050”): 204 Intake Valve Lift: .420" Exhaust Valve Lift: .420" Lobe Separation: 112 Once its opened up I can say more, this isn't going to be a simple rebuild as hoped for and I may have to make the measurement myself to get custom pushrods - after its all together.

Author:	frank79912 [ Mon Sep 24, 2018 8:30 am ]
Post subject:	Re: Camshaft for stock rebuild
Heres the cam card on the cam intake opens at 20 close @ 52 exhaust opens @ 58 closes @ 18 at .050" intake opens @9 atdc closes @ 23 abdc exhaust opens @ 32 bbdc closes @ 8 btdc

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