roller rocker 1.60 or 1.70? December 15, 2004, 10:44:56 PM What do we need to take in consideration for choosing within those? Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #1 – December 15, 2004, 10:53:14 PM Well you should consider what cam you are using in relation to what heads you are using, as well as what mods have been performed, also do you want a roller rocker or not, are the heads your using a pedestal mount or stud mount.Tell us more about your motor. Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #2 – December 15, 2004, 11:09:09 PM Here's a partial list of the engine parts I'm interested in for my project....QuoteSummit Parts #- SUM-CSUM347KIT 347 Stroker Rebuild Kit (.030 overbore, Piston, Crank, Rods, Rings, gasket etc..) - FMS-M12071-C302 Complete Engine Harness 1986-95EFI- FMS-M6513A351 Valve Springs, Dual Springs, 289/302/351W, Set of 16- CCA-851-16 Lifters, Hydraulic Roller, Ford/Lincoln/Mercury, Set of 16 - FMS-M6564A351 Roller Rocker Arms Alum 289/302/351W 1.60 Ratio 3/8 Stud Mount (or FMS-6564D351 1.70)- FMS-M6250E303 Camshaft, Hydraulic Roller Tappet, Duration 282/282, Lift .498/.498- FMS-M6565L302 Pushrods, Steel, 5/16 in. Diameter, 6.272 in. Length, Ball Ends, Hardened, Set of 16 Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #3 – December 15, 2004, 11:28:21 PM If your using stock heads or e7's or something comparable in your setup I would have to say stick with the 1.6's. The 1.7's will most likely be a clearance problem with that cam due to the good amount of advertised lift. According to Ford, Flat top pistons with E7 heads are good for .500 lift. I have 1.7 rockers in my setup, however even with these I have about .485 lift. With that cam I would ABSOLUTELY check your clearance as well. Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #4 – December 16, 2004, 12:11:03 AM Quote from: Paul FlockhartIf your using stock heads or e7's or something comparable in your setup I would have to say stick with the 1.6's. The 1.7's will most likely be a clearance problem with that cam due to the good amount of advertised lift. According to Ford, Flat top pistons with E7 heads are good for .500 lift. I have 1.7 rockers in my setup, however even with these I have about .485 lift. With that cam I would ABSOLUTELY check your clearance as well.With the E cam 1.7's should not be a problem. Im running that set up now in my car. Stock HO bottem end, ported E 7's. Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #5 – December 16, 2004, 12:35:08 AM The HO has Dish tops which means you can get away with more lift. Forgot to mention that. I just assumed Flat tops. Sly, we would need to know more about the specific crank/rod/piston dimensions to give you a more accurate answer. Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #6 – December 16, 2004, 09:08:47 AM SUM-CSUM347KIT 347 Stroker Rebuild Kit (.030 overbore, Piston, Crank, Rods, Rings, gasket etc..)QuoteThese Summit engine rotating kits are designed to help you get started on your engine the right way. The kits are configured to give you quality parts at a great price. They include a crankshaft, connecting rods, pistons, piston rings, rod and main bearings, gaskets, and a high volume oil pump.Vendor Summit Product Line - Summit Engine Rotating Kits Crankshaft Included - Yes Crankshaft Material - Cast iron Rear Main Seal Style - 2-piece Balanced - No Engine Balance - External Balance Style - 28 oz. imbalance Pistons Included - Yes Piston Material - Hypereutectic aluminum Piston Style - Flat Dome Volume (cc) - (Not Specified) Dish Volume (cc) - 6.5 Valve Reliefs - Two Wrist Pin Style - Floating Piston Rings Included - Yes Piston Ring Material - Chromemoly Piston and Ring - Oversize (in) 0.030 in. Piston and Ring - Oversize (mm) (Not Specified) Connecting Rods Included - Yes Connecting Rod Material - Forged 4340 steel Connecting Rod Beam Style - H-beam Rod Bearings Included - Yes Main Bearings Included - Yes Gaskets Included - Yes Oil Pump Included - Yes Oil Pump Style - Wet sump Camshaft Included - No Lifters Included - No Timing Chain and Gears Included - Yes Quantity - Sold as a kit. What u r also saying is 1.7 will make more lift than 1.6? Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #7 – December 16, 2004, 01:05:34 PM Quote from: Sly1990What u r also saying is 1.7 will make more lift than 1.6? Yes, but the ratio of the rocker only effects LIft not duration.Phil Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #8 – December 16, 2004, 11:22:59 PM Quote from: Sly1990What u r also saying is 1.7 will make more lift than 1.6?yep, you take the stock lift (.444" on HO's) and divide it by the stock ratio (1.6 on HO's), to get the lobe lift, in this case .2775". you then multiply that number by the new rocker ratio (1.7), and you get the new valve lift, .477".Quote from: 88KSXR7Yes, but the ratio of the rocker only effects LIft not duration.Philnot quite true."Many people incorrectly assume that a change in rocker arm ratio has no effect on the duration the valves are open. In actuality there is some change to the duration at the valve depending on the lobe profile of the camshaft. Comp Cams explains that by lifting the valve an additional 7-8%, but beginning and ending the lift at the same point, the opening and closing rates become steeper. This increases duration, measured at the valve at 0.050" lift, by 1-2 degrees. You can measure the actual duration change by using a degree wheel and dial indicator set on the valve retainer. Coincidentally the principle of a steeper rate of opening and closing is what Comp Cams has engineered into their Extreme energy camshafts to enable more valve duration for a given lobe duration."http://www.fordmuscle.com/archives/2001/10/rockerarms/ Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #9 – December 17, 2004, 09:25:22 AM Thanks, this is very valuable info.... :ies: If I understand correctly, 1.6:1 should be the best for me with the CAM I choosed... E303 has .498 lift so ill end up with .529 w/ 1.7:1... (piston-valve Clearance issue??)Also 1.6 has less wear compared to the few HP gain i could get w/ 1.7.... Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #10 – December 17, 2004, 01:46:57 PM well your quoted stuff from summit says the pistons are flat, but have 2 valve reliefs. I'd still check valve clearance regardless, you can never be too careful Quote Selected
Re: roller rocker 1.60 or 1.70? Reply #11 – December 17, 2004, 02:25:32 PM Besides piston to valve clearence, you need to worry about spring bind also. Check with spring companys to see max lift on various springs. :ies: Quote Selected
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