pspeaks Paul Speaks Dallas, Texas (698 posts) Registered: 07/20/2009 06:40PM Main British Car: 1972 MGB-GT 1979 Ford 302 |
Camshafts
Again, I've probably posted this in the wrong place, so forgive me. I don't remember seeing a thread about cams here, so here goes.
At the time I built my motor I was driving a 10 mpg 4x4 and was dreaming of something affordable so I built a stock 79 302. My friends told me with my personality I would regret it and sure enough Tim Allen was right, "there is no such thing as enough horsepower". I'm thinking of replacing the heads with aluminum and a stronger cam and kit. What do you guys think is an good brand (I know probably Comp) with an acceptable grind for the street on a 1979 302 with stock pistons. I'm a street rodder so I need a good lope. IRS refund is going to be coming back, last year it was new wheels, I can't forget my baby this year! Paul |
Citron Stephen DeGroat Lugoff, SC (367 posts) Registered: 10/23/2007 09:43PM Main British Car: 1970 MGBGT V6, 7004R, AC, matching trailer 3.1 liter |
Re: Camshafts
Does Edelbrock sell an upper end kit for the Ford? I know they do for Chevy. It is heads, intake and cam. A matched set.
Steve |
rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Camshafts
I'd suggest calling Summit, Jegs, & Speedway - give them your budget & let them recommend components that would work well together.
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Moderator Curtis Jacobson Portland Oregon (4576 posts) Registered: 10/12/2007 02:16AM Main British Car: 71 MGBGT, Buick 215 |
Re: Camshafts
If this thread is really about selecting a camshaft for a 302, it belongs in the Drivetrain section and I'll be happy to move it. You may want to add more specifics about the rest of your combination. (Exactly which pistons did you install? What intake manifold, carb, and ignition system? Which flywheel? Etc.)
I'm confused about where you are in your build. Is your engine installed yet? Is your car running? If not, I think you should probably stay focused on the Critical Path. Get your car running, drive it for a season, then re-evaluate your priorities. |
pspeaks Paul Speaks Dallas, Texas (698 posts) Registered: 07/20/2009 06:40PM Main British Car: 1972 MGB-GT 1979 Ford 302 |
Re: Camshafts
Thanks for moving the thread Curtis.
I haven't driven it yet because I'm still dealing with a cancer issue, which according to the doctors I'm winning at the moment. The motor and drive train is installed, all hooked up, and the car is setting on the ground. For the most part, I'm dealing with stuff like steering, interior, centering the gas tank, and a little wiring. I probably will drive it a while before I install any performance stuff but thought I'd get parts early. Sorry, I shouldn't have posted this subject to begin with, If you can Curtis, remove it rather than move it. Thanks, Paul Edited 2 time(s). Last edit at 12/19/2013 10:48AM by pspeaks. |
DiDueColpi Fred Key West coast - Canada (1365 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Camshafts
Hey Paul,
no need to delete this thread. I think that many of us can benefit from the insight that others can bring to the table. I for one would never have thought to ask the Summit guys for engine help. Apparently I'm single minded, stubborn and unable to ask for help. Which I have to agree is true. So really you're helping me to grow into a better person :) I don't think that any of us have built a car that wasn't re imagined 1/2 way through. That's the way the process works. So dream on my friend. It's what gets us through. Cheers Fred |
mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Camshafts
Paul, The Edelbrock system or Catalog outfit will get you in the ballpark but, there was a recent thread by Dan Jones that shows a Ford build up. There have been a few magazine articles where they used the Ford Racing cams and 1.7 rockers, aluminum heads and made 400HP. Maybe Dan will add some advice to this thread?
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Re: Camshafts
Many variables, I will try to make it simple. Gearing, compression, type of cam roller or flat follower.
If your small block is a roller then go with the E cam and AFR heads 195 cc bigger cc's will make the engine lazy in the bottom, great for higher rpm. This cam has moderate lift and duration with a good LS and timing, it makes power and creates a very flat and long curve of torque. If you have a flat cam follower type, then stay in the 280 and lower duration with 440- 480 but no higher than .500 lift. It may require some gearing. Keep in mind that engine timing will change and it becomes important to find the timing that you engine will need for a specific cam. Also a DLG (Degree Lobe Center) of 112 -114. There are complete kits, heads, cam etc. from Holley, Edelbrock and others. Camshafts are also available from Crower, Herbert, Schneider in San Diego.I think is perhaps the best cams. He will grind one to your needs for about the same cost of a Comp cam. Comp cams are made for the masses, but they do grind special order cams. Herbert and Schneider they grind most of the cams for the big racing teams that you do not see on TV os stickers on a race car. Yes they do street cams, I have one in my 3.4 V6 You can also get a roller retrofit cam from Crowler and others. Comp cams and Crane are great. but there are many other types of bread in the store. The main thing is to get the necessary info to give to the cam grinder and what you want to do with it. |
Re: Camshafts
Forgot the links [schneidercams.com] [www.dougherbert.com]
I have used them for years, same with Crane. Edited 1 time(s). Last edit at 12/19/2013 05:49PM by classic conversions. |
pspeaks Paul Speaks Dallas, Texas (698 posts) Registered: 07/20/2009 06:40PM Main British Car: 1972 MGB-GT 1979 Ford 302 |
Re: Camshafts
Thanks everybody, that gives me a good start. I may not install anything right away, as I said, the motor is in the car and everything is new, but I need to make purchases right after the first of the year, anyway, before my kids find out I have the money; same with the HVAC parts. I thought child support stopped when they turned 18 but mine are all over 40 :-)
Thanks Fred! I asked Curtis to remove the post because after posting it I didn't think anyone but me would get anything out of it. Paul |
MGBV8 Carl Floyd Kingsport, TN (4511 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Camshafts
Paul, don't you worry about it. We are here sending you positive energy. Do what you enjoy.
I have put 4 different cams in my Camaro, always bigger. I liked the sound of a bigger cam. It will move the powerband up or down. I prefer it on the top end. |
Dan Jones Dan Jones St. Louis, Missouri (280 posts) Registered: 07/21/2008 03:32PM Main British Car: 1980 Triumph TR8 3.5L Rover V8 |
Re: Camshafts
> I built a stock 79 302.
A 1979 Mustang 302 only made 140 HP @ 3600 RPM with a 2 barrel carb, single exhaust, cast pistons, open chamber D8VE heads (1.78"/1.46" diameter valves, 67.5-70cc combustion chambers), flat tappet hydraulic cam and low (8.4:1) compression. The valve clearance notches in the stock pistons will not permit many of the aftermarket cylinder heads with the larger 2.02" valves. The heads that should work are those with smaller intake valves. The cheapest of the lot would be the iron GT40 and GT40P Ford heads with 1.84" diameter intake valves. Given your compression ratio, if I were building it, I'd use a set of AFR 165 aluminum heads with the smaller 58cc combustion chambers. They make them for both stud and pedestal mount rocker arms. The bolt-down Crane/FRPP Cobra 1.7:1 ratio roller rockers are nice addition to the latter and fit under most valve covers. The stud mount rocker arms may require taller valve covers. What other parts (intake manifold, headers, carb) etc. do you wish to re-use? What's your transmission and final drive ratio and tire spec? Those items will factor into the cam choice. You can retain a flat tappet cam if you use the right oil (with plenty of ZDDP) or you can retrofit a hydraulic roller cam if you use the right link bar lifters (some will work with standard base circle cams, others expose the oil band) or use a reduced base circle cam kit with OEM style spider and dogbones. Be aware that most of pre-assembled aftermarket SBF heads are set up with springs for a hydraulic roller cam. You'll need to replace those if you use a flat tappet cam. Also, many are drilled for the larger 351W head bolts and you'll need shouldered head bolts or inserts. I'd be happy to spec a cam for you once we know the rest of the particulars. With the light weight of an MGB, you could run a fair bit more duration compared to a 3500 lb Mustang but you have to balance that with your modest compression ratio and the fact you have cast pistons. There are some cast pistons that will live at 7000 RPM but most are best kept under 6000 RPM for long term durability. > I'd suggest calling Summit, Jegs, & Speedway - give them your budget & let them recommend components that would work well together. I'd recommend against that. It's hit or miss whether you'll get someone who really knows small block Fords and even then they may not know the difference between a later 5.0L (e.g. metric rings) and your earlier 302. Cam companies are a bit better but it's still a game of chance. > Also a DLG (Degree Lobe Center) of 112 -114. It depends upon the intake valve size, but a 289 or 302 with the valves we are talking about, will generally run better on a 110 degrees LSA (lobe separation angle). Most of the wider LSA cams are cams that make tuning EFI a bit easier but even Ford's popular emissions legal E-303 cam has a 110 LSA. > I'm a street rodder so I need a good lope. Lope comes from overlap which is a function of the lobe separation angle and duration. The wider LSA (112-114) will have less lope and the narrower ones (108-110) will have more. Given your compression ratio, I'd stick at 110 LSA. If you need more lope, you can increase the duration but too much duration will simply bleed off what little compression you have and won't run any better (will likely run worse). > Does Edelbrock sell an upper end kit for the Ford? They sell a couple of top end kits with flat tappet cams. The cams are copies of a couple of the old Ford Motorsport flat tappet camshafts which I've run before. Note they offer heads with either 1.9" or 2.02" diameter intake valves. > If your small block is a roller then go with the E cam and AFR heads The E-303 is a nice hydraulic roller street cam for a 5.0L. Specs are: 220/220 degrees @ 0.050" 282/282 advertised duration 0.498"/0.498" lift with 1.6:1 rocker ratio 110 degrees LSA There are several flat tappet cams with similar specs: Comp 270H 224/224 degrees @ 0.050" 270/270 advertised duration 0.500"/0.500" lift with 1.6:1 rocker ratio 110 degrees LSA > Maybe Dan will add some advice to this thread? Sure thing but if I don't respond in a couple of days, you may want to remind me via private message. I don't visit the MG forum that often. Dan Jones |
Re: Camshafts
If you want thump then just install a Comp Cam Thumper cam, great for show at cruise nights.
[www.summitracing.com] Roller cams can use more aggressive profiles such a s the E cam. In a flat tappet cam it would be aggressive of a profile. That is the beauty of the roller cams. On a 1985 and up roller 302 with the E cam and AFR heads can make decent torque. This engines come with forge pistons 1979 SBF does not. Edited 1 time(s). Last edit at 12/26/2013 02:54AM by classic conversions. |
Dan Jones Dan Jones St. Louis, Missouri (280 posts) Registered: 07/21/2008 03:32PM Main British Car: 1980 Triumph TR8 3.5L Rover V8 |
Re: Camshafts
> If you want thump then just install a Comp Cam Thumper cam, great for show at cruise
> nights. Note those cams have a 107 degrees LSA and wide exhaust duration so are very reversion prone. To run those sorts of cams, you need a really efficient exhaust: long tube headers with straight through mufflers (e.g. Magnaflow). One of my dyno test engines has a 107 LSA. It never performed as well as I hoped and will be replaced by a wider LSA cam. > Roller cams can use more aggressive profiles such as the E cam. In a flat tappet > cam it would be aggressive of a profile. That is the beauty of the roller cams. Flat tappet cam lobes can have a higher acceleration off-the-seat than roller cam lobes but have a lower maximum velocity. Vizard's testing puts the cross-over point in the 270 to 278 degrees of seat duration range. Below that, a flat tappet will make more power due to the greater acceleration. Above it, the roller's higher velocity wins out. To take advantage of that higher velocity, you'll want a roller cam with higher lift than a similar flat tappet cam. A very important benefit with hydraulic roller cams is long lobe life. I have one 5.0L HO roller cam with nearly 250,000 miles and the lobes look new. With reduced ZDDP oils and imported lifters, flat tappet lobe wear is a real concern. > On a 1985 and up roller 302 with the E cam and AFR heads can make decent torque. > This engines come with forged pistons 1979 SBF does not. Standard passenger car (non-HO) 5.0L engines got cast pistons. The 5.0L HO engines had forged pistons from 1985 through late 1992. Note these pistons also got thinner metric dimension low-tension rings. The 1986 5.0L HO got higher compression flat top pistons which have do not have the valve clearance notches necessary for larger diameter intake valves and/or higher lift cams. Part way through 1992, the 5.0L HO engines got hypereutectic pistons (through the end of the 5.0L HO in 1995). All the Explorer and Mountaineer 5.0L engines also had hypereutectic pistons. Dan Jones |
Re: Camshafts
Regardless, a 302 short block with either pistons will make decent power with just a change of heads such as AFR or trick flow.
I prefer AFR 165 cc's and many others do to for the street. Technology has changed and many believes such as the old book from Vizard's have changed. New cam profiles for the roller and flat tappet have changed, mainly due to new head, manifold technology. HP # come from compression and air flow, that is one of the secrets to power and I think Vizard makes those claims in his book and has spent many hours developing manifolds etc. which still good but there is much better around now days. FI has changed the game, Vizard did all of the testing with carbs and even those carbs and manifolds have changed. Same with Smokey manifold design is now part of the past. Have attended some of the AFR's presentations in Santa Clarita (20 minutes from my house) and they have gone to the next level in efficiency, so big cams are not really needed to make power on the street, thus producing a much flatter torque curve. Race engines are different due to the rpm in which they spend most of their time. So yes, no need for lots of duration, in fact the stock cams in GM and Ford engines are acceptable, unless thunping is more improtant at cruise nights. |
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Dan Jones Dan Jones St. Louis, Missouri (280 posts) Registered: 07/21/2008 03:32PM Main British Car: 1980 Triumph TR8 3.5L Rover V8 |
Re: Camshafts
> Technology has changed and many believes such as the old book from Vizard's have changed.
The stuff I'm quoting is covered in "David Vizard's How to Build Horsepower" which was first published in June 2010. Perhaps you are thinking of his earlier 2 volume set by the same title. The 2010 book is completely new. > New cam profiles for the roller and flat tappet have changed, mainly due to new head, manifold technology. The relative kinematics of the cam/lifter interface have not changed. Flat tappet cams are still limited by the lifter diameter and roller cams are still limited by the base circle. The biggest change has been in valve springs that can control more aggressive lobes and live. Here's a Dynomation simulation comparison of hydraulic roller and flat tappet cams with similar timing in a 5.0L Ford with AFR 165cc heads: The brown line is the Ford Racing E-303 hydraulic roller cam of specs 282°/282° degrees seat duration 220°/220° degrees duration at 0.050" 0.498"/0.498" lift with 1.6:1 rocker ratio 110 degrees LSA The red line is a Cam Dynamics 13011 hydraulic flat tappet cam 278°/278° degrees seat duration 222°/222° degrees duration at 0.050" 0.498"/0.498" lift with 1.6:1 rocker ratio 110 degrees LSA These cams are right in the duration region where flat and roller cams are roughly equal and the simulation suggests that they would behave roughly the same. Beyond this duration, the roller cam will generally make more power (assuming the valvetrain can keep the heavier roller lifters under control). Below this duration, flat tappet cams will often make more power. Some are misled by comparing the visual profile of fat roller lobes with the pointy profiles of flat tappet cams, concluding that roller cams must have more area under the (duration) curve but that is partially an illusion. The kinematics of roll lifters are different than that of flat lifters so the lobes are shaped differently even for similar valve motion. > Vizard did all of the testing with carbs Actually Vizard has done a fair bit of testing with 5.0L EFI engines. If you look at the preview of his book at: [tinyurl.com] You'll see on page 5 an example of a budget built EFI 5.0L and on page 14, he presents the results of 5.0L EFI manifold development tested in multiple stage (cold air induction, Extrude Hone, thermal barrier treatment). BTW, Vizard recently that he has signed to write a book on small block Ford V8's. One of the (carb) engines covered in the book is a 347 stroked street 5.0L engine that is said to have made 562 HP and 472 lbs-ft of torque on 91 octane with a 600 RPM idle. > HP # come from compression and air flow and RPM. Engine power is a direct (mathematical) function of RPM. While cam timing has a relatively minor effect on the torque peak value, it has a large effect on the RPM at which the torque peak is produced and therefore on the peak power produced. In any event it's all a system. We've dyno tested engines where a pair of $100 mufflers had more of an effect than a pair of $2000 aftermarket heads. > So yes, no need for lots of duration, in fact the stock cams in GM and Ford engines are acceptable I've run the stock 5.0L HO speed density cam (the best of the 5.0L HO cams) with both 1.6 and 1.7 rockers. Once you've upgraded other parts of the engine, you'll see big gains from more camshaft. How large a cam you can run without experiencing a sluggish low end is a function of the compression ratio (static versus dynamic). At low speed, lots of overlap is bad because your bleeding of the compression stroke out the exhaust port. As RPM increases, overlap becomes important. To a degree, you can offset overlap with static compression. Vizard's testing suggests that, for most V8's with reasonable heads, the ability to raise low speed torque with a compression increase holds to around 285 to 290 degrees (at lash point) of cam duration. After that, drop off is faster than an increase in compression can recover. In the June 2006 issue of Popular Hot Rodding, Vizard presents an example: [www.popularhotrodding.com] "When used in conjunction with a bigger cam, increased compression can work wonders for the entire curve. When a 265-degree cam (gray curve) was substituted for a 285-degree cam (blue curve), a substantial drop in low-speed output was seen. Raising the CR from 9:1 to 12:1 recovered almost all the lost low end and gave a further increase in top-end output." > Regardless, a 302 short block with either pistons will make decent power with just a change of heads such as AFR or trick flow. Agreed, as long as you have at least a 5.0L HO stock cam with a decent exhaust and intake. If you run a stock cam from a 1979 302 or a stock cam from a 1990 Ford/Mercury/Lincoln passenger car, you won't see much of a benefit from the better cylinder heads. The cam will peak much too soon. We've run into this on the dyno before. We tested better roller lifters, intake, exhaust on an engine with heads flowing over 300 CFM. None of it moved the power peak by more than +/-100 RPM because of the cam timing. On the flip side, very long runner EFI intakes (e.g. 5.0L HO/GT40/Cobra/Explorer) can negate some of the cam timing effects because the long intact tract dominates the tuning. There was a test of eight different 5.0L hydraulic roller cams in a 5.0L with a GT-40 intake manifold and, while they made different peak HP values, the peaks all occurred in the 5400 to 5500 RPM range: [www.carbdford.com] Dan Jones |
Re: Camshafts
So ....I guess we agree right?
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Re: Camshafts
and RPM. Engine power is a direct (mathematical) function of RPM. While cam
timing has a relatively minor effect on the torque peak value, it has a large effect on the RPM at which the torque peak is produced and therefore on the peak power produced. In any event it's all a system. We've dyno tested engines where a pair of $100 mufflers had more of an effect than a pair of $2000 aftermarket heads. this was pointed out to me. I did not read the whole thing, but...I disagree on this one. Unless the engine tested was plugged up. then yes. The statement is to vague. Factory mufflers are made for the masses and to keep sound to an acceptable level, there are exceptions to this rule and any rule. Some engines actually get hurt with a muffler change, some used a tune exhaust. But if you are referring to a stock Mustang or Camaro, big YES and just a simple change of heads with the stock mufflers can not show to much of an improvement, what goes in must come out I have seen my share of dyno testing, one thing that I have learn is that it is a process,1 , 2, 3 etc. skip one and hurts everything. Some books have second third and fourth edition which have the same information with some minor updates and tell the story in a different way, end result is the same. Not saying that those books are not any good. Any air flow that is straighten out and mix correctly and the precise time will make power, nothing new there, just follow the map out process. We are beginning to go in circles here. Have a good day. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Camshafts
Dan, thanks for posting the info comparing the cam types. This was something I didn't know and it really helps define a decision point in cam selection. My take-away is that for a small displacement engine a roller cam is a good investment whereas for a large displacement one, unless it is a racing application the flat tappet cam is probably OK for most builds. I was under the mistaken impression that the roller cam always had steeper ramp angles and therefore more area under the curve but when you think about it, with the heavier lifters this would mean much stiffer springs would be needed to accomplish this.
But without delving deeply into the engineering of it, for my own personal purposes where I'm using forced induction and allowing increased inlet pressure to offset the use of a relatively mild cam, the flat tappet .212/.262 duration cam I have installed may be expected to post better HP/TQ curves than a roller lifter of similar specs, and do it with less valve spring pressure to boot, along with less complexity. That's a win-win it seems to me and less expense. At 120# seated pressure it should last about as long as the rest of the engine as well I would think, as long as I keep adding the ZDDP to the oil. Jim |
DiDueColpi Fred Key West coast - Canada (1365 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Camshafts
Okay,
So I'll see you two out by the monkey bars after school. Paul, Are you after max performance, fuel mileage, that good old hot rod idle or something else? My thoughts would lean towards the short block if you are going to change anything. Upgrading the pistons to something more performance oriented would be the most bang for your buck at this point. Some ARP hardware and quality bearings down in the nether regions would add some insurance to the package. This would open the door to future mods without the limitations that the stock pistons will haunt you with. Cheers And oh yeah "Happy New Year" Fred |