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Hello All
I am thinking about camshafts again
Firstly, what constitutes a 'modern'camshaft grind. Is it a difference in lobe separation or a different ramp profile
I have an "R"cam in one of my cars
How does a modern grind compare to the R
I see talk of the Schneider 274
what are its advantages
of the KG trimning KG10
its advantages
of the Enem 19
advantages
are these three considered modern grinds
I have 2.1 litre
mild head work
twin 45 webers
all things being equal Would one of the above produce better results than the R cam
I would like power to come on 2000 to 2500 rpm and up to 6000 (and beyond?)
I tried roller rockers, but with the R profile they were too noisy
may revisit this one
are you engine builders using the 274 instead of the euro grinds
i want to try something different and modern(if its going to be better) before i am too old to appreciate it
Big questions i know and am looking forward to being enlightened
Thanks in advance
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You don't mention your exhaust system?
The R cam should kick in at 2000 and die fast after 6000, like you want. It has a tight LSA, so degreeing it in properly is especially important. I'm pretty sure it is single pattern, so take off the tappet cover, rotate to cylinder 1 or 4 TDC at overlap at 0° and see if the intake is open marginally further than the exhaust. Ideally, you want to see equal overlap at 4° to 5° BTDC on any cam that is single pattern in a B20.
The Shcneider cam, which 274 is it? You can get a .300" and a .320" lobe lift, if you have a truely good head, the higher lift one will pay off, but at the risk increased lobe failure. I ALWAYS insist on a lower lift exhaust lobe since it doesn't need the lift + it is more prone to failure since the opening pressure is more than double.
Modern vs vintage is harder to describe in writing. A vintage cam consists of just 3 radiuses put to getter, 1st the clearence ramp which brings the parts together, 2nd the flank which opens the valve and 3rd the nose which decelerates all the parts before bringing it to a stop, then reversing direction. Modern cams have many more radiuses and can push many aspects to physical and metalurgical limits, so you get more area under the curve.
One problem with modern cams is not many people are designing them for B20's. We are using lifters the same diameter as Chevy's, so that's what you mostly get when choosing from American suppliers. Example Comp Cams all have way too much lift for X amount of duration. Crane Cams, OTOH, have a series of profiles designed for the old BMC-A Mini motor which has a smaller lifter, which means slower lifting speed and less lift, just what we want for an exhaust. Shneider has Mini cam profiles too, so I would get a dual pattern from them, if you can't make the R work.
Enem, Phil S. Sent me measured data on two of theirs, I do like the looks of them and a I would say they are 'modern', both having .315" lift. The other Swedish cams I don't know, because like most, they don't publish any meaningful data.
The Volvo cams, remember there is 3 different ages. A, B, and C are 1950's designs. The D is 1960's designed for the Amazon rally pack. K, F, R, S, T and U are fron the 1970's which makes them the same age as Isky's/IPD. Comparing the Isky VV-61 to a Volvo K, you will find the only real difference is the LSA, 108° vs 111° which basically means the VV-61 will have a little more output between peak torque and peak power.
So 1st, see if your R is installed properly, see if all the lobes are there, then try and make it work. If the head flows well at high lift, then adding higher ratio rockers to the intakes only would be great, if possible.
Some info on your exhaust is essential, flow figures on your head would be exremely helpful too! Also, what chokes and jets are in your carbies and what did you do with your ignition timing?
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69 142S Overdrive + 69 164S Manual
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You might like to look here for a modern cam. They have a good range.
http://www.microsofttranslator.com/bv.aspx?from=&to=en&a=http%3A%2F%2Fwww.tinustuning.nl%2F1-onderdelen-nokkenassen.html
If that link doesn't work uses this one and then use Bing translate it doesn't do a bad job. Click on Nokkenassen.
http://www.tinustuning.nl/1-onderdelen-motorintern.html
They have many other related parts so have a look around.
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Is www.tinustuning.nl still Ben? I don't have any detailed info about his cams, but I would spend money with him, he is 10/10.
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69 142S Overdrive + 69 164S Manual
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I'm really hoping someone with data responds - I'm really interested.
I sent a blank to Schneider to be ground to the 274 and will let you know how it feels as soon as I get it back. I'm not sure how much longer that might take, though...
Thanks for posting the question.
Cameron
Portland
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I've been meaning to email you, I've been looking for my old trade school text book which reckons a torque wrench has an accuracy of up to +/-25%
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69 142S Overdrive + 69 164S Manual
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My torque wqrench must be one of the good ones, it is only off by ~10%. Beyond not breaking the bolts off, aren't you really looking for consistancy, i.e. all the head bolts are equally tight?
Greg
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No Text.
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I was refering to the method. If you apply a measured 100ft.lbs to a fasterner, that fastener can end up being anything from 75 to 125ft.lbs (+/-25%). Depends on lubes, what the nuts, bolts and threaded holes are made of, temperature, etc. THEN there is the question of the accuracy of the torque wrench. I have a Snap-On torque wrench which when set to 38ft.lbs delivers only 25ft.lbs, I learned that the hard way.
Most things are angle torqued these days, it's a vast improvement. If you fit your old rods with new ARP bolts, or buy new aftermarket rods, then using the stretch method is the only way to do it properly, my 2nd choice is angle torque, then torque wrench is last choice. Bigger bolts like head and mains are less of a problem, but I always ensure that all take the same angle to reach torque.
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69 142S Overdrive + 69 164S Manual
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Thanks all
Paul
I have the late model exhaust manifold followed by equal length pipes longer than standard to a collector as such followed by 2 1/4" pipe and magnaflo mufflers
The cam timing has been advanced and the ignition timing set by my dyno chap
He didnt want to run it up due to the mixture too lean
so we added chokes 36mm
aux vents 4.5
emulsion F16
main jet 150
air correct 190
pump jet .40
idle jet 55f9
Havent put it back on the dyno yet
The engine in my other car is a bit tired and i wanted to try a "modern cam" when i rebuild it if ever and if the newer grind is that much better i would replace the R as well
Derek
Thanks for the info. Do you know any one that has tried these cams?
Cheers David
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Sorry I did not see this sooner, you need to reply direct to my post for the BrickBoard to notify me that you replied.
36mm chokes look to be the correct size based on the comparison of main jet to main air correctors. I am interested to learn more about your exhaust, are the secondaies (downpipes) still 1.75" OD? What is the length? Is the collector 2.125" and how long? What size is the exhaust and are the mufflers straight through type?
Headflow? Has it been flowbenched? What size valves? The R cam is single pattern, so you need a bigger exhaust valve for it, while the F cam , which is dual pattern, goes with a stock 35mm valve. What is the compression ratio? This alters the cam requirements too.
Ignition? What is going on there with the advance? You want to find out what is required on the dyno by adjusting it while loaded at peak torque rpm. You initial timing can be whatever works best at idle, then you adjust the speed of advance by brining total timining in as soon as possible.
Modern cams have lots of advantages: more lift, more area under the curve, faster from off the seat to .050" and kinder on the valvetrain has a whole are the advantages.
Schneider 284F has 240°@.050", this is comparable to the R cam. You can get it in .300" and .320" lobe lift, but the one you choose depends on how good your head flows. If your head lacks work in the SSR area, then the flow will back up starting around .25D and this will make the higher lift lobe no better and add unneccesary wear and tear. If you only have a 35mm exhaust, you would use a longer duration exhaust lobe with lower lift. If it turns out your head has a poor SSR and doesn't need the .320" version, then you won't get any real gain since the R cam has a touch more than .300" lobe lift.
FYI, The Schneider 274F is comparable to the Isky VV-71, they both have 228°@.050", 108°LSA, the Schneider will give you an extra .020" maximum lift at the valve, so should produce a few lb-ft more throughout. This level of duration would be good for a big bore twin SU engine, K-Jet or MS, so you can see why ipd sold the vv-71 as their 'street performer' cam. The slight decrease in LSA makes the powerband sligtly noticable, but for engines using the stock style exhaust, I would keep the stock LSA, which is good for getting healthy stock cams reground.
So, see if you have 8 good lobes while you set the tappets to .020", make sure your ignition is good, change out your old fuel and give it a tank of the brand and octane rating you intend to use, stick it on the dyno and install a set of new NGK BP7HS, get your max timing set to lowest best torque, and see what that is like, then it should be a matter of tweaking your advance speed.
What it should feel like is compared to a healthy stock B20B is 35+% more torque and easily 50% more power. When the DCOE'S are fully sorted, you should be able to flatten it from idle on flat ground, it should start to go at 2000 and by 2500, it should feel like a hidden 5th cylinder has kicked in.
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69 142S Overdrive + 69 164S Manual
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I've no personal knowledge of these cams. When I first became aware of them I think they only did 3 grinds between mild and wild. Did read that one the Dutch PV clubs(V44 Club)PV544 that did the Peking to Paris Rally used a TT cam. Don't know which one though. Try an inquisitive email to them and pick their brains for one to suit YOUR spec and aspirations. Note that I'm sure they will advise the use of their lightened lifters and custom push rods but that's no bad thing.
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