4.6 Bosch cam, search anxiety
- Thread starter rovercanus
- Start date
I'm sorry but, that's ignorant and lacks rational thought (being succinct rather than mean).
The camshaft "cog" must turn exactly half the rate of the crankshaft and it's keyed to go on only one way. Timing values among the various camshaft options are properties of the lobes, their relationship to each other and to the key.
Math and physics are not subject to interpretation. Nor do facts yield to unanswered rhetorical questions.
-Brad
Went back and looked at some notes I had when I did my motor.
The cam shafts from Summit and Jegs, at the time, would not work on a Bosch or GEMs engine. The cams were too long. In other words, the cams were made for the timing gear for the dizzy to slip on. Obviously these cams will not work on a truck without a dizzy. Unless something has changed, the cams from Jegs or Summit will not work in Walters case.
The timing gear set I used from D&D was a double roller. Because it was a double roller I needed the plate fastened to the front of the upper cog for the cam sensor to read correctly. Rover does not, or did not, make a double roller at the time and that was the reason for this.
The cam sensor, in conjunction with the crank sensor to a degree, control the ignition timing. The cam that I used at the time was a "test", more or less, that Mark hooked me up with. Since then plenty of the 230 cams have been sold, I'm sure. On my upper cog the holes that the cam sensor reads were adjusted to allow for better timing of the ignition system. In other words it was optimized. I do not know how much or how many degrees and the number in my head makes no sense. Mark is the only one who can answer that I guess.
I also had written down that the button on the 4.0 front cover had to be ground down so the cover would fit over the new cog. Also, the new cam did not accept a thrust washer like the stock cam did.
The cam shafts from Summit and Jegs, at the time, would not work on a Bosch or GEMs engine. The cams were too long. In other words, the cams were made for the timing gear for the dizzy to slip on. Obviously these cams will not work on a truck without a dizzy. Unless something has changed, the cams from Jegs or Summit will not work in Walters case.
The timing gear set I used from D&D was a double roller. Because it was a double roller I needed the plate fastened to the front of the upper cog for the cam sensor to read correctly. Rover does not, or did not, make a double roller at the time and that was the reason for this.
The cam sensor, in conjunction with the crank sensor to a degree, control the ignition timing. The cam that I used at the time was a "test", more or less, that Mark hooked me up with. Since then plenty of the 230 cams have been sold, I'm sure. On my upper cog the holes that the cam sensor reads were adjusted to allow for better timing of the ignition system. In other words it was optimized. I do not know how much or how many degrees and the number in my head makes no sense. Mark is the only one who can answer that I guess.
I also had written down that the button on the 4.0 front cover had to be ground down so the cover would fit over the new cog. Also, the new cam did not accept a thrust washer like the stock cam did.
you can buy from crower directly... they sell 4 different cams for the 4.6...same ones you can get from summit/jegs, but the are machined for both the thrust plate and notched. any of the 53's are labeled (short nose) are machined this way. you can even spend $ on their adjustable timing gear. while it will allow timing change, they informed me that is a waste with the bosch rv8.
As the thread is about camshafts, I inferred we were talking about valve timing. Either way, I still take issue with this statement:
Different shaped lobes will do exactly what they do without regard to ignition or fuel or whatever "timing" and provide exactly the "benefit" they were designed to provide. Perhaps I'm just picking nits...
If you want to argue tweaking the fuel timing may yield additional positive results, I'll give you that. It's true whether or not I concede it.
-Brad
Well the first important thing to understand is we aren't building race cars.
Two, you can open a valve faster and hold it open longer and still gain a little bit of power at the same given timing ABDC.
These motors are old and displacement wise, they are small. To see any real difference you would need to radically straighten out/shorten the intake plenum (the LR design is wack but the longer runners aid in torque production), as well as turn it to higher RPMs. As nether one of these things are doable (fair to say the majority of the LR crowd wouldn't take the time or spend the money to go that route), and tuning the ECM is such a headache; we have to pick from cams (very few) which will work with the hardware we have to run and that don't produce crappy results in a untuned form. Plus I feel like D2s are pretty close to their MBT in stock form anyways. I personally wouldn't add any timing if I was tuning it myself. I would simply tweak the VE and fuel tables to where they were good and leave it at that. Again, not building race cars, so I wouldn't worry about those last few horsepower. Especially on a frail fragile set up like the one we are talking about.
Thus we have like 3 profiles to choose from, all of which are pretty close in specs, and lobes are pretty mild (compared to some of the other stuff I see). I mean IT IS an old as flat tappet motor, that you can't adjust the timing, VE, or fuel tables to make it take advantage of better springs, longer duration, and higher RPM ceiling. So for us EFI guys whom are bound with those parameters yet want to run a cam that is a little better than stock we have a couple choices. Could the engine be optimized more? Of course it could have, but we would have to loose a lot of things in the process or ship our ECU overseas to get a map flashed in. Trust me, you wouldn't want a bench tune for an aftermarket cam anyways, not without being able to email the tuner datalogs before hand. Then you might be okay. An important thing to remember is that OEM cams are designed with a lot of other things in mind, such as valvetrain noise, valvespring life, lobe wear, ect. Taking that into acount it is easy to see how one of two cams very very similar in specs might still make a better driving vehicle without any additional changes outside what two crappy narrow bands can do.
I bought mine mainly because I thought it would last longer than another stock one, plus it was cheaper. Which I would dare to say is usually the case with everyone else that changes cams. "Hey I'm rebuilding the motor, why spend $20,000 on a Land Rover cam when a Crower one is $150? Plus it makes more power too man!" *chug beer, high five*.
Two, you can open a valve faster and hold it open longer and still gain a little bit of power at the same given timing ABDC.
These motors are old and displacement wise, they are small. To see any real difference you would need to radically straighten out/shorten the intake plenum (the LR design is wack but the longer runners aid in torque production), as well as turn it to higher RPMs. As nether one of these things are doable (fair to say the majority of the LR crowd wouldn't take the time or spend the money to go that route), and tuning the ECM is such a headache; we have to pick from cams (very few) which will work with the hardware we have to run and that don't produce crappy results in a untuned form. Plus I feel like D2s are pretty close to their MBT in stock form anyways. I personally wouldn't add any timing if I was tuning it myself. I would simply tweak the VE and fuel tables to where they were good and leave it at that. Again, not building race cars, so I wouldn't worry about those last few horsepower. Especially on a frail fragile set up like the one we are talking about.
Thus we have like 3 profiles to choose from, all of which are pretty close in specs, and lobes are pretty mild (compared to some of the other stuff I see). I mean IT IS an old as flat tappet motor, that you can't adjust the timing, VE, or fuel tables to make it take advantage of better springs, longer duration, and higher RPM ceiling. So for us EFI guys whom are bound with those parameters yet want to run a cam that is a little better than stock we have a couple choices. Could the engine be optimized more? Of course it could have, but we would have to loose a lot of things in the process or ship our ECU overseas to get a map flashed in. Trust me, you wouldn't want a bench tune for an aftermarket cam anyways, not without being able to email the tuner datalogs before hand. Then you might be okay. An important thing to remember is that OEM cams are designed with a lot of other things in mind, such as valvetrain noise, valvespring life, lobe wear, ect. Taking that into acount it is easy to see how one of two cams very very similar in specs might still make a better driving vehicle without any additional changes outside what two crappy narrow bands can do.
I bought mine mainly because I thought it would last longer than another stock one, plus it was cheaper. Which I would dare to say is usually the case with everyone else that changes cams. "Hey I'm rebuilding the motor, why spend $20,000 on a Land Rover cam when a Crower one is $150? Plus it makes more power too man!" *chug beer, high five*.
Simplest way to get more HP out of these motors is to hog out the heads. There's 35 untapped HP in there. There is a lot of meat in there that can be trimmed. I have a set of ported heads and it's a big difference.
The sales/marketing info on the 229 cam "promises" increased low end and mid range torque and "improved" gas mileage. Have these marketing claims proven to be realized? I would like to hear what real world experiences are. I didn't realize US manufacturers were finally making late Rover cams. Thought you had to buy Kent or Piper.
Crowler has been making Rover/Buick cams for decades.
I don't know if I buy the improved MPG's claim, but they do provide increased power.
I don't know if I buy the improved MPG's claim, but they do provide increased power.
fb111 look at my post here. http://www.discoweb.org/forums/showpost.php?p=1000124&postcount=5
the crower has higher dynamic compression ratio than the stock cam and a higher expansion ratio. higher pressure ratois higher torque, higher exp ratio uses more of that pressure. but wtf do i know, call dnd and buy some snake oil after you hog out your cylinder heads
the crower has higher dynamic compression ratio than the stock cam and a higher expansion ratio. higher pressure ratois higher torque, higher exp ratio uses more of that pressure. but wtf do i know, call dnd and buy some snake oil after you hog out your cylinder heads
I don't understand where this huge cost savings is. D&D sells a cam, lifters, and doubler roller chain set for $450. If you're a cheap fuck and don't opt for the roller chain you save a hundred bucks. So what are you saving?
I don't buy that at all, sorry.
I know you have a cajillion post but that graph offers no tech behind it to back up those numbers. How could different pistons make that much of a difference? The valve reliefs are that big.
I also don't see how porting the heads could increase horsepower if you aren't spinning the motor higher. You would actually hurt low and mid lift flow numbers if you are increase CSA. Were are talking about OHV engines here, no matter what kind of magic cam and head work there is you are going to have to have a trade off somewhere.
You can't just "hog out" the ports and say it will pick up power. A swirl ramp will kill high lift flow but help low lift atomization and combustion properties. It also won't help if you can't make changes in the computer to compensate for any changes. If it was carbed and had a distributor... sure, go crazy. That is not the case though. All you would be doing is hurting efficiency (because the motor limited in performance by its tune up), and wasting time.
35hp IS ALOT, a set of ported buick heads might see that kind of gain in a TVR where you can put a short runner single plane on it and jet the carb or tune the EFI but slapping those heads on a LR would likely make it run like a dog.
the dish is 10cc different. im not going to hold your hand through calculating a compression ratio, but it is what it is wether you buy it or not
More air, more power. Easier to get air, more power.
This is the end all be all... 1 of 1 in existence, 2nd pic helps. and third pic is really the best solution.
http://www.pirate4x4.com/forum/12179786-post64.html
This is the end all be all... 1 of 1 in existence, 2nd pic helps. and third pic is really the best solution.
http://www.pirate4x4.com/forum/12179786-post64.html