General Chat
Q:
So who can tell me why the two parts will not work together?
signed pseudotechnician view point, Sniper S^$ker, with girly arms : UCC 1-207
A:
firstly, it's spelled hydraulic.
secondly, it's lobes are ground differently:
http://www.zcar.com/forums/read.php?f=1&i=620721&t=620602#reply_620721
A:
Well thank you for the spelling lesson, I will take that under advisement and make sure to spell perfectly for you the next time.
I did not read the entire post, but from what I did read, the answer was not exactly correct. True there are differences, but when speaking regarding cam dynamics between the two, the differences in lobe ramp, and general duration numbers are ambiguous as is the lobe centers.
So basically, you reached the correct conclusion, but the answer is incorrect.
signed pseudotechnician view point, Sniper S^$ker, with girly arms : UCC 1-207
A:
just passing along what i saw in the TECH FORUM after a 2 second search...
maybe you SHOULD read the whole post, tony_d says you "can".
you are welcome.
79 280ZX -The best selling sports car of all time
Post Edited (Dec 8, 1:25pm)
A:
The mindless Internet Parrot Skwaks again!
ERRRRRRRRACH!
People Are Idiots, Just look around here and you will see!
Tony D: "Knowledgeable but Caustic"... rationull
My brother from another mother calls himself "Willie D"
A:
just passing along your answer tony_d since he refuses to search for it, much less READ it when offered...
79 280ZX -The best selling sports car of all time
Post Edited (Dec 8, 2:08pm)
A:
I still have not gotten the absolute technical answer to the question. I will give you a hint, think of the cam as installed in the engine.
And although, you CAN use the cam in both applications, there is a reason you would NOT want to do so. Most of your answers are correct, well except Steve's answer, the ramp has little to do with the actual reason. I will say this though, increasing the ramp, or decreasing the ramp time on the beginning of the lobe is desirable to open the valve faster, and higher per degree of crankshaft rotation, but that is still yet another topic of consideration.
Try again, Tony don't tell them.
signed pseudotechnician view point, Sniper S^$ker, with girly arms : UCC 1-207
A:
tkr514 don't bother, remember it's only cyberspace.
A:
oh, it's a guessing game? Sorry i did not get that from your post. i thought for some odd reason that you were seriously considering it. never mind.
79 280ZX -The best selling sports car of all time
Post Edited (Dec 8, 2:26pm)
A:
Well, actually you can run a hydraulic cam in a non hydraulic head. I've done it. Its noisy and likes to float valves over 6000rpm, but it worked. I ran it for about 5000-6000 miles because I believed some internet bull about how it was okay...well its not. Below 6000 rpm it was fine and didn't show any signs of strange wear on the cam or rockers. Infact I ran 12.33 @112 with that cam. Anyways, I'd be curious to know...
---------------------------
James Roraback
1983 280zxt 11.39 @129.38 - FOR SALE
ZCAR.COM member since Nov 1999
A:
A guessing game? I think NOT. I was hoping to get the correct answer but I did not. I was really hoping to find one person that would show their experience and knowledge of cam selection, timing, opening and closing points, lobe centers and duration. Apparently no one here really knows what they are doing aside from the general answer this worked good for me yada yada yada, maybe that is the reason there is such a difference in the overall performance from engine to engine.
SO, just for the people who are really interested in cam dynamics and the L engine, I have written up a article on that very topic. The article may be published in Sport Z. The rest of you, well you can keep your head stuffed where it apparently belongs and work on your car on a nice shady day.
The article is somewhat long, but well worth the time to read
HERE WE GO :
DEGREE YOUR Cpm
Degreeing the L series cam, Let me tell you a story.
When I first began working on the L engine adjustable cam head, P90, I asked what the lash should be adjusted to. My reply was from one person that they adjusted the lash at .008 on the intake and .009 on the exhaust and that worked out well for them. Thinking this person was correct in their advice, which made perfect since at the time, I set up my engine with the standard timing marks on the cam sprocket and back plate and left it at that. Coming from a ford and Chevy background, I did not think about how the lash could affect the actual cam profile, it just never occurred to me the lash adjustment would change the cam profile. I did not take the time to think out the effects of the valve lash adjustment.
I fired up my new engine, broke the cam lobes in with the engine at 2000 RPM’s for about 20 minutes. My first drive in the car was less then the results in power I expected from idle to about 3000 RPM’s and the engine really felt like it started making power above that RPM range. I decided to retard the cam timing to gain a little more power at the lower RPM’s to get better drivability for street use. The low RPM power seemed to improve, so I left the cam as it was and chalked it up to the correct timing for my engine. The engine did make good power and the car was in fact very fast.
I decided to dyno test the engine to get the power and torque data, and that test was the beginning of my quest for the ideal cam grind. The engine made power and looked very much like the stock engine did from the factory, except for the fact that the peek power was about 2.5 times the stock engine made. The one thing that troubled me was where the peek power started falling off. I designed a cam grind that should have taken the power curve to a significantly higher RPM range then the stock cam did, but in fact it did not.
I decided the next step was to degree the cam to ensure the cam timing was correct, so I could begin to spec out a grind that would work to the specifications of power and more importantly the RPM range the engine made peek power.
When I indicated the cam I found that the cam profile was nowhere near the profile the grinder specified. I made a number of calls to the grinder to figure out what the heck the grinder sent me. I was thinking at this point that the incorrect cam was installed and sent to me for my engine. The grinder assured me the cam was ground correctly and that there was, or mush have been something I was doing incorrectly while degreeing my cam. I contacted another authority on cams and the L series engines specifically, and together we degreed the cam again, and sure enough the readings were not as specified by the grinder. I was confused at this point, and felt the grinder was giving me incorrect information. My decision was to just replace the cam with a different cam grinder and go that route with the cam grinds. I decide to go with a grinder that has been grinding cams not only for the L series Nissan engines, but just about every engine ever put out to market, ISKY cams. I spoke to Ron Iskiderian and together we came up with a grind that I felt, and Ron felt, would give me the results I was looking for.
I installed the cam, consulted the cam card. The card called out for .010 of valve lash, and I made the adjustments and began to degree the cam into specifications. I was very confused when, once again the cam did not meet the specifications of the cam card. This case, based on the degree wheel indicated the cam duration was 20 degrees to long, which affected the cam lobe centers. I was sure I was doing something wrong, but I could not for the life of me figure out what that was.
I decide to compensate for the longer duration, and changed the opening and closing points of the valve to correct the cam lobe center. I completed the intake lobe, and went on to the exhaust lobe as a sanity check to make sure the exhaust was correct with the modified opening and closing points of the intake valve. What I found was very disturbing, the lobe center of the exhaust was in the 120-degree range. Any knowledgeable engine builder, understands that lobe center was totally unacceptable, and would affect the operation of the engine and where the engine made power to the extreme extent. I ended my day in total frustration, with the intension of giving Ron a call regarding my findings of the cam profile, and to get help to figure out what the heck was going on.
I thought about this problem all night, and when I woke in the morning I had a game plan that I wanted to test.
Since the VALVE LASH, would affect the overall duration of the cam, I decided to increase the valve lash until the duration was correct as specified on the cam card. As it turns out, increasing the valve lash by .001 shortened the overall cam duration, so I increased the lash until the duration of the lobe was correct. Taking readings and writing them down as I increased the valve lash, I found that .012 valve lash correlated to the specified duration of the cam card, not .010 as stated on the card. I did this also on the exhaust lobe, and again .012 valve lash yielded the correct duration as specified on the cam card.
The next step was to set the opening and closing points of the intake lobe. I set the opening point of the intake valve, and checked the closing point of the valve. The cam profile matched the cam card. I was very happy about that, but the second test is where the rubber met the road. With the cam degreed to the intake valve opening and closing points, the duration correct, and the lobe center correct, I started the exhaust valve check. I degreed the exhaust valve and it to was correct as specified by the cam card. Needless to say I was very happy with the results. My cam is dialed in exactly as specified by the cam card.
The point to all my ramblings is that to arbitrarily pick a valve lash because it sounds good, or the way you have always adjusted valve lash , may or may not be correct. The cam timing and duration could be correct, or it could be way off the cam card specifications. The correct way to degree the L series cam is to first start with the total duration adjustment by adjusting the valve lash to reflect the correct duration. The second step is to then set the valve opening and closing points as specified by the cam card and the rest of the specifications will fall into place if the cam was ground to the specifications as stated on the cam card.
Cam timing is critical to the operation of the engine, how well and when the power comes on in the engine, and where peek power is produced. Check the cam profile and make sure the readings of your degree wheel correlate to the cam card provided with the cam. Failure to verify the cam timing will give the builder, and more importantly the driver a false characteristic of engine operation and performance. A builder can not always rely on the cam card, in my case, the lash specification was incorrect. Take the time to reason out the cam and its profile, and make sure it is correct. A builder cant simply install a cam and hope for the best. Testing and verification will make all the difference in the world, and how your engine will run. Correct cam degree procedures can be a tough lesson to learn, but well worth the time and effort.
As I have stated before, and will state again, the cam will make or break any engine build. Regardless of the components utilized, compression, all the goodies installed, a cam that does not promote the effective use of all your new performance upgrades will only yield disappointment and frustration.
AND THAT "BUILDERS" IS WHERE THE RUBBER MEETS THE ROAD!
Incidently folks, when I spoke to Ron about this issue, because I was less then happy about the .012 valve lash, as it clacks now, and I was a little concerned about the high RPM potential issues that could occur, my findings tripped him up for a second as well. Now I dont feel so bad about not realizing what was happening from the get go. Seems Electromotive would also adjust the lash a little lose at times to acheive different torque for various applications according to Ron.
signed pseudotechnician view point, Sniper S^$ker, with girly arms : UCC 1-207
A:
So what did Ron say about the valve lash being set so loose? As I'm sure you're aware, loose settings can be disasterous. I've thrown a rocker or two from an adjuster loosening up. Never could get it to hold properly so I ended up replacing it. In the meantime I wiped out a cam as the rocker came loose and gouged it pretty bad. Atleast it was just a stock cam. Higher RPM only magnifys the probem. Lastly, I'm still unclear of your answer (or lack of answer) why the hydraulic cam won't work properly in the non-hydraulic head. I tried several lash settings and never could get it to work properly (.012-.006) Or do you not have the exact answer for the hydraulica cam and you are looking for answer. I'm still unsure if this is actually what you were wanting to know, or just see who else knew thier cam design stuff.
---------------------------
James Roraback
1983 280zxt 11.39 @129.38 - FOR SALE
ZCAR.COM member since Nov 1999
A:
<I'm still unclear of your answer (or lack of answer) why the hydraulic cam won't work properly in the non-hydraulic head. I tried several lash settings and never could get it to work properly (.012-.006) Or do you not have the exact answer for the hydraulica cam and you are looking for answer. I'm still unsure if this is actually what you were wanting to know, or just see who else knew thier cam design stuff.>
Ron indicated to me the .012 lash would be fine. Seems Electromotive ran their las as lose as .004 on their engines, and ran the engines up to 8000 rpm's. I got the bypass air working to acceptable parameters, at lest it will idle @ 750 RPM now. I will make one more mod to the valve and it should be good to go.
I thought I answered the question in the article, indirectly. But here we go, The turbo hydraulic cam was designed by Nissan, for the most part to have nearly ZERO lash. You can easily see this by the wipe pattern on the heel of the lobes.
So when you run the cam in an adjustable head, and set the stock lash
to .010 and .011 like the manual recommends, what you do in effect is to decrease the overall duration of the cam. A shorter duration can equates to the equilivant RV cam. You will get a relatively low RPM range of the engine and still make power, the low end will be better, and the midrange will be good, but the topend will be like turning a switch off at the high rpm levels. Now for a street car that for the most part will see 5000 rpm's max, that is really not a problem, but for the race engine that will see a redline of 7000-8000 rpm's the cam simply put will not work.
Looking at the cam specifications posted earlier :
http://www.zcar.com/forums/read.php?f=1&i=620721&t=620602#reply_620721
Looking at the duration numbers you can see that a shorter duration will in effect make less power and overall an engine that will run best in the lower rpm ranges. When I did the degreeing of my cam, by changing the lash by .001 changed my duration by 10 degrees, keep in mind though, that may change according to the rocker geometry for any particular cylinder head. A good example of this is installing the shims under the cam towers to compensate for a surfaced cylinder head. I wont go into whay that is done, but what that effectively does is to change the rocker ratio of the rocker arm. Now Nissan designed the head to have a 1.5 rocker ratio for the most part, so movint the cam away from the rocker will change that STATIC rocker ratio. Also since everyone seems to want to grill me now on this stuff, I will also add that the rocker ratio on this cam/rocker design will change as the cam wipes across the rocker and introduce an overall different characteristic and interaction of the cam to rocker arm.
Now, if one goes by the standard cam timing procedure, notch on the timing chain sprocket and the spacing plate, you could easily then move the lobe center of the can, and you will, if you dont take the time to degree the cam the no doubt way and make the approperate cam timing changes to maintain the lobe centers.
So what you end up with is an engine that will not reach its full potential for intaking air/fuel into and out of the combustion chamber. The valve being open less degrees of overall duration will effectively kill the power making potential of the engine. Better fuel economy, but less power, and a shorter effective power band the engine will be able to produce.
How is that for an answer specifically?
And YES I was curious who knows cam desing and dynamics as related to improving the pump. Oh and disregard mis spelling please.
signed pseudotechnician view point, Sniper S^$ker, with girly arms : UCC 1-207
A:
ROTFL im laughing my butt off reading this.
___________________________________
Got-Z.com http://got-z.com Converting Z'ers into bastards, one at a time.
Ghostkilla's personal website http://ghostkilla.net
Absolute Z Club http://absolutez.org L.A./Orange County
A:
makes since to me...as when talking to my machine shop he mentioned that I should get as close to zero lash as possible to get the hydraulic cam to operate properly. The problem was I didn't feel like getting things too "tight" and risk burning a valve. So guess what, I had a real cam ground instead of the stock one.
On a side note...can't I make fun of your spelling errors...I mean, aren't you perfect? lol
---------------------------
James Roraback
1983 280zxt 11.39 @129.38 - FOR SALE
ZCAR.COM member since Nov 1999
A:
i'll bite.
at the risk of someone going apeshyte, why not just buy the right cam for the right application?
79 280ZX -The best selling sports car of all time
Post Edited (Dec 8, 8:09pm)
A:
"Now for a street car that for the most part will see 5000 rpm's max, that is really not a problem,"
It will "work"...just like the 4bbl conversion "works"!
And for most of the people here, having something that pulls well below 5K is all they need. Hell, they can't get SU tuned right----what the hell difference will a cam only being good to 5K make?
lol
People Are Idiots, Just look around here and you will see!
Tony D: "Knowledgeable but Caustic"... rationull
My brother from another mother calls himself "Willie D"
A:
n/c
Post Edited (Dec 9, 4:33am)
A:
so if you miss-match parts, then don't use standard procedures for tuning? well, yea.
A:
Thanks for the info Jeff, that is informative. I'm more of a suspension, chassis and body person. I've put together a few motors but by no means have I learned as much as I want to. Because I did not know about the cam dynamics like you write about, is exactly why I went with a well know head builder and custom cam grinder. I wanted a motor that would pull from 2K - 8K and just keep building power the longer you stay in it, had to run on premium, at least in mild tune, and would hold together like a stock motor.
The bottom end was easy to get strong enough, the tricks are in the head esp. for a N/A engine.
What I'm wanting to know about is building a turbo motor, stock bore and stroke, but upgraded turbo, exhaust, Lonewolf or spork intake, nice intercooler yada yada. My real question is that I'm not going to be happy with a motor only building power to 6K, I'd like it to turn at least 7-7500. So what kind of cam selection do I have or would this be another custom job? And how about head porting, with the turbo is bigger always better? You just had a head built didn't you Jeff? How is it?
Thanks
Matt
A:
Nice article.
'74 260z---NA L28 MSnS-E w/ Innovate Wideband
Already sparking, soon to be squirting.
Cogito, ergo dolorum.