Bigger cam?

[jmortensen]

It's tough to say how a cam will work. If it's the MSA Stage III I think its USUALLY too small and gives fairly crappy results. Then again, there's Jeff's car over at Hybrid Z: http://forums.hybridz.org/showthread.php?t=145256 How he's getting that result with that camshaft I'll never know. I do know several people who bought it and then took it off because it sucked. One thing that I can say is that a cam should be just one component in a larger system.

I ran that .490/280 on my relatively stock L28 (8.5:1 compression) and it ran great. I wouldn't be afraid of more cam with a stock motor.

[Ksteve]

I had Delta regrind my cam a couple years back to the same .460/280 spec. I have been happy with the change, noticable diffrence from 3500 and pulls hard to 6500 now. Idle is a bit rough and had to be increased to 1000. This was on an L24 with N42 head at 9.5:1 compression. They will regrind your cam and resurface your stock rockers for about $120, which I think is a bargain. They even got it back to me in about a week.

The resurfaced rockers will require slightly thicker lash pads which can be ordered from Courtesy Nissan. Mine took a combination of .180 and .190.

Hope this helps,

Steve

[NismoZ]

I had Delta regrind my cam a couple years back to the same .460/280 spec. I have been happy with the change, noticable diffrence from 3500 and pulls hard to 6500 now. Idle is a bit rough and had to be increased to 1000. This was on an L24 with N42 head at 9.5:1 compression. They will regrind your cam and resurface your stock rockers for about $120, which I think is a bargain. They even got it back to me in about a week.

The resurfaced rockers will require slightly thicker lash pads which can be ordered from Courtesy Nissan. Mine took a combination of .180 and .190.

Hope this helps,

Steve

Thanks for your input Steve, every little bit helps. About The cam you had ground, was the duration split 270/280? or was it 280/280?

[Diseazd]

Isky will regrind your cam to stage III, provide the proper valve spings (stock is good for only .450 lift max.) lash pads and retainers for $390.00. New rockers are an absolute must for a new regrind ($200.00 from Nissan). The L28 stage III is 10 degrees greater duration than stock with a .490 lift. You really feel this cam come on above 3,000 rpm. Head work helps as well as headers, but increased compression with flat tops does the most for a hotter cam. www.iskycams.com

[Marty Rogan]

I have been considering putting a hotter cam into my track day car for a while now. It has an '83 L28, bored 40 over, running the stock SU's and a header. The motor only has around 2,000 miles on it and I have been waiting for the warranty to expire (next May I think) before doing any modifications.

Will changing the cam alone make that much difference? Or do you need to switch to tripple Mikuni's to really get the benefits?

How tricky of a job is this? I have swapped out the entire drive train and suspension on my own, but I have never really done any work internal to the engine.

Please provide the website or contact info for Delta.

thanks,

Marty

[jmortensen]

I have been considering putting a hotter cam into my track day car for a while now. It has an '83 L28, bored 40 over, running the stock SU's and a header. The motor only has around 2,000 miles on it and I have been waiting for the warranty to expire (next May I think) before doing any modifications.

Will changing the cam alone make that much difference? Or do you need to switch to tripple Mikuni's to really get the benefits?

How tricky of a job is this? I have swapped out the entire drive train and suspension on my own, but I have never really done any work internal to the engine.

Please provide the website or contact info for Delta.

thanks,

Marty

Changing the cam does make a difference if you get the right cam. My car with the wimpy cam would get to the 6800 rpm redline, but barely and there wasn't much point. When I went to the bigger cam it would smack the redline. With Mikunis it would slam against it. The SU's and the big cam were the best perfoming combo I had. I could have done better with the Mikunis but really had diff gears that were too tall. The Mikunis wanted 4.11s or 4.44s for autoxing, not 3.70s.

Getting the valvetrain geometry right is not hard but takes time. Timing the cam is more difficult, but still is mostly about taking the time to do it, not about learning new skills. I think there is info on both here: http://forums.hybridz.org/showthread.php?t=111523

Edited June 5, 2009 by jmortensen

[Diseazd]

Marty.....Changing the cam to a Stage III will give you about 20 h.p. Changing the cam and increasing compression to 10 to 1 will give you give or take about 30 h.p. (flywheel). To do so you need to shave and shim the head. New cams require correct rocker geometry........installation best left to a pro with access to multiple size lash pads. With parts and labor, a correct installation will cost $1,000.00 to $1,200.00 for everything! Well worth it IMO.

[jmortensen]

Diseazd, for a guy who (apparently) doesn't do his own work you sure make a lot of absolute statements. In my experience with probably 10+ reground camshafts between myself and my friends with Zs and 510s, it is NOT necessary to change the rockers. Installation is really not that hard either. Just requires that you keep checking until you get it right. Lash pads can be dealt with in a couple ways.

1. Follow the link that I posted and it shows you how to cut up a feeler gauge to test different lash pad thicknesses. Then buy the right pads the first time.

2. Buy one of a bunch of different thickness pads, then use them to test and buy 5 more of the right ones for the intake and 5 more for the exhaust.

That said I would say that the hp numbers quoted are pretty close to correct, as judged with the butt dyno.

[Ksteve]

The regrind Delta did for me was a 280/280 duration (230@.05 lift). I had read a lengthly debate either here or on Hybridz about using resurfaced rockers vs. new, and to me it sounded like resurfacing was a safe way to save some of the parts expense. I have put over 5K miles on my engine since with no cam or rocker wear problems.

Steve

[Marty Rogan]

Thanks for the good info guys. I should have mentioned that the car also has a 4.11 R180 diff.

It is good to hear that you can get a significant performance improvement without the need to go with tripple carbs.

Marty

[Diseazd]

Jon.....Who pulled your chain?......I do all of my own work and have done since 1970. I've built over 20 L series motors including the 5 I currently own (3 L-24's and 2 modified L-28's). If you want to build an engine with old rockers do it........however most good builders recommend reconditioned or new rockers with a cam regrind. You build it your way I'll build it my way!!!!!

[jmortensen]

Sorry, Diseazed. I guess I'm a little sensitive on this topic. Mostly I get a little uptight at the "internet imperatives". Examples include:

Anything bigger than a mild cam will have absolutely no low end at all and will make the car slower.

You ABSOLUTELY POSITIVELY MUST change the rockers or resurface them or the cam will self destruct.

Finding the right size lash pad is next to impossible.

You must have at least 10:1 compression to run a cam that is significantly larger than stock.

It's really easy to go with too much cam, so stay conservative.

There's more but those are the usual myths that I find myself getting annoyed with. If you've done the work yourself you should know that it's not rocket science. Just takes some time to understand the fundamentals of what you're doing and the patience to get it right before you start driving the car with the new cam.

Probably the one that annoys me the most is the "don't go too big" myth. I don't think I've EVER seen a post from somebody saying: "My cam is too big", but you see hundreds warning not to get too large a cam. I fell victim to this one myself and spent time and $$$ installing a barely larger than stock cam and then really felt like I was taking a risk getting my second aftermarket cam at .490/280 and it was a night and day difference. I had listened to the "conventional wisdom" to my own deficit.

As I said, I've run my rockers on 3 cams, no resurfacing between them, and my friend used to install cams on all of our little group of Datsun guys cars and a couple Toyotas too. None of us EVER changed the rockers out or resurfaced them, and nobody EVER had a rocker failure or a lobe go flat. Most of the cars were autoxed, and all of them were either L series or 22RE's or 20R's.

My feeling is that most of the warnings you hear related to the rockers have to do with Schneider cams. If you look up "cam lobe failure" here or at Hybrid Z I think you'll be hard pressed to find one that isn't a Schneider. To me this is reminiscent of the Fel-Pro gasket deal, where Fel-Pro proponents generally seem to think that Fel-Pro gaskets are the best, and also that L6 engines are prone to head gasket issues. That's my take on it anyway...