Bigger cam?

[NismoZ]

I agree with Jon, i have read forum after forum and there is too much miss information and myths it gets ridiculous...from what i see people are too extreme with what to do and don't do if they even know what to do, it makes people like me confused and not sure what end is up, so we make threads to try and clear up the confusion but end up only making a repeat thread.

Anyways thanks to you guys and Jon, i now know rocker arms are not a must with a cam swap especially if you using oem parts. A resurface is recommended but not mandatory if currant condition is acceptable. As for the cam choices im going to go with a 490/280 based on your guys experiences. Now all i need to know is what a 490 lift requires...such as do the guides seals need to be shorter etc..

[jmortensen]

You'll need springs, Schneider springs and retainers are fine, but some others have a LOT of seat pressure, so look out for that. I wish I could recall the "acceptable" seat pressures, but I do remember that when I installed the Schneider springs and retainers my machinist checked the open and closed pressures and made sure they weren't excessive. Hybrid Z has a good thread about shorter seals here: http://forums.hybridz.org/showthread.php?t=90825

Plenty of room for any sane cam size with those seals installed.

[five&dime]

I wouldn't necesarily trust the forums. I would talk with the people that actually do this work and know what they are talking about. We need Carl Beck, Geezer and HLS30 to provide their opinions here as well.

And please add my L20 and my BMW M52 to the list of engines built by Diseazd.

I can't imagine why anyone wouldn't replace the rockers at minimum with remans. It's only $200!!!!

I agree with my dad as well as Rebello, Wolf Creek, Z doc, Riley Curtis at Lynchburg Nissan and the countless others who will tell you that you should absolutely replace the rockers with new ones when changing your cam. Hell call Isky and ask them.....

I also don't understand how you say you "know rockers are not a must" If you knew that with 100% certainty than how can you ask what is needed with the swap? You are also contradicting your own previous post #25 with that claim.

You claim in post #1 you don't want to go through all the trouble to be dissapointed. Do it once and do it right.

And while we wait, read this taken from http://datsunzgarage.com/

ROCKERS and LASH PADS

I couldn’t believe it, but luckily every one of my lash pads’ wipe patterns lined up fine. Even after shimming up .080 with the .080 longer valves, the wipe patterns were fine. Some were biased slightly towards the valve end (more lift), but they were still positioned on the rocker OK.

Keep in mind that you will need new rockers arms. Even the slightest change in wipe pattern from this mod will cause damage if you reuse the old rocker arms.

In June of 2003 I rebuilt my shaved P90 a second time and added a new cam, rocker arms and lash pads. The engine went from standard mild Z clicking to nearly silent now. I suspect the worn lash pads were causing a bit of noise. I now feel lash pads should be replaced on any new head rebuild. They may look ok, but they wear like anything else, and can add slop into the valvetrain and increase noise.

Go to Motorsport Auto or Black Dragon Auto and buy "Modifying Nissan OHC engines", by Frank Honsowetz. Review the section in it about measuring and adjusting your lash pads. While I was lucky, having all this machine work done can leave the valve height a little weird. And if the wipe pattern is off you can destroy your cam! Don't underestimate the lash pads!

Edited June 5, 2009 by five&dime

[NismoZ]

For post #1 i didn't know what to expect with a cam swap with stock engine that why i asked, as for the rocker arm issue i came to that conclusion with people's experiences from this forum and others having no problems reusing rockers. I know its always best to replace new with new, but if you can get away with it then why not? If this was a high dollar motor than yea its all gonna be new, but since its a stock motor to get me by for now i dont want to spend to much on it if i don't have to..

Edited June 5, 2009 by NismoZ

[five&dime]

Good luck

[jmortensen]

I wouldn't necesarily trust the forums. I would talk with the people that actually do this work and know what they are talking about. We need Carl Beck, Geezer and HLS30 to provide their opinions here as well.

I would only listen to people who have ACTUALLY TRIED what they're talking about. If they've only ever replaced or resurfaced the rocker arms, then they haven't tried NOT replacing or resurfacing them. I've only tried NOT replacing or resurfacing them, and as I said, in 10+ camshafts installed that way I haven't seen a single cam or rocker failure.

I can't imagine why anyone wouldn't replace the rockers at minimum with remans. It's only $200!!!!

Send your $200 to me, and I will give your rockers and cam an internet blessing. Since you'll get the same result from either expenditure of your $200 in my experience, I think giving it to me would be more useful (to me).

I agree with my dad as well as Rebello, Wolf Creek, Z doc, Riley Curtis at Lynchburg Nissan and the countless others who will tell you that you should absolutely replace the rockers with new ones when changing your cam. Hell call Isky and ask them.....

Ask them when the last time they changed a cam and didn't change the rockers was. Might be worth a check to see if they make any money selling you rockers too.

And while we wait, read this taken from http://datsunzgarage.com/

Why is Bryan Little suddenly such an authority? What qualifications does he have to be the person who says yea or nay? I agree that his site is useful and I've pointed many people to it myself, but that doesn't mean that he should be the arbiter of right and wrong. As I recall his site has quite a few (small) errors.

Keep in mind that you will need new rockers arms. Even the slightest change in wipe pattern from this mod will cause damage if you reuse the old rocker arms.

Except if you're me or one of my friends. Then our special camshaft mind meld techniques will magically prevent this damage.

In June of 2003 I rebuilt my shaved P90 a second time and added a new cam, rocker arms and lash pads. The engine went from standard mild Z clicking to nearly silent now. I suspect the worn lash pads were causing a bit of noise. I now feel lash pads should be replaced on any new head rebuild. They may look ok, but they wear like anything else, and can add slop into the valvetrain and increase noise.

It is possible to measure the lash at the pad instead of between the rocker arm and camshaft. Discussed in some depth on the link I posted earlier to Paul Ruschman's writeup at Hybrid Z.

Go to Motorsport Auto or Black Dragon Auto and buy "Modifying Nissan OHC engines", by Frank Honsowetz. Review the section in it about measuring and adjusting your lash pads. While I was lucky, having all this machine work done can leave the valve height a little weird. And if the wipe pattern is off you can destroy your cam! Don't underestimate the lash pads!

Part of doing a valve job correctly is ensuring that the valves are all the same height in the head. Some places don't do this, but that's because they've done the job wrong. Checking the wipe pattern on every lobe ensures that you won't have a problem here.

[jmortensen]

One more thing--I think if you look on zcar.com you'll find Norm's writeup on resurfacing your rocker arms yourself. I believe he used a flat concrete slap and some emery cloth. Yet another DIY method that has been decried as horrible and insufficient, and yet he is the 12 second SU dude...

[Diseazd]

Jon.......If you wish to cut corners in building your engines go ahead. Five and and Dime has been taught by his "Old Man" "Diseazd" that if you put $5,000.00 into a "well built engine" you're a "dumb arse" if you cut corners to save $200.00 by not putting new rockers into that engine. You build your "half arse" engines the way you want and we'll build our pristine smokers the way we want!!!! See you on the race track!!!!! "Ojects in my rearview mirror are losing"!!!! Author unknown!

[five&dime]

We don't cut corners. We take em at full speed.

If you can't afford to do it the right way now. You save until you can

Edited June 5, 2009 by five&dime

[Diseazd]

Amen!!!!!

[five&dime]

What is $200 on a car build? Something to be said about doing the job right.

Final product speaks volumes. These are our builds. Any questions?

<a href="http://www.flickr.com/photos/14049800@N00/2611722439/" title="IMG_9284 by RVAE34, on Flickr"><img src="http://farm4.static.flickr.com/3008/2611722439_84a7cdb694_b.jpg" width="1024" height="683" alt="IMG_9284" /></a>

<a href="http://www.flickr.com/photos/14049800@N00/2612559530/" title="IMG_9287 by RVAE34, on Flickr"><img src="http://farm4.static.flickr.com/3203/2612559530_d63d3b38d9_b.jpg" width="1024" height="683" alt="IMG_9287" /></a>

<a href="http://www.flickr.com/photos/14049800@N00/3448422649/" title="IMG_0368 by RVAE34, on Flickr"><img src="http://farm4.static.flickr.com/3556/3448422649_e128f040ba_b.jpg" width="1024" height="670" alt="IMG_0368" /></a>

Edited June 5, 2009 by five&dime

[Diseazd]

Jon....These are pictures of the last 2 engines we built....now post yours!!!!