SR20 Camshaft Issue: Looking for some input - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

*2_Liter_Turbo* · 02-21-2013, 09:25 PM

So I got all of my head stuff back today, and I noticed something I've missed when I took everything apart. On the #4 lobe of my exhaust cam, one edge seems to be slightly higher (.001"-.002" is the best I can measure atm) as if the rest of the lobe was worn down but not that edge maybe? These cams have at most 3k miles on them between two failed motor builds (sad I know). They haven't been run since I sent them out for WPC treatment and they were used for adjusting the lash between the rocker and cam by Port Flow Design.

Here you can see that the rocker arm (if sitting in the middle) rides right on the edge. If you slide the rocker arm across the lobe, it does catch on the lip of the groove.

I'm not sure if I should run the cam or not. Part of me thinks that if the rocker arm doesn't hit it, I should be fine. I'm mainly worried about rocker arm tilt. Any constructive input would be greatly appreciated!

*TheRealSy90* · 02-21-2013, 09:43 PM

What kind of cams are they?

*2_Liter_Turbo* · 02-21-2013, 09:51 PM

Tomei ProCams (Solid Lifter) 260 duration 12mm lift. New motor is fairly built, expecting to turn 8500 RPM and running a Twin Scroll GT3071R. So it's definitely going to see abuse... lol. I'll only run that RPM if it makes power there though, otherwise less depending what the power curve looks like.

oni jake · 02-21-2013, 11:39 PM

I can only assume a lack of oil caused the wear. I would definitely start tracing oil flow and pressure throughout the motor system. Maybe a oil port was clogged?

Personally, I would take 600 grit sand paper and try to feather edge the height difference as much as possible, then install and do moving burnouts. Of course, you should call whomever you bought the cams from and check to see if they can do anything for you such as replacement or give you recommendations.

steve shadows · 02-24-2013, 01:25 PM

The cams are fine to keep using so is the rocker arm. It may have happend on first fire because the cams were not properly pre-oiled and were dry after being installed in the head but the cams themselves are fine. As previous poster said you could use some sand paper. I have blown rocker arms apart in the head and scratched the crap out of HKS cams and run them for another year with no problems, track days everything until I felt like upgrading them again to different cams...

Croustibat · 02-24-2013, 02:52 PM

It is on an SR20, so you probably have blocked oil spray bars in the head. Clean/change them before it damages another set of cams ...

*2_Liter_Turbo* · 02-24-2013, 04:28 PM

Quote:

Originally Posted by Croustibat

It is on an SR20, so you probably have blocked oil spray bars in the head. Clean/change them before it damages another set of cams ...

Spray bars work just fine. It was from rocker arm tilt.

codyace · 02-25-2013, 10:35 PM

That will be fine.

Call me the sloppymechanic, but I've put top ends together after rocker arm tossing/find the shim easter egg hunts, with cam lobes looking less than ideal, onyl to have them go thousands of miles without major issues. Not everyone has the time to wait for new junk and is willing to risk it on used/less than ideal parts ya know?

It is perfectly correct? Certainly not. In the same regard we're not building rocket engines here either. Heck my old roomates car made over 400whp with a clone of my setup on S3's that weren't in the best condition due to rocker arm scattagory. 25 thousand miles later you wouldn't be able to tell me it's got any issues, it still blows the tires off in third

Seriously serious. Sometimes the forums get too carried away with perfection and loose track of 'get er done'.

With that said though, just make sure you're not shimming the valvetrain too tight with the solids.

*2_Liter_Turbo* · 02-28-2013, 09:51 PM

Quote:

Originally Posted by codyace

With that said though, just make sure you're not shimming the valvetrain too tight with the solids.

I'm on the tighter side of what the spec range is. It's at approximately .005" or larger.

jamg · 02-28-2013, 10:05 PM

that wear and tear is normal for cams for an SR. it's metal against metal with oil as lubrication. Just make sure oil flow is working correctly.

steve shadows · 03-02-2013, 07:56 PM

Quote:

Originally Posted by SnapS13

I'm on the tighter side of what the spec range is. It's at approximately .005" or larger.

eh that's a bit tight but should be ok...

*2_Liter_Turbo* · 03-02-2013, 08:16 PM

I'm going to do a start up, warm it up and do a cam "break-in" for a few minutes, then shut it off and pull the valve cover to check everything. If it needs to be re-shimmed I will, and if not, I'll drive it for a few hundred miles then check them again. I want to be 100% sure that everything is solid before going in for my high boost tune. I'm currently on a break in low boost tune. Only running about 10-11psi, 5k rev limit and some timing pulled. Still make 250/250 on a mustang dyno though, lol.

02-21-2013, 09:25 PM	#1
2_Liter_Turbo Premium Member Join Date: Mar 2005 Location: Arizona Age: 37 Posts: 798 Trader Rating: (28) Feedback Score: 28 reviews	SR20 Camshaft Issue: Looking for some input So I got all of my head stuff back today, and I noticed something I've missed when I took everything apart. On the #4 lobe of my exhaust cam, one edge seems to be slightly higher (.001"-.002" is the best I can measure atm) as if the rest of the lobe was worn down but not that edge maybe? These cams have at most 3k miles on them between two failed motor builds (sad I know). They haven't been run since I sent them out for WPC treatment and they were used for adjusting the lash between the rocker and cam by Port Flow Design. Here you can see that the rocker arm (if sitting in the middle) rides right on the edge. If you slide the rocker arm across the lobe, it does catch on the lip of the groove. I'm not sure if I should run the cam or not. Part of me thinks that if the rocker arm doesn't hit it, I should be fine. I'm mainly worried about rocker arm tilt. Any constructive input would be greatly appreciated! __________________ 96 S14: Grip Track Car 90 R32: Bucket List Car 92 S13: Just for Fun Car Instagram: @SS.Maxey

02-21-2013, 09:51 PM	#3
2_Liter_Turbo Premium Member Join Date: Mar 2005 Location: Arizona Age: 37 Posts: 798 Trader Rating: (28) Feedback Score: 28 reviews	Tomei ProCams (Solid Lifter) 260 duration 12mm lift. New motor is fairly built, expecting to turn 8500 RPM and running a Twin Scroll GT3071R. So it's definitely going to see abuse... lol. I'll only run that RPM if it makes power there though, otherwise less depending what the power curve looks like. __________________ 96 S14: Grip Track Car 90 R32: Bucket List Car 92 S13: Just for Fun Car Instagram: @SS.Maxey

02-24-2013, 01:25 PM	#5
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	The cams are fine to keep using so is the rocker arm. It may have happend on first fire because the cams were not properly pre-oiled and were dry after being installed in the head but the cams themselves are fine. As previous poster said you could use some sand paper. I have blown rocker arms apart in the head and scratched the crap out of HKS cams and run them for another year with no problems, track days everything until I felt like upgrading them again to different cams... __________________ Like Me on FaceBook !

02-25-2013, 10:35 PM	#8
codyace Post Whore! Join Date: Dec 2004 Location: Poconos, PA Age: 36 Posts: 8,030 Trader Rating: (58) Feedback Score: 58 reviews	That will be fine. Call me the sloppymechanic, but I've put top ends together after rocker arm tossing/find the shim easter egg hunts, with cam lobes looking less than ideal, onyl to have them go thousands of miles without major issues. Not everyone has the time to wait for new junk and is willing to risk it on used/less than ideal parts ya know? It is perfectly correct? Certainly not. In the same regard we're not building rocket engines here either. Heck my old roomates car made over 400whp with a clone of my setup on S3's that weren't in the best condition due to rocker arm scattagory. 25 thousand miles later you wouldn't be able to tell me it's got any issues, it still blows the tires off in third Seriously serious. Sometimes the forums get too carried away with perfection and loose track of 'get er done'. With that said though, just make sure you're not shimming the valvetrain too tight with the solids. __________________ *Want Air Conditioning in your SR20 Swapped car? Check out www.sr20acbrackets.com for more information! Quest Alternator Conversions for SR20!* Check my Group Buy! Tired of lousy internal gates? Go external wastegate with one of my manifolds, Check out my group buy

03-02-2013, 08:16 PM	#12
2_Liter_Turbo Premium Member Join Date: Mar 2005 Location: Arizona Age: 37 Posts: 798 Trader Rating: (28) Feedback Score: 28 reviews	I'm going to do a start up, warm it up and do a cam "break-in" for a few minutes, then shut it off and pull the valve cover to check everything. If it needs to be re-shimmed I will, and if not, I'll drive it for a few hundred miles then check them again. I want to be 100% sure that everything is solid before going in for my high boost tune. I'm currently on a break in low boost tune. Only running about 10-11psi, 5k rev limit and some timing pulled. Still make 250/250 on a mustang dyno though, lol. __________________ 96 S14: Grip Track Car 90 R32: Bucket List Car 92 S13: Just for Fun Car Instagram: @SS.Maxey

02-21-2013, 11:39 PM	#4
oni jake Zilvia Junkie Join Date: Sep 2007 Location: Tallahassee FL Posts: 416 Trader Rating: (5) Feedback Score: 5 reviews	I can only assume a lack of oil caused the wear. I would definitely start tracing oil flow and pressure throughout the motor system. Maybe a oil port was clogged? Personally, I would take 600 grit sand paper and try to feather edge the height difference as much as possible, then install and do moving burnouts. Of course, you should call whomever you bought the cams from and check to see if they can do anything for you such as replacement or give you recommendations.

02-24-2013, 02:52 PM	#6
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 41 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	It is on an SR20, so you probably have blocked oil spray bars in the head. Clean/change them before it damages another set of cams ...

02-28-2013, 10:05 PM	#10
jamg Nissanaholic! Join Date: May 2009 Location: GA Posts: 2,106 Trader Rating: (7) Feedback Score: 7 reviews	that wear and tear is normal for cams for an SR. it's metal against metal with oil as lubrication. Just make sure oil flow is working correctly.

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