New Cam and Rockers - odd looking at 500+ miles

[inline6]

- I have been told to run the turbo oil pump. I am doing this currently so will report back to you maybe this weekend.

Ok.  Good to know, and I feel better about the "internal oiling + spray bar" issue as I am using a known good turbo oil pump.

 

inline6, sorry to hear you are having some issues with your 3.1 build.  Your engine build thread is a goldmine of information. 

 

Couple of thoughts that may not be worth anything:

 

1.  You say that the rocker wipe pattern is good - and holding the rocker in person is certainly better than viewing a small picture - but the first picture of rocker #10 appears to show the lobe contacting the rocker off the edge of the pad.  In any event, your lobes are clearly picking material off of your rockers. 

 

2.  I know that you consulted many professionals in your build, and Lord knows they know more than I do, but an installed spring pressure of 54# for a high revving engine seems awfully light.  As engine revolution increases, and the combustion event timing shortens, you generally need more spring pressure to keep your valves from floating.  Perhaps your ultra light titanium valves (and valve train components?) permit such a light spring pressure, but I would expect to have a closed seat pressure in the neighborhood of 154# and up to 290# open (~100# more than your springs) for a +7000K redline engine. 

 

Just my .02.  Hope you find a simple and inexpensive solution.

 

Thanks for the input.  If you look at the third rocker picture (going down the page), you might be able to discern the spot where the cam lobe wear spot stops.  I looked closely at each rocker and can see that the lobe is not running off of that end.  I do note that we could have "cheated" a bit more towards the passenger side and picked up a tad more effective lift, however. 

 

Yeah, I hear you on point #2.  If I was the test mule for this cam, I never would have gone for it.  But, Kinetic used this set up in race winning engines - a long time ago, so there is some history of success here.  I will have to check with them though about valve spring life.  I am sure since this is a race setup, they wouldn't dream of sticking in a car and running it 50k miles.  And I shouldn't dream to either.  Probably need to buy a spare set or two now assuming I still can.

[PMC raceengines]

i was looking at the first pics off the cam , you can polish the cam and rockers , but the damage is done its never good after it has galled up , the rocker has been over heated and needs to be resurfaced ,   there has been times when i have tryed to fix then to get thro a dyno sesion but its never good , at the end off the day if you fill your sump with metal from a cam that is failing ..

 

it happens so fast, no lube on the rocker and its over just cranking a new engine to get oil up can do it

[clarkspeed]

I don't know if this has anything to do with this situation or not, but I did an extensive experiment with the "dual" lubrication method for the cam. I was driving my oil pump with a heavy duty drill and actually watched the results of the internally oiled cam and the spray bar combo. The oil from the spray bar didn't even reach the cam followers, and this was with a heavy duty pump with heavier pump spring. There was still decent pressure coming out of the cam holes, I believe enough to lubricate the cam, but the spray bar was doing no good. To me, it was just more things to go wrong and i eliminated the spray bar. I think the internally oiled cam is WAY more than enough lubrication for the cam-especiallly if you see how it sprays out those holes.

There is a thread on Classic Z somewhere that i started, but I'm to lazy to look it up.

Hope you find your issue, I have enjoyed watching your build 

 

 

Question for MadKaw: When you did your experiment with both cam and spray bar oiling did you enlarge the orifice in the block any? My understanding is the orifice maintains pressure on the lower end in case of catastrophic failure on the top side.  By doing so it limits the volume of oil that can be pumped into the head. 

[clarkspeed]

Before I removed the one rocker I took a picture of, I checked the valve clearance on a few...  3 to be exact.  .25 mm and .30 mm were the feeler gauge sizes. I forget which is for intake and which is for exhaust, but I was just doing a quick check.  Two of the clearances I checked were intakes and one was exhaust.  The .30 mm fit in one only.  The other two accepted the .25 mm gauge.  So, seeing the clearances were close, I obviously moved on rather quickly to pulling one of the rockers for examination.  No dark areas on my rockers.  Heat like you experienced did not occur with this engine.  

 

Sorry to hear you have had such major problems.  I know that has been difficult to deal with after hoping for a nice experience from the new engine.

 

 

I had come across the posts about zinc before in the forums, but since my stock cam and valve train (old engine) had been rebuilt in the 90's and run for many ten thousands of miles over the years with absolutely no issues, I really didn't feel the need to invest a lot of time reading about it.  Definitely more interested now...  My engine builder is pretty top notch, and I know he used cam lube.  I just haven't bothered calling him to see which.  I found an assembly pic that shows the cam lube...

 

InstalledRockers2 (640x361).jpg

 

 

Thanks... I am running a "high capacity" pump which is most likely a 280ZXT pump.  I bought it from Malvern Racing - (Datsun Competition dealer) back in the 90's, and ran in my 4 cyl. 510 motor for a long time.  For this engine build, we took it apart and modded it a bit for improved flow.  Instead of running the high pressure spring, I run with the standard spring and a washer (used as a shim to bump the pressure up just a tad).  I'll definitely need to check the spray bar for flow issues.  Since all the lobes are looking very consistent with regard to the amount of deposits on them, it would seem my problem is also very consistent.  I'll also need to check oil pressure across the engine operation spectrum.  Perhaps I don't have enough pressure for 7700 RPM.  I don't think that is a problem, but it I have not checked it.  The rule of thumb is what 10 psi per 1000 RPM?

My head always looks like that when I get it back from the builder also.  But after a dozen test fittings and mutiple rotations for clearance checks it gets rather dry again.  I always give it another good coating before starting.

[inline6]

i was looking at the first pics off the cam , you can polish the cam and rockers , but the damage is done its never good after it has galled up , the rocker has been over heated and needs to be resurfaced ,   there has been times when i have tryed to fix then to get thro a dyno sesion but its never good , at the end off the day if you fill your sump with metal from a cam that is failing ..

 

it happens so fast, no lube on the rocker and its over just cranking a new engine to get oil up can do it

 

Wow.  This is hard for me to believe.    

 

So I need a new cam and rockers... or to resurface these rockers...  Any chance that because this cam was nitrided, I may be able to polish the lobes and salvage it?  I mean, the case of the part is hardened up to 0.65 mm (0.025") in depth during the nitriding process.  Maybe after polishing them to mirror finish, I could still use it with the same rockers (once they have been resurfaced, of course)?

 

G

[PMC raceengines]

I would try polish it with scotch brite pads , and i would do the rockers that are damaged as well , then run it again and check it after 20 min  runing time if it looks good then your fine , but if i had built it for a customer i would replace it with out thinking about it ,

just not how i do things. Just to not have a problem later is well worth the cost .

 

This was a problem we had on race engines with spray bar N42 style cam , when we changed to internal oiling cams it hardly was seen again , on my full on race engines i make a oil spray bar that runs on the other side off the cam as well as the factory intermal setup .

[inline6]

I would try polish it with scotch brite pads , and i would do the rockers that are damaged as well , then run it again and check it after 20 min  runing time if it looks good then your fine , but if i had built it for a customer i would replace it with out thinking about it ,

just not how i do things. Just to not have a problem later is well worth the cost .

 

This was a problem we had on race engines with spray bar N42 style cam , when we changed to internal oiling cams it hardly was seen again , on my full on race engines i make a oil spray bar that runs on the other side off the cam as well as the factory intermal setup .

 

I have been talking to the engine builder and he was saying the spray bar should optimally run on the other side...  How much for the spray bar - to the U.S.?

[PMC raceengines]

I only build them for my race engines , there not for sale ,  im sorrry there one off the cool parts that make the race engine what its is ,

and i have not seen to many other shops with it , ,

 

I must say there not hard to make , if i can find a pic i will pm you . 

[madkaw]

To answer Clarkspeed; to the best of my knowledge -YES. When I took my engine to the builder, I also handed him the "how to Modify' book , which i believe mentioned that little trick of enlarging the orifice.

 

I will also add that i bought the so called "turbo oil pump' when i did that experiment. Everything I tried( pump springs), failed to get oil to reach the lash pads from the spray bar.

[Tony D]

Yes 10 psi / 1000 - most engines easily have this by 3,000 rpms (like 60psi+!) unless there are clearance issues or something on the suction side causing problems. Recently someone here had a relief valve plunger sticking open, but that was aberrant.

[inline6]

I only build them for my race engines , there not for sale ,  im sorrry there one off the cool parts that make the race engine what its is ,

and i have not seen to many other shops with it , ,

 

I must say there not hard to make , if i can find a pic i will pm you . 

 

Ok.  Well, thanks very much for the info you provided... which you didn't have to, and I appreciate it.  

 

I've been talking to my engine builder and thinking about the initial engine start experience a lot.  My engine didn't fire immediately, but I was very cognizant of not turning over "too much" as I was told that assembly lube only protects for a bit... then engine oil pressure needs to happen.  And yet...

 

So... here is something everyone who builds a L series (or buys a rebuilt one) needs to know - and it is my main takeaway from my unhappy experience.  At engine cranking speed, there is not enough oil getting to the cam and rockers... on an L series.  Period.  Freshly rebuilt motors with dry oil passages?  That... times 10!  

 

When newly rebuilt, these engines NEED to start quickly.  That is, you can not crank newly rebuilt L series engines for extended periods of time... or many short periods of time.  If it doesn't start within a few seconds.  STOP, and find the problem.  

 

Yes, you have to have everything lubed and in my case, everything was... properly.  And even though you have everything lubed with the trick-est lube on the planet, if you crank it over many times without it starting - you absolutely are making a mistake - one that may cause cam and rocker failure in a hurry.  

 

As MadKaw has discovered, the stock spray bar set up is not ideal.  At cranking speed, it is basically doing nothing but waking up from a knap.  And, It is sitting on the passenger side of the cam towers with its holes pointing (at best) at the "back side" or the valve closing side of the cam lobe.  The loading from the spring and valve while closing is much lighter than on the opening side.  Spraying oil onto this side of the cam is not optimal.  Spraying oil at the front side, or the opening ramp, which is the high load side is much better.  

 

And yet more, if your cam is drilled for internal oiling, check out those oil hole locations on the lobes.  Half or more of them are in very sub-optimal locations instead of spraying the pad just before the front side of the lobe comes into contact with the rocker pad.  

 

Now, at engine speed - let's just say 3000 RPM for example, the oil coming out of the spray bar and the holes drilled in the cam is coming out big time.  There is lots of oil everywhere, and it is getting whipped all around, and in fact is creating a fog of oil inside the valve cover.  Though not optimal, as discussed above, at speed, it is adequate.  Turning over at starter speed?     Not so much.

 

I pulled the rockers and cam from the car today.  The silvery stuff on the cam lobes is not the rocker pad material transferring from the pad to the cam. It's very tiny flakes of cam that are now gone... due to lack of lubrication during initial start up.  

 

Since the cam is nitrided, and should as a result have a "case" that is hardened beyond .015 - .020", I am going to send it off to have it polished just enough to clean up the lobes (I estimate .001" max).  The rocker pads will be resurfaced as well.  When I get it all back together, (with lots of lube) I will have my starter fluid ready.

Edited April 7, 2013 by inline6

[PMC raceengines]

People have no idear how long the rockers have no oil on them on start up ,when the engine starts get the rpm up and make shore the timing is right then hold the rpm at 3000 to get the oil flow up to the cam , this is not a good time to start and stop the engine , try keep it running for 15 min at a good rpm , at idle the spray bar type engines have on oil on the cam , and also replace them if you have had a blow up as there is no real way off cleaning them  , if you block a hole even a small amout the cam is dead .

[Tony D]

We used an old fire extinguisher filled with oil to "pre charge" the lube system before first crank. You blast in the oil at 125psi (or whatever your shop compressor can pump air to I suppose) until your sump is full, then go to it. A check valve in the charge line allows you to immediately start the engine without physical disconnection... If you have some HK Hydraulic Disconnects you can pull it immediately after firing up.

 

It sprays from the bar or the cam pretty quickly this way. Everything is flooded before start.

[inline6]

People have no idea how long the rockers have no oil on them on start up ,when the engine starts get the rpm up and make shore the timing is right then hold the rpm at 3000 to get the oil flow up to the cam , this is not a good time to start and stop the engine , try keep it running for 15 min at a good rpm 

 

Since, I thought it was necessary for the cam break in, on first start, I ran my engine for 20 minutes at 2000 RPM. 

 

We used an old fire extinguisher filled with oil to "pre charge" the lube system before first crank. You blast in the oil at 125psi (or whatever your shop compressor can pump air to I suppose) until your sump is full, then go to it. A check valve in the charge line allows you to immediately start the engine without physical disconnection... If you have some HK Hydraulic Disconnects you can pull it immediately after firing up.

 

It sprays from the bar or the cam pretty quickly this way. Everything is flooded before start.

 

My engine builder offered to send me such a setup, but being ignorant, I thought it was unnecessary.  C'est la vie.

[madkaw]

...or, you use a pump drive shaft without a drive gear and prime the motor with a drill. I was just trying to prove to myself about the cam oil reduntancy, the side effect was my engine was fully primed before I ever started it.

It was always a worry for me to start a fresh engine and be able to satisfy the cam manufactuer with the 20 minute/2000 rule. Lets face it, a brand new motor with all kinds of parts that have never worked together before and now i expect to turn the key and MAGIC happens on the first revolution. I don't think so.

Then there's the Schneider Cam issue-or at least the one that has been alluded too many times on this site. It doesn't have the proper metallurgy because it's not a nissan core and they will fail. And any failure reported by someone on this site has been because of poor metallurgy of these cams(schneider)

I have 10k miles atleast on my cam now(Schneider) and the lobes look perfectly poilshed. What I know I have done right is primed the motor, have proper valve lash, and used ZDDP. The one thing I DIDN'T do right was the 20/2000 rule. I had issues and the motor probably ran 5 minutes the first time before I had to shut it down-can't remember why. But I do remember thinking that I fu@ked up and I have ruined the cam.

[inline6]

What I know I have done right is primed the motor, have proper valve lash, and used ZDDP. 

 

My engine builder is telling me that ZDDP shouldn't be used long term... that it is good for break in, but not after.  He says it acts like an abrasive or a polish - it helps parts mesh together, but is only detrimental long term.  

 

Just thought I would toss that out there.

 

As far as "priming" my new engine... I had the spark plugs out, cam nice and lubed... and I turned the engine over with the starter continuously for about 45 seconds while watching the oil pressure gauge.  I saw the needle on the gauge swing up... and I kept the starter engaged for another 5 or 10 seconds.  I was thinking this was a good way to prime the engine...  and it obviously isn't.

 

G

[NewZed]

Oil is Mobil 1 - the full synthetic 10W30 stuff.  I would have thought Jim Thompson from Kinetic Motorsports would have raised a concern with regard to getting the camshaft nitrided.  I just now sent a note via their contact form asking about the issue, and will see how that goes.

 

 

I tracked down some of my emails with Kinetic where we discussed the nitriding...  Here are some excerpts:

 

"The cam blanks used by our cam grinder have never been "CWC" blanks.  Though Kinetic has tried Nitriding and Parkerizing in the past, the fine polish finish on the lobes has worked best for lobe durability.  I asked Jim to confirm the cam grinder used the same cam blank (Estas) as usual."

 

There's a lot of good information in this thread.  Were you just being extra cautious with the nitriding?  Trying to avoid the new camashaft disaster?  The comment above looks like Kinetic doesn't recommend it, but doesn't recommend against it either.  But does say that the standard finish works best which implies that they've seen both in action.

 

Googling "estas camshafts" brings up some interesting web sites also.

[inline6]

At the time, I was reading alot about "CWC" blanks and cam lobe failures.  I actually started the project with a 490/290 Schneider cam I bought off of ebay.  It was a "CWC" blank.  I found a place online that nitrides cams (Web Cams).  I figured nitriding would fix that issue no matter what the blank, and didn't get push back from Web Cams (nor Kinetic with the later cam) about the matter.  So, I sent it off to Web Cams and had it nitrided.  Unfortunately, they didn't check the cam before nitriding, and it turned out that the three inner main journals were "octogons" instead of round.  I still have that camshaft - it is basically  "a display item", if you will. 

Edited April 8, 2013 by inline6

[clarkspeed]

Yes, good thread. The take-away for me is you can never be too careful on new engine start up. Like Tony mentioned, I also use a modified air tank to flood the bearings and cam on first crank. I previously thought it might be overkill.

[Tony D]

"...or, you use a pump drive shaft without a drive gear and prime the motor with a drill."

 

I hear this over and over an over.... and think "This isn't a SB Chevy, you have to drop the oil pump to put the distributor drive back in, not just drop the dissy and drive in place from the top and fire it off in 5 minutes.

 

Has anybody who suggests this ACTUALLY done this procedure? 

 

I mean, HOW EXACTLY do you clamp on that distributor shaft with the Jacobs Chuck, that little nubbin piece way down inside the front cover?

 

Inquiring minds want to know.