Broken Rocker Guides in my L-Series Motor

[BREdatsun]

I have started this 2 Door 510 project in the late 80s.  Many other cars, hobbies and life put this car on the back burner.  

 

My motor is a L-18 with SSS head, Dual Mikuni 40s, Datsun Comp long manifold, flat-top Z pistons, Racer Brown Cam (high-lift/short duration), Tilton oil Spray-Bar, MSD, Allison Ignition, Electric Fuel-Pump, Roadster Clutch & lightened Flywheel. Everything is new, barely broken-in around 200 miles.  Machine work was done by Stirtz in the 80's. The engine was put together by my buddy's shop the 90s and sat on a stand for 2 decades.  A few years ago, a local tuner shop got the car in running order and I drove back to my garage.   I occasionally start it and back it up when I want to get to my lawnmower. 

 

After hearing a valve-train noise, I decided to adjust my valves today.  

 

Lifting the valve cover, I knew something was wrong when I saw that 2 rocker arms was out of alignment.  I could swing them

L<->R.  The 2 Broken Rocker Guide (Lash Pads) were loose on top of the head.  I was totally bummed.

 

https://picasaweb.google.com/lh/photo/sUvSlIr04vNFHK7yXDoeohCj9dPUYz1_7kJSIyEk_P0?feat=directlink

https://picasaweb.google.com/lh/photo/sFDV0yPzGj14ZC_7hBsxoxCj9dPUYz1_7kJSIyEk_P0?feat=directlink

https://picasaweb.google.com/lh/photo/61yuOK58xOt7YzyTy2bV3BCj9dPUYz1_7kJSIyEk_P0?feat=directlink

https://picasaweb.google.com/lh/photo/JG_4xV5dQUqoG3rpUw2pvBCj9dPUYz1_7kJSIyEk_P0?feat=directlink

https://picasaweb.google.com/lh/photo/Ihp_TghXi31GhwcKYbGhFxCj9dPUYz1_7kJSIyEk_P0?feat=directlink

 

I dropped by the Nissan dealer and they had a few parts options but he had no idea what the specs were....  They had a digital calipers at the counter and I measured .20 mm on my broken valve guide.  One of my pics had the 3 part options:  13218-21000, 13218-A3500,  13218-21010 was shown on the Nissan computer.

 

My questions:

Where should I go to buy the Valve Guides?  

Do you think the 2 broken loose pieces will cause any damage?  Can't find them.

Any ideal if I need to regrind or replace my cam? 

Any ideas of the root cause?  I have my guesses.

 

Pardon the long story, but I wanted you to have a frame of reference.

I'm a long time lurker, 1st time poster.  Thanks!

 

 

 

 

[datzenmike]

 

Try as I might I sure don't see a spray bar on this head. Lack of any visible oil makes me wonder if it was getting any. Look at the contact area on the rocker pads. They look like divots on them from wear against the cam lobes. The blue tint may be from over heating. The cam lobes can be measured to see if they were ground down. Too bad.

 

This lobe looks worn down...

 

These broken parts are not valve guides they are called lash pads and they are selected by thickness to adjust the contact patch on the rocker arm. Most likely you can simply replace them and keep going. Usually over loose valve clearances will cause them to pop out. Rockers worn?

[banzai510(hainz)]

Think you better throw that cam away and start over.Thus lobes are fucked  New rockers also

ger new cam and rockers and you might be fine.

 

a spray bar system will have a hole in the back of the cam and the valve cover will have the spraybar(mine does on a motor I never ran).

One I seen but seen the othertype also.

 

 

did this have oil pressure and the oil pump was primed before start up?  might not be the proplem. Maybe the holes in the sparay bar were misalighned

[datzenmike]

I think it would still have oil on it somewhere, I don't see any.

[thisismatt]

Yeah, that cam and those rockers look toasted, lack of oil to cam lobes

[Sealik]

Might want to confirm that you have the proper valve spring retainers to go with those .200 pads

Should be running .190 -.220 .........they keep the thicker pads from falling out.

That's if you're replacing the cam with another that has the same specs (lift)

 

Which...could of been part of the problem.

Add some excessive valve lash clearance.....not good.

[john510]

As others have said,those parts are done.I also dont see a spray bar or the oil holes in the cam lobes.

[BREdatsun]

First of all, thanks for the quick and helpful replies:

 

Good point about the oil pressure.  I will get a pressure gauge before restarting it.

 

Here is the add on oil Spray-Bar

https://picasaweb.google.com/lh/photo/5-Em8woYye_p8zX0LSxxihCj9dPUYz1_7kJSIyEk_P0?feat=directlink

 

Rocker arm (keep in mind this was new just broken in)

https://picasaweb.google.com/lh/photo/A4LaDwDxgEyeY8yFbK5sLhCj9dPUYz1_7kJSIyEk_P0?feat=directlink

 

I'm suspecting the assembly of the motor and/or incorrect parts as being responsible.

 

I need to figure out a plan of action.

 

 

 

[cj8281]

I would verify that you are getting oil to the spray bar.  As others have said, cam and rockers are now scrap.  Definite lack of oil.  Does the spray bar have metering orifice that might have gotten plugged?

[Sealik]

Rockers look aftermarket?

 

 

That is a lot of metal....hopefully you're not sporting a Fram

 

[datzenmike]

Get an L20B cam, the eight rockers and their lash pads from an old head. Boom back on the road. The stock cam should have the oil holes so plug that spray bar.

[BREdatsun]

The Tilton Spray Bar accessory that I installed was intended to supplement the factory oiling mechanism so I believed.  Are you saying that it maybe reducing the oil pressure to the cam?

 

This engine was being broken in, I did not over rev it or put less than 200 miles on it.  Can say I know exactly what the shop did when they started it up initially.  Sigh, a lot of damage for a short time frame.  I would prefer to replace components with new parts, after all, most of this motor was new.

 

The "Blue/Purple" tint on the rockers is assembly dye to see what contact points are during wear, not for overheating.  Also, this car is not driven, so the valve train would be oil free at top.  I did not crank it before removing the valve cover.  

 

I don't recall if the rockers are aftermarket, could be.

 

I just checked the valve clearances, Not good:

E - Tight

I - Loose

I - Loose

E - Loose

E - Loose

I - Broken Lash Pad

I - Broken Lash Pad

E - Tight

 

Thanks for posting my photos, I have not figured that out yet.

[datzenmike]

If the engine was even started it should have oil all over the valve train.

[hang_510]

was the oil pump primed?

[ggzilla]

L-series oil pumps are self-priming. But the Nissan Competition pump is not.

[datzenmike]

The small hole in the block that supplies oil to the head, would that be sealed off if you have a spray bar? I ask because the engine would never have traveled 200 miles without oil.

[HRH]

Dumb question, are there holes in that spray bar?  It sure doesn't look like it.  I would prelube the motor after getting a new cam/cam followers (rockers).  Remove the distributor and drive spindle, put a screwdriver or other apparatus down the hole and turn counter clockwise with a drill and socket attachment.  It should turn easily for a second until it gets oil pressure, then it should get a bit harder to turn.  You should have oil poor out of the cam holes with continued drilling.  Disconnect the spray bar, test that separately.  That will tell you if any oil passages are clogged.

[BREdatsun]

To my knowledge, the person who assembled the engine did not know I was putting on a spray bar.  Why would a builder block the oil passages?  But then again why was it put together with some valves tight and some way loose?  I'm over it, there were too many people that touched this motor and too much time has passed.  I trust it was put together properly.

 

Not shown in my photos, are oil holes on the Racer Brown cam.  I did my 1st oil change a few months ago and it just sat in my garage. The oil came out dark and there was metallic particles, thought it was normal for new motor.  You guys could be right about oil starvation, with only standard gauges on the dash, who knows for sure.  I'm going to attach a oil pressure gauge before restarting this motor.

 

Is the dealer the best place to get new rockers and valve lash guides?  

Any recommendations for mild cams for SSS L18 with 10:1 compression?  To be used on the street and a few track days.

 

Thanks for all the replies.  Too bad none of you are near San Francisco  :crying:

[BREdatsun]

Thanks for the oil tip KAZ.  There are several holes on the spray bar.  

 

My goal is to build period correct 510 within my budget.

 

 

 

 

 

[thisismatt]

Where are the oil holes on the cam?  There don't seem to be any on the cam lobes.  With that much visible wear it's not surprising that valve lash is loose...more surprising that it's tight on any of them.

[hang_510]

how did it run?

 

was the spray pattern checked?

 

 

L-series oil pumps are self-priming. But the Nissan Competition pump is not.

a dry initial start and if they were over tightened to begin with, that could start some bad things...

 

thats extreme wear on the rocker. which does look like the 1 piece style.

[ggzilla]

That's what assembly lube is for. There will be no dry start.

[john510]

To my knowledge, the person who assembled the engine did not know I was putting on a spray bar.  Why would a builder block the oil passages?  But then again why was it put together with some valves tight and some way loose?  I'm over it, there were too many people that touched this motor and too much time has passed.  I trust it was put together properly.

 

Not shown in my photos, are oil holes on the Racer Brown cam.  I did my 1st oil change a few months ago and it just sat in my garage. The oil came out dark and there was metallic particles, thought it was normal for new motor.  You guys could be right about oil starvation, with only standard gauges on the dash, who knows for sure.  I'm going to attach a oil pressure gauge before restarting this motor.

 

Is the dealer the best place to get new rockers and valve lash guides?  

Any recommendations for mild cams for SSS L18 with 10:1 compression?  To be used on the street and a few track days.

 

Thanks for all the replies.  Too bad none of you are near San Francisco  :crying:

I wouldnt bother trying to restart that motor at this point,you might cause further damage to things that arent ruined yet ! you said there are several oil holes on the spray bar ? there should be 8,one for each cam lobe.

[cj8281]

It does not surprise me at all that some valves were tight. When you rebuild a cylinder head you grind the valves a half a degree shallower than you grind the seats. This creates a sharp edge that helps the valves seal initially. This edge breaks down as the valves fully seat and the valve seats a bit deeper in the seat, this causes the valve lash to tighten up.

[banzai510(hainz)]

Sealik has a point on the rockers. Most atsugi rockers are 2 pc as the pad is harder and brazed on . sealed power had some 1 pc rockers and they are bad news. I seen them and they are bad.

The good rockers will have the Nissan outline or say Atsugi on them.  most are about 25$pc now if you can find them but seen places selling them for 13$ apc back in the day.

 

as for oil pump I always fill them with oil. I don't trust self priming as I never seen oil/assembly lube in them from O rileys or Schucks or where ever they come from. When I was new to L motors I seen a guy pout the pump in and start. Rockers made a lot of noise. pull the pump and full of shavings.  So I don't get the self priming part. oil needs to fill in the airgaps to creat the vacuum.  But I have a feeling your pump was working.

 

get the timming chain tool and time it then  pull the head. Fuck drain the oil to get the shavings out.also.

 

Persoanlly I never like those spray bars and cam with the hole in the back. Just get a turbo/KA pump and run a reasonable cam and all will be fine. Baz in Australia don't run spray bars. Its just a thing to brag about at the 510 gatherings to make your dick feel bigger.

 

 

the more I look at those rockers I bet they are the USA made Sealed Power units maybe noting else is bad except those. Would have fail anyway with oil or not. Go to Sealed Power and sue them if they still in business. really the engine builder/part supplier should have know these units have a bad rep.