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Lash pad fell off top of valve spring

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I bought some new tires and hit the old two lane highways to rack up some miles for the break in. Smiling from ear to ear. Guy in an older 3 series BMW got behind me and heard the sound. We pull into a quick shop and I shut it down talked for a few minutes got back on the road and realized I had a dead skip. Pull over again raised the hood and clackaty clack valve sound. Slowly limped back home to do a hot valve adjustment. Pulled the cover and found a lash pad off #3 intake valve spring. Can I take that rocker arm off and put it back on? The lock nut was tight as I had done a cold adjustment when I put the motor together. Don't understand how it happened but I want to fix it ASAP. Only got 53 miles out of my scenic break in. Also the valve didn't fall as my Dad scared the crap out of me with that, maybe a Chevy does that or something.

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It's possible that you weren't completely on the base circle when you set the lash and it was larger than you measured. When you put it back on, remeasure and see where it was before it fell off. Open and close that valve and make sure it isn't sticking.

I had one come off my race car 4 hours into a 14 hour race and it turned out to be a weak spring. I was still using the original springs and they didn't like high RPM operation.

Edited by Jeff G 78

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Lash pads can kick out from over revving, poor valve adjustment, weak spring causing valve float, or because its Tuesday. Loosen the rocker arm, reinstall the lash pad, and adjust the valves.

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Ours fell out on Friday (maybe that's an east coast thing) while on the dyno at 7000rpm and wonder be told didn't destroy the cam or other moving bits and pieces in the head. Cam tower spacing was off. Our bad.

Hope you recover from this event. It was quite a shock to have happen and depressing until we found out it was okay.

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When ours fell off in the race, we stayed on the track for another 2 hours before we pitted to diagnose and fix the tick. we lost only a handful of laps pulling the valve cover, finding the problem an fixing it. There was no damage from the mishap. Once it's off, it simply lays in the head.

Edited by Jeff G 78

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Thank you John Coffey, you got my arse off the floor. Jeff I'm so glad you race because you've given me insight I wouldn't have otherwise. That lash pad replacement was 1 of the easiest things I've done so far, thank you also Gnosez for the re-asurrence. It is purring like a souped up wildcat now.

l'll keep my rpm's low for awhile since I'm still unsure about stuck valves. Olzed your a treasure of information, thanks for all your post. Thank you all again, I'll sleep good tonight

Edited by siteunseen

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A lash pad came off on my '71 240Z today.  I had never heard of that happening so I searched and found this thread.  Valve adjustment nuts were tight and valves were adjusted a few months ago so I'm not sure why it came off.  Fortunately, it happened in the garage while I was working on it (trying to get the float height set correctly) so I was able to shut it down quickly, pull the valve cover and locate the problem.  Thankfully the lash pad was just sitting there right next to the valve it came off.

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When I was putting the lash pad back on I didn't notice anything strange but I agree when looking at that picture it doesn't look right.  I'm going to take the valve cover back off tomorrow and have another look at it!

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It does look like the spring is leaning.  Check and make sure the outer spring seat, big flat washer looking thing, is in place and the spring hasn't fallen off it's perch.

You may have to replace a spring?  I may need glasses. LOL

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2 hours ago, Lumens said:

A missing keeper may cause that unless I need to change my glasses prescription. 😃

That sounds better to me too, now that I'm looking at it on my laptop instead of a small phone.  Thank you Lumens!

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I had the entire rocker arm dislodge. It was laying on top of the head when I took off the cover. Reinstalled and had no problems. My wife had definitely over revved on stock springs. These L engines are really tough durable runners. 

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18 hours ago, Lumens said:

A missing keeper may cause that unless I need to change my glasses prescription. 😃

If it is a missing keeper, fix it immediately before firing it up again. If it drops the second keeper, your valve will have a close encounter with your piston. A friend of mine had his new gas tank liner dissolving in his gas. The viscous mixture was causing his valves to seize and throw keepers. It was always only intake valves (how he figured it out).

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I removed the valve cover again and double checked the valve and everything looks fine.  I'm not sure why it looks so strange in the picture, I'm guessing the camera zoom may be "distorting" it in some way.

Diseaszd, before putting the lash pad and rocker back in place, I checked that both keepers were in place so I'm ok there.  I'm interested in the tank liner issue as well (as jonathanrussell just posted) as I did have the tank cleaned and relined last year and the valve in question was in intake.  Any more information on that would be greatly appreciated.

Thanks for all the replies, these Z forums are just a wealth of knowledge and a great help when it comes to troubleshooting and fixing these old Z cars.

Edited by 240Znomad

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It was the Red Kote Liner....not sure if they didn’t get the right formula or didn’t let it cure correctly, but you could see the red color in his gas. They redid his tank and there was no further problem. He would throw lash pads everytime he fired it up until he fixed the problem. The intake vales were all that was affected....the liquid under heat would gum up the valve stems and cause the valves to stick. I know that many have used the Red Kote successfully for years, so I hope this is just an isolated example. I like to use Por 15 gas tank sealer myself....IMO only.

Edited by Diseazd

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I just fired up the engine on my '71 240Z to do some carburetor adjustments (car had been sitting for a week), and had 2 valves (both intakes, #3 and #5) where the rockers nearly popped out of the lash pads.  Here's a quick history:

1. I had a lash pad pop off about 6 months ago, see pictures above in this thread.

2. The car has since been sitting for the last few months (I have been working on the heater core and a few other items) and fired it up last Friday.  Warmed it up and took it out for a drive to the gas station and drove a few miles.  No problems.

3. The car sat all week.  I went to fire it up today and before it even started up (ie. while cranking the engine over) I could hear some loud clicking.  Finally fired up 10-15 seconds (after filling float bowls) and clicking was loud so I immediately shut it down and thought of the previous lash pad issue.

4.  Removed the valve cover and saw that the lash pads were "****-eyed" and the rockers were off line on both the #3 and #5 intake valves.  I loosened the nuts to lower the rockers and got everything back in place.  Re-adjusted both valves (cold), put the valve cover back on and fired it back up.  Everything sounds and runs ok.

@Diseazd  mentioned earlier in the thread about a possible issue with the gas tank liner (Red Kote) dissolving in the gas and gumming up the valve guides causing the valves to stick.  This sure seems like a possible cause since it ran fine when I shut it down last week and was clicking immediately on cranking today.  I did have the gas tank completely re-done at a local shop about a year and a half ago so I think I need to run down and talk to them about what they use to line the tank.

Does anyone have any other ideas or things that I might check?  I think I read someone mention valve seats possibly being an issue, and another mentioning possible weak springs.  Has anyone tried an additive like Marvel Mystery Oil to clean carbon deposits or gumming on the valve guides?

In the pictures below, the first two (015 and 016) are intake #3 and the second three pics (017 to 019) are intake #5.

Any help would be greatly appreciated.

 

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Edited by 240Znomad

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