Lash Caps....Seven Came Off

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tonysrt said:
604b1duster had the answer. Lifters collapsed from you turning motor over without oil being pumped into them. So on your initial start too much clearance with lifters due to collapse and giving the caps the room to come off. So in a sense you created a problem by eliminating the problem of pistons seizing by turning motor over. lifters may have collapsed any way just sitting there.
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weren`t they for solid lifter cams only ???????????
 
That would explain why it might not be a good idea to use them with hydraulic lifters. Solids never collapse.
 
Lash caps are put on the top of the valve stem to keep from mushrooming the head of the valve. They serve a useful purpose, like if you have tear a head down for inspection with one of the sanctioning bodies at the track. Ask me how I know.
 
Funny lash cap story.
So I've got the hot rod Honda motor for the go kart 75% together. The billet rod, flat top, big :rolleyes: cam, ported head, stainless valves, the bottom end is all sealed up. I put the rockers on and the lash caps. Time to set the valve lash. Rotate the rocker towards the valve stem. There goes the lash cap right down the valley for the push rods directly to the crank case :eek:. Now 200cc Hondas aren't very heavy, let's turn it upside down and give it a good shake. Nothing. OK, a magnet, nope the magnet is too big to fit down the push rod orifice. Smaller probe I need. Found that. Let's experiment out here on the workbench. little magnet is too small to magnetize the long probe. Bigger magnet. Hmmm, only bigger magnet I have is the OE flywheel that has a tendency to grenade when revved much above the limit that the governor sets. Retrieved the lash cap from the crankcase with the 12" long screwdriver attached to the magnet on the flywheel. Glad no one was around to take pictures :rofl: They do provide a much better target for those tiny valve stems to hit the rockers.
 
I'm not a proponent of lash caps. I would think they would be an issue with hdraulics, and my gut says that because there's no oil pressure in it that's a big part of your issue.
 
Demonracer said:
Lash caps are put on the top of the valve stem to keep from mushrooming the head of the valve. They serve a useful purpose, like if you have tear a head down for inspection with one of the sanctioning bodies at the track. Ask me how I know.
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I've only seen that if the valve doesn't have a hard tip. The mushrooming I mean.
 
I personally think lash caps are used as a crutch for poor geometry, most of the time. There might be other reasons to use them, but I'd bet money there is a geometry problem with the valve train in this case. Waiting on a picture! Otherwise it's just a bunch of wild speculation at this point.
 
yellow rose said:
Never seen a Ti valve without a hard tip. Unless you are buying blanks and putting your own groove in them.
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I have two sets of 7mm intakes/6mm exhausts that need lash caps... Not just for wear but for a large enough target for the rocker arms.
 
Krooser said:
I have two sets of 7mm intakes/6mm exhausts that need lash caps... Not just for wear but for a large enough target for the rocker arms.
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I agree. I said earlier if the stems are .312 or under you need a lash cap. So 7mm is ~.278ish and 6mm is ~ .238ish. And those damn sure need a lash cap.
 
Stock Hemi's are 5/16 and don't have lash caps from the factory. My friend ran them on a ford 11/32 valve, solids and kept loosing them, this was back in the late 80's and I thought the springs weren't stiff enough, but the cam manufacture said they were good, he finally got rid of them. There has to be a big gap for them to fall out. As for the mushrooming I have seen a chevy with a rocker ball wobble around and mushroom the valve but I haven't seen a mopar with hardened tips mushroom.
 
Lash caps. They are only good for three situations.
1. As mentioned, on very small valve stems, and that limit is generally 7mm. Anything larger is going to have enough contact area if the geometry is correct.

2. Again, as mentioned, for Titanium valves that do not have hardened tips. If a valve with hard tips is being mushroomed, regardless of material, it is being beaten to death by an unstable valvetrain.

3. To correct geometry. BUT, not with a roller rocker. This only applies to running high lift cams with a non roller type rocker. That is why Mopar recommended them for Hemi engines. The small valve stem combined with the increased scrub of the rocker from high lift, and the need for a lower pivot location in relation to the valve tip, is what necessitated the lash caps. Outside of that, there is absolutely no need for them, and they are detrimental to proper geometry on a Mopar with roller rockers. Period. When you can run .750" lift and have the rocker sweep .050" or less, the lash caps are a bad idea.

I'm not here to bash anyone, but I do have some professional inside knowledge that would tell me that if lash caps were used on an LA rocker setup, it was a bad move. Most likely they were installed to increase clearance between the rocker and valve spring/retainer, or to center the sweep pattern and keep the roller from running of of the valve tip. In either case it's a bad move, and is a misunderstanding of proper geometry.
 
Well, we tried looking at the sweep without the lash caps and it was way off. I not swift on Mopar engines, but it appeared the have a curved metal piece under the shaft, where the shaft fasteners go, that altered the angle of the shaft. I had to make a decision on this thing. We were getting paralyzed by analysis. We re-installed the caps, adjusted the valves, primed the heck out of it. With the valve covers off, we turned the motor over quite a bit, watching the oiling and re-checking the lash caps to see if they were secure, and they were. We buttoned it up, started it up, and put maybe 20 road miles on it, with a few hard hits shifting at 6200. Everything seems to be fine. Valvetrain is quiet and runs great. I'm going to race it this weekend in a no box class. I had to take into account that Mike at MRL has built no telling how many of these engines, and I had to put some faith into his knowledge and experience. Like they say.... I'm sending it! I appreciate all the input, and as always, I've learned a lot. Thanks!
 
brian6pac said:
Stock Hemi's are 5/16 and don't have lash caps from the factory. My friend ran them on a ford 11/32 valve, solids and kept loosing them, this was back in the late 80's and I thought the springs weren't stiff enough, but the cam manufacture said they were good, he finally got rid of them. There has to be a big gap for them to fall out. As for the mushrooming I have seen a chevy with a rocker ball wobble around and mushroom the valve but I haven't seen a mopar with hardened tips mushroom.
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-----LAH CAPS--------
They were suggested by Chrysler fot the 426 race engines , back in the day, "IF" u had a big cam. 5/16 valve stems needed them with a huge cam. We had dick landy re grind the rocker arm pads to go w/ it, just to make sure they were correct. I suspect they were from the factory tho. Hemi`s were "right" , not like chevy stuff !
 
famous bob said:
-----LAH CAPS--------
They were suggested by Chrysler fot the 426 race engines , back in the day, "IF" u had a big cam. 5/16 valve stems needed them with a huge cam. We had dick landy re grind the rocker arm pads to go w/ it, just to make sure they were correct. I suspect they were from the factory tho. Hemi`s were "right" , not like chevy stuff !
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Jst read br3e `s post -----agree. I have a new set of lash caps, I was going to use on my 505, but they threw the geometry off , so I didn`t use them.
 
OP, your re-start probablyh worked because the lifters were pumped up again. Going forward, keep an ear out for any lifter ticks at start up. If 1 or some tick at all at start up, then those lifters are leaking down and you are open for the possibility of the lash caps falling out there once again.

Keep an ear on them as long as you have the caps in there; this type of lifter leak down problem can develop at any time. So this problem may dog you forever 'til you get them out of there... 'specially after the engine is sitting for a long time.
 
Jay Anderson said:
Well, we tried looking at the sweep without the lash caps and it was way off. I not swift on Mopar engines, but it appeared the have a curved metal piece under the shaft, where the shaft fasteners go, that altered the angle of the shaft. I had to make a decision on this thing. We were getting paralyzed by analysis. We re-installed the caps, adjusted the valves, primed the heck out of it. With the valve covers off, we turned the motor over quite a bit, watching the oiling and re-checking the lash caps to see if they were secure, and they were. We buttoned it up, started it up, and put maybe 20 road miles on it, with a few hard hits shifting at 6200. Everything seems to be fine. Valvetrain is quiet and runs great. I'm going to race it this weekend in a no box class. I had to take into account that Mike at MRL has built no telling how many of these engines, and I had to put some faith into his knowledge and experience. Like they say.... I'm sending it! I appreciate all the input, and as always, I've learned a lot. Thanks!
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Please elaborate on these curved metal pieces under the shafts. It sounds like this may be one of the engines Mike built with my geometry kits. A pic would be nice.
 
Jay Anderson said:
Well, we tried looking at the sweep without the lash caps and it was way off. I not swift on Mopar engines, but it appeared the have a curved metal piece under the shaft, where the shaft fasteners go, that altered the angle of the shaft. I had to make a decision on this thing. We were getting paralyzed by analysis. We re-installed the caps, adjusted the valves, primed the heck out of it. With the valve covers off, we turned the motor over quite a bit, watching the oiling and re-checking the lash caps to see if they were secure, and they were. We buttoned it up, started it up, and put maybe 20 road miles on it, with a few hard hits shifting at 6200. Everything seems to be fine. Valvetrain is quiet and runs great. I'm going to race it this weekend in a no box class. I had to take into account that Mike at MRL has built no telling how many of these engines, and I had to put some faith into his knowledge and experience. Like they say.... I'm sending it! I appreciate all the input, and as always, I've learned a lot. Thanks!
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There you go, good luck this weekend
 
Jay Anderson said:
Well, we tried looking at the sweep without the lash caps and it was way off.
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What do you mean by 'way off'? Being off center is not very important, as long it is not waaaay off center. That old folklore of being perfectly centered being the desired end result needs to go away. It is the width of the pattern that matters; you can have a nicely centered wide pattern and that is not where you want to be.

Not saying that you could run without the lash caps but just trying to make sure you are looking at things the right way.

Posting pix for B3RE is a good next step.
 
I asked for a pic earlier in this thread, before it got this far, but was ignored.
 
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