lewtot184
Well-Known Member
the only way to check the tappet and lobe with the RPM heads is yank the intake. i never set the lash hot with alum heads anymore, inconsistent pain in the butt. i do the minus .006" thing and am much happier.
Valve lash keeps getting loose
- Thread starter Garys1969RR
- Start date
Garys1969RR
Well-Known Member
That's what I was thinking, as you can't really see the lifter valley by pulling the valve covers, with the RPM heads. On iron heads I have been able to remove a lifter by pulling a valve cover and sticking a lifter removal tool in there, or a strong magnet can work if the lifters aren't stuck. Buts it's a real pain if you're pulling all the lifters.
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miller
Well-Known Member
Gonna cross my fingers on your cam lobe!
lewtot184
Well-Known Member
it could be a cam lobe but i'm not 100% convinced of that; only an inspection will tell. i know when i went from iron to edelbrocks, using crane alum rockers, there were some valve train issues. one major difference was geometry vs the two heads. i had to shim the shafts .030" to get decent geometry with the edelbrocks and the crane push rods i was using on the iron heads ended up being .170" too short. i also ditched the thin jam nuts on the adjusters and use a full 3/8"-24 nut. sometimes header tubes and trying to work around hood hinges can hinder accurate adjustments. i've found that almost all of my lash errors were due to inconsistencies in adjustment.
I guess the big question is how much lash change is there? More than .004"-.005" on the same valve 2 times shows an issue with one of the valve train components. I have found on the EOIC method (at least on my roller) that the heel of the lobe varies maybe .001"-.0015". To be accurate you need to check in the same spot of rotation. Such as intake just opens, open 1.4 distance, 1/2 distance etc. Not a huge difference but when you are looking for a .001" change it matters. The other item is to learn the "feel" of your settings. When in doubt use one size larger/smaller feeler gauges. When I first learned I always set it to tight on the feeler gauge. It was always about .001" tight. Use a micrometer with the thumb screw and you'll get a better feel for it. Surprising how loose it feels.
Garys1969RR
Well-Known Member
Well it looks bad. After adjusting #7 ex to .016 cold, then driving it 1 mile, it is now at .024" cold. So I re set it to .016 lash and checked the total lift with a dial indicator, .340" at valve. It used to be at .520" total lift. So I have lost .180" of lift. Plus the rocker starts closing just after it reaches full lift as I rotate the crankshaft. The others stay open for about 1/8 turn of the crankshaft before they start to close. So I'm 99% sure it's the cam lobe/lifter. I must have gotten some grit or something on that cam when I changed the heads. So now it looks like it's time for a Lunati Voodoo roller cam.
Garys1969RR
Well-Known Member
So I think I should change the oil/filter before I install the roller cam. I had put new oil in it after the head change, now the oil has a slight gray tint. I'll have to change it cold, as I don't want to run the motor anymore. The #7 lash even loosened up .002" just turning it over by hand, as I was checking the other valves, which were all still OK.
moper
Well-Known Member
Given the measurements - I'd agree. Nows the time to stop and resign yourself to fixing it. However, that said, if the oil is a grey color, it's full ofiron dust. Which means so is the oiling system and the piston skirts and anything else that oil can get pumped to or splash on. I'd pull the engine and take it apart for a thorough, stripped block type cleaning. Basically do a freshining to it and at that point replace the cam.
dieseldazzle
Well-Known Member
Man crap like this worries me with rollers when I'm using flat tappet... what are they making cam cores out of nowadays? Pepsi cans?
Garys1969RR
Well-Known Member
Yes, I am surprised this happened, never had a cam lose a lobe before. This was a flat tappet cam, so I'm going to a roller now. The cam was in there when I bought the car over a year ago, and no probs until the head change. I think the higher spring pressure on the Eddy heads contributed to this happening. I did notice a few pushrods had some surface rust on them, so maybe the cam did too. The car sat for awhile in Ca before I bought it, so there could have been some condensation in the motor. But it ran fine for the previous year.
lewtot184
Well-Known Member
i hate to here this! a camshaft and oil change by itself isn't a cure. you'll end up running crap thru the rollers. take the engine apart and clean it up.
My machine guy taught me early on. There is no better cleaner than hot engine oil. If there is dirt in there the oil will find it and carry it. Will it make it through the filter??? That being said I swapped plenty of wiped cams as a dealer tech. Never pulled one down. Never had one come back. I would at least take a look see at the bearings. In the words of Clint Eastwood, "do you feel lucky"
Doug
Doug
miller
Well-Known Member
Stick a magnet in the oil! If there's metal, it will show real quick.
not so famous bob
Well-Known Member
I have been dong the cold setting , 006 tighter. I have a little more noise on the pass side than the drivers side. think I`m going to try it .at 010 cold. -----'' solid compcams streetroller ' procomp raised port alum. heads. recommended lash is .016 and .018.
Garys1969RR
Well-Known Member
lewtot184
Well-Known Member
good luck with this!
miller
Well-Known Member
Sorry to hear about all that. Good lookin' ride!
Feel your pain. Know you'd prefer not hearing this, but with all that 'missing' metal, and the oil color (you ever do the magnet thing?), I would at least do this...
I'd drop the pan. Good chance the bottom has a coating of the metal dust on it. And at least pull #2, or #4 main cap, to look at the bearing shell. Might save you some problems down the road. If it looks good...then decide.
Feel your pain. Know you'd prefer not hearing this, but with all that 'missing' metal, and the oil color (you ever do the magnet thing?), I would at least do this...
I'd drop the pan. Good chance the bottom has a coating of the metal dust on it. And at least pull #2, or #4 main cap, to look at the bearing shell. Might save you some problems down the road. If it looks good...then decide.
Garys1969RR
Well-Known Member
Pulled the intake this morning, and the lobe is smaller by about .120". It has clearly been worn away some. Haven't pulled the lifter yet, but I'm sure it has lost some metal too. All the other lobes look good. Still a mystery as to why this one failed. Here is a pic of the lobe. (center one). Hard to see, but there are a few small grooves/lines on there.
I'm glad I finally figured out how to get pics from my phone over to here. Lol
lewtot184
Well-Known Member
have you bought the roller yet?
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