pull your valve cover and look closely at your valve springs and rocker arm nut for clearance!!! I'm having to shave off some of the nut and some of my valve springs are bottomed out with delta's valve lash specs. If you have loud valve train noise check this out!!!! some of my lobes bottom out while some others do not and seem to have decent amount left to compress at delta's valve lash. This confuses me a little. I'm going to use my dial indicator to measure each lobe and see if the cam is consistent. I am wondering if I might have some bent valves.
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are u still using the stock valve lash spec?.....in other word what are the clearance your using.? i had the same problem till i use the .008 .010 numbers
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I still have a spring bottoming out at .011", and who knows how much further beyond that. I would check everything if I were you, If you don't have a problem then use delta's specs. I think for now, I'm gonna use what ever valve lash I have to to make the spring not bottom out, unless it lash gets ridiculous. I might buy a head and swap that out very soon, If I determine that I have a problem there.Last edited by dbsharp; 03-28-2008, 08:57 PM.spin cityComment
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something is really messed up with my cam or head. out of the 5 lobes i tested, one has 5 thousandths more lift than the others. The two intake valve spring on cylinder 1 were compressed pretty different amounts at the same lash, one had to have a lash of .012" just so that I could get a .0015" feeler gage in between the coils on the spring, while the other had plenty of room left before the spring would bottom out set at .006" lash. I was told by a guy who knows his shit that if the valves that were binding were bent that my motor would run like shit. I'm gonna run a compression test to see If maybe I bent valves since the motor was last run, I don't think it is very likely but I think it is possible. also since material is ground off of the cam, you have to make up for this by adjusting the rocker arms, which changes the angle and point of tangency on the cam. this changes the rocker arm ratio and the valve timing slightly.spin cityComment
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slightly, not enough to make a huge difference. The timing is more affected because well, thats the entire point of the cam.
I think you may be worrying a bit too much about this. The DOHC has a weird way of meansureing them and if you have to get the perfect angle, or it won't be right.
It took me about 3 tries to do it correctly before I got mine down.
All the 3 previous times, I measured with the same exact gauges but had to adjust the lash differently. It all depends on the angle you have the gauge at. I can't explain it, it's just something you learn as you do it.
If it's loud on start up, then you measured at the wrong angle.
SOHC's are easy because you don't measure between the cam and the rocker, you measure between the valve stem and the rocker.
It varies so much with the dohc because even its easy to have the tdc alignment for a certain cylinder off by even 1 tooth, which makes a big difference.
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Originally posted by d112crzy
you're right, thats how i fucked the valve lash clearance on a BMW head. the drag that the valve or bucket lifter put as well as the cam feels like it is tight when it is actually not.
worse thing was that the BMW head was non adjustable meaning the only way to adjust it is either by grinding the valve tip, sinking the seat, grinding the valve face and i also ended up surfacing the entire upper half of the head that holds the cam .002".
finally got the clearance that i wanted.Comment
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yes the difference is minor but It is there, that is not the problem though! I think a picture is gonna be worth a 1000 words. some valve springs are compressed as far as is possible before the top of the cam lobe is pressing down on the rocker, and as a result I cannot turn the motor all the way over! This is a major problem and I am sure that these springs would be trashed very quickly if I tried to run this motor.Originally posted by d112crzyspin cityComment
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big problem espcially since it is recommended at least .100 before coil bind.Comment
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I have bent valves on cylinder 2 and 4 for sure. 1 and 3 might but if they are bent it isn't bad at all, because they have good compression. when I was putting in my cams, the crank got turned about 30 degrees off where it was supposed to be and I moved the cams around while purring on the cam gears. Or it could have happened when one of the valve springs was bottomed out. I did a compression test before I did anything and it was fine then. I'm pulling the head. anyone got a h23 or f22b head they wanna let go for a decent price? I'm thinking that I will rebuild the head I have on their now and make dam sure that the cams are straight before putting it on my motor. this sucks so bad......spin cityComment
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im getting this head fixed asap. I wanna run this cam. im going to measure everything I can to make sure that this cam is ok to run. I think im even going to clay my motor to make sure. I haven't quite figured out how or when I bent valves. I was cautious when I installed it but I was also very tired, and it seems that I made a mistake somewhere. next time I will be even more careful.spin cityComment
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ok so I pulled the head. I put water in the combustion chamber and it leaked past 3 intake valves. two were in the same cylinder. the circled ones are leaking water and the cylinders they are in have bad compression. when I measured compression before I tore the motor down, the throttle cable was not properly connected and so the compression test was preformed with throttle body closed. I don't know if this would affect the results that much.
I do not understand how only one valve could be bent in a cylinder If I bent it during installation. also, and this is the most confusing part to me, the cylinder closest to the timing belt had one intake valve spring binding and one intake valve spring with plenty of clearance but no bent valves or any other irregularities that I have seen so far and had good compression. I measured both lobes on this cylinder (intake), while they were installed so the measurement should be correct, and they are both the same at 247 thousandths. I am going to get these valves replaced and I'm going to try to figure out what is causing the inconsistent lift I noticed.
Any thoughts or suggestions?Last edited by dbsharp; 03-31-2008, 01:45 AM.spin cityComment
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I'd get your camshafts measured.
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motor was at tdc?
cams installed at tdc?
correct cams installed int he correct places?Comment
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yes I checked everything 10 times, and verified that tdc was true with a 10 inch extension down the spark plug hole and it is dead on. this motor has been over revved twice. the day I tore the motor down, it revved up to 8k (according to my tach, which is off a bit) in a miss shift, I have a 7k rev limit in crome though
, It is possible that they got bent before I tore it down, because the throttle body was closed I can see how it could build pressure in the IM, so I'm not trusting the original compression check.
spin cityComment
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I think that I have 3 bent valves, is the water test a good indication of which are bent? Also they are bent so very slightly that it is not something you can visibly see, do I need a valve job on the valves Im replacing or will new ones seat just fine? I know that a valve job is a good idea, but Im starting to run out of spending money and time.spin cityComment
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