speed_demon24

iTrader: (6)

I figured i would get more responses in here since right now I have no idea what to do.
I had my heads ported by Lloyd earlier this year, and now they have about 3000 miles on them since I got them back. I had him port them, mill them, put in 2.0" and 1.56" valves, and put in new bronze guides. I'm in the middle of putting on new springs (changing out 918's to pac 1518's) and I noticed all of them seemed lose to me, but I have no idea whats acceptable or not. But now I just got to one exhaust valve, and it seemed VERY lose to me, so I set up my dial indicator real quick, and it has .020" play in it. Is this accepteable? Or am I going to have put pull my heads and have this fixed?

:edit:
I'm not sure if you measure the play at the valve tip, or the base, it has .020" of play at the top, or .013" of play at the bottom of the vavle stem.

Grimes

iTrader: (3)

that sounds crazy loose...

first hit on google:

http://www.aa1car.com/library/ar696.htm

405HP_Z06

iTrader: (11)

If the valve guides have the play you say they do than you have an issue.

General bronze guide clearance recommendations:

Recommended clearance is .0015"-.0016" for the intake valves, and .002"-.0025" for the exhaust valves.

speed_demon24

iTrader: (6)

Here's a video showing the play.
http://s86.photobucket.com/albums/k1...t=100_0363.flv

Grimes

iTrader: (3)

yeah, wow, that looks unacceptable. do you think you have some sort of abnormal loading on the valve, or perhaps the wrong size guides were used?

Formulated

iTrader: (16)

I've had problems like that on other engines. Check your valvetrain geometry by looking at the wear or contact area between the rocker arm and the valve tip. If it's off center, then your valvetrain setup is the culprit.

This is assuming that it was correct when it was assembled.

1997bird

iTrader: (2)

+1 on this info.

speed_demon24

iTrader: (6)

I put the spring back on and put the rocker on, the guideplates centered it fine, and when the cam was on the base circle the tip of the rocker was dead center. (I don't have the intake manifold off yet so I can't put in a solid lifter right now to check it) I'm guessing the geometry would have to be way the hell off to cause a guide to wear like that in 3000 miles, so I'm thinking something else caused this.

LS1curious

Bad Machine work and improper guide sizing. Sounds like typical Lyod work to me.

1997bird

iTrader: (2)

Did you use a light spring rate, check spring, on it or just the old valve spring? If you used the old valve spring on a hyd. roller lifter, you were compressing the plunger body inside the lifter, and will not get a true reading. One other question I have is whether or not the guide plate was centered on the initial install? You might want to check and see if you have more wear on your pushrod for that cylinder compaired to a different one.

JPH

iTrader: (2)

was the motor ever really rich, when you got it running, or has it been rich all the time?

speed_demon24

iTrader: (6)

Nope, it was never rich with these heads on it.

speed_demon24

iTrader: (6)

Here's the wear pattern, this was tested with a 918, I don't have a solid lifter with me or a checker spring right now so this is the best I could do in the mean-time. The heads are going to have to come of anyway though so I'll worry abuot all this when I get them back.
http://s86.photobucket.com/albums/k1...t=100_0370.jpg

edcmat-l1

iTrader: (10)

Thats the problem right there. The tip of the rocker should not be dead center on the base circle.
It should be dead center @ 50% of the lift
The roller should start on one side of the tip, and roll across it.
Say its a .600 lift cam, the tip should be dead center at .300 lift.
You're side loading the guides.
BTW, whats up 97bird.....

speed_demon24

iTrader: (6)

I know the geometry is off, but is it off enough to wear the guide out that bad in 3000 miles?

Formulated

iTrader: (16)

The picture shows the wear way off center. A proper contact should be centered and very narrow. The rocker should actually move over the same contact area twice on lift, and again on seating. If you imagine an arc, or circle, with horizontal and vertical lines through it you can understand this. The vertical line is parallel to the valve stem, and the horizontal is parallel to the stem tip contact area. On the base circle of the lobe, the rocker arm should be tipped up slightly from the horizontal, and inboard on the horizontal along the arc. At mid lift, the rocker should be horizontal, or perpendicular to the valve stem, and reach the furthest out on the stem tip. Then at peak lift, the rocker will be angled down the same amount it was angled up at zero lift, and contacting the stem at the same point as zero lift. Therefore, at zero lift and peak lift the rocker arm should be inboard of the valve stem center, and at mid lift, it should be outboard of the valve stem center by the same amount.

Sorry for the verbage, it's difficult to explain. If I had some more time I could sketch something up.

I'm guessing that your pushrods are too short.

1997bird

iTrader: (2)

In short, yes it can. Also looking at your pic that you posted you can see that the rocker arm was not square with the valve. If you look at the pic, you can see that one side of the marking on the valve tip is farther forward than on the other side. So as the rocker was opening and closing the valve, you had most of the pressure pushing the valve towards the outer left (with the picture posted) on the valve guide. I bet if you take the valve out of the cylinder head, you will see that the valve guide is oblonged towards that side on the top and oblonged the oposite way on the bottom side.

1997bird

iTrader: (2)

Just got back from a trip to Texas. I had to go sign some papers on a new peice of equiptment we bought for a new business my dad & I just started.

edcmat-l1

iTrader: (10)

Post 16 and 17, dead on. I didnt even look at the pics, just based on what he said about it being centered on the base circle was enough for me.
And, they all wear on the outer side of the guide, as the rocker pushes the valve tip outward at the same time its pushing it down.

JPH

iTrader: (2)

diffently a geometry problem. pushrods are to long. shorting them up atleast .050-.100. trial an error with your pushrod length checker.