yella terra roller rocker adjustment problem

[cameljockey]

I am trying to install the yella terra kit from Classic inlines on a 250 ci L6 going into my mustang.

I am using a Comp Cams custom grind in conjunction with the CI aluminum Head.

has any one here had any trouble adjusting the rockers after installing them.

I am trying to do a cold adjustment before I start the motor and then I will do another warm adjustment but I can't even do that yet because on the cold adjustment with the #1 cyl at TDC of the compression stroke I try to adjust the valves and the adjustment screw of the rocker on the #1 Exhaust has to be screwed all the way in such that it can't be locked.

there is no threads for the lock not to engage with.

my suspicion is that the pushrods in my kit might be the wrong length for my application.

I was very lucky in that the Block had never been rebuilt before and it only needed to be decked like 0.005" (I have the real number written down somewhere) to get it true again but I don't know if that is indicative of any pushrod short comings?
what are the stock push rod lengths for the 250 CI L6 versus the 200 CI L6
I remember reading somewhere that the Yella Terra's use Buick V6 Push Rods
if any one has had this problem please let me know how you solved it

Best Regards,
Keep Sixn'

Dan

 

[Bayrunner]

Dan, look at the letterature that came with the rockers. It explains how the rocker has to seat/touch the tip of the valve. Now, from this point being that the pushrod has enough length to carry the stance as per the illustration. If not, you need longer push rods. Although these things are agjustable, they will not compensate for short pushrods. Assuming that you are using the CI head, it is far taller than the stock head. Also, will your cover clear the rockers? you might need to modify or put a spacer on that as well.

cheers

 

[cameljockey]

so I wished that they came with some literature but I had no such luck but...

I remember that there was a blurb some where that the aluminum head was taller on one side than the stock cast iron one but I thought that this only applied to the head studs on the intake side of the head? does this height difference also come into play on the pads that the rocker bar mounts too? if so then I definitely need some longer push rods but how much longer? I have a spare Cast Iron Head out back in the shed I will make some measurements and find oot?


Thanks for the heads up

 

[Broncitis]

Its really quite simple, if your not sure, get an adjustable pushrod in the plus and minus range of your old pushrod and set it to where it swipes the top of the valve stem as much to center as possible, lock the adjustable pushrod and measure it and order some pushrods that length or very close, Mike keeps some different lenghts, I got my different length pushrods from him, since I zero decked my 200. I eyeballed mine, but there are more technical ways explained with the yella terra info.

 

[cameljockey]

adjustable pushrod is on the way from summit racing thanks as soon as I get a good number I will give Mike a buzz and order some different length pushrods but a question remains:

when checking the length do I back out the adjustment screw all the way when I've seated the roller tip on the valve stem?

Thanks Again,

Dan

 

[Broncitis]

Hope this helps a little, when my roller tip was just about right on the valve stem and this should be similar since there should be no difference or very little is when my adjusting screw was about a 1/16 to 1/8 above the lock nut. be very carefull, since some of the lifters can be very very soft, another thing I noticed with the yella terra is the mounting blocks have a small amount of play with the bolts, so I tried to push them inboard towards the lifters while I tightened them. You will do well, just take your time.

 

[cameljockey]

thanks for the extra pointer Broncitis I just got the adjustable push rod yesterday and will be employing everyone's advice

thanks again guys for the pointers over all this is going pretty smoothly for my first engine build ;-) if this is the worst thing that happens right?

Keep Sixn'

Dan

 

[falcon fanatic]

Just had my engine rebuilt and I was having the same problem: right ont he edge of the adustment range for the rockers. I even had to remove the washer under the adjuster screw to get one of them adjusted. Ran it that way for a couple of years, but when I took it in for the rebuild I pointed this out to the builder. He did mill the deck a little, which helped, but in the end he used valve lash caps to make the valves a smidge longer. I'd never heard of them, but as he pointed out, twelve valve lash caps are cheaper than twelve pushrods. In my case they also altered the geometry slightly for the better.

 

[falcon fanatic]

valve lash caps

http://www.google.com/products?clie...esult_group&ct=title&resnum=3&ved=0CCcQrQQwAg

 

[cameljockey]

Ok so I didn't go the route of the lash caps but I did already have the adjustable push rod so here's what I did and maybe you guys can provide a sanity check here....

0. I backed the Adjustment Set Screw as far back as I could until the cup on the end of it was flush with the body of the rocker
1. I installed the Adjustable Push Rod (APR) on the the #1 exhaust with the #1 Cylinder @ 0 deg before TDC on the compression stroke
2. I proceeded to extend the APR until I removed all slack in the assembly (presumably this is an unloaded zero lash condition)
3. I then tightened the Adjustment Set Screw another 1/2 turn to "pre-load" the lifter (as if to make a cold adjustment)
4. I then actuated the valve train through one cycle to observe the motion of the roller tip across the tip of the valve stem
5. I repeated this procedure on the #1 exhaust and the #1 intake until I observed the motion of the roller tip that satisfied me

The result was a push Rod length of approximately 9.100"-9.15" I will measure it more precisely when I get home from work today

does this sound about right if pictures are needed I will try to post those tonight

Keep Sixn'

Dan