valvetrain geometry issue

I am putting a 355 l98 sbc together with a comp magnum 270hr, oem replacement roller lifters, TFS 195's w/ the 1.46 dual valve spring option, and crane gold 1.6's.

My problem is that at the shortest recommended pushrod length(7.25") the rocker still rides on the outside of the valve stem, but when I shorten the pushrod to bring the travel to the center of the valve(6.9") the rocker is almost bottomed on the stud and the nut is so far down that i can't get the lock on.

the block is zero decked, the head gasket is not on now(should it be?) but is .041" thick, and the heads have not been milled. if you need any more info i will try to get it for you.

What should I do? Do I need longer valves?

I have pictures of how the rocker sits with the 7.25" pushrod if anyone wants.

Thanks!

you need the gasket on when you check it....
I had a similar problem...had to switch rockers

Put lash caps on the valves,then go with a longer pushrod(adj length pushrod) to raise the rocker.
Then get the geometry right-- narrow and as close to center as possible. Then order the right pushrods.

yeah you have to check/measure with a head gasket in there. Then do what 1racerdude said;)

I have a similiar setup on my L98. With heads milled, blocked decked and a .028" head gasket I went with 7.365" custom pushrods. This also includes .015" lifter preload.

anything special i have to do for lash caps, machining? or do i just toss 'em on and start measuring?

right now i have some really light springs on to make it easier to turn over, if i torqued the head gasket on would it hurt it? could i use it when i finally assemble the motor? it's a felpro composite.

so when i finally measure i have to add in the .015 preload? whats more important, a narrow sweep or having it as close to the center as possible?

Just put them on. In this case they will have the same effect as if you put in .050" longer valves.

Just snug the gasket. Don't torque it down. The untorqued gasket will offset the lifter preload more or less.

The pattern will be narrow if you get it in the center of the valve.

ok, will do!

the lash caps on summit are .060" or .080",i'm thinking the .080 ones are a better bet but i don't want a stupid mistake to mess up my engine.

i went and stuck .080 worth of feeler gauges on top of the valve to get a rough idea of how long my pushrods would need to be and came up with 7.180. the shortest trick flow says they should be is 7.250 without lash caps, why would they be so wrong, would decking the block make that much difference?

Go over all your parts again and make sure you have all the stuff that matches what you ordered - post up the part numbers. You should not have to run lash caps; with the correct parts ordered, I have never had to run lash caps except when using my own custom valves that did not have a hard tip. Something else is wrong if it takes a pushrod .300" shorter than recommended to make things look somewhat right.

The pictures would be nice.

7.25 pushrod without the head gasket
http://img341.imageshack.us/img341/227/valvetravelbd1.jpg
http://img341.imageshack.us/img341/6982/valvegeomva0.jpg
http://img341.imageshack.us/img341/7599/wholeengineiz0.jpg
355 ci
0 decked block 1987 L98 block
.041 head gasket
eagle balanced rotating assembly
speed pro hyper pistons
comp magnum 270hr cam
- 215/215 @.050
- .532"/.532" lift
- 110 LSA
crane gold 1.6 roller rockers part number:CRN-10759-16
roller lifters part number:CCA-850-16
- called CS O-E HYD ROLLER LIFTER on invoice
TFS 195 heads part number: tfs-30400007
- 1.46 valve springs

I have a feeling that this may not be a hardware issue, but more of an error on my part. When measuring for a pushrod what am i exactly looking for, to have the sweep in the center of the valve stem regardless of how wide the sweep is, or am i looking to have the sweep as narrow as possible regardless of where on the valve it is, or some combination of the two?

http://web.camaross.com/forums/showthread.php?t=483886

a lot of guys here helped me out when i was doing this also. we ended up with a very good thread with good pics.

Again, you MUST check WITH a head gasket. If not then your work and measurements mean NOTHING! Having all the part numbers and pieces in the world mean nothing till you check it with an adjustable pushrod.

Put a head gasket in there and then measure. read tat thread and you will get a feel for what pattern to shoot for.

BTW, I ended up taking the advise of some reputable people here and going with shaft mount Jessels but thats beside the point. The thread still shows you what to shoot for. I used Lash caps so taking them off for pics was easy. If you do not use lash caps then you look for teh pattern on the stem.

If I go by that technique then I can't get the set screw in the nut on, leading me to believe that i need lash caps. I don't think that i should need them for this setup, both the trickflow people and the crane people say I shouldn't(i got to talk with an engineer from crane, not just one of the tech line people :cool: ).

all my measurements past the first post, excluding the pics, has been with the head gasket.

with the 7.25 rod the sweep is very narrow and just a little off center, closer to center than the pics. it goes as far to the exhaust side as your 8.1" but is much narrower and in your pic you wouldn't be able to see the little hole. my camera is dead or i'd take another picture.

right now i've got a bunch of people telling me to go for the shortest sweep and a bunch telling me to just center the sweep and not bother with the size of it, but if i center the sweep i would need to run lash caps to keep the rocker away from the bottom of the stud and allow me to get the set screw in but i've got a bunch telling me that lash caps are bad. i'm lost.:confused:

first off have you done this with the gasket on it? If not then its like the man said your just pissin in the wind

I don't see why you woul need lash caps.....thats is a pretty simple parts list with nothing exotic......

personally I would want the sweep centered, but i'm no expert

Do you have any pics of this....it would help alot, and make sure you are doing it with the gasket on.......

yes, i have been doing it with a gasket.

i'll have pics later today, i'm not at home right now and the camera should be charged by the time i get there.

yes, i have been doing it with a gasket.

i'll have pics later today, i'm not at home right now and the camera should be charged by the time i get there.

do you know the base circle of the cam? you should not be having this problem so something must be getting overlooked.

do you know the base circle of the cam? you should not be having this problem so something must be getting overlooked.

no, as far as i know it is a regular magnum 270hr. would it list it on the cam card?

here are the pictures with the head gasket.
7.25
http://img296.imageshack.us/img296/1805/maybefh8.jpg
7.15(can only get set screw/lock 1.5 turns in, is this enough?)
http://img409.imageshack.us/img409/7739/7150gz0.jpg

You are having the problem because you are using the springs. You need to remove the 2 springs on the cylinder you are checking and use light tension checker springs.

You are having the problem because you are using the springs. You need to remove the 2 springs on the cylinder you are checking and use light tension checker springs.

i am, if you look closely you'll notice silver springs on the ones i'm checking and black normal springs on the ones i'm not.

i think i've decided that a 7.2 pushrod will get me closest to the center with out being too short.

I like the 7.250 pushrods from that picture. I like the sweep pattern and it is close enough to the center. 1.5 turns is not anywhere near enough.

ummm...i am, if you look closely you'll notice silver springs on the ones i'm checking and black normal springs on the ones i'm not.

i think i've decided that a 7.2 pushrod will get me closest to the center with out being too short.

Ummmm, you are right. I am wrong . Sorry for attempting to help with your problem. I will not confuse your posts in the future.

i didn't mean to offend anyone, sorry.

the 7.2 gives me 2.5 turns on the lock, and looks to have the same sweep pattern and just a bit closer to the center. and i already ordered them.

Are you referring to the set screw inside the adjusting nut that has the 2 /2 turns?

yes

If it was me I would like to see more than 2 1/2 threads holding the lock screw in place. One option would be to install a shorter rocker arm stud. By shorter I mean on the upper half of the stud not the portion that screws into the head.

I'll look into those, but I think that being screwed almost halfway in would be ok. I don't know how much these like to loosen up though, I didn't have any trouble with the stock nuts loosening with an xe268 and stock rockers in my 327.

from what I can see the 7.2's look like they should be ok. I would not be comfortable with only half way in on the lock screw. Something isnt right there. I think you need shorter studs. The set screw should be in much further than that.

Back from the dead!

Did you ever figure this out?