Valve train help needed...

[MotorMouth]

I picked up my 1.6 GMPP roller rockers today and noticed what I am sure is going to be a problem.

Here is a pic of the intake and exhaust valves, exhaust is on the right. When I set the rockers on I notticed that due to the exhaust side being a bit higher on the stem the rocker hits the retainer before it engauges the valve stem.

What can I do to correct this? Is there another retainer available that I can use to reduce the ammount that it sticks up over the top of the stem?

Heads are L35 and again the rockers are GM Performance Parts 1.6 Self Alighn roller rockers.

Any help is greatly appreciated!

(Sorry for the fuzzy second pic, I am still learning the new camera)

 

[jwaller]

the correct pushrods would fix this issue. you could also swap the retainer to a non oil deflector retainer, but with that spring it's not goin to gain you much clearance.

 

[MotorMouth]

the correct pushrods would fix this issue. you could also swap the retainer to a non oil deflector retainer, but with that spring it's not goin to gain you much clearance.

Is the non oil deflector retainer the type that is on the intake valve? If so that will gain the clearance I need.

The heads are jusr sitting on the bench but no matter witch way I rotate that rocker the result is the same. The rocker body its self contacts the spring

 

[jwaller]

you shouild be able to remove the oil deflector from the spring combo while still being able to use the stock retainer.

 

[Boosted]

...the correct pushrods would fix this issue.

?
I do not claim to be a pro but I fail to see how the length on the pushrod will affect the body of the rocker hitting the deflector.

 

[leroy]

I agree with John about getting the correct push rods. http://www.compcams.com/information/Products/Pushrods/

Adjustable or custom guide plates are also often needed to center the roller over the valve stem.

Jim

 

[Boosted]

Hmm maybe its my view. It looks to me like the body of the rocker is hitting the top of the valve spring. :-?

 

[jwaller]

with a short pushrod it will lower the point at which the rocker pivots, thereby lowering the whole rocker closer to the spring. a longer pushrod will push the rocker further from the spring.

 

[leroy]

Hmm maybe its my view. It looks to me like the body of the rocker is hitting the top of the valve spring. :-?

It looks like that to me also, now that you mention it.

Jim

 

[MotorMouth]

Hmm maybe its my view. It looks to me like the body of the rocker is hitting the top of the valve spring. :-?

It looks like that to me also, now that you mention it.

Jim

That's what the problem is. It is only hitting on the exhaust side due to the differance in the rotator cap height.

What I am trying to figure out is how to increase the clearance with out clearancing (see:cutting the sh*t out of) the rocker body.

Removing the oil deflector will not do it, that will just reduce the seat pressure because it sits under the rotator cap inbetween the spring and the cap.

What I am wondering is if I remove the exhaust rotator cap and replace it with one like on the intake side will it work? My concern is what exactly is the rotator cap there for anyway and with a normal cap there (similar to the intake side, witch will give the clearance needed) will it affect the spring installed height or the seat pressure.

 

[BillC]

Probably the easiest thing to do is to get some offset retainer keys (the split wedge "thingies" that lock the spring retainer to the valve stem). They come in various sizes, to move the retainer up or down relative to the stem (changes the spring install height). Both Comp and Crane make them, there are probably other places too.

So, get some -.030 keys, remove the oil deflector, and install the new keys. That should give you extra clearance from the rocker and not change your seat pressure too much.

 

[MotorMouth]

OK, after some research I figured out what the rotator cap or "roto cap" is in place for.

Apparently it is designed to slightly rotate the exhaust valve every time it is opened to help reduce the build up of carbon deposits and decrease the chance of the valve sticking improving overall long term valve life.

So now I know what it dose.

Still trying to figure out if it can be switched out with out any problems...

 

[MotorMouth]

Probably the easiest thing to do is to get some offset retainer keys (the split wedge "thingies" that lock the spring retainer to the valve stem). They come in various sizes, to move the retainer up or down relative to the stem (changes the spring install height). Both Comp and Crane make them, there are probably other places too.

So, get some -.030 keys, remove the oil deflector, and install the new keys. That should give you extra clearance from the rocker and not change your seat pressure too much.

I will check into those, thanks!

 

[Boosted]

I would call comp cams or crane to see if they have a set of valve springs that have abouht the same range for cam lift to avoid coil bind and pressure but have a narrower top section....maybe some of the new "beehive" style springs like they are using on the LS-1's.

 

[myclone]

As was stated if the rocker is hitting the rotator and you keep the rotator in place (which I recommend if youre going for max eng life not max hp) you have two options:

1. Longer push rods (easy and cheap to buy as well as install).
2. Offset valve locks (cheap to buy but a little harder to find as well as a PIA to install with the heads on the motor IMO).

Swapping the rotator out for a smaller retainer isnt a huge deal as long as the valve guides are in good shape. If the valve guides are worn/high milage then the deposit build up that will occur over time from the oil leakage will kill the flow eventually.

IMO if youre running the stock cam or close to it then the slight loss of seat pressure isnt a huge concern unless you like to wind the motor past say 5500 RPM a LOT. With the stock cam going past 5500 RPM is just making more noise and less power than 5000 RPM in most instances IMO anyway.

My .02

 

[MotorMouth]

Myclone

That is kind of what I was thinking on the seat pressure but I was not sure.
I am still running the stock cam and the L35's are freshly rebuilt. It is not going to be a high millage daily driver so hopefully it wont be a huge concern.

I think I am going to experiment with removing the rotator on the stock LB4 heads and replacing it with the cap. If the installed height looks close the seat pressure should be close as well. As I recall the springs are the same intake to exhaust.

Thanks for the help guys!

 

[jwaller]

if your worried abuot keeping the seat pressure the same stick a shim under the spring.

 

[MotorMouth]

Little more research tonight...

I took the old heads apart and made some measurements.I found out that the exhaust spring pocket is machined 0.10" lower into the head than the intake side.The L-35's are the same way.

So taking out the rotator is going to increase the installed height that .10 of an inch. That seems like way to much to me.

Is it safe to shim the exhaust valves 0.10" and have a some what reliable valve train?

I am kind of stuck with these. According to everything I researched they should have had no clearance issues but that is kind of a non issue now.