Valve cover clearance with Gold series 1.6 rockers?

[blackbombshell95]

I read somewhere in the past that the 1.6 gold series rockers won't have enough room because of the 3X00 valve covers. What has been documented to work to resolve this issue?

[treeZ24]

the rear one fit no probs for me...?

[TurboZ24]

I heard it was the upper edge of the lower intake manifold that was the issue. Might not be a problem with stock or lower lift cams.

[blackbombshell95]

Yes. Those are the same rockers I'm using and the stock valve covers fit fine. I'm runing .52" of lift too. It's the lower intake manifold that doesn't clear. You need to do some modification to the manifold and four of the rockers to get them to clear.

I just found that

[blackbombshell95]

When i made this thread i wasn't thinking. I knew it was the LIM. lol. I need sleep badly

[DEI37]

Sleep? What's that?

[geoffinbc]

Lift wont make a difference. The least amount of clearance comes when the valve is closed. This is where you need to modify the lower intake. When the rockers is lifted by the pushrod the back end of the rocker moves up and away from the runner.

[blackbombshell95]

I wish someone had pics of a modified LIM made to fit the 1.6 rockers

[geoffinbc]

Dude where have you been in the last year? I started a huge thread on it.

http://60degreev6.com/discussion/viewtopic.php?t=765&highlight=crane+gold+race

[treeZ24]

http://www3.telus.net/treeZ24/myZ/Heads/clearance-issue.jpg

http://www3.telus.net/treeZ24/myZ/Heads/clearance-issue2.jpg

i have many more pics of the clearancing + feeler guages, but didnt upload them.

[AaronGTR]

I actually ground down the bottom of the runners that needed clearance on my LIM until I saw pinholes on the inside of the runners and the rockers still made slight contact. I had to JBweld the inside of my runners then and ruined the port job I had just finished. One of these days I'm going to buy a new LIM and start over.

It's just the top edge of four of the rockers that don't clear the runners. I ended up having to put a .25" radius on that edge to get it clear properly. It's kind of squared off anyway so I just had to round them. It doesn't remove much material or weight, and it doesn't remove anything from the area above the pushrod cup so it shouldn't weaken it.

[AaronGTR]

Here's some pics just for clarification of exactly what I did to the rockers. You can see where I rounded the top edge. The top edge is where it touches the LIM so by rounding it you can effectively gain 2-3mm of clearance. The last pic shows the position on the heads of the rockers that need modification. It's pretty obvious when you test fit the LIM too. You'll see the four that are touching the bottom of the intake runners.




As for how I went about modifiying them, first I measured some points on the corner and used a circle template to draw my radius with a fine black marker so that I could keep them all as close to the same as possible. Then I used a grinding wheel to take off material until it was close to the line. Finished up the radius by hand with a fine hand file. Then I smoothed the surface with a sanding flap wheel and a buffing pad in an electric drill.

[bonecrrusher]

Thanks Aaron for the pics, just those 4 rockers then? how much needs to be taken off the LIM, would you suggest grinding that first, and then the arms?

Too bad there isnt a HowTo for this swap, I need to find some older 3.1 rocker arm guides or something.

Ive still got the info in a PM that Aaron sent me awhile ago.

[AaronGTR]

NP. I know there's not an exact "how-to" on it but the old thread had pretty much all the info needed. You just need the pushrod guide plates from a 3.1 "T" motor or from an early 3400 before they had self aligning rockers (don't know the part number). And the heat treated pushrods of course. The ones in the early 3400 will work IF you can find any, otherwise it's custom for about $114.

I'd say grind the rockers first because you gain a lot more clearance that way than by grinding the LIM. Then grind the LIM just a much as need for adaquate clearance. The material on the runner isn't really that thick to start off with and you don't want to go thru the bottom like I did. I found those green abrasive disc's that go in an electric drill work best for grinding the LIM.