New L31 - HT383 Cam - COMP Cams 1418-16 Roller Rockers - Rubbing

[m002922]

Finally getting my new engine put in with all the goodies.

The one place I deviated was I went with the Comp Cams rockers

https://www.summitracing.com/parts/cca-1418-16/overview/

vs

https://www.summitracing.com/parts/scc-scp1036?rrec=true

which I had seen recommended.

I went with the Comp Cams because from the reviews and comments on Summit it didn't seem like there were any issues with these working with the L31 (hindsight being 20-20, maybe they work fine with an L31 with a stock cam, but not with the HT383) . . . and they were a bit cheaper, but adequate for my purposes.

Well, the Comp Cams rockers make the push rods rub in the guide holes. I would figure a self-aligning 1.6 rocker is a self-aligning 1.6 rocker . . . but then again, maybe what I bought aren't self-aligning (even though one of the answered questions says they are).

Anyone know for sure why these didn't work?

 

[df2x4]

I'm no help on your specific issue, but for what it's worth I used a set of standard Scorpion 1.5s for the 400 SBC in my Monte Carlo. They worked great.

 

[m002922]

We put the stock 1.5s back on there and everything seems to work fine - everything dead-center of the hole.

So for now that is what I'm going with until I figure this out . . . maybe I'll end up with 1.5 rollers. I appreciate the input.

Everyone of the pushrods was hitting with the 1.6s on there. I believe I've confirmed I have the right part - the 1418 - they didn't send me the wrong part. After staring at the rockers pictures side by side for about an hour I figured out the difference was the little tabs that extend past the roller on the self-adjusting rockers.

 

[df2x4]

I wonder if it's possible that the 1.6s need a different length pushrod to work properly... I'm far from an expert on this stuff, just thinking out loud.

 

[Supercharged111]

I had to hog out my pushrod holes on my 1500 for the Comp Pro Magnum 1.6s to not rub. Let me guess: they're rubbing on the side of the hole that faces the rocker stud?

 

[arrg]

1.6 ratio rockers move the pushrod cup on the rocker closer to the pivot ball than a stock 1.5 ratio. That's how the increased ratio is achieved. It's normal to have to enlarge the guide hole with 1.6 ratio rockers.

 

[m002922]

Supercharged111 - you are correct.

arrg - I read everything I thought I could read on this engine combination and don't recall anyone saying that guide hole *********** was necessary for 1.6s . . . no one buying them on Summit mentioned it, despite multiple people putting them on L31s. Comp cams didn't mention it either - but obviously its necessary.

Not sure I want enlarge the guide holes with the engine installed and the likely possibility of metal going down the holes . . . even with a vacuum on the scene not sure that is the best idea. That said, it is a miniscule amount of metal that needs to be removed - I'll have to think on that for a bit.

Thanks for the input.

 

[Supercharged111]

I pulled my heads to drill the holes out.

 

[L31MaxExpress]

I have had 3 sets of 1.6s on Vortec engines without rubbing. The only ones that rubbed were 1.7 ratio. 1/2" drill bit works great. If you pull the heads grab 0.016" compressed steel shim head gaskets.

 

[slowburb]

Or you can return those rockers and get a set of scorpion 1.6 full rollers. Much much better hardware man.