Irregular valve tip wear pattern

[gpmorgan]

I had to do a lot of justifying to the old lady as to why I needed a 632 and come to think about it, I don't think I came up with enough. Lol

 

[Honky Kong jr]

I put a can and an electric vacuum pump in it last spring, which helped a lot. Before that, the pedal required quite a push to stop in any reasonable amount of distance.

That's a good thing, the vacuum pump that is.

 

[gpmorgan]

I put a can and an electric vacuum pump in it last spring, which helped a lot. Before that, the pedal required quite a push to stop in any reasonable amount of distance.

Is the vacuum pump very loud when running? I thought about using one.

 

[SHOTROD81]

Is the vacuum pump very loud when running? I thought about using one.

It's a little loud, but it's easily eclipsed by engine noise. This plant makes plenty of it.

 

[gpmorgan]

Yeah the solid lift small block I had was loud also. The tall valve covers muffled it some and the 40 series mufflers dumped at the rear axle pretty much took care of the valve noise.

 

[MikeB]

I suspect your pushrod guide plates do not center the rocker arms on the valve stem tips, but instead the rocker arms were leaning to one side. The fix for that on factory Vortec heads is using self-aligning rocker arms without guide plates.

Wow, 628" lift? That means the retainers can't hit the seals, and springs can't coil bind until .678" valve travel. Which components did you use to get that much travel? Did you have the spring seats cut? Even a large-port Bowtie Vortec head is spec'd for .530" max lift out of the box.

And FYI, even on re-worked Vortec heads, flow maxes out under .550" lift. They were designed to flow well at 400" lift and outflow all previous GM designs at that lift. And 20+ years later still outperform aftermarket heads at that lift.

Simply put, your monster cam is not even close to being a good fit for these heads. In fact that would be true for just about any 23 degree small block head not designed for all-out racing.

 

[SHOTROD81]

I suspect your pushrod guide plates do not center the rocker arms on the valve stem tips, but instead the rocker arms were leaning to one side. The fix for that on factory Vortec heads is using self-aligning rocker arms without guide plates.

Wow, 628" lift? That means the retainers can't hit the seals, and springs can't coil bind until .678" valve travel. Which components did you use to get that much travel? Did you have the spring seats cut? Even a large-port Bowtie Vortec head is spec'd for .530" max lift out of the box.

And FYI, even on re-worked Vortec heads, flow maxes out under .550" lift. They were designed to flow well at 400" lift and outflow all previous GM designs at that lift. And 20+ years later still outperform aftermarket heads at that lift.

Simply put, your monster cam is not even close to being a good fit for these heads. In fact that would be true for just about any 23 degree small block head not designed for all-out racing.

Other than a build sheet for the engine, which only said "customer supplied iron vortec" on the line for cylinder heads, I don't know what all was done to it before I bought it. I wish I had more details.

In your opinion, what would be the better (and honestly, less expensive) investment: replacing the cam with one that better suits the current heads, etc...., or replacing the heads to some better suited to this cam? It currently has a 750 Mighty Demon with a Super Victor intake, if that steers it in one direction or another. No matter what I do, it will have plenty of power for my tastes. I just want to get to a point where I can have some fun without feeling like I'm on the edge of another breakdown.

 

[Guardian]

What type of rockers did you have on these?

 

[SHOTROD81]

What type of rockers did you have on these?

Harland Sharp

 

[Guardian]

I agree with MikeB. The guide plates are not aligned and causing the rockers to not contact the stems properly. The solution is either correct the geometry with these heads or replace them. You might be able to utilize offset rockers but that isn't common.