Lifters, maybe? ... Probably

[Astro]

SELF-ALIGNING rockers? If not, you need to stop running that engine NOW, before the real damage happens.

Did you verify clearance for the pushrod against the openings in the head that the pushrod pokes through?


Springs, and retainer-to-seal clearance.

Schurkey, when you say retainer to seal clearance, what exactly are you referring to and how do you check it? Sorry, I'm trying to picture it. When I spoke to the company I bought the rockers from, the guy there told me there was no modification necessary for installing the 1.6 rockers in my application. When I installed them, I visually checked clearances that was obvious to me, like the pushrod guides and they looked good. Nothing else stood out though. They otherwise fit in there like the stock 1.5's... visually lol.

 

[Schurkey]

Schurkey, when you say retainer to seal clearance, what exactly are you referring to and how do you check it?

Valve spring retainer on top of the valve spring. Seal rides on the top of the valve guide.

As spring compresses, underside of the retainer gets close to, or bumps into, or totally squishes the seal.

You won't be able to see that there's clearance (the compressed valve spring is in the way)...but it can be calculated, or seen if the spring is removed, the retainer and keepers reinstalled, and the valve pushed open as far as the cam/rocker would push it at max lift.

 

[Astro]

Valve spring retainer on top of the valve spring. Seal rides on the top of the valve guide.

As spring compresses, underside of the retainer gets close to, or bumps into, or totally squishes the seal.

You won't be able to see that there's clearance...but it can be calculated, or seen if the spring is removed, the retainer and keepers reinstalled, and the valve pushed open as far as the cam/rocker would push it at max lift.

Gotcha ok. So, I don't recall the added lift numbers I looked at when I was considering the 1.6's, only that the added lift was well below what the stock head setup could handle, springs and clearances. Bear in mind, most of the info was only based on google searching and talking to people who have done the swap before.

 

[Supercharged111]

Retainer to seal clearance can only be known for sure by checking. I stuck a hardware store spring in an intake and exhaust valve and stroked it to measure clearance when I had my heads off.

 

[L31MaxExpress]

Depending on the specific head casting and rocker arm used, the pushrods may be rubbing the heads themself. I have not run into that issue, but others have.

 

[Astro]

Depending on the specific head casting and rocker arm used, the pushrods may be rubbing the heads themself. I have not run into that issue, but others have.

I watched the pushrods moving up and down, but I didn't see them touching the guides. I'm not sure it would make that sound either, unless they bent, increasing clearance between the valve and rocker. This is not ideal or wanted lol, but what would probably happen is it would wear into the guide until it didn't touch anymore. But this is unlikely since I was observing them.

I had a pushrod eat sideways into a guide a long time ago because the top of the valve chipped and the rocker was canted. I didn't know it was happening until the valve just stopped opening when the rocker arm finally fell off of it. The rubbing was not audible. On the other hand, that engine had a bigger cam and was loud.

I do not think it's in the rocker to valve clearance. Reason being that tick was audible when I backed off the nut on the rocker arm stud. Then I was able to make it go away by adjusting them on the fly. It seems like its just in the lifters. Unless SOMEHOW those danged header gaskets didn't seal. Doubtful though. I tightened those bad boys real good, from the center bolts out. I did a heat cycle on them too, and when I went back to check tightness, I couldn't turn them anymore.

Quite the mystery haha. I'm putting new wheel bearing hubs in there today. After I'm done I'll try and put some mileage on her with the MMO. I will keep you guys posted though.

Gosh I'm really trying to avoid disassembly. My wife will be pissed and I can't blame her lol.

 

[Supercharged111]

I watched the pushrods moving up and down, but I didn't see them touching the guides. I'm not sure it would make that sound either, unless they bent, increasing clearance between the valve and rocker. This is not ideal or wanted lol, but what would probably happen is it would wear into the guide until it didn't touch anymore. But this is unlikely since I was observing them.

I had a pushrod eat sideways into a guide a long time ago because the top of the valve chipped and the rocker was canted. I didn't know it was happening until the valve just stopped opening when the rocker arm finally fell off of it. The rubbing was not audible. On the other hand, that engine had a bigger cam and was loud.

I do not think it's in the rocker to valve clearance. Reason being that tick was audible when I backed off the nut on the rocker arm stud. Then I was able to make it go away by adjusting them on the fly. It seems like its just in the lifters. Unless SOMEHOW those danged header gaskets didn't seal. Doubtful though. I tightened those bad boys real good, from the center bolts out. I did a heat cycle on them too, and when I went back to check tightness, I couldn't turn them anymore.

Quite the mystery haha. I'm putting new wheel bearing hubs in there today. After I'm done I'll try and put some mileage on her with the MMO. I will keep you guys posted though.

Gosh I'm really trying to avoid disassembly. My wife will be pissed and I can't blame her lol.

Mine didn't appear to be rubbing at first. I took 2 rods out, marked with marker, reassembled and turned over by hand, and when I removed them there was a section of marker missing. So I yanked the heads and drilled the holes out.

 

[Schurkey]

OEM small-block pushrods aren't hardened unless the engine came with pushrod guideplates; and that hasn't happened for a long, long time.

I marked Pontiac pushrods the same way--except I used a paint-pen. Watched for paint transfer from pushrod to the iron of the cylinder head. Had to grind a heap of metal out of those heads for pushrod clearance with high-ratio rockers.

 

[Astro]

I suppose we'll have to see what happens. Man I wish I had the time to really dig into it, but it's been about 110 miles on MMO so far and the ticking is still there, but barely audible.

I do really appreciate all your input guys.