Notching stock pistons

[fidstang]

I purchased the Isky cams piston notching tool last week. Started the first piston, placed the gasket and head on the block with the tool in intake valve number one. Tapped the tool till it hit the piston and set the collar to the depth I needed the valve to be cut. After removing the head when the cutting was done, I immediately noticed that the notch was below the stock relief. Is this normal? Has anyone used this tool before with the same results? I have stock 91 pistons and the notching tool matches my new valve size of 2.02 exactly. What gives, I try to do a clay check but now the clay is sticking and I can't get a good reading. I even tried oil on the head and piston. Still sticks to the head. Has anyone put edelbrock RPM heads with 2.02 valves on a stock bottom motor without any clearance problems before?

 

[Deleted member 87397]

Are you running flat top pistons? I thought everything after 86 was notched already? I could be wrong. I'd ask I someone at Isky. How much was the tool? I might use it to notch the pistons on my 86 if it works well and is cheap enough.

 

[fidstang]

The tool and pilot cost $133.00 with shipping. Yes, the stock pistons after 86 have 4 valve releifs. But, when I first recieved the RPM's I did a clay check for piston to valve contact. The check showed that I was hitting the edges of the releif(eyebrow). So I bought the tool to notch the pistons in the correct locations. Only problem is it's not notching them in the correct location. It's the notcher that Isky recomended when I call them to order it. I'm not sure if the tool is somehow flexing when it hits the piston!

 

[blue302stang]

Are you running flat top pistons? I thought everything after 86 was notched already? I could be wrong. I'd ask I someone at Isky. How much was the tool? I might use it to notch the pistons on my 86 if it works well and is cheap enough.

86 pistons are the only pistons that are flat top, but all the other pistons have valve reliefs for the stock size valves and not 2.02s.

 

[2000xp8]

With my cam and my TW's, mine had to be notched.

The notches in mine were in different spots too.

As long as you have the piston all the way up, when you do the notching, and you get valve clearance you should be fine.

Also be careful with that thing, just give it small turns, that bitch cuts the pistons like a hot knife through butter.
My first thought was to put a cordless drill on it, imagine that, it would of cut a hole in the piston with one pull of the trigger.

 

[fidstang]

I tried with the piston all the way up but, the tool sticks to far out the the chamber for the head to fully seat on the block. I had to start with the piston about half an inch or so in the block on the compression stroke. Maybe that's were I went wrong. I'll have to try to gaskets with the piston TDC. Any other suggestions if this doesn't work?

 

[2000xp8]

When we did mine with the piston a bit down in the cylinder, it actually notched the wrong place.

I think if you turn the crank to the point where the piston just starts to pick the head up off the block, that's the perfect spot.

 

[fidstang]

I did just that, put the head on the block and turned the crank untill the head slightly lifted then backed it down till the head was back on the block. Bolted the head down and I used a speed variable drill for cutting. I set the collar for 0.145" as the depth of the cut. It turned out perfect. Thanks for the help!