piston hitting head!

[steve68]

got it all together to find out that the piston was tapping the head at #1. So i have to pull it apart and open up the chambers. Is this because i used a h20 gasket?

thanks
steve

[SLOroadster]

Thats not good. If you have one hitting the head, you have 4, or a bigger issue, such as a warped head. I hate when I put something together and find that something else is majorly wrong.

good luck,

Will

[steve68]

i just had it cut because it was warped. its still above the min.
im working on a ka24de and i already had to take the head off once after getting it alltogether. and then now this one.

on the bright side tho' i got my fiberglass hood today.
i like the flat style.

anyone want pics?

well so far that is the only piston. it looks like the piston and the head have a really poor casting. the top of the pistons arn't smooth. neither are the chambers on the head or even.

steve

[sgriffin]

Steve I'd really like to see your pictures. Please post them and good luck. Sam

[itsa68]

Steve:
I measured several new head gaskets and they are pretty close to each other.
2 H20 aftermatkets measured .055 and .056 thicknesses
3 Nissan R16 measured .055 , .056 and .061 thicknesses

I did not measure any of the used compressed ones that I had kicking around.

Measure you head at the ends and the center to make sure it has been machined evenly.
I'm under the impression that if the head was warped, they may have milled off the high spots only. That would cause a piston to hit the head.
All the recesses in the head for the pistons should look to be the the same volume wise.
The perimeter shape of each should also be the same.
Hopefully the top deck of your block has not been touched by any previous engine rebuilding to clean up its surface.

It is the piston hitting , not valves ?
Are you posting any pics showing the head and piston condition?

Oh, I forgot to mention, also align and place the head gasket onto the head to get a visual on the difference of the head recesses.
Some people use the gasket as a guide template when re-establishing the recess volumes to get equal cyl compressions.

Ray B.

[toolsnob]

Steve,

I had this exact problem with my 1600 a few years ago when I had the head rebuilt, except mine was piston #4 that was hitting. What has happened is when the machinist cut the head they did not relieve the valve area of the same amount they cut. They may had taken enough out of the other 3 cylinders but not enought out of #1. So, take the head back off and back to the machinist. Remind them that you are running domed pistons and have them take the appropriate amount out of the area.

On the down side (even worst than before) you may have bent a piston pin. After I had the head reworked I noticed a little noise from 4, a bent piston pin. I drove the car as is and is still going strong today.

Also make sure all 4 chambers on the head are the same to get even compression across all 4 cylinders.

The only time in my life that I felt like I could faint is when all my friends were standing around when I started the car and we all heard that piston. My head got light and I had to lean against the car...

Alexi

[steve68]

ill check and take pics. When i take it apart. I was so frustrated that i just left it alone.

Im sure its the piston it was hard to turn over (by hand never started it!)
i loosened the head and it turned over easliy. It couldn't be the valves i took the rockers off!

yeah the getting the compression to match all 4 will be a challenge.

thanks
steve

[dbrick]

Steve, Have you heard of "Claying in" an engine? Old time hot rod stuff. It's like giant plastigauge. You put a layer of clay across the top of the pistons and assemble without torquing, you then turn it through and you can measure the thickness of the clay to get clearance at any point. prevents later suprises when things warm up and expand.
Just my 2 cents.

[jbush]

Steve,

I would be most interested in the pics of your hood. Have you decided what you are going to do about the fenders? Fiberglass or metal? Best of luck with your head.

[steve68]

yes i do know about claying. Thats what im goign to do to figure where i need to take some material out of.

I found a nice 69' fender that im buying so metal.

thanks
steve