Engine HELP

[Dean23]

So I was setting up the valves on my 350, I have a 284 2h cam, 1.5 roller rockers flattop pistons etc. So I was done setting up #7 and went to crank the engine to set up # 3 when it suddenly started to bind. I found that the intake valve is toching the piston. PISS me off. I"m hoping its just a rocker that is stamped and boxed wrong. All I have left to set up is 3 and 2 all other cylinders are fine. Anyone else have any ideas of what could be wrong. Help will be appreciated

[lngbed71]

A couple of questions come to mind.....I assume it's hydraulic. Did you by chance add an additional 1/4 or so turn after the pushrod stopped free turning while tightening?, and were your heads milled more than .010?

My experience with rollers has been just leave the setting as is when you can not spin the pushrod when tightening and forget about the additional 1/4 turn after. If you are running hydraulic lifters, remember there is no pressure to pump the lifters until after the the engine is running. The recommended setup instructions are to get the engine running. You will have to do another valve adjustmemt after cam break-in.

Having your heads milled removes material from the head and lowers the valetrain geometry closer to the pistons. Just a thought or two, hope it helps.

[Dean23]

The thing that puzzles me is it is the intake valve that is hitting, I have more lift on the exhaust side. The adjustment instructions say to turn it .5 to 1 turn after 0 lash, I went 3/4 turn. The other thing is it cant be a milled head because # 1,6,8,5,4 are all ok. Im thinking it might be a rocker problem > tomorrow I am going to try a different rocker on that valve.

[lngbed71]

Sounds as if it may a lash problem, try backing off to zero lash and check clearances. Hope it helps

[Dean23]

yeah I backed it off and it comes clear of the piston. I guess i will play around with it after work tomorrow. So you say not to give them any more of a turn after zero lash then??????

[Dean23]

Any other suggestions??????

[lngbed71]

That is what has worked for me in my projects. After the break-in, I go through each rocker and make sure they are snug, and not noisy and leave it at that, runs good, lasts long time.

[Dean23]

Yeah ill try that , I have never used roller rockers before, so I am not to sure. It just pi##ed me off when that happened. I guess better now then when I tried to turn it over with the starter though.

[lngbed71]

Check in with an update after you start it up.

[Dean23]

It will be a while til i start it, the truck is getting a ground up. I am just doing the engine while my body man is doing the cab etc. I am going to try a different rocker in that position, then I will try just setting them at zero lash in stead of 0 plus 3/4 turn.

[GMC Jim]

my thots are that you should NOT attempt to start the engine untill you have determined why the valve is hitting the piston.....

[Dean23]

Problem solved too many cooks in the kitchen too many beer. I was watching the lifters so i could set the valves but instead of watching the valves on the running mate I was watching them on the one I was setting.

Mental note....beer is bad

[Randy70C-10]

Originally posted by Dean23
The thing that puzzles me is it is the intake valve that is hitting, I have more lift on the exhaust side.

This is because your intake valve is bigger. Here are a couple of questions, What size are your valves? If your intake valves are 2.02's, your pistons have to be cut for 2.02's. With a high lift cam, it will always be the intake valve to hit if the pistons aren't cut for the valve size. If you are running stock pistons with the 2 or 4 valve recesses cut the same size, these won't work with 2.02's, or even in some cases 1.94's. In your case I could be completely wrong, hard to tell without seeing the engine. Hope this helps!

[Dean23]

as it turned out i readjusted them and it is all ok. just was adjusting them at the wrong phase of the cam. too many beer and engine building is not a good mix.