Valve/Piston Contact Post-Cam Installation

[Advorsor]

Hey all,

We just finishing installing 280 / 272 CAT Cams (reused OE followers with 60K miles) along with a valve adjustment.

When we went to turn engine over on first startup (low RPMs) we got valve-to-piston contact.

The pistons are fine and we are getting new valves but any idea what would cause this?

Thanks.

[Lukem3]

Timing was not set up correctly most likely. Was the motor turned by hand prior to startup. Are the cams standard lift or higher lift

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[Advorsor]

Wre these cams:

https://www.ecstuning.com/b-cat-cams-parts/280-272-242-234-1250mm-1225mm-050mm-605mm/1301804~cc/?gclid=EAIaIQobChMI2oXW9fzC8QIV8QWICR1ioAiYEAQYASABEgJEjfD_BwE

12.5mm

I wasn’t near for the hand turn. So would you rule that most likely?

[Lukem3]

Was the head machined now or in the past? If not thoes cams should have no clearance issues so yeah timing was off or something was left loose. (tensioner or other timing/vanos items)

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[Advorsor]

Don’t know about the head in the past. Would that matter?

But thanks for your info - we’re going to throw in new valves and go back over timing process. Hopefully good then.

[Syfon]

I have the identical cams in my motor.

Recently rebuilt the entire thing; stock valvetrain bar cams & stock bottom end.

Block was decked and head faced, valves re-seated etc..

I did not have any valve/piston contact.

If you have valve/piston contact there is only one reason - you did not time the motor correctly.

Edit - After timing the motor you should always turn it by hand to ensure nothing contacts. I did this with mine on a stand. Reciprocation was smooth as silk.

[Sharocks]

I have the identical cams in my motor.

Recently rebuilt the entire thing; stock valvetrain bar cams & stock bottom end.

Block was decked and head faced, valves re-seated etc..

I did not have any valve/piston contact.

If you have valve/piston contact there is only one reason - you did not time the motor correctly.

Edit - After timing the motor you should always turn it by hand to ensure nothing contacts. I did this with mine on a stand. Reciprocation was smooth as silk.

All of this.

[jet_dogg]

Sounds like you should have paid someone who knows what they're doing.

[Icecream]

Sounds like you should have paid someone who knows what they're doing.

and the dick award goes too.....

[jet_dogg]

and the dick award goes too.....

If you make a mistake as elementary as this that could be catastrophic, then you have no business doing it in the first place.

Facts hurt you?

[fullyflaredd]

and the dick award goes too.....

shit happens, don't take it too seriously. I just replaced my rocker arms and if I had made this mistake and someone told me I should have paid someone to do it, I would have agreed that I should have paid someone to do it lol

[Thoglan]

If you make a mistake as elementary as this that could be catastrophic, then you have no business doing it in the first place.

Facts hurt you?

That's not a fact. People can do whatever they want with their own cars whether they mess it up or not. However you feel about whether they should or shouldn't have done it is irrelevant to OPs questions and intentionally unproductive.
Fastest way to let everyone know you're a donkey.

[Cubieman]

Hey all,

We just finishing installing 280 / 272 CAT Cams (reused OE followers with 60K miles) along with a valve adjustment.

When we went to turn engine over on first startup (low RPMs) we got valve-to-piston contact.

The pistons are fine and we are getting new valves but any idea what would cause this?

Thanks.

Was an OE timing tool used? I know we have had at least one member that used an aftermarket one and ended up with bent valves. In any case hand cranking will let you know if there is interference so long as the hub bolts are properly torqued. Shit happens, I broke a timing tool when I turned the crank with the timing tool pin still inserted into the EX cam, it snapped the pin and the broken piece went all the way down to the pan. That was a lesson for me to work nice and slow and triple check everything when doing critical work.

[Obioban]

Not time correctly for sure.

Turning the engine over a dozen times +- by hand is an easy safety check. I still do it every time.

[jet_dogg]

That's not a fact. People can do whatever they want with their own cars whether they mess it up or not. However you feel about whether they should or shouldn't have done it is irrelevant to OPs questions and intentionally unproductive.
Fastest way to let everyone know you're a donkey.

No, it is my opinion that some people agree with, therefore, they share it.