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Anyone ever put in larger valves?


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Posted

Gen II aluminum heads. 1.72 intake and 1.42 exhaust. anyone ever put in anything bigger or is it even possible ???

 

It looks tight as it is, thats why I ask

Posted

You would have open up where they seat, that would be a lot of work. I have never heard of anyone doing that, altough, you could go with a 3 angle valve job, I have head of that being done

 

Robby

Posted

Every machine shop I have ever tried has told me that this wasn't possible. Probably could be done though, they're just scared they aren't good enough, and would mess up my shit

Posted

Yes it can be done. The aluminum heads on these motors had replaceable valve seats. I had that done on my 92' Grand Prix SE, and the car is still running like a champ. :)

Posted

Thats interestin, how much power did you get from the larger valves? I mean was it a noticeable gain. Did you get a valve job at the same time?

 

Robby

Posted

Probably be better off with a good port/polish, 3 angle, 1.6 rockers, and diff cam. I think you'd see more improvment with that than bigger valves.

 

Jason

Posted

I think Vegeta(Ben) or either Brad(bzopi from the GMForums) said that you could only get slightly bigger ones and it wouldn't be really worth doing.

Posted

I wasn't sure if it was possible. When you look at the size of the chambers, and the valves. those valves take up a lotta damn room.

 

What I am probably going to do is get a whole new valvetrain, get some SI valves, and leave em the same size & just get the heads polished.

Posted
Probably be better off with a good port/polish, 3 angle, 1.6 rockers, and diff cam. I think you'd see more improvment with that than bigger valves.

 

Jason

 

Yeah thats what I was thinking, theres not that much room to put in huge valves.

 

Robby

Posted

Hey, as long as eveyone is looking at this post, and I see one other guy asking about comp cams roller tipped arms (1.52) Let me ask another question.

Does anyone see any problems if I were to use the Crane Powermax H-260-2 with a set of the Comp cams roller tipped in a 1.6 ratio? (Stock length on the rods), and the specs on the cam are:

Lift intake:.427 Lift exhaust:.454.

 

I have the 1.52's right now but they are not installed yet and Summit told me they would take em back no problem for exchange.

Posted

Yeah Im looking at the 1.6 rockers and pushrods too from Comp Cams. I dont think there would be a problem, but with more lift from the cam and rockers, you might want to make sure, somehow, those valves dont smack the pistons. Make sure you got enough clearance. Just a thought

 

Robby

Posted

Wasn't there someone on here that had successfully done the install? I think I have asked the same question myself. Heh, if you are rebuilding the motor from scratch, then it's pretty easy to tell, however, normally it may not be...

Posted

The valves I had put in were not much bigger than the stock ones, But you could tell they were bigger than stock. The intake runners were ported/polished by me. I kept the 1.52 rockers in favor of the 3 angle valve job the machine shop did. I did not go with the 1.6 because it would have been a bigger tire fest at every light. The cam was a special grind from a comp cams dealer in alabama. The most noticeable gain I saw out of it was starting and highway cruising. Throttle response was very nice, big gain there!!!! hence tire fest! :D All I can say is if you have the money to experiment, "who cares if its worth it, do it!" I'll see if I can find cam and valve cards and post them here. If you all want the specs you'll be more than welcome to use them and/or refine them.

 

Have fun cuz I did!!!!!!!!!!!! :twisted: :cheers: :rocking:

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