will tightening the exhaust valve slack help on 04.5

[zzman]

I've been reading that the 04. 5 engine has an idiot idea of emission control with shorter exhaust valve opening along with other weird stuff.

So I was thinking that maybe if I set the exhaust valves to maybe . 010 or . 015 if that would possible help, with less engine oil junk and a better breathing engine.

I am not going as far as changing the cam or pistons but thought maybe just maybe a cheap help could be the exhaust valve setting.

Thought some one may have tried this already, any experience there?

Thanks

 

[jakprince]

i would stick with what it calls for. You dont want to burn a valve setting them too tight

 

[rscurtis]

Automotive engines with mechanical tappets use silencing ramps on the cam lobes to gradually take up the valve lash before the cam actually starts to move the lifter. To achieve what you are trying to do, you would have to run the valves at practically zero clearance, a difficult situation at best with solid lifters. This could also have some unintended consequences regarding the way the engine would run. Years ago, I saw the result of a solid lifter cam used with hydraulic lifters in a BB Chevy engine. The engine would barely run, as the silencing ramps were completely altering the intended valve timing.

 

[07 ThunderRoad]

I did the tighter valve lash on the exhaust valves. It made no differance and was the biggest waist of time. I did set the valve lash back to . 026 and also checked the intakes. Engine still runs the same.

 

[zzman]

Is the 07 the same as the 04. 5?

I thought it was just 04. 5 and maybe 05 with exhaust thru the engine stuff.

I'm not real keen on all this but I did read where the 04. 5 exhaust valve closer earier.

I'll see if I can find that post.

 

[cerberusiam]

Is the 07 the same as the 04. 5?

No, they are different. The 04. 5 is the same as it has always been . 010 Intake, . 020 exhaust.



You can set them at . 008 Int and . 018 Exh for a little smoother running quieter engine.

 

[07 ThunderRoad]

Again, I had NO difference in the way my 5. 9 ran or sounded at . 018 or . 026 on the exhaust. As for the black oil, I use the Valvoline premium blue extreme and the Fleetguard #LF16035. The oil is still black but I can see all the bright aluminum parts and the valve rockers thru the oil fill cap. No soot sticking to the engine is the best you can hope for.

 

[CKelley1]

the only way to do it is to change the cam to a pdr or colt. the grind on the stock cam is vastly different than what is needed. you will pick up 2. 2 mpg with the cam change

 

[p-Bar]

I like the mileage gain with that cam

 

[AH64ID]

Is the 07 the same as the 04. 5?

OEM valve lash is different, but the hp is the same and so is the cam.

 

[zzman]

OK then, I guess there is no need to jack with the valves.

Thanks guys.