VT Stage 1 Installed!

[purdyboy3]

Finished my cams!
Started up and sounded great. There was valvetrain noise for less than a second before the oil got moving. Took it out and noticed a big improvement in the higher RPM's. Drives almost like normal otherwise. I did raise my idle to 980 with my predator to help with the fast idle drop.

Now the bad news.
I took it over to a mechanic to have him check it out and listen for anything abnormal. He was impressed and said everything looked great. Then I shut the engine off. It made some kind of noise. Its very hard to explain. He said it sound like and intake leak. I thought, that's not bad. Then he said an "intake valve" leak . We started and stopped the engine several times and it continued to make the same noise again and again. It's not a loud noise and I thought it was just because I have a longer duration, but he said it shouldn't sound like it does.

So, here's his thoughts:
Worst case, bent valve not allowing valve to close all the way !
Or something not as bad; lash adjuster holding the intake valve open.

Right now I'm going to drive it for a week to see if it goes away. Maybe the adjuster needs more time. The motor sounds as smooth as silk and there is little to no valvetrain noise while the engine is running. Its almost as quiet as before the cams.

In the mean time, I thought this would be some good tech to get everyone's idea's.

Let me know what you guys think.

 

[nickthegenius]

Uhmm....what does this sound like? I'm not saying that I've driven my car for 1500miles after my cam install with this wierd sucking sound when I shut the engine off or anything. Just curious....

 

[dub_c39]

Subscribing

 

[purdyboy3]

It is very hard to explain. I need to record it and put a post up. If it was a bent valve or something like that, I think that my car would run pretty bad.

But It runs great!
Maybe someone knows.

 

[Phoenix00GT]

I wouldn't drive around with intake valve leak if I were you...if it is bad like you said and the valve is bent and leaving a gap during combustion you could have combustion up into the heads...VERY BAD NEWS

Take the heads off and check the clearances...don't drive around if you have any question because you could turn a $200 problem in to a $2000 problem very quickly

 

[GinoGT]

Do a compression test, that should point out a bad valvetrain component, if any.

 

[nickthegenius]

I did a compression test on mine and all were within about 5psi of each other. As stupid as it sounds....press your lips together and blow. My car makes a similar noise to that when you shut it off as the engine is winding down.

 

[GinoGT]

I think I mean a leakdown test. Whatever it is I'm thinking about, if an intake valve isn't sealing right, that kind of test will show it.

<--- Needs sleep.

 

[Phoenix00GT]

mine hisses a little on shutdown as well and all cylanders are within .3% of each other as of the compression test done in March

 

[vidmaster]

my car hisses when i shut it off but it's from my cold air intake

 

[purdyboy3]

I guess I will try the leak down test. It just seems like it would be way down on power if an intake valve was being held open. I'll try and get a vid or sound clip posted today after work. Maybe if I wish it away...
Keep any more ideas coming.
Thanks.

 

[bullitt1723]

I have a stock engine except cold air and I have just developed this sucking when I shut off the engine. I have also notice a little loss in power.

 

[purdyboy3]

Just thought I would give an update.

I tore everything back down last night. Checked the timing and it was right on. Did a leak down test and every cylinder was less than 5% leak down.

So, I guess it was a lash adjuster. I bled these down several times to make sure they were all the way down.

When I get back from work tonight I'll button everything up and see what she'll do. Hopefully any problems will be gone.

Any other ideas would be great.

Thanks guys.

 

[Dan_Soprano]

if it was an intake valve not sealing, then you would be hearing a backfire through the intake while the car was running. Think about this. A motor is a vacuum. When you shut it down, there is still a vacuum in the intake. the noise that you are hearing is air slowly being sucked in through the T/B. This is normal. shut the car off next time and once the motor stops turning step on the gas pedal. I bet the hiss goes away after the negitive pressure is gone.

 

[purdyboy3]

If it still happens after I get everything back together, I'll give it a try.
Thanks for the help.

 

[Dan_Soprano]

no prob. good luck!

 

[stang976]

I have a stock engine except cold air and I have just developed this sucking when I shut off the engine. I have also notice a little loss in power.

i get that sound too. the sucking sound is normal for a CAI

 

[Rocketman]

Just thought I would give an update.

I tore everything back down last night. Checked the timing and it was right on. Did a leak down test and every cylinder was less than 5% leak down.

So, I guess it was a lash adjuster. I bled these down several times to make sure they were all the way down.

When I get back from work tonight I'll button everything up and see what she'll do. Hopefully any problems will be gone.

Any other ideas would be great.

Thanks guys.

Just curious, did you use the Camsaver tool. And, did you take all the lash adjusters out when replacing your cam?

 

[purdyboy3]

Finished putting everything back together...again. I did the leakdown test and every cylinder was less than 5% leak down. So thats not the problem.

Started her up and everything was fine...once again. When I shut it off, it made the same sound . I tried opening the throttle some when I shut down and that made the sound go away, but I would have to do that every time I turned the engine off.

When I was taking everything apart (again) I did notice that the PCV was leaking oil at the passenger side valve cover. I'll try replacing that this week.

The first install was done with the AFM cam tool. Well, I tried to use it. The tool broke at the weld once I had it between the chains leaving a big chunk of aluminum in the front cover. AFM said that they had never heard of this happening and have already sent me another one. I think that the idea behind the tool is great, but its a cheap tool and needs a delicate touch. Which isn't easy when you are frustrated. Once it broke I just started taking the front cover off.

I'd say that pulling the front cover isn't that bad at all. It just take more time a patients. It allows you to "set" the timing, not assume that it didn't jump a link.

The performance of the cams are great. I'm getting my tune via Predator this week, then I'll take it down to the local dyno this weekend and see what I make.

I'll keep updating.

Thanks for the replies.

 

[Dan_Soprano]

Like I said before.....its just the vacuum equalizing in the manifold. It's not a problem.