Dr. Jeckel

iTrader: (12)

Search is down so here we go.
Swapped out my 918's for Patriot Duals last week. Yesterday I started my car(with the wondows down) with a car on my passenger side and the valvetrain noise seemed excessive and there was a louder ticking from the passenger side valve cover. With the windows up I can't hear anything.

I was going to take a video of the car idling but camera is at my parents house. Probably will post one up tomorrow.

Everything was torqued down properly and locktited. The car idles fine and runs smooth and strong. Is the added seat pressure of the duals what is causing it to be louder? Anyone go from 918's to Duals and feel that the valvetrain noise increased? I'm just a little scared the new springs caused another problem. Car has 46k miles on it.

Thanks for the help, James.

Beaflag VonRathburg

iTrader: (176)

I'm prettty sure spring pressure has something to do with it although I could be wrong. Just think of how much harder the valves are being slammed up and down. That's gotta increase valvetrain harmonics.

Another possible question is did you properly adjust everything to compensate for the new springs? I'm not sure how things such as lifter preload, pushrod length, installed springs height, valve spring shims, and other things are affected by a spring swap or how those affect valvetrain harmonics.

Dr. Jeckel

iTrader: (12)

I put on the new seats and seals along with the titanium retainers and super 7 locks that come in the kit. I have 7.4 pushrods. I'm just getting kinda paranoid about a problem, since the car is forsale.
I guess I need to listen to a couple friends cars to compare.

Dr. Jeckel

iTrader: (12)

Everything sounded just fine this morning. I'm starting to think the warmer weather (mid 90's) has something to do with it. I'll see at lunch what it sounds like.

Dr. Jeckel

iTrader: (12)

I removed the passenger valve cover and all was well. Re-torqued the rocker bolts just incase, but the ticking was still there. I changed the oil also.
The one thing I noticed is that when the springs were not loaded, I could slide the rockers from side to side slightly, but easily. I guess my 7.4" pushrods are not optimal for this setup and maybe some 7.425" pushrods would be enough to keep a slight pre-load and quiet things down.
Here is the video, but honestly it's not a very good one, cause I couldn't hear what I heard in person.
Valvetrain

Phil'sC5vette

iTrader: (4)

Mine was louder going from 918 to duals

silver-mod-o

iTrader: (15)

duals are always going to be louder than a single spring... and make sure you give them ample time to warm up before taking off....

Dr. Jeckel

iTrader: (12)

Yeah, I have never gone over 2000rpm until my car is at full operating temperature...even with the old 918's.

After being able to slide the rocker, I'm sure its the fact that I just don't have enough preload/long enough pushrod, for my particular setup.

slt200mph

iTrader: (42)

7.4 inch pushrod should be fine for that cam ... your noise is related to the dual springs you are running now ..

GuitsBoy

iTrader: (4)

The springs rub slightly against one another to damp out vibrations and harmonics from what I understand. This is the likely cause for increased noise.

john563

iTrader: (17)

off topic,but are you selling the car? you just put that cam in.

Dr. Jeckel

iTrader: (12)

I put the cam in it in December, along with the 918's. Two weeks ago I check the 918's and had a broken one. I then replaced them with Patriot Golds.
To answer you question though, Yes, the car is for sale....click the "FOR SALE ->" hyperlink in my signature.

Thanks for relping put my mind at ease guys

Dr. Jeckel

iTrader: (12)

Had some LS1 friends of mine listen to the sound today. It sounds like it is coming from the passenger side of the engine, but more towards to center. It is not at the valve cover, but more like where the lifters are. It is not all the valvetrain but a single distinct "ticking/tapping".
If you raise the rpms slightly, then the ticking goes away and is replaced by the normal valvetrain noise. We were kinda thinking maybe a weak lifter and that the stronger springs just showed it. No one thinks it sounds like bearings. My oil pump holds atleast 40psi at idle, fully warm.

Sound like a pretty good guess at the problem?

Thanks for any input, James.

tylerdj

iTrader: (31)

TTT for ya James. My first guess would have just been increased noise from the stronger springs as well but it appears it's something else. Let us know what you find out!

Dr. Jeckel

iTrader: (12)

I went by and asked George (Boost-Performance) about it too and he agreed that he didn't think it was anything like rod or main bearings and that it did sound like it was in the valvetrain. I think the added seat pressure brought out a weak lifter. It doesn't do it until the car gets warmed up and is definitely in sink with the normal valvetrain noises and doesn't get any louder with rpm, but more or less blends in with the rest of the valvetrain when rpms are increased. If you increase rpms a little bit, you can't hear the distinct ticking/tapping unless you try REALLY hard.