I just got done installing my Competition Clutch Stage 4 Sprung Clutch with their 11lb flywheel. This got rid of the obnoxious clutch rattle/chatter from my twin disc setup.

However, I am still having a slight metallic rattle that was masked by the twin disc setup and it's coming from the head.

If I rev it to 3.5k the noise occurs. If I rev any higher it goes away like it never made a noise and any lower rpm you never hear it.

When I put the motor together a few months ago I put a crower stage 2 cam in and had a few rocker arms smoothed out. It has ferrea stock size valves, crower valve springs, new valve seals, stock cam gear.

I've ruled out:
-no noise outside the head
-no cam play. I'm looking at cam gear and it's not moving side to side or up and down, so I know the lobes aren't hitting any wall in the head.

I've already adjusted valves to factory spec.

Like I said, I can rev the car all day and the sound isn't there but if I keep it at 3500 it's just a constant metallic rattle noise in the head. If everything in the head fit perfectly is there still a chance something isn't installed right? I just got done tearing the head apart to grind the walls just in case the cam lobes were still hitting but I know that's not happening anymore...

Tomorrow I'll be swapping the crower cam to stock, see if that helps any.

This build probably has 40ish miles, oil has been changed twice and no metallic deposits were found before.

Old build, no horrible metallic noise:
-competition stage 4 clutch, using this in current setup
-competition clutch flywheel, using this in current setup
-transmission with mfactory lsd, using in current setup
-wiseco pistons, using in current setup
-darton mid sleeved block, 75.5mm bore, 75.5mm cometic headgasket
-stock valves
-crower steel retainers and valve springs, using in current setup
-stock cam, worn lobes
-old worn/unbalanced rocker arms
-eagle h beam rods
-z6 crank, never polished, clearances never checked
-oem water pump, using in current setup
-oem tensioner, using in current setup
-endyn oil pump
-original 200k mile crank pulley with chunk missing
-gates timing belt, using in current setup but will put a new one one as soon as I find problem
-old turbonetics t3 super 60 turbo with shaft play
-3" exhaust, using in current setup


New build after spun main bearings, new parts, has metallic noise now:
-ferrea stock size valves
-valve seals
-crower steel billet rods
-heavy duty wiseco wrist pins
-polished original Y8 crank
-all bearings clearanced by machine shop
-darton mid sleeved block, 75.5mm bore, 76mm golden eagle oem headgasket
-new oem oil pump
-new oem crank pulley, last one had a chunk missing from one of the smaller pulleys
-like new rocker arm assembly
-new arp rod/head/flywheel/pressure plate bolts, properly torqued
-new turbonetics ball bearing, billet wheel turbo

Makes sense how things are done right and the pos has that horrible sound at 3500 rpms, but before on a not so well build the engine sounded fine...although it somehow spun main bearings when it was in a shop ready for a tune(had 1000 miles on that build while I drove it everyday to work).

I can't figure out how the parts I changed are causing this noise....Please help...

 

ttt

anyone?

I'm about to buy another head and start swapping parts over eliminating any probable cause...

 

bump

 

It's rattling at your motors resonance point. To me it sounds like a loose bolt/washer somewhere. Maybe in the exhaust.

 

When using the crower cam are you adjusting valves to OEM specs or the specs for the cam? When the head was assembled was it everything torqued to spec?

 

originally I set it to .007" intake, .009" exhaust, then found out the cams call for .006" intake and .008" exhaust.

But I found the problem. I bought a stethoscope with a long metal tip for detecting pinging/scratching noises and it pointed me to my dump tube and manifold where the wastegate sits.

Apparently my manifold flanges on the cast iron manifold and dump tube aren't flat and I was reusing old flimsy gaskets, the sound was coming from the pressure collar under the wastegate rattling inside. Some of it was coming from the dump tube gasket.

I have some 4 layer dumbtube/wastegate gaskets coming in(also had a thick center ring in the gasket for the wastegate insert) and I'm going to install a thicker aluminum composite gasket between the manifold and turbo, same material as the exhaust manifold to head gasket.

I know my problem was going to be stupid and sure enough it was. I'm just glad it wasn't in the motor because I didn't everything myself on this build to make sure I didn't have problems...

Thanks for the help