Chasing False Knock

[mustangflanagan]

Got that bolt out. Now the only prob I see is on a uneven surface which ever side the car is leaning towards the cat leg flanges rub up on the frame. I have no clue how to fix this. The bolts holes are clocked horizontal so they rest on the frame when the car leans on that side. There are wear marks on the flange.

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[Evo_Rob]

Time for stiff motor mounts

 

[mustangflanagan]

After looking on a level surface it's drivers side cat flang that 8s against the frame wtf

 

[rainier446]

Too close? I'm running kooks headers but I'm only getting a max of 0.6 knock. At first I get -4 but around 5k it creeps up and then levels out in the -1 range.

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[Ultrakla$$ic]

Too close? I'm running kooks headers but I'm only getting a max of 0.6 knock. At first I get -4 but around 5k it creeps up and then levels out in the -1 range.

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That looks good to me.

 

[rainier446]

That looks good to me.

I loosened the motor mounts and pushed the motor over about 1/4" just for peace of mind, I need someone to rev the car for me in order to see which way it rocks and how far. Seems much better than what some folks have to work with. Gotta get some torco just to be sure I've cured it and it's just bad gas...

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[dubster99]

Yeah, that looks like you have enough clearance to me too. Also check your O2's and make sure they're not contacting anywhere, and all of your connection clamps.

 

[cpelaez1]

Does this look too close? Car pulled timing today during a WOT log for Lund due to false knock. Looks like the header may be nicked a little but hard to tell.

 

[SolarFlare]

Quite possible on SP LTs. Remove the bolt once you verified it's not fuel related.

 

[RubyRedBoost]

It definitely looks like it is making contact. Shift motor and remove or modify the bracket.

 

[SolarFlare]

My header installer just punched the bolt off and folded the bracket up.

 

[Nerass]

very glad i stumbled upon this thread.. gonna see if mine are touching. unfortunately i'm scheduled for the dyno tomorrow so hopefully this is easy enough. fffffffffff

 

[Joe 5.0]

My car is pulling timing during WOT and my pulls don't feel nearly as strong.

I took a peak at my header bolt and I can see a clear scrape on my SW header. I would assume this bolt is touching the header during WOT.

Will filing down the bolt threads be sufficient enough to fix this problem?

 

[BmacIL]

I'm getting a decent amount of knock at WOT and I'm not convinced it's real. Been looking for false knock in the exhaust and came across this. Anyone heard this before? Stock headers. It sounds like the catalyst buzzing/rattling. Other side doesn't do it.

 

[Frenchy480]

I'm getting a decent amount of knock at WOT and I'm not convinced it's real. Been looking for false knock in the exhaust and came across this. Anyone heard this before? Stock headers. It sounds like the catalyst buzzing/rattling. Other side doesn't do it.

I had a similar sound, but on the opposite side where the flex pipe is at (stock headers). I was getting alot of false knock at WOT between bad gas and a bad flex pipe. Did 100 octane fuel, eliminated most of it, then had an exhaust shop cut out the flex pipe and hard line it and i haven't had any issues since (now on e85). Does it rattle around the flex pipe? Hopefully it's not a bad cat.

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