Can anyone help me I have a 96 cobra that has a ticking noise upon startup,seems to quiet down after it warms up any ideas on what this might be? Also the idle seems to stick up around 1500-2000 rpms with a/c on when i stop then gradually goes back down any Ideas of what is causing this. Any help would be greatly appreciated. car has manley rods and ross pistons,bottom end was professionally assembled,everything else is stock except for a c&l maf,bbk longtubes,underdrive pulleys,kingcobra clutch,steeda triax,4.30 gears and a autologic chip. Thanks Brian
Need Help! 96 cobra ticking noise at startup
- Thread starter fireman2004
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Well I can tell you that the gradual increase in rpms is natural when you turn the ac on. Mine does that, although I dont know if it is as high as yours. The ticking I have heard on ocassions but it goes away almost immediately. I would imagine that if you bring it into the dealership they are going to look at you as though you are being rediculous. Apperantly dealers only want to see a customer if you have something majorly wrong with your car.
Cobras have forged pistons. Although the properties of forged pistons are strength and durability, the downside is they have poor thermal characteristics. They expand quite a bit on heating. This means machine work (bore) must be bigger than for cast or hyperutectic piston types. Here's whats happening. You crank a cold DOHC engine and you get piston slap until the engine comes up to temperature. Once the pistons have expanded, no noise. You can prove this in the following way. See if the noise occurs when starting a hot engine. I'll bet dollar to donuts that you don't hear any slap...only when engine is started cold. One thing this should tell you is not to rev your DOHC until the temperature needle reads normal.
Its not a problem...its characteristic of the DOHC with forged pistons.
Jeff
Its not a problem...its characteristic of the DOHC with forged pistons.
Jeff
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