So Sick Of This....

[stuartlaw_78]

Hi all,

Now, you have probably heard of posts saying... "Ohh, my engine taps, what is it?"

Now, this is different..

I've rebuilt my engine and it's got Forgies in it.. did it all properly. Got pro to bore block, balance parts, etc... spent some coin doing it..

anyway, when I start my car, i get a tapping noise coming from it. I first thought the hyd lifters were shot because they were the only thing I didn't replace with the rebuild. I have since put in near new lifters and it still does it!

What could this be? I thougt of piston knock but it sounds to be coming from upper end.. not 100% though.. very hard to tell..

Is it possible of worn lobes on the cams? Only does it while engine is cold and when it's half cold half warm, if I drive it, it tapes at 2grand and not on either side...

when stone cold, taps all the way through the range.

the engine runs great and doesn't blow smoke.. has good power and I've done about 25,000 since build..

Any fresh ideas people??

thanks,

[kjb_r33]

Hi all,

Now, you have probably heard of posts saying... "Ohh, my engine taps, what is it?"

Now, this is different..

I've rebuilt my engine and it's got Forgies in it.. did it all properly. Got pro to bore block, balance parts, etc... spent some coin doing it..

anyway, when I start my car, i get a tapping noise coming from it. I first thought the hyd lifters were shot because they were the only thing I didn't replace with the rebuild. I have since put in near new lifters and it still does it!

What could this be? I thougt of piston knock but it sounds to be coming from upper end.. not 100% though.. very hard to tell..

Is it possible of worn lobes on the cams? Only does it while engine is cold and when it's half cold half warm, if I drive it, it tapes at 2grand and not on either side...

when stone cold, taps all the way through the range.

the engine runs great and doesn't blow smoke.. has good power and I've done about 25,000 since build..

Any fresh ideas people??

thanks,

Id say piston slap, pretty common with forgies. Forgies need the piston skirt to bore clearence to be spot on because of the different expansion rates to cast pistons. Clearence will be high when cold though which causes the piston slap.

Edited April 8, 2007 by kjb_r33

[stuartlaw_78]

Id say piston slap, pretty common with forgies. Forgies need the piston skirt to bore clearence to be spot on because of the different expansion rates to cast pistons. Clearence will be high when cold though which causes the piston slap.

Well, I thought that as well.. maybe... I just think that piston slap would be a deeper, heavier knock where as this knock is quick light and tappy...

hhmmm..... dunno.. anyone else??

[nizmo_freek]

Injectors, my stock injectors make a tapping nose as the car is warming up, the noise goes away once it is up to full temp. An easy way to check is to get a long screwdriver, start the car up then put the screwdriver on the little metal injector cap (cant remeber what it is called exactly) then put ur ear on the handle of the screwdriver while the car is running, this will amplify the tapping noise and you can then clearly hear were the sound is coming from. You can do this anywere on the engine to try and find the noise.

Edited April 9, 2007 by nizmo_freek

[stuartlaw_78]

Injectors, my stock injectors make a tapping nose as the car is warming up, the noise goes away once it is up to full temp. An easy way to check is to get a long screwdriver, start the car up then put the screwdriver on the little metal injector cap (cant remeber what it is called exactly) then put ur ear on the handle of the screwdriver while the car is running, this will amplify the tapping noise and you can then clearly hear were the sound is coming from. You can do this anywere on the engine to try and find the noise.

yeah, thanks.. I'll give it a go.. Doesn't sound like injectors but I'm open to suggestions and trying anything to resolve this at this stage.

Thanks mate..

[blind_elk]

My money is on piston slap of the cold piston in the bore. Forgies need to be HOT to work properly.

[NickR33]

another vote for piston slap here... the Arias forgies in my car made me wince on cold startup for months after the rebuild lol... they tend to throw out all your knock readings as well, noisy bastards! apparently you can run them at slightly less than the recommended piston to bore clearance to eliminate slap but I just went by the instructions from Arias... its been over a year now and it still uses next to no oil... even at the track