Piston Slap

[Hakosuka22]

Hey guys,

Have a little bit of a problem. I have had this tapping noise coming from my engine bay. Finally got it around to a mates house who is a mechanic. We narrowed it down by listening to the engine via this big screwdriver and putting it to the block (may have tech term) but looks like a big screwdriver. Anyway, heard a bit of a slapping in the 6th cylinder or top left corner of the RB26. Subsequently we removed the coil pack plug and ran it on 5 pistons and it disapears. Found! Now that I have this nasty slapping in this cylinder only what are my options? It has only started in the last couple of months. Engine is from factory with 115k on the clock. Not too noisy but noticable. HELLLP!! I love my baby, and want to fix her. I have heard the word "rebuild" mentioned. I would like to take that as my last resort at this stage in time. Any suggestions welcome.

Cheers,

[yup21t]

do you know the cars history, how much boost are you running?

[Hakosuka22]

Yeh dude sorry 95 R33 GTR. Imported in 2000 been here since, 1 owner and has vouched it has the factory engine as far as he knows unless it got changed before it got here. Umm. Had regular services every 5000kms with good oil. Thats about it.

[yup21t]

A mate of mine went through 3 motors in a 96s2 he just kept pumping up the boost and everytime it went to the shop number six piston was shagged, my advice get a compression test asap this will tell you wether or not its stuffed, worse case one of 2 things bottom end rebuild pistons rings and bearings, or source another power plant. thats all i got to offer, but get the compression tested. good luck let me know how you go

[teng]

BTW May i know what causes a "piston slap". First time i come across a term like this ><

Edited July 14, 2008 by teng

[GTR-32U]

done a compression test ? or leakdown test ? I would love to know if that cylinder reads lower than the others... Cracked ring land maybe ? just guessing here as I havent heard the car

[yup21t]

BTW May i know what causes a "piston slap". First time i come across a term like this ><

caused by a few things from craked rings broken gudgen pins stuffed bearings

[Hakosuka22]

Nah will get that done 2moz. Let u guys know my results. Thanks for the assistance.

[racin8]

Does the tapping noise dissappear or become less noticeable after the car has warmed up ?

I had ( still have ) a Holden Ute 2002 SS ( LS1 Engine ) which developed quite a loud piston slap noise ( many of these engines suffered from this issue and it was well publicised at the time ). Many owners had Holden rebuild the engine under warranty but they were real pricks and very difficult to get anything done. They refused a rebuild on mine because it had aftermarket cam and heads etc....

Point of the story being it has been driven hard actually very hard for 6 years and whilst the noise is still audible when cold ( the 5.7 V8 with headers cams and open exhaust do help to drown it out ) the engine has not missed a beat. With 190,000 km on the clock

It is worth noting that ever since the problem was diagnosed I have been using a Moreys Oil additive which is made for older engines ( ie with more wear ) it seems to have a thicker property to it and I just add about 500ml of it to my oil.

Like I said earlier she is driven very hard and has been for 6 years and still going strong.

I would get the problem professionally diagnosed but if a rebuild is out of the question due to cost etc... then consider using the oil additive and keep driving until a rebuild is really really required.

[arep3]

continuous driving with piston slap can and most likely will do more damage and requiring a more expensive rebuild. It may not be anything major though.