pink pantha

hi just finished rebuild on motor with eagle rods je pistons n pro seal rings new standard crank and acl bearings basically everything new inc cdb with oil squirters all honed, heads done ,but it can still hear a knock i think ,it done about ten hours runnin in and still sound knocky help pls oh and happy new year

jd5217

was the block honed to suit the pistons?

pink pantha

had each cylinder checked for sizes and texture measured gaps in each ring used standard size pistons all the bores were near identical all rings gapped identical

StickyMicky

but were the bores honed to suit the pistons?

some of the simple "drop in" sized ones are supposed to be a bit rattly.

pink pantha

i never gave chap who honed any pistons or figures why should i have????

NXG

Don't all forged rebuilds sound like a bag of spanners on startup, and a bit rattly until they're hot?

Peanuts

iTrader: (15)

no, you are wrong.
They can sound a little rattly if the clearances are generous, CPs used to have a rep for being rattly however if a build is specced correctly with the right tolerances then no, you are wrong, they will not sound like a bag of spanners.

NXG

Hmmm, need to have a word with my engine builder then....

Peanuts

iTrader: (15)

depends on what level you requested and how much you were willing to spend.
I have a forged 2.5 with Wiseco pistons and unless it is minus degrees C then its no more rattly than my old uk99 and sti99 standard engines.
Having bores honed to suit and having correct clearances makes the difference.

There are varying compositions of piston material though so it may be that if you had say a high silica content it may require a higher clearance due to greater thermal expansion, just a thought

NXG

Wiseco pistons, forged rods, ACL bearings.... as used by a certain, popular, well know engine builder

Peanuts

iTrader: (15)

then I'm sure it will be fine

steviecrump

I have a just run in forged CDB Wossner,ACL bearings,Ect.no rattles on start up even in this cold weather.I put this engine together myself.

pink pantha

i guess only time will tell cheers gents

mje_wrx

iTrader: (6)

im currently building mine and the engineers who rebuilds engines rebored my block didnt want pistons 2 size too as they said the technology these days due to manufacture techniques of the pistons all they need is the oversize ur doing, so they .5 over sized mine from what the standard cylinder was when manufactured as thats what pistons r .5 oversizes too. not.5 over worn cylinder i gave him.

Fat Boy

Mine sounds like a skeleton wanking in a biscuit barrel until it gets to about 75C, after which it smooths out. Built by a very reputable engine builder.

P1Marty

iTrader: (1)

Mine is the same ,once it gets to 80c it sound normal.

jd5217

so how many here have studied the mentioned "skeleton wanking in a biscuit barrel"???

mjtelectrical

Jeez that is so f***in funny, best thing I've heard / read this year. Got the mental image now, thats the trouble you can't unthink something once you've thunk it!!!

Mrchips

iTrader: (7)

Cure blimey, doesn't sound to good, was thinking about forging up, but reading this might just stick to and normal BHP. So many thoughts go through my head should I shouldn't I. Think I'll stick to my target 320, think it'll be a good fast road car.

Fat Boy

And strangely both our cars are P1s and both engines were built by the same outfit/man

Mine is 4 years old now, Mr Chips, and running around 450BHP so don't let a little noise put you off

MartynJ

My 2.1 stroker is silent, hot, cold whatever, only noise that comes from it is from the exhaust.

NXG

If you know it's going to be noisy to start with, and it's meant to be that way, and runs high power perfectly, as do many others built the same way, then what's the problem?

Fat Boy

I'd better pull my engine out and throw it away then...

Pavlo

At least you can hone your own block when the pistons pickup!

merlin24

iTrader: (1)

Damn near spat me coffee over me keyboard reading that - lol

Fai17

iTrader: (2)

ha ha ha....mines sounds knocky and i think they should sound knock with the clearance.

Fat Boy

NXG

As I understand it, if a forged build isn't a fraction lose and doesn't sound a bit 'knocky' when it's cold, everything will be too tight when it's up to normal running temps, causing problems.... Something to do with the materials expanding more with heat than standard items.

GazTheHat

Thanks! Everyone in the library just lOOked round.

jd5217

you wanking in a biscuit barrel?