well its a long winded story but i could really do with a bit of advice this time

ok, rebuilt my engine, new forged pistons, rebore, block deck skim, new head, all bearings replaced,


ran it up for the first time yesterday and had a faint tapping sound, asumed it was tappets, so ran it for 20mins it wouldnt go away,

did some testing this morning, and the tapping stopped when no3 injector was unplugged.

i bit the bullet and removed the head,


why would this stop when i unplugged the injector? the only thing i can think off, is the kick of the ignition making the piston kick over was enough to make it contact?


now, i did dummy build this and it didnt show up then. so must only happen at speeds above me turning it over by hand

number 3 piston now has a clonk when i rock it from side to side, the others have the same movement but no noise....could this have damaged the skirt?

number 3 cylinder was also runing rich by the look of it, as all the valves were clean, and exhaust port wes sticky, i have been aware on my last engine of no3 running richer than the others, so maybe i have an ecu issue aswell? and maybe it was borewashing no3 hence the noise when i rock the piston?



so what do it do now? what do you reckon?

obviously im now going to remove the pistons, get them measured up, and skimed if ok, but they only ran for 20mins

 

ehh piston have tuched the head???
how about the valves, are they ok?
Sounds like you might have a small end bearing failure or even big end

 

oh bugger gudgion pin?

 

it has massive valve cut outs, so the valves have not touched,

big ends are new, and it didnt sound like a big end at all,

small ends were a real nice fit,with new pins i cant see it being that, but i will find out tomorow

 

the pistons do protrude the block now after its deck skim, martin told me to be aware of contact, so i did a dummy build...but its touching when it runs

 

badly machined piston perhaps?

 

sounds like you have your answer

 

its weird isnt it, as none of the others touch, or are noisey when rocked side to side,

they all have the same movemnt in them, but only no 3 clonks as the skirt taps the bore

 

why only no3 tough trev?

 

yes it is strange, if its only 3 it either has to be the physical measurements of the piston are different to the others or you have big or little end problems, or your crank has been very badly ground.

 

crank is standard...

 

The pistons should only rise above the block 15thou, the rest will only be a guess until you strip it.

Mark

 

shit man, this aint sounding good

 

were these the rods used in your last engine

 

makes me wonder if its this overfuelling issue washing the oil off the bore...

i know the tapping was the head contact...but what about the slapping?

 

very strange? maybe one for the pro engine builders to answer? cant get my head round that at all James

 

yeah...same ones

 

thats true, il see tomorrow....

 

did you measure the rods lengthbefore the build as for the slapping if it goes away when injector is un plugged surely it has to be a injector or ecu fault

 

Wounder James, hope it gets sorted mate

 

in one way its odd that it goes away as it must mean that you cant hear the piston to head contact? as when you remove the injector the piston should still be hitting the head? mabe your just hearing slap

 

i can only think when it fires, the piston kicks, which is normal, but cos the heads so close it kicks and the high side taps the head???

 

maybe the block have been skimmed to much?

 

had this when i done a engine on my old saph and it turned out that the pistons were all different hights so had them miled off 10 tho and it was fine and is still going now have alook how high they are out the block like mark said should not be out the block no more than 15 tho

 

4 thou....however, i can just deck the pistons to match...

 

0.004" difference between pistons I assume?

 

block was skimmed 4 thou


turning it over by hand i felt no contact at all, its only when running.

 

is this what it is now m8

 

I don't mean to seem rude, but I was once told by one of the best in the game; when referring to what people had advised me on here; and they said "Yes, and how many of them are professional engine builders?" I then ended up taking his advise, on what a lot of people on here said was a bad idea, 3+ years later, and my engine is still PERFECT

Ring a professional Monday

 

get a clock gauge and check how much each piston protudes the block

 

the block was skimmed 4thou, but i didnt skim the pistons, as it felt fine on the dummy build...

 

i am more than quaified thanks

this is my toy, that i have built, i will overcome any issues i have, and people on here help me on my way, as its not quite normal anymore, and many have experience with engines of a similar spec to mine.


no fun in paying someone to build it at all imo

 

Was the pistons bored for each pot and fitted that way, did you check bearing clearances and crank size.

Mark

 

well, the block was bored by martin at reyland, and they waited for pistons before the bore, so i assume they were measured up mark, however they wernt numbered, so must have been close enough to each other id guess?

the crank was checked and polished but still perfect in std size, and was perfect in my old engine, as were the rods etc

 

can you re uise the wrc gasket? or is it going to cost me another Ł170

 

did this ever get sorted?

 

I assume so, but the head was damaged and the engine is apart again at the moment.

 

yeah, twas a rogue piston,

now i had valve seat failure..


god im lucky!


back soon!

 

Bigger and better than ever

 

thats the plan mate ,lol