hello peeps need help!!!!!!!!

just built a 1.8 16v zetec turbo engine

problem is after having cambelt fitted (engine out of car on engine stand) I have found out that after turning the engine over manually with a spanner on the bottom pully,that the pistons are hitting the head

have removed cambelt & camshafts so to make sure that its not the valves,but it still hits the head

bottom end turned ok before head was put on,pistons did hang out of block at T.D.C did'nt really think much of it as standard pistons stick out by apx 0.5mm,
been told that pistons should be 2mm below block deck at T.D.C with a comp ratio of 8.2.1?????????????
could anyone offer some pointers,advice point me in the right direction!

the pistons are forged accralite crowns have been machined to achive 8.2.1 compression ratio,standard 1.8 mondeo head gasket (was recommend to use it!)

any help would be GR8

 

cant really help as to why they are hitting but im using the same pistons on mine and they did sit lower in the block that stds also had the face cut out leaving a lip



obviously not at TDC

 

what compression ratio are you running? is your crank & rods standard?

 

8:1 apparently and yeah they are std jus ligthened and balanced and stress relieved

 

what head gasket did you use?

 

don't mind if i ask where you got your pistons from & who did your machining?

 

head gasket is focus 1.8 three layer job and Burtons supplied the pistons and CTM did the engineering work all in Ilford, E london

 

The 3 layer gaskets from Burton are quite thin.

Use a ford item from a 2000 focus. 3 layer steel type just a fraction thicker or you can use two gaskets one ontop of the other to reduce compression / give you more clearance. Make sure to drill out the rivits if going this route though

What rods are you using?

Early engine use smaller rods than the later ones.


The last alternative is to get the pistons machined

 

pistons have aleady been machine down to achieve 8.2.1 comp ratio!!!

if i use two head gaskets surly i am going to be upping the comp ratio not reducing it.

engine is early type mondeo zetec 'E',rod are standard

this problem is doing my head in

has anyone got any ford part numbers or burton part numbers for head gaskets?

 

have'nt got a clue how much was machined off crowns of pistons to achieve 8.2.1 comp ratio.

if extra machining is required surely this is gona make the pistons weak by taking an extra 2mm + off?

don't wana f**k them up as they cost me best part of 500 big ones including the machining i had done before i took delivery!!

something ain't right need to get to the bottom of this

 

F.A.O chrissy bwoy

your piston crowns seam alot different!,mine are machined flat,could this be the problem why mine are fowling???????????????????

bought mine from burton as well & they done the machining!!!!!!!!!

 

hmmmm


Burtons farm there machining out to Charlie at CTM hes the guy who did mine

strange they are different when the same guy did em

 

no idea who did the machining,presumed they did it in house not farmed it out!

paid them Ł100 note for the privilage of getting the job done right,not slagging them off in any way top guys know there stuff & upmost help full!

when pistons arrived they appeared to "unmachined" apart from a tiny raised nipple in the centre of each one,quick phone to the just to check that they had been worked on & was assured that was the case

 

not exactly farmed out, its next door,

perhaps an idea to call em and ask who did the machining just to clarify, Charlie is a top man altho very busy atm as hes moving into new premises

 

chrissy need to eliminate some areas>>>>>>>>>>


what make part no is your head gasket?

i take it you are running standard rods crank bearing shell etc?

 

chrissy sound a gd idea will try that,wana estiblish what the cause is 1st b4 i take engine apart but it sounds like is something to do with pistons!!!

 

no idea on part number matey

but its a 2000+ 1.8 focus head gasket

and all std shells etc, slitley oiversize if i remember the convo correctly

 

u aint got ya cams 180 degrees out have ya???

 

engine at mo on stand no cam belt,camshafts removed, turn engine over on bottom pully at almost to the point of TDC pistons touch head

 

u got any gasket on now?

mite just be catching

 

offered up head gasket on dowels on block & rotated engine pistons did not catch gasket in any way!!

got to wait till monday to speak to top tech guy at burtons,as he is at autosport show N.E.C


will let u know what the out come is

 

Chrissy - Jay's got 2 problems here, the pistons touch the head before TDC and the CR is way too high as the pistons are flat and come to the top of the block (i fact slightly higher than standard evidently) To get CR 8.2:1 there needs to be 13.5cc capacity below the block level at TDC - ideally as a bowl in the piston. In the event the pistons are machined flat, they need to be more than 2mm below the deck height to get that extra volume to get 8.2:1 CR..

James - the more i think about it, the more i feel those pistons haven't actually been machined! They should really be machined with a bowl (like Chrissy's picture) and make sure the outer raised ring clears the head at TDC obviously.. This will give much better combustion characteristics than a flat top.
No real way of telling i guess without taking it apart and measuring piston height... Presumably there are no markings on top of the crowns, whick would indicate they are unmachined??

Rich

 

i know burtons dont do off the shelf low comp pistons for the 1.8, but they do forged std comp ones, so im guessing thats what mine r machined,

form what ya say about the raised nipple in the centre they DO sound unmachined

 

rich, i might of said when pistons turned up in post it did'nt seam as though that they had been machined apart from raised nipple in centre of crown,so i got on dog & bone to burtons & they reassued me that they had been machined.

by what you & chrissy are saying that they have'nt been machined somebody may have been telling porkies!!!!!!!,i have invoice showing that they have been machined & paid Ł100 big ones for the privilage!!!!!!!!!

phone call in the morning to confirm this will let you boys know the out come

thank for your in put so far

 

Jay, if they need to be machined, it's significantly important to get them machined as a bowl rather than flat for combustion efficiency... this is partly what's making me think maybe they are not done.. I would expect someone like Burtons to know and do this as a matter of course...

 

perhaps they sent the wrong ones out

 

simply this iswrong!
the pistons should sit lower than standard .
silly question but is the block shorter in any way than standard or the rods longer?
have you had the block skimmed??
mike

 

went autosport show on sat spoke to top tech guy from burtons,did'nt really get ant further forward with this problem as,i told him that pistons where fowling & of a flat machined apperence not dished as chrissy boys he did really say that the pistons are the problem,but did say to take pistons out measure skirt so they can calculate comp ratio?????????

its got to be the pistons that are causing this problem,don't know what else it could be is there an issue of different con rods depening on age of engine,came from mondeo,escort????????

it is doing my head in now

 

James,
The pistons are just plain WRONG mate, really..!

a, they shouldn't foul the head for ANY reason, variations in headgasket thickness etc shouldn't be that critical. The block hasn't been machined short, as it was OK before with the standard pistons.

b, the compression ratio isn't even worth discussing, it WILL be 10:1 as it stands, same as standard, since the pistons come to the top of the bore..

There's 2 possible explanations in my view here:
Either they machined the wrong pistons, so haven't ended up with the dimensions they were expecting, or they actually haven't been machined at all.

As a secondary issue I would also expect someone with the knowledge/expertise that Burtons should have, to machine pistons for lower compression with a dish/bowl rather than flat - it really isn't good practice to have flat pistons with a large flat combustion space between the piston and head at TDC.. this also adds to me thinking that they haven't actually been machined..

 

every time i try & sort things out with them it seam they don't want to admit that the cause is the pistons,i agree with you that they should be dished thats why i contacted them when they arrived because they did'nt look like what i thought they should be.

surly the easiest way to sort this out is take pistons out send them back so they have them in front of them,they must be able to work out that there is something wrong rather than try to explain something over the phone

as you sais the issue is that they sholud be of a dished apperence & NOT stick out of the block

gota be the best way to sort this out!!!!!!!!

 

get on the fone, and TELL them they are wrong and they are gonna be in the post to them soon, and that you either want a refund as you have been sold goods not fit for the purpose they where intended, or ud like the matter resolved

jus get onto em till ur happy

 

piston taken out! spoken to burton on sat very helpful advice,asked to "box them up" send then back.


hopefully have this problem solved by end of week

will post a reply when i hear back from them

 

good man!

let us know

 

chrissy what kinda power, boost u running in yours?

 

no idea as yet mate, ahmed still has it and it aint run it yet.... mite get it baxk some point

 

Btw, old reply... but using two head gaskets does *not* increase CR, using an extra gasket would raise the head, thus increasing the volume available at TDC, thus reducing the compression ratio.

This is not my forté really, but as I understand it, if you have an 1800cc engine, making each cylinder 450cc, for 8.2:1 CR you'd want the volume of the chamber at TDC to be 54cc ?

Raising the head by a millimeter, might add 1-2 cc of volume, thus lowering the compression, example, lets say 1 mm raises increases it by 2cc, that gives you 56cc of volume, meaning a compression ratio of 450cc / 56cc = 8.03:1 CR.

(Perhaps I should add to the equation the fact that a more volume at TDC would also result in more total volume, but relatively the 2cc change is much more drastic for the TDC volume, so even if we'd add the 2cc to the total volume, 452cc / 56cc we'll get the reduced CR of 8.07:1)

This might be an oversimplification, but it should reveal the obvious, raising the head increases volume at TDC, thus reducing the compression ratio.

 

pistons have arrived at burtons,a phone call on thursday i was informed that the pistons supplied where the WRONG ones!!!!!!!!!!!! ,just proves that we all make mistakes,they are going to supply me with the CORRECT dished ones.

glad to here i was right all along

do i have a claim against them for postage,new gaskets, bolts etc,as i have reciept for so called correct pistons & machine work!,as i built the engine up in good will as pistons where at the time supplied correctly even after a phone call just to double check.

 

best off mentioniung it to them, i guess u have a case for postage etc, but really bolts etc may be down to you. ask.... if you dont ask you dont get

but gud to hear its getting there

 

James, as you rung to check to see if they were right due to your suspicions, I'd be pushing them for replacement of gaskets and bolts at the very least... even ignoring the labour time to build/strip/build it...

 

imagine if you hadn't first turned it over and just fired it up