fiestaturbo.com

[Red16]

just been reading the http://www.zetec-turbo.co.uk/ site and was wondering how they have bonded the spacer plate to the engine block, the following is an extract from the site,

The plan was to seal the laser cut steel plate to the top of the block, firmly located on the head-alignment dowels. A single normal head gasket would seal the plate to the head. This way the plate would expand with the block whilst unable to move around freely due to the dowels, and the head and head gasket would be able to move and function as intended - using a gasket both sides of the plate was going to be asking for trouble.

The plate thickness was calculated to be 2.5mm for a 8.2:1 CR, was drawn up on CAD by ourselves (using a gasket as a guide) and manufactured by a local engineering firm for a very reasonable price. Much attention was given to ensuring that the main bore diameters were such that we the gasket was seating entirely on the plate with no risk of overhang into the bore, whilst also ensuring clearance for the pistons, as they protrude from the block about 0.5mm at TDC.




What would you use?

Where would you get it?

[AndyKam]

Use 2 head gaskets.

One between the block and the plate and one between the head and the plate.

[Fezzy Turbo]

If your going to lower compression, do it properly.

Adding plates and gaskets is asking for trouble!

[chubbs358]

this might sound like a retarded question but what advantage is there with low compression

[Red16]

If your going to lower compression, do it properly.

Adding plates and gaskets is asking for trouble!

i know, everyone says this, but the engine im building is just a trial really, to see if it will actually work, not looking for silly power figures, just a working diy turbo engine.

[FezzR]

only things i can think of are silcone and chemical metal niether of which i would advise

[285Andy]

this may be of some relivance, but after a head skim on a 2.0L zetec mondeo, the engineering firm i use sudgest the use of a spacer plate (although its not the thickness of that plate) and they also supplied a compound to seal the plate to the block, then you just use the new head gasket as per factory intended.
2 head gaskets isnt a good idea although it says that in the write up you put up Red16 that they didnt do it with 2 gaskets anyway.

unfortunatly, i cant remeber the piggin name of the stuff as it was quite a while ago when i done it. you must have a fairly local rebore center you can ring to find out what it is though?

may or may not be of use to you Red

[285Andy]

this might sound like a retarded question but what advantage is there with low compression

i think he's intending to do a turbo conversion hence the need for a lower compresion ratio

[FezzR]

this might sound like a retarded question but what advantage is there with low compression

i think he's intending to do a turbo conversion hence the need for a lower compresion ratio

the advantage is it wont go bang! the if the compression ratio is too high then it will just mash its self into a million pieces
ideally u want the compression ratio as high as the engine will take otherwise u loose power




just thought that there was lots of sealant in the back of the burtons catalogue and sure enough the sell a sealant suitable up to 350 degrees C

[chubbs358]

i wasnt taking the piss or any thin i just didnt realy know what the advantage of a low comp engien was in any situation not just this one

[FezzR]

i wasnt taking the piss or any thin i just didnt realy know what the advantage of a low comp engien was in any situation not just this one

didnt think u were in summary if u wanna turbo an non turbo engine then u have to lower the compression ratio UNLESS the engine is INSANELY stong or because it is trying to sqwish so much more mass it will brake into pieces

[chubbs358]

ah now i understand abit more makes sense realy

[PhilM]

Heres my reply as per passionford (ignore the first few words ):

100% agreed with Steve, they look cheap etc...but, have you considered that stainless steel will expand at a different rate to the cast iron block???

When you get a failure (common among those with spacer plates), and water pours into a bore, and the piston coms up on the compression stroke and finds it cant compress water, hydralic'ing the engine, bending rods, wrecking the engine etc.....probably find on reflection it would have been worth money for propper pistons

NB. There will ALWAYS be people who swear blind by them, they havent had any trouble, they may not have....but you might....think about it, is it worth it?

[MOONDUST FRST]

I wouldnt use one as it would almost certainly cost you more in the long run than just fitting low comp pistons!

[Project]

No reason why a decomp plate won't work.

Cost-wise, it depends how much work you put in; if you can make up the CAD drawings in a format readable by the engineering firm then they won't have to put in so much effort and costs will come right down.

I don't know what you use to bond the plate to the block, and even if I did, I wouldn't be able to tell you

One headgasket is fine as long as you have perfectly flat and surgically clean mating faces. I wouldn't really recommend using the tri-metal Zetec-R gasket in this situation - the Zetec-E HG has more room for error.

Phil - I don't really agree with your example there; surely any failure would have to be absolutely massive on a running engine to be able to dump enough water into the piston to cause water lock???

Al

Ps. I know nothing about engines. Please ignore everything I just wrote

[gareth231]

im running a decompression plate on mine at the moment (1.8 zvh) hadnt had any problems with it, runs at 1 bar, just used 1 head gasket and jointing compound, i admit its not the ideal solution but it will do intill i get my 2.0 zetec turbo in there, cant really see the point at throwing money at the 1.8 engine

[andymac]

How about that manky horrible stuff you use for glueing k-series engines back together ? Works a treat on hair, fingers, testes etc...

[DaveZetec]

Works a treat on hair, fingers, testes etc...

speaking from experience andy? gluing hairy fingers to testes

[Project]

I uhhmm... glued myself... to myself...

[Ian C70T5]

My personal opinion. if you're gonna do it, do it properly.. even if it is a test DIY.

Either dont run much boost and have the block standard compression

OR

Fit the correct pistons to lower the compression.

No point doing DIY test to make sure it works, if it aint gonna be done properly cause it wont work.

[gareth231]

well im running high boost and had no problems.... so im 400 quid + better off, i know its not ideal but it works, so why spend the extra cash?, obvously your payin for peace of mind!

i`d rather spend the money on a 2.0 zetec turbo, hence why i didnt bother with new pistons for the 1.8

[StreetDragster]

Is there a general rule of thumb for what compression ratio you want?

eg, is it like

9:1 for standard boost
8:1 for 20 psi boost
7:1 for 30 psi boost etc etc

Thanks

Matt

[Ian C70T5]

Dunno. but my 2.1 16v Zetec turbo is running 7.4:1 and not sure what boost it will run until Friday when Stu maps it

[StreetDragster]

Stu at Motorsport Developments?

I live round the corner from them (literally)

Thanks

Matt

[gareth231]

wow i reckon that will be able to run BIG boost! have to yet me know how it gets on...

[Ian C70T5]

Matt, yes mate. M Developments Stu.. he is having it Friday from 10am

[StreetDragster]

Cool, might bob down for a natter or if your at a loose end for the bit your more than welcome to come round for a brew if you want mate

Thanks

Matt