Just want to confirm a few rumours regarding ST170 engines as there's a lot of info floating about that no one seems to be able to confirm.
I have just bought a ST170 engine for turbo charging so...

Do they have uprated valve springs?

Do they have stronger or steel rods?

Are they higher comp. ratio?

Are the blocks any dfferent to standard?

What exactly needs doing to stop the VVT?

Anything else worth knowing? Cheers

 

yes, yes, yes, yes, and tap an m6 thread in the front cap where the oil feeds in and stick a grub screw in it.

 

Or just dont' connect the wires up for the VVT!!
It is only a on off state nothing high tech at all, so leave in off state by not connecting.
tabetha

 

You couldn't be more wrong if you tried.

 

Why turbo?

I heard these supercharge really well, although I think power works have stopped making the kit

 

instead of just saying that, why dont you explain how he is wrong as im sure 1) he wants to know how he is wrong and 2) XRT Si wants to know as well and 3) i want to know

 

it's not 'on-off' - it's variable cam phase +/- 20degrees (or it might be 20deg retard only) controlled by a PWM output from the ecu. This opens/closes the solenoid by variable amounts, adjusting oil flow/pressure into the cam pulley and pushing out/letting in a sprung helix arrangment which causes a rotation of the shaft relative to the pulley.

I *think* from memory that with no PWM output / solenoid shut, the shaft defaults to fully retarded.

Valve springs are '10% uprated' according to ETIS, but from what rate I don't know.

Block is the same as 2.0L black top, head has smaller combustion chambers to give 10.5:1 compression iirc.

Rods are sinter-forged like in the zetec-se.

 

Good man! Have a 170 turbo myself

Yes, they are stronger than normal Zetec springs but dodnt know the exact strength.

Yes forged rods. Mine held 291bhp without issue, although I upgraded later just to be sure.

10.5:1 ratio

Blaock wise I dont think so, although they do have oil spray bar for the pistons, which is a nice addition.

To truely eliminate the VVT you need to fit a venrier pulley on the inlet cam.

Anything else worth knowing: the heads are alot better than the Zetec's and dont need to be fettled. Dont use the standard inlet, as the rubber bungs come off the dual tract inlet and get stuck in the inelt runners. The port spacings are different from the Zetec, so inlets from those dont work. I got mine custom made by Danny B.

If you want anymore info let me know, as I went down this road about 3 years ago now... and I'm still loving it

 

ah, another thing... the pistons are not forged

the block is definately not the asme as the mondeo blacktop, but appears to be the same as the US Focus block. i haven't had a UK focus block yet to compare to though.

the rods are US length too, the small ends are 20mm

all 2.0's have oil spray jets


Why are you using the st170 out of curiosity? are you after monster power?

 

I think most of the questions have been answered above!

To eliminate VVT you need to block the oil pressure feed to the inlet cam - i used a grub screw on mine. You'll also need a machinist to turn you up an adaptor to drop in the resulting gap when you remove VVT pulley then fit a vernier pulley and dial in accordingly

 

MD COS: No the pistons are high pressure cast, they are stronger than the 2.0 Zetec ones, but aren't indestructable.

Will: Have you gotten rid of the VVT on the Focus?

 

are they mahle pistons as i went in burtons and the engineer was saying they were but i couldnt see "mahle" written on them

 

Thanks for the sound info guys!

MDCOS - I just got the engine at a very good price, cheaper than getting uprated valve springs for the 2.0 Silver Top I now have sitting next to it

Simon - Cheers for the great info, guess my next question is what are the limits to these parts? At 291bhp was it still on standard valve springs? Has anyone pushed the standard rods etc...

Also did you uprate the rod bolts as I've heard they are uprated too?

Also very interesting info on the inlet, didnt know that. Guessing ill have to have an inlet made, is there no way of at least salvaging some of the zetec inlet? Cheers again!

 

the ports on the rover one line up nice mate and i was getting valve float @13psi on a t34 on standard springs. and im making a tool to do the springs with the head still on .

 

[quote=XRT_si;3644899]Thanks for the sound info guys!

MDCOS - I just got the engine at a very good price, cheaper than getting uprated valve springs for the 2.0 Silver Top I now have sitting next to it
/quote]

 

Mine is running 310bhp now and is still running standard springs with no issues.
The standard rods will take 300bhp with standard bolts.

Ian Howell (Area Six) supplies uprated valve springs if you want them. He also does a really nice inlet to. As Crazycage has said, the Rover inlet manifold is a popular choice as well.

 

Cheers for the info, what boost and what turbo did you make 300bhp on?
As this contrasts with what Crazycage has said?

I built a zetec turbo before and still got loads of parts like 1.8 inlets knocking around, guessing ill have to knock up a Rover one!

Paul - The pistons ARE mahle, and it IS printed on the inside of them. Just had a look

 

thats what i get for looking in the dark using my phone as a light

si- keep sat free, we'll head over jb's drop diff off get my seats, turbo and calipers lol

 

yes, there are a lot of roumours about ST170 engines.
i used to build ST internals into silvertop blocks and use silvertop heads to loose the VVT setup, they are NOT electronic operated and use centrifugal force with pressure opperated gel to make the cam pulleys advance/retard.
they are electronicaly sensed to advance/retard ECU effects on fuel/spark maps.

they ran forged rods and pistons, longer rods and very shallow pocketed pistons and look very very well engineered for a mass produced motor.

ST170`s do have completley different heads to any other 2.0 zetec (which is basicaly a modded black top 2.0)

if you look on a petruding front facing lug on cylnder head it has SVT stamped into it, this proves an ST170 head.

they have high lift cams, stronger springs, slight change in port shape and one off head cast that accepts VVT setup, normal non ST cams/valvetrain in not compatable in ST heads, journals and pulleys etc simply do not mate up with the head.

each head was specificaly biult by hand and shipped to be mated to botom end and fitted to production car.

any questions at all you may have, please ask

regards Sean

 

Great info cheers fella!

 

Out of interest, why did you put the ST bits into Silvertops ?

Why not just use the black top head ?


With the VVT I understand that its not simply on or off, however I know a few guys who either have their VVT on a manual switch or it is switched to the ON position using the shift light function on ECU's not capabale of controlling VVT

What effect does the bolt in the oil way have ?

 

Oh and arent the ST170 pistons 'Slipper' Pistons and the rods forged as one piece and then broken ?

 

The rods are cast as one then broken yes.

Please remind me what slipper pistons are? Is it the way they are cast? Ive heard the expression before somewhere

 

Try that

http://www.accralite.com/accralite/slipper.htm

 

i used ST internals into silvertop block as the engine went into mk3 escort and was much much more adaptable than the black top block.
u used the silvertop head for reasons i cant remember but after trying to use 3 different heads i settled on the origional silver top head with Auto inlet or exhaust cam fitted, i think it was due to the later cam timing pulleys not being in correct position with black top/ST top end and early silvertop block/crank?

cant remember 100% but at the time simply no combination would work except ST pistons/rods in a modded silvertop block and head assembly.

engine was on Dellorto 45`s, maby this made a difference at the time? memory serves me no ideas at this time.

Sean.

 

i'm afraid the information you've given about the pistons is incorrect, they are not forged. I have spoken to mahle themselves about this.

 

I'd be surprised if they're anything other than LPC.

 

simon170 - still running VVT on the focus!

I took it off on the 500bhp engine i was building earlier in the year

I gave mine relentless abuse at Oulton Park on Wednesday, 8000rpm in 3rd, 4th and 5th on standard ST170 valvetrain without problem

 

why remove the vvt?,wont this help power delivery if mapped correctly?

 

certainly will, i'd be keeping it. Rods aren't longer on the ST as such - but on all blacktops.

 

ST170 Rods are mix of ali nickel and steel powder sintered, cold forged then big ends are snapped then the lot is machined. Powder sintered rod is cheaper to mass manufacture, lighter and good tensile strength. Pistons are same with different metal ratios mostly being ali. Will take lots of rev but shocks, knocks and det will break them easier.

The forged EN24 steel is heavier and more expensive to produce is stronger coping with higher tensile and compression forces at higher temperatures.

HTH

 

Mine makes 310bhp at a peak of 20 and a held 18psi (I think that what Chris told me lol), thats with a GT28R turbo.


BTW the pistons are high-pressure die cast.

Will - Nice one

 

you cant compare mine to simons mate my comp is a lot higher than his and i was running a t34 .48 and .55 and a really poor 2.5" system all of which is gone now

 

Lol - for those in doubt as to what sort of abuse a standard ST170 valvetrain can tolerate may want to watch this
http://uk.youtube.com/watch?v=aVrk8I6m2sQ

 

So keeping high comp. ratio on a T34.63 running say 18psi or so would cause valve bounce?

 

I'm running 1.0bar at 10.0:1 CR at 8000rpm without valve bounce... :S

crazycage - what valve clearances are you running?

 

great vid will, sounds awesome looks to go well to !

 

What C/R are you running mate? Mine runs 8.8:1

Will - Well peddled I assume it was you driving lol, was going well. Sounds like there was some vibration in the corners? Was that Neils track car infront of you that was looking a bit unwell?

EDIT: I could have sworn that Ian dropped the comp lower than that when it was rebuilt Will?

 

XRT si - The 170 also has a higher pressure oil pump. Just remembered....

 

Yeah - when i bought the car it was at 9.5:1 - i upped it when i did the top end rebuild last week, had a head skim and a different thickness head gasket.

It was me pedalling - i think it was alright to say it was my first time properly driving on track

Not entirely sure what that knocking is - felt like tyre scrub - could well be as i'm now on R888s with the stiffer sidewalls....