Anyone know about 1.8 zvh turbo conversions?.

[Dan Le Moignan]

Evening guys,
A friend on myne is mid build on a 1.8 zvh turbo engine conversion for his mk 2 fiesta.
He is trying to gauge if stretch bolts are required at 300hp?.
Think he had read the head can lift at that power on the normal m10 studs and wreck the gasket in time.
Does anyone know if you need to upgrade to m12 stretch bolts at that power level?
Many thanks for any help

[Scott_Rst]

Im on arp stud and nut at 480bhp on a 2ltr zvh, standard size

[Dan Le Moignan]

Thanks Scott, this is a zvh/ cvh build but guess the same thinking applies?
He is just having the block sorted now so think he will stay m10 as you have done for 300hp

[Scott_Rst]

Mine is a cvh head zetec block also,

If its not to late id advise him to go 16v zetec turbo, it wont cost more and will have a much smoother power delivery,
My zvh is at best a nightmare, if i could go back id have gone full zetec turbo!

Also you dont need to get oil ways in block blanked off, there is a cometic gasket available that does it, i have one and its never caused any issues!

[Dan Le Moignan]

Scott did arp make the kit up for you and do you know the price as he told me they don't do an off the shelf kit for cvh head?
I think he wants cvh top as its for a series 1 rs turbo and not the fiesta so keep it factory looking.

[Scott_Rst]

You've got me thinking now, was a few year ago now,

my studs may not be arp, the 'tuner' (use that term loosely!) i used may actually have his own designed stud and nuts! Aswell as the headgasket may only be available through him also,,

Yes thats also why i went zvh, and preferred the more 'oldschool' look,

Currently breaking my engine and planning on building a nice cvh once the escos has stopped stealing my time!

[Scott_Rst]

Unhelpful to you but this is a new design of water cooled exhaust that i found was being trialled on my engine!!!
Now i will always travel to find a trusted engine builder!

[steveboyslim]

Drill and tap the block to accept YB head bolts and then drill the head bolt holes to suit.

Steve

[Dan Le Moignan]

Wow, was it keeping the exhaust gas temps in control?!
He is adamant about using the cvh head, and has already blocked the galleries in the block so just need to sort studs now

[Scott_Rst]

Actually went out to garage and checked and looked at some receipts, im not on stud and nut im on re usable non stretch bolts, £39.99, have never had any head lift, @ 2 bar of boost

You can see there is a conversion plate from cvh to zetec due
to having a zetec tubular manifold, when they drilled head to fit plate (which is easy enough) they went to far and straight through into a waterway!

Then they tried to bodge it with sealant,

Wondered what was going on when the escort was pumping out water and steam straight out of the side exit exhaust!!

[Dan Le Moignan]

Nuts the work that people try to cover up
His block is built up so can't decide what to do as tapping the block would mean it all needs to come apart.
He had a lot of head gasket issues on his cvh turbo engine untill he made his own stud and nut kit up and the problems stopped, but 300hp is a fair bit more than the cvh is running.
He was also told the cast blocks don't like the stud route and can come lose

[Dan Le Moignan]

Steve out of interest if you were building a zvh with cvh head would you use aftermarket/ home made stud and nut or go to the bigger m12 with stretch bolt?
Guessing they don't run that much boost for 300hp?

[Scott_Rst]

I know alot of big power cvh's would lift the head but that was often pretty much always due to big boost,

Never heard of zvhs lifting really, i know plenty people would just run standard head bolts!
Biggest issue with cvh head with high boost/raised rev's is the rocker studs getting pulled out of head! But for 300bhp on a zvh it wont be under that level of stress,

As much as i didnt want to advertise this but go on sitech racing site, zvh section, head bolts there are specific length also the headgasket i mentioned is there, if your friend uses these he wont go wrong!

[Dan Le Moignan]

Scott he got his original bolts from sitech but was told 65lb ft was max torque and was still seeing issues untill he binned them and made up his own stud and nut kit and went to 70 or 75lb ft on them, that's not to say another issue was causing it and the higher torque masked the issue.

[Scott_Rst]

Hmm, im on same bolts and torque and never had an issue, assumed theyd be more than upto job if they were keeping mine clamped together!

What sort of head gasket has he been using?