how big can you safely bore a 1.6cvh?

 

A 1.5mm over bore works out at about 1660cc IIRC. I think thats the biggers piston available for direct fitment into a CVH (without straying to pistons designd for something else).

 

and im sure thats what safe gus and to get hight capacity they pu stroked crank and different lenth rods ect but will have to ask the professionals ... what about american tall block comes as 1800 them bored to 1900

 

yeah i didnt mean off the peg daz

mark's reading me mind i think

just wondering how far you can go safely before you hit the water ways

 

could you not bore out the original bores then fit liners to get a bigger bore with a stronger wall? i'd imagine you could go quite big with that if it's possible to fit liners to a cvh block.

 

yeah thought about that

think i just spent that 112 mil from the euro tonight

 

lol that'd be one seriously expensive engine my man.

 

My 1.9 is based on a 1.6 block but is bored and stroked to get the extra capacity. I have no idea how though lol. IIRC Power Engineering used to do a systems 2 1.9 with just oversized pistons and were prone to failing

 

yeah i heard about that

 

werent the power engineering 1.9 conversions done using some crazy combination or merc pistons and triumph rods, or something weird like that?

and im fairly sure phils is a jamsport special block, best to ask them the exact spec of how they achieve it, but im fairly sure i remember it involving 1.8t audi pistons

 

jamsport do a good 1900 but it aint cheap as your needing uprated crank/rods/pistons/ ect ect

 

I thought a 1.5 mm overbore on Accrilites resulted on something like 1740? Or am I imaging it?

 

power engineering 1.9 use 83mm bore i have cracked one block
running 1.6bar

 

Depends on a few factors like piston height and combustion chamber volume but my engine on a 1mm overbore is 1640cc. I could bore it to 1.5mm but to reach 1740 i'd have to look further than just bore size.

 

If I was to go down the road of increased capacity, I'd get a spacer plate cut from a head gasket and bond it to the block. I'd then liner through the whole lot and use a longer stroke crank and longer rods.

 

yeah we spoke about that but tommy is fancying the idea of short stroking and bigger bore

was only a short chat as he was on the dyno at the time, so will need to sit down and go thro it all properly

 

no there cast at 1900 in the us but 1800s have been bored to 1900

speak to specialised engines

http://www.specialisedengines.co.uk/index.htm

 

aint that a harvey gibbs conversion i was offered a 1700 apraently gibbs built

 

To destroke will reduce the capacity but make it revvier. The issue then is the valve train as it's not good for high revs. The CVH is rev happy anyway up to 7500 rpm. This is also the point where valve heads like to drop off.

I'd sooner try to keep the rod ratio as it is (by increasing the length of the rods as well as the crank) and increase the capacity by increasing the stroke as I know there is only down sides to trying to rev over 7k rpm.

 

yeah this is what i said

but he was double busy on thedyno so didnt really go into anything

 

Gus.... why not a zetec? lol or is this all hypothetical?

Rob,

 

should do really as its alot easier

but

i like the idea of keeping the cvh

its o hypothetical no, i will be doing it as and when i can afford to

 

I love the idea of sticking with cvh's too mate, but i guess when you look at it.... there is only so far you can develop a cvh bottom end until its not too unlike a zetec bottom end....

Rob,

 

to be honest if i done another i would zetec turbo it .....

and my missus is having a supercharged duratec fitted in her rs1600i shell... although i keep telling her to zetec turbo the thing

 

Tell her to ditch the supercharger and get a turbo on there instead! Duratecs (true Duratecs) make shit loads of power.

 

its a st150 engine but will be on after market management.... with cams /cosworth inlet/ custom exhaust manifold and system and with a stage2+ supercharger it will be 300/320bhp..... and its gunna be used on track aswel...

i spoke to jamsport a few times and about it and at this spec they have still used standard internals lol and its still reliable the weak point is the gearbox but they reckon with a quiafe atb fitted this seems to make the more reliable for some reason