200 replies to this topic

[vocky]

I thought some of you would like to see my latest project

I am aiming to create a 7600 rpm rev limit, high compression, 2.2 engine

It started off with some wiseco special order 11:1 CR pistons, closely followed by a saab head from Dude, the head was quickly stripped and the porting work commenced.

after 10 hours work the combustion chambers are done, but the ports have not been touched yet

[EdButler]

Ohhh dear, here we go again!! Great work mate, you must have a VERY understanding better half!!

[snoopstah]

Dumb question - if you ran the engine for (say) 500 miles, would it still look like that or would it be back to how it started?

[EdButler]

Dumb question - if you ran the engine for (say) 500 miles, would it still look like that or would it be back to how it started?

Polishing to a smooth surface should help prevent the soot from sticking. Its a bit like painint on a polished or a keyed surface - the polished surface will loose the paint much easier as it has nowhere to 'bite'. I guess more importatly it lowers the drag coefficient of the air going in, swirling in the chamber and exiting as the surface will cause less turbulence... Thats the theory anyway

[vocky]

Great work mate, you must have a VERY understanding better half!!

after fitting the throttle bodies she thinks my vx is too fast, so making it quicker might not get her approval

[drpau]

Great work mate, you must have a VERY understanding better half!!

after fitting the throttle bodies she thinks my vx is too fast, so making it quicker might not get her approval

Jesus Vocky, even though you do all the work yourself it must still cost you a few quid for all this fettling!
I like it shiney, I am like a magpie. I just wish mine was running goes in to be fixed tomorrow

[vocky]

I expect it will cost a couple of grand for this upgrade, but thats the problem with tuning, the higher the engines spec the more it costs for the next stage, I think mine will be stage 7 after this it's the same with the vxT's, stage 5 isn't cheap

[Boss VX]

Dumb question - if you ran the engine for (say) 500 miles, would it still look like that or would it be back to how it started?

I used to work in the cylinder head department and swindon Racing engines. We did all the cylinder head conversions for the Works Mini Cooper not to mention piles of other projects. We would have cylinder heads come in with delivery miles and they were all covered in carbon. A polished surface will help keep this down but so will a good blast through the gears now and then. You will eventually reach an equilibrium where the carbon will only reach a certain build up depending on driving style.
The only ports we would polish were the exhaust ports (valve throats and mouths to exhaust manifold). The key is to get the air out as quick as possible following combustion. Inlet mouths and throats were not polished as the casting surface (slightly rough) agitates the air entering = better conbustion. Its the shape that is critical. Polishing of the whole combustion chamber was mainly used on cyl heads that would be displayed at shows.

[FLD]

I would expect you'll need to spend more time on the balancing of the bottom end than the head. I've built high revving engines but then spent an eternity balancing the bottom end (to 0.5 g). It helps loads and at tickover you cant tell its running as there is no vibration. Have you also considered tinkering with your fuel? This can allow you to run more advance which will also help. Although 7600 isnt unreasonable for an engine on pump fuel.

[vocky]

A polished surface will help keep this down but so will a good blast through the gears now and then. You will eventually reach an equilibrium where the carbon will only reach a certain build up depending on driving style.

thats the only reason the combustion chamber is getting polished, to minimise the build up of carbon

The only ports we would polish were the exhaust ports (valve throats and mouths to exhaust manifold). The key is to get the air out as quick as possible following combustion. Inlet mouths and throats were not polished as the casting surface (slightly rough) agitates the air entering = better conbustion

quite correct, I will be polishing the exhaust ports after reshaping the throat area and enlarging them in certain places for better flow.
the inlet ports are just reshaped, especially the throat area

I would expect you'll need to spend more time on the balancing of the bottom end than the head. I've built high revving engines but then spent an eternity balancing the bottom end (to 0.5 g). It helps loads and at tickover you cant tell its running as there is no vibration

the conrods and pistons were static balanced by the manufacturer's, so only the crank and flywheel needs balancing, although most report the cranks are well balanced anyway.

throttle bodies smooth out the lumpy tickover and vibrations caused by uprated mounts as well, mine has no teeth rattling vibrations anymore

[Winstar]

The only ports we would polish were the exhaust ports (valve throats and mouths to exhaust manifold). The key is to get the air out as quick as possible following combustion. Inlet mouths and throats were not polished as the casting surface (slightly rough) agitates the air entering = better conbustion

quite correct, I will be polishing the exhaust ports after reshaping the throat area and enlarging them in certain places for better flow.
the inlet ports are just reshaped, especially the throat area

It depands what your after leaving the inlet ports rough will increase the turbulence at low revs and increase torque through better combustion however the surface roughness will create extra loss at high revs. Also the ports in the z22se engine are shaped to create alot of 'tumble' at low revs to give good torque at the expense of power as high revs.

[speedster]

Way to go vocky! Please tell us more about those HC pistons. How did you go about calculating/get to this compression ratio? Are you going to do anything with the oil/lubrication system? Steve

[Arno]

the conrods and pistons were static balanced by the manufacturer's, so only the crank and flywheel needs balancing, although most report the cranks are well balanced anyway.

I'd still suggest giving these guys a call: http://www.vibrationfree.co.uk/

Properly dynamic balanced engine will last much longer if you're going to bump up the revs as the various frequency harmonics are what causes most of the issues at high RPM.

Bye Arno.

[vocky]

Please tell us more about those HC pistons. How did you go about calculating/get to this compression ratio?

I have no idea how wiseco figured out the ratio, I bought the pistons off the guy who had them specially made

Are you going to do anything with the oil/lubrication system?

I have been thinking about piston oil jets, but not sure whether to fit them or not

they help cooling the pistons but also create drag on the rotating assembly, so whats best

I'd still suggest giving these guys a call: http://www.vibrationfree.co.uk/

they are only 30 minutes from me, so will be using them

[luna_s]

you can see how rough the lost foam head castings are on these pics, not sure how good they are on the sand cast (get some more pics vocky )

exhaust before



exhaust after



inlet before



inlet after

[vocky]

some pics as requested

this is what the standard exhaust ports look like on the saab head



this is what the standard inlet ports look like on the saab head



this is what an inlet port looks like after a couple of hours work, the shape is roughly correct, just a couple of more hours work required to clean it up, it will be smooth but not polished when finished

[MaDFreeBiRD]

your mad! i love it

[techieboy]

Think about the weight saving. That's got to be a lb or two in metal filings saved there. Vocky, you're truly bonkers but can't wait to see the results....

[vocky]

I plan to carry out many of the ideas I have been dwelling on with this build, so it will be different to the average z22se

[techieboy]

I plan to carry out many of the ideas I have been dwelling on with this build, so it will be different to the average z22se

Uh oh.

I hope the ITB's will be able to cope with it all? I sense additional cold air intakes mounted in the butresses feeding straight into the throttle bodies or a bastardised Exige style scoop to feed enough air in to make the most of the mods.

As ever, will watch with interest and am happy to lend a hand if ever needed.