project 26 ,ecotec 1.6

[rrrobert]

so , a new project looms ,
its a 1.6 x16xel vauxhall engine ,to be used for rd use on propane and no cam change .
so far i have read that the inlet maniofld was highly restrictive ,and so tested it on my flow test apparatus (read'lash up' ) and the head flowed 171 cfm@25 and the lower inlet 154 and the upper inlet 133 !
so thats all been cut up and now im making a 4 straight 41mm tube stonko manifold that will flow a big amount wilst still keeping up velocity .time will tell.
cams wize ,gm time them in at 108 and 99 lca ,so thats all changed to 110 and 113 , iv made an assumtion that the 99 ex timing was to drop cyl pressure for emmision purposes .
i will port the head and top exhaust manifold ,hoick out the cat ,and feed the dog ,er no , i mean remove the catatonic converter .(its getting late) .

little bit indecisive on the valve to piston clearance i can get away with , when on normal gm cam timing it was 1.04mm ex and 1.46 in . now its at 2.48 ex and 1.42 in .most clearance charts show 80 and 100 thou for valve clearances ,so im well below that allready , is it safe to wack off .38mm to get down to the original gm setting ,that was on the ex, and would now be on the inlet ?,

that would take my cr from 10.48 to1 up to approx 11.2,not as high as i would like but better than nothing ,particularly for economy.

cams are 8.5mm lift and 1mm timing 216 in 224 ex .
any input on the valve to piston clearance greatfully recieved ,
heres some pics ...




























regards robert

[FlowSpecialist]

A nice timing for standard road cams is 111 LCA 3 degrees advanced which means inlet full lift at 108 ATDC and exhaust at 114 BTDC. On that basis the OE inlet timing looks correct and the exhaust was as you say a bit odd.

Valve piston clearance on a small engine like this is usually OK at 1.5mm but of course if you never over-rev it you can go a bit tighter. You'll have no margin for further experiments with cam timing though. I wouldn't retard the inlet cam just to get more clearance though. Do it properly and machine the valve cutouts deeper.

Dave

[rrrobert]

Originally Posted by FlowSpecialist

A nice timing for standard road cams is 111 LCA 3 degrees advanced which means inlet full lift at 108 ATDC and exhaust at 114 BTDC. On that basis the OE inlet timing looks correct and the exhaust was as you say a bit odd.

Valve piston clearance on a small engine like this is usually OK at 1.5mm but of course if you never over-rev it you can go a bit tighter. You'll have no margin for further experiments with cam timing though. I wouldn't retard the inlet cam just to get more clearance though. Do it properly and machine the valve cutouts deeper.

Dave

hi dave,
im happy with the timing i have now it gives me the characteristics i want ,but yes ,that ex timing was odd , my theory is that they needed to drop cylinder pressure ,so reduced the dynamic cr that way ,thus dropping nitric oxides (or watever their called) pollution . i
not bothered with future cam experiments ,just wanted to get the cr as high as poss ,without taking the bottom end apart .
how did vauxhall get away with the 1.04mm clearance it had with the ex at 99lca!!!
gulp , maybe thats why there are a few bent valves and broken cam belts on those engines .maybe ill have to stick with the 10.5 to 1 and move on with it ,much though it grates: !

[rrrobert]

so , as bit of good progress and a bit of disaster !
here are some port shots to show my mods to the head .










heres a pic of the manifold halfway done



now for the problem , upon starting the engine is ok ,then ,when driving its ok ,but when left till the fan comes on the white smoke starts ,so i took it all apart again ,and found this strange pattern in the port ,and thought oh ,steam holes ,the heads porous where iv ported it too much ,but i only went in about 1 to 2 mm ,anyway ,have a look at this port .see the white streaks on the black , thats ally showing through the oil .


so then i built a pressure testing setup ,, filled thehead with green water ,and pupmed it up to 25 psi ,....nothing ,so then drained out water and pumped it up to 40 psi and filled the ports with water .... no bubbles ,see pic , whats going on !!!!??
header tank was not pressurizing ,no oil in water etc .car has no missfire and runs well .



heres the pressure setup ,and my manifold finished .





bit stumped , oh and i did do the prsssure test with a blowtorch on thep ort to get it hot .in case the holes opened up under heat . but maybe not hot enough .


regards robert

[rrrobert]

update ,now tested at 100 psi ,still no leaks !!??

[mpgmike]

I'd love to see the tops of the pistons and the cc side of the head. I can see the oil coming out past the ex valves, but more input might spark some thought.

Mike

[rrrobert]

Originally Posted by mpgmike

I'd love to see the tops of the pistons and the cc side of the head. I can see the oil coming out past the ex valves, but more input might spark some thought.

Mike

mike
theres a little oil misting on 2 of the ex valve stems ,and i feel the inlet guide stems may have been machined with too small a diameter on the oil seat part ,the inlets were a bit slippery with an oil layer ,just a sheen.
thing is this smoke is definately white ish .
specs 11.3:1 cr
82000 mile engine .cat equiped still .
header tank not pressurizing ,no water in oil
head gasket new
head skimmed
drives as expected ,very little smoke
then leave it for 5 mins ticking over then even smoke output ,no missfire at all smooth tickover still ,,and billowing white smoke on rev ,clears after a mile of driving .could the cat be creating smoke in some way , it was v gunked in the throttle valve ,so could the old bloke who had it before have never got the cat hot enough ?
im now tending to cracked liner ,but then , why no oil in the water and no pressurization of the header tank ?

regards robert

[KLR142]

Originally Posted by rrrobert

then leave it for 5 mins ticking over then even smoke output ,no missfire at all smooth tickover still ,,and billowing white smoke on rev ,clears after a mile of driving .could the cat be creating smoke in some way , it was v gunked in the throttle valve ,so could the old bloke who had it before have never got the cat hot enough ?

Sounds like the situation we sometimes get at our shop for valve guides that are leaking oil on Volvo's 5cylinder "whiteblock" engines. Somewhat common on them. Then again, the smoke isn't always there, we even get some oil consumption through engines that don't smoke.

Are you using any oil at all?

[rrrobert]

Originally Posted by KLR142

Sounds like the situation we sometimes get at our shop for valve guides that are leaking oil on Volvo's 5cylinder "whiteblock" engines. Somewhat common on them. Then again, the smoke isn't always there, we even get some oil consumption through engines that don't smoke.

Are you using any oil at all?

I HAVE NO IDEA KYLE , I DROVE IT 10 MILES TO SEE IF IT WOULD CLEAR ,THEN TOOK IToops all apart again ,found 3 of the guide seals had popped off ,so ill be a bit more assertive this time ,and decided to do the rings and big ends with it apart as well ,so now have the rings on there and will put it together tomorow ... lets hope it works .
im still baffled by the whitish smoke ,and im wondering if oil in the cat could become whiter .

[rrrobert]

success... new rings and big ends in ,and no smoke for a couple of weeks ,runs a bit flat ,with no remap ,but will be on propane this week and development can continue ,hurrah .