Converting a 1.9 head to instal on a 1.6 mech. block

[saurkraut]

Since we had a warm stretch here, i figured I better move this project along so its ready to go this spring.

There were shoulders on both sides of the cam towers that made it impossible to remove the valve lash shims with the cam in.  So as long as I had the head off, I took it appart and dremeled out the shoulders:



Here is what the shoulders next to the cam towers looked like befor the Dremel work:



Its all back togather now.  The exhauxt manifold is out getting machined flat along the ports.

I should have it all buttoned up in a couple weeks.

[saurkraut]

I did the k24/k26 compressor swap, so i had to do some changes to clear my intake manifold.

Since the flange on the exhaust manifold is angled away from the motor, I guessed that a 3/8" shim would help the situation.  $75 to the local Fab Shop, and here it is out of 304 stainless. 



I decided to use stainless because both the turbine housing, and exhaust manifold are NiCr 202 stainless and I wanted to keep the materials similar.  Here's the numbers on the bottom of the manifold after I wire brushed it:



And here's the turbo with the bigger compressor bolted up:







I had to do a little Dremel work to both the intake manifold, and one of the bolt bosses on the compressor to get things clear.  I have about 1/8" now:



I picked up some M10 - 1.5 x 60 18-8 stainless allan screws from Fastenal to replace the OEM flange bolts.  I could have purchased new stainless flange bolts too, but I would have had to buy 100.

Hopefully I'll get the head back on this weekend.  I think I can re-sculpture the supply line, but I think I'll go to a hydraulic shop and see if they can put a longer flex hose in the stock drain line.

I'm going to use 2 of Prothe's turbo flange gaskets to seal it up.  Should be rolling soon!

[saurkraut]

The head is on and torqued: raceware studs and 1.9 metal head gasket.  I used  53 willys idea and plugged the block heater in for four hours to give it a heat cycle with out running.  It got hot enough so that it was uncomfortable to hold your hand against the head.  I'll re-torque it tonight.

It was a real monkeys-vrs-footballs getting the 3/8" turbo spacer and two Prothe gaskets under the turbo, but its in now:



The K26 compressor sits about in the same location as the K24 compressor:



I have to lengthen the flex section on the turbo drain pipe, throw the belt on and re-time it, adjust the valve clearance, and fire it up.

[Rabbit on Roids]

so, you have a K24/K27 then?

[saurkraut]

Nope, my brain fart.  K24 hot side, K26 cold side.

[Rabbit on Roids]

lol, ok, that makes a little more sense. my first thought... HOLY CRAP, a 24/26 hybrid wasnt enough so he had to do a 24/27 hybrid! it would probably still work wouldnt it?

[jtanguay]

How hard do you think the start will be with the lower compression. Also I heard that reducing the compression increases MPG's, do you know if thats true.

high compression ratio is only for cold starting.  you can go to around 18:1 with excellent compression & working glow plugs without too much cold starting issues.  i think 15:1 would even work but you'd need to start the car with some starting fluid.  once up to temp that thing would rock! 

[Rabbit on Roids]

how do we lower our compression? h/g spacers?

[saurkraut]

lol, ok, that makes a little more sense. my first thought... HOLY CRAP, a 24/26 hybrid wasn't enough so he had to do a 24/27 hybrid! it would probably still work wouldn't it?

Nut's, now you've gone and done it. I'm wondering if that K27 cold side would bolt up to the K24......

how do we lower our compression? h/g spacers?

Nope, got to keep the flat part of the pistons close to the flat part of the head so the squish and quench do their thing: cooler pistons & better turbulence in the swirl chambers.

The bigger 1.9 swirl chambers drop the compression from 23:1 to 19:1.  The bigger ports are a bonus.

The lowest CR from off the shelf parts is a 1.9 head on a 1.5 block (1.6TD block with appropriate 1.5 parts in it) which yields a CR of: 17.68:1

I wonder how bad the combustion process would get hozed up if the flame pockets in the pistons were machined deeper.

[macka]

That would be hit and miss, if you took .030 or less you probably would be OK but Im guessing too deep and you'd be euchred. The other thought going through my mind would be having a hotter spot on the piston due to less material. I know we shave pistons on gassers, but with all the aftermarket support we just pick up the phone and order the piston with the deeper pocket, and it is shipped the same day.A nicely CNC's piston would be pricey to pay with, but at least it would be a consistent thickness across the dome.

[Rabbit on Roids]

lol, ok, that makes a little more sense. my first thought... HOLY CRAP, a 24/26 hybrid wasn't enough so he had to do a 24/27 hybrid! it would probably still work wouldn't it?

Nut's, now you've gone and done it. I'm wondering if that K27 cold side would bolt up to the K24......

how do we lower our compression? h/g spacers?

Nope, got to keep the flat part of the pistons close to the flat part of the head so the squish and quench do their thing: cooler pistons & better turbulence in the swirl chambers.

The bigger 1.9 swirl chambers drop the compression from 23:1 to 19:1.  The bigger ports are a bonus.

The lowest CR from off the shelf parts is a 1.9 head on a 1.5 block (1.6TD block with appropriate 1.5 parts in it) which yields a CR of: 17.68:1

I wonder how bad the combustion process would get hozed up if the flame pockets in the pistons were machined deeper.

not quite sure...
but now, knowing that i can build a 1.5 with 17.5 compression, im going to...
should be able to run quite a bit more boost with lower compression right?
and it wont be nearly as rattley either. or is my thinking not right?
and will it still start on normal glow plugs?
or would this engine be addicted to starting fluid?

[saurkraut]

not quite sure...
but now, knowing that i can build a 1.5 with 17.5 compression, im going to...
should be able to run quite a bit more boost with lower compression right?
and it wont be nearly as rattley either. or is my thinking not right?
and will it still start on normal glow plugs?
or would this engine be addicted to starting fluid?

I started this 1.6 block/1.9 head contraption with the correct 1 notch head gasket last fall when the temp was in the 30s and it started better than it did with the 1.6 head with the three notch head gasket.

So there's a chance that the 17.5 might fly.  Might be a little dicey below 30.  There's also the possibility of running a thinner head gasket, but you'd have to have the cam bug nuts on.  I'm seriously considering it for my 1.5TD experiment.

[Rabbit on Roids]

30* is about all the colder it ever gets here, so i doubt it will be much of a problem.
and also, i located some 1mm O/S pistons from a fellow dubber, 50 miles from me no less.
and they are german mahles no less...
now i just have to talk him out of them.

[macka]

30* is about all the colder it ever gets here, so i doubt it will be much of a problem.
and also, i located some 1mm O/S pistons from a fellow dubber, 50 miles from me no less.
and they are german mahles no less...
now i just have to talk him out of them.

Here is an idea to help you get those pistons...........beer 

[saurkraut]

Well, its alive.  Still chaising the timing.  The lower compression requires more advance.  I'm at 1.15 and the engine is coming around.  At 1.00, EGT and coolant temp is high, at 1.10, EGT is OK ,but the coolant temps rise a little too fast.  I think I'll try 1.20 before I raise the fueling to the point of the previous 1.6block/1.6head.

It's measurably faster though.  With the fuel at the stock setting, its 5 MPH faster than the 1.6head set up with tire fire smoke trail on my measured test strip.  IE 75 MPH for the 1.6 head and allot of fuel, 80 MPH with the 1.9 head and NO SMOKE.  i figure its the porting somewhat, but mostly less cranking loss with the 19:1 compression ratio.  The start was a little smoky, but it was 28F this morning.  Kind of out of its normal operating range.  Almost time for it to go nite-nite for winter

Hopefully I'll get it dialed in before I put it away for winter.  I've contracted a degenerative nerve disease, and I'm losing the use of my right hand, so it takes a while for me to adjust the timing.  pulling a cylinder head is a real treat too....