has anyone really modified a NA diesel?

[scopefrfd]

1,9td block is taller

[lesharoturbo]

If the block is taller and the stroke is longer then how about the pistons?  What is the height of the pistons from pin to dome compared to the 1.6 pistons?  I tried to look for piston specs for bothbut I could not source any good info from the web.

Bernie

[Audi80]

The compression height of 1,9 turbo pistons is ~45mm, 1,9 non turbo ~39mm and 1,6 ~41mm. The 1,9 turbo also has bigger pin than others, 26mm/24mm.

[lesharoturbo]

So the best bet would be the NA 1.9 pistons which would lower compression slightly.  The pin size difference could be bushed at the piston or maybe enlarged at the rod?

Bernie

[Audi80]

1,9NA has same 24mm pin as 1,6. You will need longer rod and/or cut the block, compression will drop way too much.

[greyrabbit]

Since we're speculating about combinations --

I've been looking at putting the 1.6 NA diesel head on the block used by the 1.8l 16 valve gasser.  That block has the same stroke, same main bearings and same big end rod bearings as the 1.6 diesel and as a bonus has piston squirters and is commonly tweaked to 180 to 200 hp with 15 psi of boost, spinning at over 6500 rpm ... a really stout block.  In fact those turbogasser guys often use diesel cranks in these gasser blocks.  The pistons and rods are different of course, but the 16 valve engine has a large aftermarket in Europe and quite a range of performance piston options are available including forged heavy crown for heavy boost applications -- names like JE and Karl Schmidt.  The standard 1.8l rod is 144 mm quite a bit longer than the 136 mm for the diesel.  The bore will demand some piston customization but I suspect that the blanks normally  available will allow the correct pin height in combination with either the diesel rod (136) the normal 1.8l rod (144) or the late 2.0l rod (141).
Anyway there are lots of options to play with -- rods, pistons, head gaskets.  If you can work it so the only customization you need is specing the pin height for drilling a 1.8l piston blank, this doesn't have to cost a boatload.  On the other hand quality pistons are never cheap.
These blocks are 81 x 86.4 mm and unlike the 1.9l diesel, the scrapyards around me a full of them.  Because of the larger bore if you have the same piston protrusion (assume midrange 0.85 mm) and you use a the mid thickness Cu 1.9 gasket (1.57mm) the larger bore jumps the compression up to slightly over 25 to 1.  This is assuming a nominal 1.6l head volume of 142.4cc.
Slight relieving of the head could bring this in right on the money at 23 to 1, but I suspect it would run just fine at 25:1.  

Since we're just foolin around consider that (relieved or not) the larger bore might  allow larger valves to be fitted.  The small valve 8v gasser has 38mm intake and 33 mm exhaust,and  the big valve (A2 8v high compression gasser head) is 40 mm intake and 33 mm exhaust.  The 1.6 diesel is just 34 mm intake (yikes) and 31 mm exhaust, these small valves combined with a low lift/short duration cam chokes the engine --52 hp out of 1.6l is not very much.  It will be interesting to see what size valve will fit given the prechamber etc. but I strongly suspect that the "small valve" 38/33 combination will work.  Comparing a 38 mm intake valve versus the stock diesel 34 mm -- valve flow at low lift will scale like the head perimeter so you might see a 10% increase.  As with pistons quality performance valves are available off the shelf.  Like I said I'm just noodling some ideas around for now haven't done anything yet, but glad to see this discussion of options for the 1.6na.

[lesharoturbo]

Audi80

Since there is a 2 mm difference between the 1.9 na and the 1.6, you could possibly machine the head or the block 2mm.  Or maybe use the 1.9 turbo pistons and a thicker copper gasket.  To bad you couldn't get some custom pistons for a reasonable price.  If you had the complete specs, Ross may be able to make them.  Some guys at a gasser site had some custom ones made for around $500 american......

Bernie

[2mAn]

well my headgasket is leaking so instead of having that repaired im going to have the shop install a 1.6TD with either a TT or passenger performacne downpipe plus a TT exhaust wiht no cat. the cost of rebuilding is almost as much as the cost of the TD motor so its a no brainer...

to response to questions about my pump. it made a difference everywhere except fuel economy, im still getting 40mpg. pulls real good all over,  BIG difference over the stock pump and like i said i havent touched the max fuel screw at all...

my pump might be in classifieds soon so keep your eye out

[malone]

im going to have the shop install a 1.6TD

to response to questions about my pump. it made a difference everywhere except fuel economy, im still getting 40mpg. pulls real good all over,  BIG difference over the stock pump and like i said i havent touched the max fuel screw at all...

my pump might be in classifieds soon so keep your eye out

Just out of curiosity, do you plan on having your TD pump done up by Giles? Have you checked how much it'd cost to upgrade your existing Giles NA pump to TD vs. rebuilding an entire TD pump?

[v8volvo]

to response to questions about my pump. it made a difference everywhere except fuel economy, im still getting 40mpg. pulls real good all over,  BIG difference over the stock pump and like i said i havent touched the max fuel screw at all...

my pump might be in classifieds soon so keep your eye out

Thanks, I'll watch for it. Was there any increase in smoke?

[RabbitJockey]

well my headgasket is leaking so instead of having that repaired im going to have the shop install a 1.6TD with either a TT or passenger performacne downpipe plus a TT exhaust wiht no cat. the cost of rebuilding is almost as much as the cost of the TD motor so its a no brainer...

to response to questions about my pump. it made a difference everywhere except fuel economy, im still getting 40mpg. pulls real good all over,  BIG difference over the stock pump and like i said i havent touched the max fuel screw at all...

my pump might be in classifieds soon so keep your eye out

you can fix a headgasket in like 2 afternoons, just fix that, but it sounds like you just wanna stick a turbo diesel in it and be done haha

[2mAn]

you can fix a headgasket in like 2 afternoons, just fix that, but it sounds like you just wanna stick a turbo diesel in it and be done haha

thats not what im worried about. i dont have my tools with me right now and my motor just feels like its ready to go, i mean it still runs good, but it smoke a LOT more on cold start now, i dont think my 1000 mile trip to seattle helped. yea i do wanna stick a TD in it though, jus sucks cuz ill have to sell my rabbit ASAP.

[2mAn]

Just out of curiosity, do you plan on having your TD pump done up by Giles? Have you checked how much it'd cost to upgrade your existing Giles NA pump to TD vs. rebuilding an entire TD pump?

yea im trying to decide whether to have giles rebuild my pump or just start with a new one. rebuilding mine will cost around $400, a whole new pump (with core charge) is almost a grand US so im probably going to have him rebuild my pump. i doubt ill be able to sell my for ~$500 even though it has less than 10k on it...