Frankenwagen build thread AKA TD Corrado

[Smokey Eddy]

in other news, i brought over the tool i made for removing the crank bolt which astonishingly came out very easily. There was also no locktite on the bolt? Matt was able to pull down on his 1.5meter long breaker bar and hold the plate i had bolted to the pulley with the other hand and  turn the bolt out...
The tongue and groove of the pulley & crank were near perfect!!!
Removed the crank & pistons and started on the tedious and seemingly endless cleaning job. The rings were well worn but nothing out of the ordinary.
Also mic'd the crank. The mains had some wear but the rods were hardly over original spec. I think the most was 0.002"? two thousandths of an inch? Matt wrote it all down. I didn't check any of my tolerances as i didn't have to tools to do so, so i wonder how sloppy my crank is
We go the blocked cleaned up for the most part and Matt (RadoTD) has a very appropriate colour scheme planned.

[RadoTD]

Haha, got Ed updating my thread for me
Yes, I understand what you mean now, Andrew about how to turn those. It would be incredibly difficult and probably not worth the effort. I could make pins with each degree of taper I could imagine in less time, so if I were to go that far, I could just swap pins completely to adjust it. If I had the machine set up fully, I could make each pin in under an hour. Trial and error though. I'll get the car running on this one and see if there is any way I could make it better

I was just properly measuring my bores a few minutes ago. Nothing was out of round by more than 7/10000" but my numbers were consistently about 15/10000" sloppy. Still within the spec of 4/1000" (that seems huge to me), but I was surprised as I could see cross hatching everywhere but about 1 square inch and the front of the cylinder wall, presumably from piston slap (that patch was where I was taking my measurement for x axis). Then when I went to measure my pistons, I realized I was checking my bores off of the spec for my pistons! Once I figured that out, I'm amazed how good the numbers for my bore are. Funny thing is that I was out of round 6 and 7/10000" on cylinders 1 and 4, but 2 and 3 were both within 3/10000"

Main bearing journals made me unhappy though. I spent about 2 hours measuring them; repeated it until I was within a ten thou every time. Measured left and right to check for tapering and 90deg out to check for out of round. Every measurement was 2.1241 +/- 2/10000". Spec is 2.1260 and the limit is 2.12435, so I'm just outside the limit. So either I'm measuring wrong, my mic is out in that range or I have immaculately consistent wear and need to get it turned. I'll probably give it to a machine shop and have them check it for me and machine if needed. I was hoping to not have to though
Rods are in spec

Also, Ed got me a bit paranoid about replacing the IM shaft bearings. I've got 2/1000" play and the limit is 10/1000". I'm thinking of just leaving them alone. Is that a dumb idea? I figure it should be fine because even though the engine is going to be pushed harder, that doesn't change forces on the IM shaft. Should I replace them anyway?

[RadoTD]

Am I way off base?  It would seem like it might double the machining required, but not more than that. 

Interesting... the way I had thought of doing it involved cutting the body of the pin itself angled out of the piece of square (or actually rectangular) square stock. I didn't see cutting the taper like that and just finishing it from the body. It certainly wouldn't be as difficult as I was thinking.
I can still think of 3 difficulties. First two are more specific to my situation
First, I don't have a milling machine to cut the flat spots. It could be done tediously with a drill press though.
Second, I don't have a 4 jaw chuck
The third thing that makes it difficult is that particularly when cutting the taper, due to how the toolbit is cutting, it's very hard on the tooling. With wood lathes, cutting square stock isn't as tough due to wood being fairly soft. With a very hard/brittle tool bit, with the square stock coming around hitting the tool bit every single time, you can't take very much material off at all. If I were turning a piece of square stock down until it's round, I would actually put the toolbit in far enough that the very tip of it is always cutting. Cutting that taper, I'd have to go straight in.
A proper machinist could probably make one fairly quickly, but for me, I'm probably still looking at a few hours. Certainly doable though, I never thought about turning it quite like that!



And an update on the build... turns out the degreaser I got to clean all the internals with (which specifically says it's for cleaning engines!) reacts with aluminum.
Are the cam towers on an AAZ the same as any gasser? :/

I'm pretty lucky I didn't submerge my head in it like I was thinking.. or my piston tops

[arb]

Thanks for the info.  Yeah, lacking milling machine or 4-jaw chuck might be a deal breaker.  I can understand how cutting into the square stock would be hard on the tooling.  The initial cut would all be on one side of the stock and definitely out of balance.  That said, the finished taper would all be inside the circle of the finished pin so the tooling wouldn't really know the difference.  Anyway, not trying to get you to do it, I just find it interesting.

Tough break on the degreaser.  

Yeah, its noisy and can break your cutter. Its called and "interrupted cut" and is the norm for making tooling from what ever tool steel chunk you find in the material bin at the engineering place I cut steel and aluminum.

[RadoTD]

Sounds like he knows more about it than me ^^

Apparently the cam bearing caps are line bored. Does anyone know how critical that is? I'll get pics up hopefully tonight. There's actually a build up on the cap itself so I might be able to get that ground off and it's just a few mm on each one. The hard edge is rounded off though...
I'm heading to the machine shop tomorrow so I'll see what they say

[RadoTD]

Engine is basically back together... there were cracks in my precups, so I've got some new ones on their way in.
I want to know if I'm crazy here or not, but I'm thinking of grinding them out a little, for the purpose of lowering my compression ratio. I'll have to figure out what their volume is and how much I can actually remove... planning to keep the CR similar or a bit higher than the 1.9 head on a 1.6.

Any opinions on this? Can I safely remove enough material to make that much of a difference? It shouldn't take much and then I can run more power with less peak force trying to bend the rods/lift the head.

Also, while I'm there, any experience on actually porting out the openings to them? Good idea for better flow out of the precup or bad idea because it'll more significantly change the swirl inside the chamber?

[745 turbogreasel]

IMO, your  old cups are shown not to be thick enough, don't grid the new ones, just use a different HG.

[RadoTD]

your  old cups are shown not to be thick enough

That, my friend, is a very good point. Level headed people are good... they help keep me from doing stupid things

[url http="http://www.vwdiesel.net/forum/index.php?topic=24642.0"]This thread[/url] I just found has, among others, 2 significant points that I saw. First, inconel work hardening quickly. Baaad if they're already cracking. Plus, I'd be slowly carving out of them with a carbide burr - taking small chunks out a few hundred thousand times per minute. They probably wouldn't last all that long.
Second thing is that apparently not all of your combustion is intended to happen in the precup! I always thought the idea was to get as much of the combustion happening in there as possible.

Looks like a thicker HG is the way to go. Once I get my rod bolts in, I'll torque that all up and see what HG I'm supposed to have and see what I can do to my CR by going thicker.

Another thought I just had is what about turning my valves on a lathe? Both undercutting the stems for more flow and carving out the face for lower compression. Might have to think on that one

[Smokey Eddy]

Just my experiences here, I had a 3 notch in place of a 1 notch on my very tired 1.6 and it wouldn't start under about 5C.
I mini-rebuilt it (rings and valve lapping) but kept the same thickness head gasket and stranded my self at a ski hill because it wasn't enough compression to get going. It would always roll start straight away but off the starter was a no-go.
Lowering CR in my honest to god opinion is just like asking to not be able to start the car with the starter... for almost no benefit except for a strange possibly false? sense of peace of mind about ... having less ?pressure? in the cylinders but if you think about it - the CR difference between a gas engine and diesel is so massive that to be anywhere near the pressures of a gas engine the idea of diesel is just totally out the window.
i would leave it alone... just look at anyone running a super charger + turbo in combination. Torque bends rods...
On the 1.9/1.6 with a 1 notch i had to cycle the GP's at least twice and force them to stay on while i cranked for a good 10 seconds before it would start up at Whistler... very very annoying and killed my battery and eventually starter. Massive white cloud of embarrassment too.

I suppose if you plan on running 50+psi (somehow - but would be amazing) and the car not being your dd and you're ok will roll starting it then give'r!!!

[RadoTD]

For some reason I can't find the compression ratio of the 1.9 head on 1.6 block... IIRC it was like 19:1? Stock I'm 22.5:1. The 3 notch HG seems to be .008" thicker than 1 notch, which equals pretty close to 1cc, bringing me from 22.5 to about 21.3. If I took .5cc out of each valve, then I would be sitting at just over 20:1.
Given that I could start any day of the week on the first turn without my glow plugs even hooked up, I don't expect to have many issues. I also don't spend as much time up the mountain as you, Ed And even if I was having trouble, I can swap a different HG on again and get back up to 21.3:1 compression.

The advantages... possibly better gas mileage, less wear daily driving the car and more power potential without destroying things. Those all sound pretty sweet to me. Gas engines in comparison are able to put out crazy amounts of power and it's often knock limited, so the closer I can get to gasser kind of forces on the internals, the better. It's far from just being a strange sense of peace of mind.

Does anyone know the compression ratio of the 1.6/1.9 hybrid? There are enough people running those, I'd be comfortable running a CR near what that is. Edit - looks like it is around 19.5:1, so I would hope to get mine to the 20:1 range...
Also, any other ideas on dropping CR?

[lord_verminaard]

I put a 3-hole metal head gasket in the 1.6 when I rebuilt it.  It starts instantly every time, the only time it requires a bit more cranking is when it's below 0 F outside and I have not run the block heater.  Usually a double-glow will get it to fire pretty quick, then it needs to sit and idle for a few minutes before it smooths out.

I don't think you would see an issue at 20:1, especially if you took the compression out of the valves instead of out of the squish area. (like with a thicker headgasket)

Brendan

[745 turbogreasel]

I'd leave the valves  themselves alone, they live in a tough place.  You can cut the seats back so the valve is deeper up in the head, less risk of a crash, and you get room for  bigger cam
...but the head is less rebuildable.(there is a spec in the Bentley)
IMO, cutting the intake guide  is better than the exhaust which always wears more, and will probably be needing to shed more than stock heat.
Not exactly scientific, but I redid my friends ALH  that VW had assembles with 1 step too thick of gasket, and it climbs the local grade at 55+ instead of struggling at 45.  New nozzles at the same time though, bone stock otherwise.

GM thought bigger cup ports would help on the 6.5 turbo heads, but CW seems to be they mostly just get worse MPG.

[RadoTD]

I'd leave the valves  themselves alone, they live in a tough place.  You can cut the seats back so the valve is deeper up in the head, less risk of a crash, and you get room for  bigger cam

Are the forces really that crazy on them?
The valve seat is the thinnest part and takes the largest amount of force, but I can easily take enough material out without going near the valve seat. If I were to take a 3/4" drill bit for the intake valve and 5/8" bit for the exhaust, then drill those into the valve just until the tapered head is all the way in, that'll give me right around what I need. A 19mm diameter cone at 22.5deg (135deg drill bit) isn't a whole lot taken out of the valve in a non critical area. I also don't have to pay a machine shop for that

Drilling the valves like that would give me about 1cc/cyl and a 3 notch instead of 1 notch gives another cc, bringing my CR to just over 20:1, with the option of putting the right head gasket back on to bring my compression half the way back.

Not a huge effect on squish/quench (something I'll need to do some reading on to understand better!) while bringing my CR right where I want it

[RadoTD]

And I was actually thinking about a bigger cam... I could get the valve clearance for an ABA or other similar gasser cam, but the lobes from my diesel cam are very close, so anything higher lift would involve more head machining and get more and more difficult. I'm trying to keep this as low budget as possible! ABA cam would be sweeet though!

[truckinwagen]

I have an OBD2 ABA cam lying around if you need one

-Owen