1992 urS4 family sedan

[kenax]

http://www.youtube.com/watch?v=nPoVS5J2f2o

I will update the specs list later, the engine is now installed and running. I will need to fabricate exhaust and a few other things before it's driveable.

[eske]

Nice

[Thuppu]

Wow! 1000+hp?

[V6quattro]

The engine measurements have been done.

There's a few hundreths of millimeters too much clearance in the conrod bearings, being at 0.10-0.11mm. Conrod bearings are going to be changed. Main bearings have a bit of wear to them, although clearances are ok.

The biggest problem of all in the bottom half is that the conrod small ends have taken some beating and deformed. The lower half of the eye has started to push out from the rod itself and the clearance has grown to around 0.03mm on the bearing ends. The bearings are pretty much in the correct clearance in the middle of the bearing. The top half of the eye still had the honing pattern visible, so the wear was only on the bottom half. This tells me it's not rpm-caused. The rods are now being fitted with new small end bearings. My rods are a set of unbranded chinese rods, so I'm suspecting the material of the small end bearing was not the best possible and I think there might have been some axial misalignment between the pin and big end bearing. The clearances were checked when the engine was put together two years ago.

As suspected, the piston to head clearance was a lot higher than it has to be. This is probably the reason why the engine was so knock-prone with gasoline. For some reason the piston-rod assemblies have a different height, which has to be corrected now. The lowest piston only comes 0,06mm over the deck while the highest comes 0,20mm. I measured some 0,05mm differences in the piston pin to piston top heights, so that counts for the problem only partly. The conrod eye-to-eye length will be corrected with the new small end bearings. Once I get my rods, I will measure the piston-rod assembly lengths with different rods and pistons and try out them in different cylinders. Once I have the differences leveled to as small as possible, I will then decide how much there will be cut down from the block deck, based on the lowest piston. Piston tops will be machined to count for the differences. I will try to get the piston to head clearance to 0,80mm, within 0,05mm between cylinders. The piston heads will undergo combustion chamber measurements after the machining. I will also deburr and buff the edges thoroughly.

Rods and pistons will be weighed and matched before they go into balancing.

I measured the head combustion chambers and they are all within a milliliter or two at around 46ml. I will measure them again once more just to make sure.

I sold my old Tilton clutch together with the flywheel it was bolted into. I will probably make a new flywheel with slightly different design and get a new Tilton.

Nice work! How many miles did you drive on this engine?

[kenax]

Nice work! How many miles did you drive on this engine?

Some 15-20000 kilometers, I'm not 100% sure about the precise distance.

[V6quattro]

Ah ok. I will take my engine apart soon for a checkup and some small things. Only did 5000km on 500whp so nothing to worry about then

[kenax]

Yeah and the rods actually endured a severe knock with the first setup, so that might've gave the conrod small end the initial beating that lead to the wearing. Also I suppose the bearing material was not too good.

I actually made new bearings from superb bronze alloy and they got pushed in the rods and honed before I noticed that the small end bearing machining was not accurate. Instead, the C-C dimension between the ends was originally set with eccentric machining to the brass bearing sleeve. My sleeves were too thin to set it perfectly (within +-0,01mm of the nominal) so I discarded the rods and got a new set. In this set I made sure they have used to thin bearing sleeves that the steel rod itself is machined within my specs.

Still using cheap chinese H-beam rods, which I have modified slightly and examined thoroughly for defects and physical and metallurgical aspects.

[vcosmin]

Man, that sound is familiar :-) Nice work

[URQguy]

.8 mm piston to head is pretty small for a 8500 rpm motor. I have personally had 144x20 with JEs hit and eat rod bearings at .033" and recently with 144x20 mm with mahle pistons hitting at .032". I am building most my engines at 1 mm when they are set to 9000 rpm.

Wicked build and great documentation. Can't wait to see more.

[kenax]

I have around 0,0354"

[kenax]

The car is now up and running, I have spent the last few weeks doing small improvements and testing different things. So much of the engine has had improvements done that it takes a while to test out everything. I have also driven the car for about 500 km to break in the engine and I consider it done now.

I am now making the plans and procedure to start taking the engine out and preparing for the dyno. Currently the list of to-do's and checkings has over 100 lines in it

http://www.youtube.com/watch?v=N2QVNYpRvEY

http://www.youtube.com/watch?v=Y4NhvDChO2k

http://www.youtube.com/watch?v=urLdIcr9usw

The gauge cluster project is also in progress, I'm about to install the new shift light system to the gauge unit. Here's some testing with the prototype. It's in finnish now, but I will make a better, more informational video about the subject later.

http://www.youtube.com/watch?v=WNwzfQB1VVw

http://www.youtube.com/watch?v=huPkTfz4ZBE

[Thuppu]

Nice shift light! You could do a buildkit of it...

[kenax]

That's exactly what I'm planning to do

Right now the software only eats pulse signals in the range of 0-5000Hz, but the platform already has a CAN-bus support and I'm going to code a bus reader to it as well.

[quattro84]

Hmm i was wondering how many UrS4's were running big Holsets in Finland, but it seems to be you

http://jtmedia.kuvat.fi/kuvat/Audi-Photos/ACF+Tahkovuori/ACF+Tahkovuori+8.2.2014/_MG_8375x.jpg

[Thuppu]

What a small fist!