2 Litre KR Conversion...It's now Megasquirted!!

[roo 0]

I'm building up my rebored KR block at the moment to 2.0, using standard 9A pistons and crank, unfortunately though i've run into a slight problem that the piston oil spray jets catch the con-rods.

 

I know that a few companies offer a 2 litre conversion based on a KR block so it must be doable, so does anyone know how to overcome this oil jet problem?.

The obvious solution would be to just remove them, but i'm not sure how critical they are and i'm concerned that it may cause a general loss in oil pressure througout the block and or engine seizure or something equally as nasty?

 

If anyone's got any suggestions i'm all ears :)

[dinkus 10]

First - I have no idea about engines.

 

But looking at the rather tasty Mk1 G60 that's for sale at the moment that's got a 1.9 G60 in it - one of the specs on that says 'piston cooling jets removed' so that would imply you can run an engine without.

 

http://the-corrado.net/.archive/forum/viewtopic. ... 486#350486

 

I'm sure someone that has a clue will be along to give you a more useful answer soon tho :)

[roo 0]

Thanks Dom, yea I noticed that Mk1 when I did a search, which is good considering it's putting out shed loads more power than my valver will.

 

The evidence is mounting but i'd just like to get some more before I resign the little buggers to the bin :)

[stevemac 0]

AFAIK - piston cooling jets are the only oil supply to the little-end bearings (upper con-rod bearings). Removing them may cause slightly increased wear in the little end bearings, slightly higher piston temperatures & increased bore wear.

 

Whether or not this would be a problem will depend on car usage. If your car is a "daily driver", I would suggest that you leave the jets where they are - if possible.

[roo 0]

Thanks Steve, the little end bearings are actually lubricated from an oilway through the centre of the conrod, which is fed by the oilways in the crankshaft. I don't think the jets are intended for specifically lubricating the small ends, although more oil can only help.

[Blue_Joe 0]

You can delete the oil jets, however as Steve said you run the risk of melting your engine down!!!!

 

I am currently having my G60 bored out to 2Ltr and keeping the oil jets, however Jim from Race Power Motorsport (but for now GP Speed Equipment!) is the only person that has worked out how to do it by machining the block. But he won;t tell anyone how to do it. Don't blame him to be honest!

[roo 0]

People and their precious secrets :roll:

 

Tis strange though that that Mk1 G60 engine built by stealth has had them removed, given that it's pumping out a fair few ponies.

[stevemac 0]

Thanks Steve, the little end bearings are actually lubricated from an oilway through the centre of the conrod

Your rods are a different design from the STD G60 rods. STD G60 rods are solid & have no internal oilway.

 

I suspect that, like yours, the MK1 built by Stealth will also have oilways inside the con-rods.

[roo 0]

Interesting stuff Steve I didn't know. Perhaps the jets are more critical for G60's then if this their only means of lubrication.

[stevemac 0]

Perhaps the jets are more critical for G60's then if this their only means of lubrication.

Yeah - definitely

 

The G60 rods have a reputation for being VERY solid & strong. I suspect the fact that there's no oilway will contribute to the strength of these rods.

[roo 0]

I feel a phonecall to Stealth is probably on the cards for monday then :)

[roo 0]

Righty then!, After a quick word with Vince at Stealth this morning I now have the answer to my question.

 

Apparently the oil jets when using a KR block for a 2 litre conversion are simply removed. This is standard practice by Stealth, TSR and others apparently and despite VW obviously intending these oil squirters to be there, have had no engine problems with doing this. The resultant holes for the removed oil squirters are then tapped and plugged with an M10x1.5 grubscrew and a bit of threadlock to secure.

 

Conveniently though, the oil squirters for the 9A block (which are of a different design to the KR ones) use an M10x1.5mm pitch banjo type design, which now fit nicely into the newly tapped holes. This is good news as it means I can obviously keep my oil sprays :D

 

All this threading has left loads of swarf in the oil gallery from where the oil sprays are fed from, so i'll be flushing this out over the next couple of days and i'll post some more pics when i'm done.

 

Stay tuned!!

[roo 0]

Thought i'd better share what i've done today as i'm a bit closer to getting my C back on the road. :D

 

So after a bit of work my KR block is now re-assembled as 2 litres and also includes the oil squirters that most 2.0 conversions plug up. Whilst I have no doubt that the oil squirters can be safely removed, they were obviously deemed necessary by VW and in addition to providing extra lubrication to the small ends they probably reduce the risk of detonation when using unleaded petrol, especially as my valver has no knock control.

 

The first thing I did was rinse out the main oil gallery that supplies the main bearings, crankshaft and oil squirters as it was full of swarf from tapping out the old oil squirter holes. There are two 14mm plugs at each end of the gallery that need to be removed, these were easily drilled through and then prised out.

I used some paraffin for flushing the gallery out and it worked very nicely, taking with it loads of evil engine destroying swarf :twisted: .

 

Once this was done, the gallery was then plugged back up, this bit is quite critical as if these plugs fall out, so does all the lubrication for the crankshaft etc :shock:.

I used 9/16 imperial plugs for this as it was the closest I could get, with a bit of loctite 638 retaining compound for good measure, hammered them in and jobs a goodun!

 

The oil sprays were then dry fitted and found to interfere slightly with the shape of the block casting, in retrospect it would have been easier to grind this away when doing the other grinding work to the block, but as i'd cleaned all the swarf away it was less messy to just chamfer the corner of the oil squirter instead.

The oil squirters were then screwed in place with a little threadlock to secure.

 

I thought it'd be plain sailing from here, but no such luck.

As it happens, the face where the oil squirters sit is slighly inclined by a couple of degrees towards the bore, with respect to the top face of the block. On the 9A block the squirters sit parallel to it. This slight inclination causes one side of the oil squirter to sit very slightly higher up the cylinder wall and as a result the piston skirt hits it as it nears BDC.

The piston skirts are already relieved sufficiently to accomodate the oil squirters when used in a 9A, but need to be relieved by a few mm more when used in the KR.

As each piston skirt was relieved slightly, they were then installed and checked for interference with the squirters. If all was ok then the big end caps were torqued down properly to finish.

 

I hope somebody finds this info useful as it's a pretty straight forward mod to do, saying that, I haven't actually run the engine yet and I still have a slight oil pump problem to sort out. :) I'll update when it's sorted.

[stevemac 0]

Looking good roo, I assume you took the opportunity to "weight match" the pistons when you lightened them . :wink:

 

Is this one going to be normally aspirated or are you planning forced induction ?

[roo 0]

Cheers Steve. I didn't weigh the pistons individually as they were already connected to the conrods, these assemblies weighed in at about 905g each with as much as a 10g difference between them.

I suppose in the scheme of things though, that a 10g difference is only about 1% of the combined conrod and piston weight, probably not an issue for this kind of engine.

However, when the pistons were relieved a bit I did try to keep the total weights as close as possible to match them up, but only within about 2-3g and I was only using my mums digital baking scales. :lol:

 

This engines just going to be a standard N/A one, I was planning on building a 16VG60, but just can't really afford to at the mo...next time :)

[stevemac 0]

I was planning on building a 16VG60, but just can't really afford to at the mo...next time :)

Sounds like you'll have a good base engine & the opportunity to add a charger of some kind at a later date, if you decide you want the extra power.

 

Weight matching (blueprinting) doesn't really make any difference to power output, just makes it run a little smoother.

 

Looking good, keep us all upto date with progress . :wink:

[Henny 0]

stevemac, that's not entirely true mate...

 

Blue-printing isn't just weight matching... it involves making sure that all of the ports (be they air, water or oil ways) are the correct sizes and are clear of any casting marks as well as making sure that all parts are identical in weight and being dynamically balanced... this DOES improve power as well as making the engine smoother as it allows the engine to be as efficient as possible... simply blue-printing and balancing an engine can improve a standard engines power output by upto 10% ! :crazyeyes:

[roo 0]

To be honest, there's a few things that in retrospect i'd have done differently, but as usual it's always down to lack of time and money, plus it's the first engine i've rebuilt so i'll know what i'm doing a bit more for next time!

[davidwort 0]

Cheers Steve. I didn't weigh the pistons individually as they were already connected to the conrods, these assemblies weighed in at about 905g each with as much as a 10g difference between them.

I suppose in the scheme of things though, that a 10g difference is only about 1% of the combined conrod and piston weight, probably not an issue for this kind of engine.

However, when the pistons were relieved a bit I did try to keep the total weights as close as possible to match them up, but only within about 2-3g and I was only using my mums digital baking scales. :lol:

 

This engines just going to be a standard N/A one, I was planning on building a 16VG60, but just can't really afford to at the mo...next time :)

 

Just out of interest, why didn't you just use a 9A/6A block?

I've got a junked TSR 2.0 bored KR block in my garage, with badly scored cylinder walls after 10,000 miles, probably due to TSR not boring the block properly, but I'll look at the oil spray holes to see what they did. At the time there were few 9A blocks to be had cheaply but now I'm running a newly built 6A with pretty good power.

I just wish I'd waited and not spend £1400 quid on a TSR block :roll:

David.

[roo 0]

Good question :), I was actually planning to use a 9A block, and even went to the extent of stripping it and cleaning it.

Unfortunately though, I couldn't seem to get hold of any oversized pistons for it, VW don't list any on ETKA and despite Kolben and the like listing them in their catalogues they were seemingly unobtainable.

 

David, if you get chance to take some piccies, I'd be very interested to see if TSR have indeed plugged up the oil sprays and also how they've managed to fit the larger 2.0 oil pump driving gear.

[olly elworthy 0]

To be honest, there's a few things that in retrospect i'd have done differently, but as usual it's always down to lack of time and money, plus it's the first engine i've rebuilt so i'll know what i'm doing a bit more for next time!

 

your doing really well getting round all these little problems especially on your first build,, keep up the good work,, :wink: :D

[Henny 0]

yeah, it's interesting to read about the oil squirters and the other little bits you've done to make the whole project work and why you've done them.... 8)

 

If you got the pistons to within a couple of grams, then that's pretty good for a home-brew jobbie and I'd reckon will probably still be smoother than factory... 8) Mine were kinda done over the top when I got them machined to clear the oil squirters as the engineering shop who did it specialise in model diesel engines and aeroplane parts so there's under 0.5 grams difference across all 4 pistons! :crazyeyes: :lol:

[GazzaG60 0]

there are a few 83mm pistons you csan use. requires a 0.5mm overbore. ive got JE at 9:1

[roo 0]

Thanks chaps, sharing the wealth and all that :)

 

Henny, 0.5g difference thats pretty impressive 8), my mums scales only do 1g increments and to be honest they're a bit pants...perhaps thats why her baking tastes a bit funny :)

[Henny 0]

yeah, the engineering firm I use have this completely over the top attitude which results in anything they do being as near to perfection as they can possibly get it... hence why I'm happy to pay for their services! :lol: They're not the cheapest place around, but they're happy to do the silly little jobs and fabrication that I need doing for cash and at bugger all notice... 8)

 

The scales they have does 0.5g increments and the pistons all read the same weight when weighed individually, although when all 4 were on at the same time, it went up to 0.5g over what the combined weight should have been when you added up their individual weights... I suppose that technically, theres potentially more than 0.5g between the heaviest and lightest when you work it mathmatically, but I can't be arsed to work out the standard deviation and all that crap, I just know that they've as close as they're gonna get! ;) :lol: