2008cc 8.75:1 CR 3A G60 build.

*** This has been moved from another forum so if it don't make sense in parts please ignore. Cheers Chris ****

Hello,

Seems like the place to be for my build. This is an Audi 3A block based engine. It's commonly referred to as a bubble block as it's effectively a 1.8 pb code or similar casting with enough room for a 92.8 mm crank.

Bit of history.......

I bought my G60 back in Sept 2005 and spent lot's of money restoring and replacing the brakes suspension and running gear trying my hardest not to be tempted to go aftermarket. Always hankered after a G60 engine based car but wanted right hand drive (I'm in the UK) and after 10 years of owning a book about the golf and other derivatives was finally ready to get my bum in gear and go get a 1991 Inca Blue Corrado G60. It needs some body work but I'm not fussed about the body until I can put together a car that mechanically is what I want.

My first changers were a 65 mm pulley and SNS 5.5 which was a subtle change in performance I then went for a new VAG G60 supercharger as my old one had done 100k without a service and was starting to make wooping/whiney noises and a Golf G60 FMIC.
These mods gave a massive increase in performance from my perspective and after bedding in the new charger for 250 motorway miles saw me at 150 mph @ 6000rpm with a CBA gearbox and 15"x 6.5" wheels with 195 50 tyres.

Well this only gave birth to an appetite for more so next on the list was a tubular manifold with 1.75" primarys and a decat straight through custom exhaust. I was still on green 250cc injectors at this point and at a Rolling Road Day managed 206bhp at around 5800rpm before fueling and ultimately knock became a problem. Managed 198lb/ft at the wheels running UK 98 RON petrol.

I have now rechipped and using 310cc Red Injectors which has sorted the fueling issue above 5000rpm.

Anyway I always wanted to do 2ltr 3A conversion to my old mk2 golf gti's. So I thought rather than going down the usual route of porting the charger and head I thought I'd go the difficult and expensive route of an increase in engine capacity. Call me mad but I hope to produce a very drivable daily use car that does not suffer a lack on engine response below 2500rpm. Area under the curve is my main aim not 260bhp at 7000rpm. =)

Here's my car on the Dyno

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And the results before 310cc injectors. Note the large drop in power at 5800rpm!

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So the starting point for this build was to get a donor car with a 3A engine. Audi 80 from 1989-1990 are the only cars you can get these engines from and they are not too easy to find locally. I found an MOT failure 45 miles away and snap it up straight away.


Once the engine was out and had a good inspection it was time to figure out how to lower the compression without stacked gaskets or aftermarket forged pistons. As the car is used regularly for short journeys I wanted to retain cast pistons and stacking gaskets really isn't my way of doing things.


So after much research I managed to discover that the later Audi 80 2 ltr engine also ran an 8v hydraulic head like the PG engine and ran pistons that gave a stock compression ratio of 9:1. =)

And here they are.............
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So I then found all the specifications on these pistons to discover they where perfect in all put one area, the piston pin! The later Audi 80 2ltr engine is a 236 mm block and runs 159 mm rods so the piston pin was 21mm. I knew I would need custom length rods to run these pistons in a 220 mm block to ensure a good piston deck height for squish areas, quench zones and compression ratio purposes. After 9 months of torture and one failed attempt I managed to get custom length rods for the purpose all the way from Australia [You must be registered and logged in to see this image.]

So combined with a mk3 golf metal head gasket. I've managed to get an 8.75:1 compression ratio. Safe enough with cast pistons and spot for what I was hoping to obtain.
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Some other parts I've gathered together include a larger radiator from a Golf G60.

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A schrick sump! :screwy: This is what you buy when your build stalls and you have cash in your pocket.

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Looks good though and will help with cooling and preventing oil starvation on track days. =)

Windage try to keep the crank spinning freely.

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Needless to say I've subtly upgraded the brakes with Audi S2 twin-pot calipers.


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Here is the engine just after I picked it up from my engine builder after a year of waiting for things to happen.

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As you can see from the images I have test fitted the sump and crank sealing flanges. There was a slight groove in the flywheel end of the crank oilseal surface so I've recessed the oil seal slightly to get on good seal on an unworn surface. I have been wondering what oil pump to use between the 3A and the PG and have decided to test the current pressure supply to the charger with my current engine and then retest this new build with the 3A oil pump once installed. If the pressure to the charger is too high or low I'll swap in the PG pump and go from there.
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To ensure I don't end up with any pulley bolt problems I got the crank pulley pinned to the crank. Unfortunately I don't have the tools to have done this myself but showed my engine builder what I wnated and left him to it. I think he did ok........


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Had the entire bottom-end balanced up to make it as smooth as possible with my shorter than standard rods.

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No wonder the keyway or bolt gives out there's some leverage on the there.

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I have my engine priming tool sorted with a hand drill and an old distributor shaft. =)

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I have my oil pump sorted out. Got a German made G60 standard replacement and it was already clrearanced for the crank. How did they know.

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Oh yes not really relevant but got myself a nice cheap little run around while I fit the corrado with it's new engine.

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It's an Audi 90 2.3 10 valve from 1989. :laugh: What a little cracker.

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So now my bottom end is buttoned up and torqued up.

Been brave and stripped down the box I'll be using once the engine is bedded in. It's an ASD code box with very tall 1 and 2 but I needed to shorten up 3 and 4 as they were a tad ridiculous but have kept the tall 5th for quiet and economic motorway cruising. I swapped in a 1.43 and 1.03 3 'n' 4 fom an AYK box. It didn't go to smoothly but it's together now and selecting all gears.

OK big image post of what I've been up to.

OK just to expand on the gearbox post previously. I currently have a CTN gearbox which was used because I wanted reliable traction in summer and winter and 1st and 2nd on the original CBA box was just letting me down all the time. So I got myself the CTN diesel box as I did't want to swap ratios around, this meant I had great traction in 1 and 2 a longer 3rd seeing me to about 96mph and a silly 4th giving slower acceleration and topping out at 136mph at 6200rpm which helps with fuel economy but wasn't ideal. 5th was great as it was more of an overdrive gear for steady cruising and has saved me a fair few pounds not spent on petrol. I then worked out from my original power run at awesome what sort of torque I had at the wheels and started thinking about the new engine and how it's increase in torque might affect my current traction and gearing. As I expect the car to have more torque lower down I conservatively estimated I might make some extra 20lb/ft with the 2 ltr block giving me around 220lb/ft at the wheels. I then considered I may end up in the same situation I had with the CBA and thought I'd do something about it. I didn't want to spend loads of money on a LSD yet so I found an ASD code diesel that is a straight fit for the corrado and with a taller again 1st and 2nd of around 40mph in first 1st at the 6000-6200 limit and 68mph in 2nd. I must point out I'll probably be changing gear at about 6000rpm in most gears and am running standard 15" wheels so I really do need the tallest gears available to get the most work done by the engine in the shortest time.

Now when it comes to the 3rd and 4th of the ASD box it all gets a bit silly 100mph in 3rd and 145mph in 2nd. :laugh: I needed to change these as the drop in wheel power from 2nd to 3rd and then 3rd to 4th was silly and would make my car feel slower than it should so I got hold of a corrado 1.8 16v box code AYK and stripped it down for it's short 3rd and 4th which would reduce the 100mph 3rd down to around 90mph and the 145mph 4th down to 125mph so these would then be shorter than the current CTN but maintain traction in 1st and 2nd and still have the economy of the diesel 5th.

This is what it looks like

Gearbox:- ASD 1.9L D+ AYK 3+4 ratios
Tyre:- Michelin all patterns 205/50 x 15
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Top Gear gives 29.779 MPH/1000 RPM and a top speed of 184.632 MPH at 6200 RPM

Engine speeds in top gear:-
30 MPH = 1007 RPM 40 MPH = 1343 RPM 50 MPH = 1679 RPM 60 MPH = 2015 RPM
70 MPH = 2351 RPM 80 MPH = 2686 RPM 90 MPH = 3022 RPM 100 MPH = 3358 RPM

Top Speed in 1 gear = 40.138 MPH
And changes into 2 gear at 3653 RPM dropping 2547 RPM
Top Speed in 2 gear = 68.121 MPH
And changes into 3 gear at 4557 RPM dropping 1643 RPM
Top Speed in 3 gear = 92.691 MPH
And changes into 4 gear at 4465 RPM dropping 1735 RPM
Top Speed in 4 gear = 128.722 MPH
And changes into 5 gear at 4323 RPM dropping 1877 RPM
Top Speed in 5 gear = 184.632 MPH
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My current box...........

Gearbox:- CTN 1.9L D
Tyre:- Michelin all patterns 205/50 x 15
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Top Gear gives 28.274 MPH/1000 RPM and a top speed of 175.298 MPH at 6200 RPM

Engine speeds in top gear:-
30 MPH = 1061 RPM 40 MPH = 1415 RPM 50 MPH = 1768 RPM 60 MPH = 2122 RPM
70 MPH = 2476 RPM 80 MPH = 2829 RPM 90 MPH = 3183 RPM 100 MPH = 3537 RPM

Top Speed in 1 gear = 35.061 MPH
And changes into 2 gear at 3475 RPM dropping 2725 RPM
Top Speed in 2 gear = 62.550 MPH
And changes into 3 gear at 3982 RPM dropping 2218 RPM
Top Speed in 3 gear = 97.393 MPH
And changes into 4 gear at 4428 RPM dropping 1772 RPM
Top Speed in 4 gear = 136.355 MPH
And changes into 5 gear at 4823 RPM dropping 1377 RPM
Top Speed in 5 gear = 175.298 MPH
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I thought I'd also post some images of the stripping down procedure.

OK the case is off in this picture which is pretty straight forward once 5th gear is removed which can be tricky but with a strong puller and a little bit off heat came off ok. In this picture I'm using a 10 tonne hydraulic jack with a large diameter bearing puller placed under 2nd gear to pull 2nd 3rd 4th, syncro hub and bearing sleaves. Even at 10 tonnes of pressure it still would not budge until heat was applied to the syncro hub. Then it let go with a mighty bang and the whole assembly jumped on the bench. It took some hard work to pull the lot off believe me. :sly:

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This is the tool kit I bought to pull all the gears.

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I used some of the other puller kit to remove 1st gear from the pinion shaft so as I could sell on the 3.68:1 pinion shaft and crown wheel/diff assembly.


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I did the same with the ASD which was easier since I now had experience. and to get each bearing sleeve and syncro hub back on I simply heated them up slightly and dropped them on to the shafts.

Here is the input shaft all done


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And the finally assembled gearing

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The hardest bit then was applying a sealant around the entire casing before reassembly.

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Believe me all this looks straight forward but it came apart a few times because things weren't right or did fit but I got there in the end. It still needs 1/4 turn on the case bolts and the shift tower sealing up but it's selecting all gear including reverse :rolleyes: thank god and can be fitted when required. I'll be running with the current box for engine comparison and simplicity of running in etc. but will slide the new box in when the time comes.

I now have a reconditioned head a polished rocker cover and schrick cam all other bit's and pieces are ready to go on. Going on a little trip first with the Corrado to the Nürburgring for the 20th Anniversary of the Corrado but when I get back out will come the old engine!

Some Pictures.


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Old Engine out after it's trip round the ring.
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EGT probe installed for a saftey net/comfort blanket.
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Valve timing done and belt tensioned
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For all the engineering and thought there you had to go and bling the rocker cover lol, never had you down as a scene queen. Keep the updates coming.

junkie wrote:For all the engineering and thought there you had to go and bling the rocker cover lol, never had you down as a scene queen. Keep the updates coming.

Funny thing is I'll probably get it powder coated as it's already a pain to keep clean. Bloody schrick sump is a b'stard as well given me no end of stupid issues. Never again! Give me a pressed steel sump any day.

I have got further with this, it is actually in the engine bay but not plumbed or wired up yet, should be almost ready to drive by the end of this weekend. Fingers crossed with the weather!

Be good to run against you at the pod again next year, see a kind of real world difference against another car and not just the rollers saying its this much better etc.

Mine will be running correctly this time though as i was down half a bar of boost to what i should have had, all down to the Haltech throwing a kind of wobbler, which will mean you will nail me even more as i will be spinning on the line even worse than last time or i will get lucky with my launch on the standard G60 box and really nail you.....

junkie wrote:Be good to run against you at the pod again next year, see a kind of real world difference against another car and not just the rollers saying its this much better etc.

Mine will be running correctly this time though as i was down half a bar of boost to what i should have had, all down to the Haltech throwing a kind of wobbler, which will mean you will nail me even more as i will be spinning on the line even worse than last time or i will get lucky with my launch on the standard G60 box and really nail you.....

Lol,large element of luck launching with a g60 box.
More often than not i find you get it wrong.
But when you get one right..

I rekon you'll have your work cut out Simon,well at least until 330ft to 1/8 mile.
Then it will get interesting.

junkie wrote:Be good to run against you at the pod again next year, see a kind of real world difference against another car and not just the rollers saying its this much better etc.

Mine will be running correctly this time though as i was down half a bar of boost to what i should have had, all down to the Haltech throwing a kind of wobbler, which will mean you will nail me even more as i will be spinning on the line even worse than last time or i will get lucky with my launch on the standard G60 box and really nail you.....

HA HA very good. As long as you think you can do a 14.5 second QMT or less! Wouldn't want to embarrass you!! weird smiley that!

Yea so chris has told you the story then of last time lol

Yea hopefully get into the 13's as it should have last time and i will be happy with that improvement.

junkie wrote:Yea so chris has told you the story then of last time lol

it came up in conversation I think.
LOL.

Quality.
What were the odds of you two rolling up side by side.

I agree its another way to measure peformance rather than just rolling road figures.
I think the spec of junkies car should have him well under 14.
Chris's car is a bit unique so god knows what it will do.
Can't wait till spring.

i've just finished the RX7 rebuild thread, so not had a chance to read the proper contents of this one yet, but, out of interest, what colour is that? Blue pearl effect by any chance?

Toad wrote:i've just finished the RX7 rebuild thread, so not had a chance to read the proper contents of this one yet, but, out of interest, what colour is that? Blue pearl effect by any chance?

Various shades of LK5T Inca Blue, not many about!

Cool. Looks a bit similar to mine and Yans.


Oooooops.... Really sould read things before I post, god knows I've complained about people doing it to me. Was certain in my head that you were going 16v though Chris.

Looks bloody good so far, especially interested in the gearbox. They frighten me, and I am not at all keen on fiddling inside them.

Toad wrote:

They frighten me, and I am not at all keen on fiddling inside them.

I think alot of people feel that way.
Well I do anyway.And the whole gearing is like some mystical black art to me.
I am starting to see what the rewards of getting it right are though.

Chris have you decided which one of the 10 billion recommended ways of bedding in an engine to go for?

Well every man and his dog has a different idea of which way is best. I bet each one of my ferrets have their own opinions on engine running in. So better not ask them or they'll start fighting!

I'm just going to take it out for a spin of an evening with a toolkit just incase. Country lanes and a bit of motorway mostly! keep it below 3k to start and slowly build up to 4-4500rpm. probably give it a bit of beans before the mapping EGT allowing!

Gearing is one of those things that seem difficult but once you've got it firm in your mind that a gearbox is there to multiply torque you can get on with it or change the engine revs to speed ratio.

O2A box is quite easy to open up, easier than the 020 with is a cnut, with the right tools that is but what is difficult is shimming and endfloats stuff like that. I specifically did this box the way I have so I don't have to get involved in all of that which is more expensive and difficult to do.

So buy a box with the diff and 1 & 2 you are wanting and then swap about 3, 4 and 5 to suite is the easy home DIY method of a custom box. If I were to go LSD or changed the diff & pinion I'd probably hand it over to the experts.

A differential ratio of 3.2:1 means the wheels of your car will rotate once every 3 rotations of your output shaft which in turn will rotate once, if your in first, every 3.3 rotations of the input shaft. So for every 10.5 (3.2X3.3) rotations of the engine the wheels rotate once which means the engines effort to turn the wheels once has been reduced by 10.5 so at the wheels you have 10x the torque of the engine! Simple!

Image Update


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And some more!


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Oooooh it's coming together! Are you working on it today then?

mrbeige wrote:Oooooh it's coming together! Are you working on it today then?

Nope pictures are from Sunday, only just got a moment and was bored enough in work to load them up. It's in the bay at the moment gearbox had to come out and be attached first. Good job to as fitting the bottom plate between the schrick sump and the flywheel was a **** I can tell you. I want to speak to the man that came up with the casting for that m'4cker!!

Getting an engine and gearbox in to the engine bay even with the front member removed on your own with archaic lifting equipment is not to be recommended. It looks like it should be straight forward but it is not.

Picked up a new throttle cable and bonnet cable today and a new reducer hose for the block breath, need to use my copper plumbing skills to feed the outlet from this up to the rocker cover breather hose. Should be a nice fun little project. Using the 3A block breather as the rear G60 support bracket does not seal the big 3A hole without a block off plate and bracket modification which to be frank I simply can't be arsed doing at the moment due to the fact I'm in the middle of FITTING THE ENGINE!

Hopefully tomorrow it'll get fitted and fired up but probably be Sat or Sun as I want the EGT wired before I do anything, or it won't get done.

I want to know the moment this thing is idling.

Good skills.

When did you start this mate?
Two year ago??

Using the 3A block breather as the rear G60 support bracket does not seal the big 3A hole without a block off plate and bracket modification

Huh?

You mean the plastic breather that goes on the front of the 3a?

Yes started about 18 months ago. Spent most of the time waiting for other people and raising cash!

Yes the aluminum box with rubber reducer hose.


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Hope the G60 doesn't mind the lack of support.

OOoohh the charger bracket support.

I won't be running one.
Thats probably of very little comfort to you.

Got all the mounts lined up and bolted down today, the exhaust sealed up and attached, the headbolts tightened, PAS pump on and tensioned along with pulley belt, starter motor in, driveshafts attached, rocker cover done, fuel pipes attached and engine filled with oil.

Tried to prime the engine with oil but wasn't convinced anything was happening with regards to the oil pump pumping oil but I'll look at that again later. Thinking of running without the air to oil cooler initially so I don't have to detach it and drain it before going semi synth or synth.

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