Sams Polo 3.0

[h100vw]

I have a bit of news. The long awaited brake master cylinders have arrived from Germany. But given it's a bitch of a job to fit. Not sure it will be a quick fit to the car.

[sambb]

I'm still here. Like Gav said a possible solution to the overly long pedal has finally arrived. It will be a bitch of a job requiring a full flush/bleed with a system that is notoriously bad for trapped air in the ABS manifold. While I'm at it I'm going to do my rear beam bushes. The ones on the new car are two piece ones which aren't really seated correctly and look way to flexible when moved with a pinch bar. So I'll swap in my one piece solid bushes but that requires the rear brake lines being separated so that the rear beam can be dropped. Then while I'm at that, I may as well fit stainless braided rear brake lines. So yeah a master cyl job that needs a full flush, pressure bleed will drag into it a dropped and rebushed rear beam with new lines is quite a biggin and may be a while. Oh yeah and my master cylinder brace will then need to be remade because the master will sit further out. I'm not even sure it'll clear the channel that the fuel lines drop into. If the parts had arrived a few weeks back when the kids were still in home schooling and we were all stuck at home I would have gotten onto it but now it looks like things might open up and the kids are on hols right when the parts arrive which is a bugger.
Yeah things just went quiet car wise when the ability to get onto a track disappeared or visiting mates and workshops etc . Then youtube, netflix and beer became a problem for me ha ha. Then I ended up on the wrong end of a company vaccine mandate and was nearly stood down. At least I have my job unlike a lot of people which I'm thankful for, but running that line where I thought I was going to loose it wasn't fun.
Other than that I got back to some E20 blend tuning with UK Dave. I mucked around with plugs and now run some Brisk plugs. They are a silver (coated I assume) plug so slightly less resistance than copper maybe but have a really fine anode like an iridium/platinum. Tried them on a recommendation and despite the ethanol blend and way more timing I'm actually able to run a loose 29 thou gap which is bigger than the 28 thou I was running on peti. Better than the 24 thou I was down to to avoid misfires. Dave checked the dwell times on the stock coils and they were up there eg 2.8ms so there wasnt really anything to be had by pushing the coils harder. I didnt have the stomach to do a coil conversion so I'm glad that playing with plugs gave me a bit of a solution, but more testing needed. I'm glad Dave did offer to do a dedicated E20 tune for me. He was probably horrified that I had just previously upped the fuel pressure and added some global timing! It just keeps taking more and more timing now and is a bit leaner (0.83's) than I had it too. Same deal as before - no more peak power really due to turbo/cams, but the mid range is a proper step up from petrol.
more to come, I've just been a bit preoccupied

[sambb]

who wants to here a mildly decent sounding NA 3.9L cosworth V12 @ 12,000 rpm
T.50 VLOG | EPISODE #12 | DARIO DRIVES GEORGE FOR THE FIRST TIME - YouTube

[sambb]

engine rebuild time!

I'd toyed with the idea of doing the bottom end myself for so long but having to get all the measuring & fitting tools needed plus knowing that finding the uninterrupted time required would be nigh on impossible, I decided to out source it. It was picked up yesterday and is now down at M.I A engine services with all the bits to get the bottom end built.

The parts will include:

- S3 BAM pistons, very good condition second hand cleaned up and sent down to Special piston services in VIC for skirt recoating and additional crown coating.

- supplied with ring set from SPS

- Forged China rods which are a knock off design of Bar-Tek X- beams. 20mm wrist pin to match the S3 pistons, force pin oiled


- ARP 2000 rod bolts

- OEM main bolts, main bearings and rod bearings

The hope being, that as its only a 90,000km block that did half its life standard and half with a stage 1 tune with good service history and an OTT one from me, that its all square and true. Hopefully it wont need line boring and can be within tolerances with just a skim and a proper re-hone.
I'll then do all the ancillaries, front/rear main seals, fit the brand new AGU Large port head (probably with VVT from one of my other engines) , the custom (by me) baffled sump which is getting welded up now too and swap all the mechanically adjusted cam timing gear across from the old engine (IE idler, 1.8L 16V KR tensioner roller and Cat Cams adjustable cam pulley).

I'm agonising over a couple of things:

- I'd have liked to go with ACL rod and main bearings but $$. If there are any issues with the supplied OE ones then we'll probably go that way where needed.

- I'm really not sure what to do re exhaust valves. The standard thing you'll hear is that you should change out the stock sodium filled exhaust valves for Supertechs. Where I struggle with that is not knowing whether the failures of the stock valves are rev related or heat related. If they are rev related then any of the turbo options and the stock cams I'm running will not rev higher than the stock redline anyway. If its a valve float issue then I don't see how adding an even heavier stainless supertech valve with a stock spring is going to be better controlled and I definitely dont have the bucks to do valves/spring/retainers or to extend to the lighter inconels. If it's a heat issue, then I do hope that sensibly tuning the right size turbo and running an ethanol blend will keep the combustion temps/EGT's in order. Also the exhaust valves I have are brand new in a head thats still in the wrapper so I'm starting with something that hasn't been pre-flogged. Still though....I'm not sure.

- Gates racing cam belt or not? Again revs are going to be stock redline, with stock turbo cams so I don't know if a belt thats 3 times the price is warranted for an engine in that guise.

- head gasket....at the moment I have a stock one with stock head bolts but again at no more than 280-300 hp do I really need more?

- turbo choice..... a plug n play Littco K280 (reworked innards in the K03 frame) is attractive just due to the convenience factor but I'm pretty sure I dont want to stay with factory manifold leaks, constant turbo-manifold gasket blow outs and leaks and the high EGT's such a small frame turbo gives.
Most likely I will go down the path of running my Golf Mk6 Gti EA888 gen 1 IHI that has nice open long runners split 1&4/2&3 (still single scroll though) with what I'm hoping will be a far more reliable and easy to work on turbo-engine connection. This is my mock up on my other engine.


anyway, stay tuned. More picks to come.
sam

[Sydneykid]

What are the inlet and exhaust valve sizes Sam? I'm not sure on VW's but a lot of manufactures of turbo engines have adopted the philosophy of going "small" on the exhaust vales for emission control reasons. The rule of thumb used to be to have the exhaust valves 80% of the diameter of the inlet valves. I have seen recent turbo engine that are in the high 60's. The advantage of a larger (more appropriately sized) exhaust valve is more power with the same boost or the same power with less boost. Either is a winner in the inlet air temp stakes. If the exhaust valves sizing is in the ballpark then I would stick with OE's.

On Nissan RB's a 1.5mm larger diameter exhaust valve facilitates the same power at 3 to 5 psi lower boost, so it is quite noticeable.


Head, OE studs or bolts? If bolts I like to change to ARP studs, cheap insurance.

I'd suggesting checking the weight on the exhaust valves, often sodium filled valves have less wasting that full stainless and hence the weight difference isn't as much as we might think.

I'd stick with the VW cam belt, ditto bearings.

Personally I like to assemble my own engines, I do get the measurements done externally, bearing sizes, crank straight, main bearings aligned, deck flat, hone, bore and piston clearances. I also get the cam bearings alignment checked and all of the moving bits balanced. Then I do the assembly myself. I don't do enough engine assembly to get bored and the satisfaction when it runs is second to none.


I have a shipment coming from the US in the next couple of weeks, if you need anything from ARP etc I can get it thrown in the box.


Cheers
Gary

[sambb]

valves are :
inlet - 3 x 27.35mm roughly
exhaust - 2 x 29.87 roughly

I had a link to a site where they'd compared the cfm of the large port head to small port heads and I remember you saying at the time that the head was heavily biased towards excessive exhaust flow relative to inlet flow. I know in the past i've seen it said that if there is a high EGT issue then its most likely due to restrictive exhaust manifold and/or turbo sizing on theses engines but not likely from an under done exhaust valve/port from the head itself. Hopefully thats true. On the inlet side, the inlet valves are the same whether you have the small or large port head, its just that the large port head has just that, larger ports and does flow more due to that. So by going large port I have swung the inlet to be more balanced against the high exhaust flow but still the head is over exhausted from OEM.
LP vs SP. all valves common. combustion chamber common. only the inlet port size varies. LP inlet cfm at 50 thou is higher suggesting a port restriction on the sP head.

The OEM head is fastened with stretch to yield bolts. Not sure if ARP do bolts too but they do do ARP studs.

Good call re the sodium filled valves maybe carrying more material to compensate for the infill and maybe actually being heavier. I'll try to find out what the weights are of OEM vs Supertech stainless.
If I have a cent left over for the head, it'll either have to be valves or ARP head fasteners but not both. Anecdotally it seems to be that that exhaust valves are seen as more of a reliability issue than OEM head gaskets/ head fasteners but i'll need to obviously detective out which is the bigger potential issue.

[sambb]

cam cover breather thoughts:


The breather port is 18mm diameter. (AN12) That's an area of 254mm sq.

It is fed though by these holes in the oil/air separator plate. They are 6 x 6mm di holes = total area 28.3mm sq x 6 = 170mm sq. Thats a single pipe equivalent of about 11mm di = AN7 if it existed.

So either the area of the baffles holes is correct and the outlet pipe is 33% too big OR the outlet pipe is the correct size and the baffles are 33% too small. I'm thinking that the outlet pipe is correct for a modded engine and that the baffle plate needs to be brought up to match the pipes flow capability. I've worked out that 3 more 6mm holes in the baffle plate ( 9 in total) will give it input flow to match the outlet pipe to the catch can. Thoughts?!

[Sydneykid]

Can I just confirm the valve sizes;
3 x 27.35 = 1763 sq mm
2 x 29.87 = 1402 sq mm
Based on the above the total exhaust valve area is 79.5% of the inlet valve area. Which is pretty damn close to the 80% rule of thumb minimum I like to use.

On a $value basis head studs probably rate higher than an exhaust valve upgrade.

Cheers
Gary

[Sydneykid]

The principle of a cam cover breather is to slow down the air speed of the blow by to give time for the oil mist to separate from the air. Having a smaller area of breath through in the baffle plate than area of the outlet fits that principle. What's inside the breather void? I use Scotch Bright stainless steel scrubbing pads to slow the airflow even more and to help the oil out of the airflow.

Cheers
Gary

[sambb]

Hi Gary,

Jeez I was definitely under the influence of shift work when I was looking at valve sizes. I only forgot to calculate area!! ha ha.
I found the official supertech std valve sizes:
inlet 26.90mm x 3 = 1705mm2
exhaust 29.90mm x 2 = 1404mm2

exhaust is 82% of inlet which is even a bit better than first calculated by you when I was just trying to jam verniers in there.


RE the breather, I was just concerned that 6 x 6mm di holes which I think came out at -AN7 equivalent (if put in terms of a single pipe) was just not enough flow area. If that looks to be ok I'll leave it alone. Basically that plate goes into an empty cavern that the exit pipe is pressed into. I could get steel wool in there but only through the exit pipe itself as the baffle plate fixings have been peened over and would need to drilled off for access and then re-fixing it doesnt look to be straight forward.

Re head bolts vs exhaust valves I was thinking that a blown headgasket can always be sorted if it happens but a dropped valve is potentially terminal, so I was leaning more towards valves. But I think there's a high chance it'll just go in as is because of dollars or a lack thereof.

I'm not even sure the AGU golf large port inlet mani will fit in the engine bay because of its different throttle body angle so i'll have to do some fab mods there that will require IPRA Andrew doing some more welding for me, so i'll need to hold some money in reserve. But yeah if I discover some money then the head bolts vs exhaust valves thing will start to make my head hurt.

thanks for your help Gary.

[Sydneykid]

I think you have it pretty well thought through Sam. I should mention that's it's unusual for a turbo car to blow a head gasket and not cause other damage, commonly to the head itself or the deck of the block. With NA cars we can often get away with a quick gasket swap, but a turbo car we are rarely that lucky.

Cheers
Gary

[sambb]

Hmm ok good point. Ok I’ll have a quick squiz at ARP bolts vs studs tonight and get some part numbers and prices.

[sambb]

just got a response from super tech. AEVN-1103 supertech stainless, stock diameter, triple groove keeper exhaust valves are 43.9g each.
Now to find out what a stock one weighs. anyone?

[sambb]

just found this. A cool aussie designed/made flat slide jet/needless carby.

Rotec TBI how it works...50 off 0.03mm jets! - YouTube

would go great on a little Ford Escorts Pinto....... just need the $30k for the car first!

[h100vw]

RE the breather, I was just concerned that 6 x 6mm di holes which I think came out at -AN7 equivalent (if put in terms of a single pipe) was just not enough flow area. If that looks to be ok I'll leave it alone. Basically that plate goes into an empty cavern that the exit pipe is pressed into. I could get steel wool in there but only through the exit pipe itself as the baffle plate fixings have been peened over and would need to drilled off for access and then re-fixing it doesnt look to be straight forward..

Don't forget Sam, the cam cover isn't the only exit for crankcase pressure