Sam's build thread

[sambb]

ha ha rostered off. could've just watched Game of Thrones but no ones ever that sick!

[metalhead]

Looks good!

[sambb]

cyls 1 and 3
cyl 4
cyl 2 dry
cyl 2 wet

So cylinders 1 and 3 were fine. Cylinder 4 is a brute (we retested that one a couple of times to confirm it wasn't a strange reading). Cylinder 2 was the only one which read a bit lower than the others - 17 dry and 14 like cyls 1 and 3 bt when the rings were oiled. When we did cyl 2 dry we could very faintly hear some blowby out of the cam cover with the cap removed.
So despite the fact that cyl2 was a tad lower than the others and adding oil did improve the reading suggesting that the rings may not be sealing as well as the others, at any rate it is all within spec. This is also considering that the water temp was up but the oil temp when I brought the car in was still under 50 degrees so you'd expect those reading s to be better warm wouldn't you?
So with regards to oil consumption that still leaves valve stem seals, oil control rings as possible culprits. I've been told that stem seal failure isn't likely/common on these engines by a local euro shop/apr dealer. Are oil control rings commonly an issue on these engines?
If neither of those, that leaves the turbo. Judging by the cylinder sealing health I'm pretty keen now to press on with my Golf Mk 6 GTI turbo swap come what may.

Now this might sound strange (was to me anyway) but in my search to understand why the car started using oil I realised it had coincided with me changing from 504 spec 5W 30 oils to Penrite 10W40 10 tenths at the time that I did the oil cooler. Initially I'd suspected the oil cooler had the oil running too cool but blanking plates and a temp gauge confirmed that wasn't the case. So I changed back to Nulon euro spec 5W30 with VAG 504 certification and the car went from using 100ml/100 to 50ml/1000. Now keep in mind i'm using less oil now on a thinner oil which suggests to me that oil quality may have been the biggest issue there. The Penrite doesn't carry 504 cert but I'd reasoned at the time that may just be because they hadn't paid for that test since newer cars use newer cert's theses days, but I'm starting to think that could be a turd oil for my engine?? Put it this way if the car had been using 50ml/1000 I'd probably never have started to worry about the engine, but when it jumped suddenly that's when my paranoia began. So I guess I could keep going through certified 5W 30's till I find the best one or if a certified 5W40 or 10W40 exists then try the thicker grades again.


noticed this too. 7 heat range NGK's with pretty hot looking tips white all the way around to the thread. Think I might need to go another heat range colder for the track!

[Sydneykid]

NGK 7 is a pretty cold plug, it shouldn't need any colder than that. Looking at the plugs the mixtures are all over the place, but all on the lean side. Had the injectors cleaned recently?

Nulon 5W30 Euro is pretty good oil, to get much better than that you are looking at their 5W30 Racing Oil. As a comparison we use 5W40 in the Honda and Toyota and for the Skyline 5W50 in winter and 10W60 in summer (they all run on E85).


Cheers
Gary

[metalhead]

Interesting with the oil! I've always had some oil consumption with the same oil... Haven't tried anything else, but maybe I should.

[sambb]

yeah Id always used liquid Moly Top Tec 5W30 or the Nulon euro which both carry VW 504 cert. The jump in oil consumption was with the Penrite. I only persevered with it because I was too lazy to drain the oil cooler on the next change and didn't want to mix oils.

To be honest Gary those plugs are 5000km at the most and I did pull them out half way through for the compression test and put them back in in whatever order they fell to hand. I have always found a difference between cyls 1 and 4 (across my two engines), which I had put down to cyl 1 receiving the lion share in rush of water with the water injection (single point pre throttle body) and cyl 4 has the PCV port right next to that runner. I do have a weeping injector O-ring so perhaps i'll get them flowed as they've been in there a year.
I always thought the whitening of the ground electrode that normally leaves a definite line somewhere down the electrode was an indicator of temperature. Fully white equalling needing a colder plug, just white at the end meaning the temp ok. So you think its evidence of leanness? My logs are all 0.82's under load. hmm

[Sydneykid]

Interesting with the oil! I've always had some oil consumption with the same oil... Haven't tried anything else, but maybe I should.

The engines are designed to use oil, without getting too deep into it it's mostly to do with backing off the piston ring tension to lessen the parasitic losses and improve fuel economy. Euro spec oil allows for that in its composition, so in general it should use less Euro spec oil than other oils not so chemically endowed.


Cheers
Gary

[Sydneykid]

To be honest Gary those plugs are 5000km at the most and I did pull them out half way through for the compression test and put them back in in whatever order they fell to hand. I have always found a difference between cyls 1 and 4 (across my two engines), which I had put down to cyl 1 receiving the lion share in rush of water with the water injection (single point pre throttle body) and cyl 4 has the PCV port right next to that runner. I do have a weeping injector O-ring so perhaps i'll get them flowed as they've been in there a year.
I always thought the whitening of the ground electrode that normally leaves a definite line somewhere down the electrode was an indicator of temperature. Fully white equalling needing a colder plug, just white at the end meaning the temp ok. So you think its evidence of leanness? My logs are all 0.82's under load. hmm

Lambda at 0.82 is O, but it is an average of the 4 cylinders, so some could be individually lean and some rich. Looking at the picture of the plugs #2 looks the richest, #4 next with #3 looks about right and #1 the leanest. It may well be the cleanest due to the water (H2O) injection bias but that also means its likely to be the leanest (more O). #1 cylinder also tends to run the coolest (closest to the water pump). Numbering the plugs is important, it's a good guide to individual cylinder A/F ratios (that's with Pump98, not so much with E85 as it burns so cleanly it's almost impossible to read the plugs).

When you get the injectors cleaned also mark their flow rates, put the highest flowing into #1, then #4, then #2 and #3. Every little bit helps.

Cheers
Gary

[metalhead]

The engines are designed to use oil, without getting too deep into it it's mostly to do with backing off the piston ring tension to lessen the parasitic losses and improve fuel economy. Euro spec oil allows for that in its composition, so in general it should use less Euro spec oil than other oils not so chemically endowed.


Cheers
Gary

I built my engine with a modern low tension thin ring set of rings. Sounds worth a try.

[sambb]

Thanks for that guide re the injectors Gary. I will do that - sounds like a good approach.
I do wonder if the Polo plenum which is far from uniform in its shape has something to do with the cylinder by cylinder variations too. It has a kink in it to clear the alternator, a huge dimple in it to clear where the secondary air pump was and another divet to clear the dipstick. It tapers down towards cyl 4 a lot. In comparison the Audi S3 plenum is much more uniform with the largest volume and the Mk4 Golf Gti one looks to fall in between that and the much smaller Polo one.