Bumble is poorly....

[Welly]

OK, so just thought I would share a little knowledge that's come to light, as it may save someone a little aggro.

I believe I have found the source of my tapping, and it wasn't what was expected.

On my original build back in 2010, you may remember that following the build, a valve dropped and mashed the various internal parts of the engine to bits. These bits that were mashed also included the piston in cylinder 1. ******. At the point the engine was built initially, it had all 4 AGU pistons in the waiting for some abuse.

Now, I have NEVER given this a second thought and to be fair had completely forgotten all about it until now.

What happened following this was that piston 1 was extracted, and replaced with an APY piston from the original engine. Again, didn't give this a second thought at the time. Fitted the piston in a rush to get the engine back together again and completed the rebuild.

This time when rebuilding, naturally I used the best 4 pistons out of the available 8 I had. Meaning that there were 7 AGU pisons and an APY piston. The APY piston was actually one of the ones I had elected to use on the new block as it was in good condition, however I noticed something a tad strange when going to fit this piston to the rod.

I knocked the wrist pin down though the rod until it hit the lower circlip on the other side. Then promptly noticed that there was approx a 2 - 3 mm gap between the end of the wrist pin and the upper circlip. This gave the wrist pin enough room to actually move inside the piston from side to side. And the sound it made when bouncing off the retaining circlips was a tap tap tap.

This would also explain why for a VERY long time (over 2 years) it would tap when cold, and then shut up once it warmed up. As the metalwork inside the engine expanded due to heat, it must have been just enough to grip the wrist pin and hold it stationary.

I talked with Tuffty about this on MSN yesterday and he confirms that the AGU wrist pin would be a tiny amount shorter than the APY due to slight differences in the piston size. This would account for the gap.

So, unwittingly, I fitted a piston with a wrist pin that was too small and had the ability to move from side to side inside the small ends...

Not only this, but at the time (first time taking a 1.8T apart back then) I also had no idea that the AGU engine runs 9.5:1 compression, and the APY 9.1:1. So I ended up building a complete and utter piece of crap engine as it turned out... Ended up having an engine running different compression ratios in different cylinders, as well as having a rattly wrist pin.

Well done me. :-/. I'm off to catch the fail bus....

 

[Welly]

Adding to the above, most people would keep quiet about such blunders.... Not me however, this may well help someone avoid making the same mistake.

Besides, all that said, it still made 445 BHP! lol.

 

[Westy]

Onto bigger and better things mate.

 

[<tuffty/>]

Adding to the above, most people would keep quiet about such blunders.... Not me however, this may well help someone avoid making the same mistake.

Besides, all that said, it still made 445 BHP! lol.

<tuffty/>

 

[aragorn]

Just for clarity, have you fixed this piston issue this time around? or have you ended up building yet another engine with different compression ratios?

 

[Welly]

Just for clarity, have you fixed this piston issue this time around? or have you ended up building yet another engine with different compression ratios?

What do you think dude? lol. No problem this time - all the same!! lol

 

[aragorn]

yeh, i just couldnt figure out from your post if you'd discovered the issue after assembling the engine, or worked it out while doing it and put it right

 

[Welly]

yeh, i just couldnt figure out from your post if you'd discovered the issue after assembling the engine, or worked it out while doing it and put it right

LOL, imagine finding that out after? God almighty I'd cry.

To be fair, it was only because the rebuild second time around last time was a rush job that it got missed.

As the saying goes, more haste, less speed. lol

 

[Dane]

Whilst a bit of a palm>face moment I bet it's nice to know what was causing it.

 

[Andrew@A.L.D]

S**t happens welly

I may of even missed that one but i know a lot more now about these engine than i did back then when i did my build

 

[MUSH]

We all learn sometime...

Great rebuild, hope it continues to serve you well!

 

[s3dave]

so the unrifled rods were not guilty then....

 

[<tuffty/>]

so the unrifled rods were not guilty then....

Not of the knocking but certainly of the wear...

<tuffty/>

 

[s3dave]

Hmmmm if the pin was moving about i would say it was inconclusive... on this occasion

 

[<tuffty/>]

Hmmmm if the pin was moving about i would say it was inconclusive... on this occasion

I wouldn't... I believe all his pins were damaged as were the small ends...

<tuffty/>

 

[<tuffty/>]

hummm after a quick chat with welly not all the pins were fecked but 2 x small ends were damaged (one more so than the other)...

<tuffty/>

 

[Welly]

As Tuffty says, 2 were were damaged and 2 were absolutely fine which did strike me as odd.

Not completely conclusive I grant you on the one hand, however 1 of the damaged pins was clearly not down to the wrong sized pin.

So, inconclusive findings really I guess.

 

[Andrew@A.L.D]

Also don't forget you were fitting old used pistons and pins to brand new rods so tolarances would of been out a tad

 

[s3dave]

The one thing that does strike me as odd, is the lack of complaints on the whole web if the unrifled rods are causing big problems, i have searched for a couple of month now, paying attention to American builds and there is nothing......
Now i would have thought they would be some pretty ****** off people out there doing builds only to find the one thing that was supposed to be a a massive positive in their builds, ends up ruining it, infact i have only heard the negatives on this site...
Yes i have unrifled rods and yes i am paranoid about it....

Also noticed IE are selling a new "Tuscan" rod now...

I have had them in for over 3 years now, but following my recent rebuild i think the engine has got noisier, i think i need to take a vid and see what you guys think.....

 

[superkarl]

stephiscope like welly used dave.

once that seed of doubt is planted tho theres no getting rid. you can only hope that all will be fine like the many builds that are out there

 

[aragorn]

I believe a lot of it depends how the cars driven.

Given they're relying on splash lubrication, if you spend all your time at 5000rpm+ then theres plenty of oil splash and plenty of lubrication.

If however your car is daily driven, and you spend an hour every day sat in traffic at 1500rpm, the lubrication is MUCH reduced, and then problems occur.

You say you've never seen anything about failures, however before all the issues popped up on here i did some research when i was building my own engine, and found a few mentions on US forums that non-drilled rods werent a great idea on daily driven cars due to sub-par lubrication at low engine RPM's as i've highlighted above. Now granted, no-one actually said "i fitted these rods and my engines broken", but what i read was enough for me to spend the extra and buy the drilled rods.

At the end of the day, Audi put those drillings there for good reason, it seems bonkers to me, that when tuning an engine to twice its original output or more that you'd choose to REDUCE the lubrication to critical parts of the engine internals!

 

[s3dave]

I believe a lot of it depends how the cars driven.

Given they're relying on splash lubrication, if you spend all your time at 5000rpm+ then theres plenty of oil splash and plenty of lubrication.

If however your car is daily driven, and you spend an hour every day sat in traffic at 1500rpm, the lubrication is MUCH reduced, and then problems occur.

You say you've never seen anything about failures, however before all the issues popped up on here i did some research when i was building my own engine, and found a few mentions on US forums that non-drilled rods werent a great idea on daily driven cars due to sub-par lubrication at low engine RPM's as i've highlighted above. Now granted, no-one actually said "i fitted these rods and my engines broken", but what i read was enough for me to spend the extra and buy the drilled rods.

At the end of the day, Audi put those drillings there for good reason, it seems bonkers to me, that when tuning an engine to twice its original output or more that you'd choose to REDUCE the lubrication to critical parts of the engine internals!

Agreed, so they are selling things that are not fit for purpose...

 

[aragorn]

Depends what the purpose is?

I'm sure they could argue that they are motorsport parts, and one would imagine that if you fitted them to a motorsport application, which is likely to see sustained high revs, then you probably wouldnt have an issue. They could probably also argue that the drilling reduces the strength of the rod, so for all out performance and strength a non-drilled rod is better. And ofcourse, proving any sort of fault with a part like that in a "tuned" engine is likely to be largely futile, as it could have been caused by any number of variables.

Ofcourse i'm playing devils advocate here, and i largely agree with you, non-drilled rods should not be offered to people who intend on using them in road cars, unless they're made fully aware of the potential issues by the retailer.

 

[Welly]

but i know a lot more now about these engine than i did back then when i did my build

Same here dude!

 

[Welly]

With regards to the rods and the rifle drilling, I am converted.

Regardless of whether they were the cause of the failure or not - Aragorn has made the point I would have.

Audi factory drill the rods that come with the engine - they don't do anything for ****s and giggles. Many hours or R&D would have gone into that decision at the time they were being designed - and they decided that it was worth the extra cost to drill them.

The upshot is that pressure lubrication for the small end is more efficient than splash lubrication - which you get anyway, rifle drilled or not.

High RPMs or low RPMs, I don't think that there is adequate lube there for the pins.

Dave, I'm not being a doomsayer here at all, so if they're working for you, then I truly hope that they continue to do so. :thumbsup:

 

[Welly]

Ofcourse i'm playing devils advocate here, and i largely agree with you, non-drilled rods should not be offered to people who intend on using them in road cars, unless they're made fully aware of the potential issues by the retailer.

I also agree with this - I would not have bought them had there been a suitable warning of the possible implications by IE.

Having said that, if you are building an engine then I guess they expect you to be able to make the decision yourself.

 

[badger5]

Agreed, so they are selling things that are not fit for purpose...

you are ignoring the fact most people buy based on price........
non rifle drilled being more popular because of (a) Price, (b) Ignorence of what Rifle drilled rods actually are

imho of course

 

[Westy]

you are ignoring the fact most people buy based on price........
non rifle drilled being more popular because of (a) Price, (b) Ignorence of what Rifle drilled rods actually are

imho of course

I would agree that people WERE buying based on price as there was no real evidence for or against rifle drilled until recently.

 

[s3dave]

There is still little evidence from what i can see, only the common sense is to now buy rifled.. as it is what Audi did, but it did not seem an issue a couple of years ago, or still doesn't now off this site..
I would have of course got the least risk ones if the info was about at the time...
Anyway mine are in and i will have to wait and see if there is going to be issues...

 

[Reesy]

Weren't various reputable tuners mainly selling the unrifled rods a couple of years back? If they were not pushing the rifle drilled one's, why would someone ignore their recommendations and fork out an extra £80 - £100 on something that at the time might have seemed unnecessary?

 

[badger5]

There is still little evidence from what i can see, only the common sense is to now buy rifled.. as it is what Audi did, but it did not seem an issue a couple of years ago, or still doesn't now off this site..
I would have of course got the least risk ones if the info was about at the time...
Anyway mine are in and i will have to wait and see if there is going to be issues...

there is evidence Dave..
choices of rifle drilled H beam were'nt available winding the clock back 8+ years ago..
No longer the case now

bought on price alone, forged will be stronger but do run the risk of splash lube not being adequate enough for some.

Mt 2005 "built" motor was non rifle drilled rods (I bought them 18 months earlier) and had small end rattle from day one.. only slight but always there. did'nt get worse.. maybe JE tool steel pins/pistons were what kept its wear down? I dont know.

2011 built engine has rifle drilled rods, cos they are available now for reasonable money. Only Pauter did rifle drilled originally as one of only a few makes I think..

time will tell.

fingers crossed.. I would'nt worry.. its not like it eats itself

 

[badger5]

Weren't various reputable tuners mainly selling the unrifled rods a couple of years back? If they were not pushing the rifle drilled one's, why would someone ignore their recommendations and fork out an extra £80 - £100 on something that at the time might have seemed unnecessary?

I would still offer both.. but my preference is rifle drilled for obvious reasons.
not everyone is prepared to spend the extra for rifle drilled..

 

[Welly]

Anyway... 200 miles came and went last night and I decided it had been run in enough...

Opening the taps was nice - and it goes really very well indeed considering that the boost is low currently.

With the current config (Yellow spring in actuator and Large UNOS Spring) the ****** thing flatly refuses to make more than about 1.2 BAR boost. Maybe this is not such a bad thing as I did rip it around last night on this sort of boost level, however may be good to give it some beans before whacking the boost up to 'all the boost'.

Sadly, the boost is very unstable at the moment and I put this down to the UNOS not being accurate enough... Bill and I tested it earlier today and it is definitely configured to open at about 29 PSI, but it does leak some air through the valve before this and I suspect this is enough to crack the actuator.

I also have an annoying blow from 'somewhere' on the exhaust system. It's not where I thought it was, but I do have a primary suspect (turbo mouth to downpipe).

With regard to the boost I am going to pop out and reconnect the N75 for testing. That requests a constant 2550 mbar which is more than she makes now. Interested to see if that makes any difference. If that fails, which I suspect it will, then the plan is to swap the actuator spring back out to the red. Not my ideal solution however needs must.

Hoping to get these little bits sorted and get over to Bill's on Wednesday for some dyno action... Excited, yet nervous.

 

[cjsuk]

I have been reading this thread since you started it, not that I have much of an idea about things, but with all the talk about the rifled rods earlier in the thread, I had a dream about them last night lol, I don't know the difference between normal and rifled but I did in my dream. How odd a dream about something I don't know anything about from a thread on a forum mmmm docs for me lol.

 

[Andrew@A.L.D]

You will have to let me know if it spools better with the work i did?

 

[Welly]

You will have to let me know if it spools better with the work i did?

Don't you worry mate, I certainly will. It feels so so different now to what the previous engine did at 1.1 Bar.

Did a few tests last night to find out what's going on. Basically, the yellow spring is weak. Not really, but in the terms of this setup. Actuator pipeless it will only make the same 1.1 bar as it did previously, meaning that the gas flow is pushing the penny valve open.

That's quite impressive to be fair, and certainly explains the need for the red spring on the previous setup.

I don't want to go back to just using an uber hard spirng if I'm honest - going to try and add some more preload to see what happens. Failing that, the red spring will be the choice.

I have also found the exhaust blow - it's from the turbo mani join annoyingly. I need to whip the turbo off tonight and ***** a load of RTV silicone round there to seal it up. It's not blowing all that much - just enough to be irritating, and with it being pre-turbine it will affect spool.

Wednesday at Bills - looking forward to it...

 

[Welly]

I have been reading this thread since you started it, not that I have much of an idea about things, but with all the talk about the rifled rods earlier in the thread, I had a dream about them last night lol, I don't know the difference between normal and rifled but I did in my dream. How odd a dream about something I don't know anything about from a thread on a forum mmmm docs for me lol.

LOL, that's the oddest reply to a thread I've ever had!! :thumbsup:

 

[Andrew@A.L.D]

Don't you worry mate, I certainly will. It feels so so different now to what the previous engine did at 1.1 Bar.

Did a few tests last night to find out what's going on. Basically, the yellow spring is weak. Not really, but in the terms of this setup. Actuator pipeless it will only make the same 1.1 bar as it did previously, meaning that the gas flow is pushing the penny valve open.

That's quite impressive to be fair, and certainly explains the need for the red spring on the previous setup.

I don't want to go back to just using an uber hard spirng if I'm honest - going to try and add some more preload to see what happens. Failing that, the red spring will be the choice.

I have also found the exhaust blow - it's from the turbo mani join annoyingly. I need to whip the turbo off tonight and ***** a load of RTV silicone round there to seal it up. It's not blowing all that much - just enough to be irritating, and with it being pre-turbine it will affect spool.

Wednesday at Bills - looking forward to it...

Good I knew it would help but didn't know how much on your set up, sound like it will really help your set up and make it much better to drive with better spool

You want to feel what my engine is like, 2.1 with a GTX .. torque monster with little lag

 

[Welly]

Morning all - back at work after a weekend of hell basically.

Friday night I went to do the 'quick' job of whipping my turbo off and sealing the flange up as it was blowing slightly. Now with a top mount this should be a nice quick job and I genuinely didn't think it would take more than an hour or so.

Remove charge pipework and drop the downpipe off takes 5 minutes., no problem. Then I find that ALL three of the turbo bolts have cold welded themselves to the nuts. Managed to simply snap the first bolt by giving it some handlebar which was cool. Then comes the the hardest one which is closest to the head... Not snapping for love nor money. Had to cut the head off and grind the remainder away. Lush. Third one wound out after some coaxing.

So the quick hour job took me about 5 hours to complete. Annoyingly, there is still a slight blow on the system, but not from the flange. Coming from the downpipe gasket I think as it tore a smidge. Ordered a new one, but that will keep for now as it won't arrive until after I have been to Bill's on Wednesday.

I went to add more preload onto the actuator yesterday morning as I wanted to bring the boost up from 1.1 Bar. Again irritatingly I couldn't as the rod is as far into the turn buckle as it will go, so I need to cut some off the rod to add any more preload. Didn't have any tools at home as my mate has borrowed them so slapped the red spring in. That gives 1.5 Bar actuator pressure. Awesome

Gave it a spanking on the way home with some boosty which felt REALLY good. Feels like it goes as well now on 1.5 Bar as it did previously on 1.8 ish but that may just be me.

Then disaster strikes.

Gave it a panning up the road towards home, about a mile straight which is always good for getting the shoe in, slowing down for a car and realise it's running on 3 cylinders.... First thought = 'I've killed it'.

Then I realise I can smell fuel. LOTS of fuel. Open the bonnet leaving engine running and have a look, there is fuel spraying everywhere under the bonnet from injector 4. Engine straight off and investigate. Injector 3 & 4 side retaining bolt had worked it's way loose and allowed the injector to work it's way out of the fuel rail completely. I lost about 1/4 of a tank of fuel into the engine bay in about 30 seconds... Allow fuel to evaporate and tighten up and loctite then bolts in (had tools in the car fortunately).

It drives fine thank god but that could have been a million times worse.

I know I keep threatening to burn it, but I don't want it to burn itself....

So, we're all set now. MBC is down on lowest setting so actuator pressure only at 1.5. I want to modify the actuator rod really to enable more preload on the yellow spring - better boost control.

So, roll on Wednesday...

 

[Westy]

Blimey mate, that could have been nasty! You need to keep an eye on everything after a rebuild. I was well paranoid