A Query for those technical out there

[PJC]

FIngers crossed.

['R'e'S'pect_4]

hoping all will be well with the car.

a core plug - not what you'd expect to happen nowadays

[stu]

Any news on the car P_G?

[P_G]

Well there is good news and bad news. Well being honest the bad isn't that bad apart from I haven't had my car for two weeks and severe withdrawal symptoms. But it is still at Revolution who have been lookiing after me well. They opened up the manifold last week and bore scoped all 8 cylinders not to find anything; no damage, nada. Not even a rogue core plug and all cylinder walls are as smooth as a baby's bottom. Bizarre.

So the theories are it it has been sucked into the manifold, made its way from cylinder 5 to 1, in through the inlet valve past the piston giving the plug a knock on the way to faltten the electrode and through the exhaust manifold flap with no other damage and is sitting in the cat and I am the luckiest man on Earth or rather than being sucked in it has been blown out.

So post inspecation the guys at Revolution have been trying to source someone to chemical weld the core plugs into the manifold as really they are surplus to requirements (holes are there to access manifold intake flap screws and as there are no flaps no need to access screws. That said it's a tricky job welding metal plugs into an aluminium alloy manifold. So Stuart at AAS has stepped in and machined me new aluminium core plugs with a diference. They have a retention ridge on one side. For those of you who have looked at core plugs they are essentially a small rod of metal and they sit tightly in the manifold holes but can be moved in or out with a bit of force. Naff Audi design so mine now have ridges on them so they cannot be sucked it sort of like a screw head.

So with new design core plugs in place the manifold should be with Revolution again tomorrow (cheers for picking it up Glenn ) fitted, oil change as a precaution and under IM vacuum hoses extended outside for future easy access to the one way valve and car back to me on Friday morning. Can't wait!

Big thanks to Revolution for taking the time to giving it a thorough look over and rolling the car in and out of their workshop for the last 2 weeks (you forget how heavy these cars are!) If anyone is in doubt about what customer service is try them. They have been courteous and kept me informed at all stages.

Also a big thank you to Stuart at AAS, not just good for exhausts but custom engine parts as well at short notice when he has a 8 week order book; that's how good he is!

[sonny]

Nice one Graeme, glad to see it all came together at a cheapish cost. The ali rods with the lip chemically wielded is what I had done when I had my stage 2 IM fitted. Agree it is a bit of a design flaw by Audi.

[2manytoys]

Wow, now I've seen everything. I would have thought if it was swallowed it would have caused some visual signs of damage.

What about the low compression Audi found. Did Revolution do a compression test and found something different?

Glad it's turned out this way, and yeah I agree, you must be the luckiest man on earth, well done!

PS: The core plugs should not have been reused. Most normal car parts places carry them, they are basically a welsh plug. If they were replaced with new ones it would have been almost impossible for this to happen (seeing first hand how tight the new ones are when fitted).

[sonny]

PS: The core plugs should not have been reused. Most normal car parts places carry them, they are basically a welsh plug. If they were replaced with new ones it would have been almost impossible for this to happen (seeing first hand how tight the new ones are when fitted).

Yep common sense, but there are still idiots out there who refit the old ones.

[Doug_S2]

you don't need to remove the plugs to remove the flaps - but if you are refitting the flaps, or from factory, they would want to get a tool with a torque setting on it.

[P_G]

PS: The core plugs should not have been reused. Most normal car parts places carry them, they are basically a welsh plug. If they were replaced with new ones it would have been almost impossible for this to happen (seeing first hand how tight the new ones are when fitted).

Just to clarify the core plugs were not reused, these were new ones that had been put in and it was one of the new set that went AWOL causing the issues. Sorry I wasn't as technical in my description or the core plugs / reason for the holes Doug but that was what I was getting at. I could have had the modified core plugs with a bolt washer system in them as well to allow easy removal but as I'm never likely to need to use the functionality that the holes were designed for again decided just on solid plugs.

Compression test was OK and within range, all valves are seating OK, no leaks and no damage. I always wondered what conditions compression testing should be done under as if cold then surely the oil seals will not be at optimum and would affect the test results? IIRC Audi did it from cold after cranking over the engine several times for short time periods (less than a minute each time) so surely not the best conditions?

Will see what it feels like when I get it back tomorrow, after driving my Ibiza for 2 weeks it will feel epic no doubt.

[adsgreen]

Depends what you are trying to measure.
If you are looking for leaks in the cylinders then cold is fine - usually you have a dry test (cold engine) and then you repeat with a wet test by putting a teaspoon of oil in the cylinder. The wet test should be higher than the dry and it's generally ok. The key thing you are looking for is differences between the cylinders - if all of them are relatively close (say 10psi) then it's resonable to assume the compression is good. It's unlikely you'd have a compression problem affecting all cylinders (possible say if a gasket had really gone but still very unlikely to affect all cylinders equally).
If you do have a problem flagged up then depending on the actual differences it could be wise to follow up with a hot test to make sure.

If you are tuning and measuring actual compression then you'd need to do it when the engine is hot as you're interested in specific numbers more than testing any compression loss.

[2manytoys]

+1 (except I'd say 10PSI is too much. I'd want it within a couple of PSI at most on the same bank).

If something entered my cylinder I'd probably get a leak-down test done. You probably won't feel a slightly lower compression on one cylinder.

Hopefully everything is all good though.

Cheers.

[P_G]

Got the car back this morning and it runs like a dream bar a minor hiccup which was soon rectified. Initially I just thoguht it had been too long since I drove it as it sounded immense but then soon realised there exhaust actuators were working so valves were wide open. Quick scan revealed a host of codes that all added up to no vacuum. Quick trip back, Glen under the bonnet burning his hands on the manifold and soon found one the extended vacuum hoses from under the manifold was pinched against the fuel rail. Manifold loosened, pipes wiggled free and now sweet as a nut and no codes.

Once again a big thanks to Revolution for doing all the work on the car. Going to enjoy driving it for a while before any potential 'next stage', I'm sure Glen and co. are sick of the sight of it but they now can take an RS4 IM off in 30 minutes / in their sleep! I'll take pics of the new core plugs as well and they are beautifully machined.

BTW, for those interested in the dry compression test, all cylinders were around the145psi (143-146) mark with one exception which was cylinder 1 which was at 141psi so pretty consistent and well within 5% of each other.

[sonny]

Happy days fella, glad it all worked out fine.

[P_G]

CheeRS sonny.

['R'e'S'pect_4]

glad it is sorted P_G.

With your story and Gumball0r's failure, didn't make for happy reading - one of the reasons for me opting for the RS4 over the S4 was the presence of cam chain and not rubber belts, a better feature on a hi-po engine IMO.

Just the clarify, you've had your flaps removed hence the removal of the core plugs? Is this part of a mod you've had carried out on the motor? Just interested.

Cheers.