Audi TT 225BHP HEAD CHALLENGE

[skysurfin09]

My apologies if this item is in the wrong place mods: Can anyone help who has a mechanical bent. I've an Audi TT that i've thrown a lot of money at. I need someone who could strip the head off and see if the cam seats are worn. As when she gets hot I lose oil pressure. I've had the crank reground new shells and journals, new cams and followers, new oil pump and timing chain. I'm at a loss, someone mentioned that the seats for the cams are famous for losing oil pressure if worn as the cams rest on these seats rather than shells. If you're interested please PM me. Thanks Rob

[skysurfin09]

Anyone?

[937carrera]

Wrong part of the world for me, I was going to recommend a Porsche specialist I know in Bristol, but have discovered he has now retired. I have other friends in the south west world and have asked them for suggestions.

[tobydog]

My apologies if this item is in the wrong place mods: Can anyone help who has a mechanical bent. I've an Audi TT that i've thrown a lot of money at. I need someone who could strip the head off and see if the cam seats are worn. As when she gets hot I lose oil pressure. I've had the crank reground new shells and journals, new cams and followers, new oil pump and timing chain. I'm at a loss, someone mentioned that the seats for the cams are famous for losing oil pressure if worn as the cams rest on these seats rather than shells. If you're interested please PM me. Thanks Rob

Was all this done because of low oil pressure?

[937carrera]

I have been advised that Peter Chambers Automotive in Tewkesbury could be worth a chat

http://www.pcaltd.co.uk/

Don't worry about them being mainly Porsche specialists, you just need a decent engineer. By the way, Boxsters and wc 911's have the same design with the cams running in the cam covers without separate bearings.

[skysurfin09]

My apologies if this item is in the wrong place mods: Can anyone help who has a mechanical bent. I've an Audi TT that i've thrown a lot of money at. I need someone who could strip the head off and see if the cam seats are worn. As when she gets hot I lose oil pressure. I've had the crank reground new shells and journals, new cams and followers, new oil pump and timing chain. I'm at a loss, someone mentioned that the seats for the cams are famous for losing oil pressure if worn as the cams rest on these seats rather than shells. If you're interested please PM me. Thanks Rob

Was all this done because of low oil pressure?

Hi, Initially i had a partially blocked strainer in the sump and very low oil pressure as a result. The engine was stripped down and it was found that the was damage to the crank , so it was reground and fitted with racing shells and main bearing caps at Owlesbury Crankshaft services, (highly recommended). At the same time the garage noted that the oil pump was faulty and also that the cams had a little scoring on them so they and the followers were replaced. This was the second pair of cams and followers fitted to this engine as on purchasing the vehicle I decided to replace the timing chain and tensioner. At this point it was spotted that the original inlet camshaft as scored so I replaced the pair and the followers as good practice.
Now when the engine gets hot, (above normal) at about the 105* mark the oil pressure warning light comes on and the oil can flashes red. Upto that point in normal running she's beautiful, in journeys of 150miles or more.
Thank you for your interest it is much appreciated...Rob

[937carrera]

Lots of questions, more for diagnostics than a solution:

Are you sure that the low oil pressure signal is correct ? I assume it is because there's a relationship with temperature, but worth checking
Have you put an oil pressure gauge on to see what the actual pressure is
Why do you think the oil is getting hot, what's the water temperature doing, what do you need to do to get it hot
Any mixing of coolant / oil
You've replaced the cams, but not the cam covers, are you sure they are in good condition
Are all oil coolers in place and working correctly - not blocked / thermostats shut closed
What was blocking the oil strainer originally - any chance that there are other residues blocking galleries ?

[skysurfin09]

Hi, unfortunately I'm going to be as much use as a chocolate fireguard in answering your questions as it will all be information relayed to me by the garage.
I had been doing a 30mile journey engine temp normal for my car (75*) although the book says in should run at (90*). I got caught in the rush hour traffic going through Devizes and was reduced to inch forward for approx 15-20 mins. I noticed that the oil can red light started to flicker on and I went into panic mode. I put the heater on full hot and as the road cleared I got some cool air flowing through the engine bay the light went out and I very carefully made my way home. The next day I took the car to my friend, a VAG specialist garage owner, and asked him to find out what had caused the oil problem and as he rebuilt the engine he would know what to look for.
He said that the engine was producing approx 60psi quite nicely until the engine got upto 105* approx when literally the oil pressure suddenly dropped to less than 10psi. He hand on heart swore that head thoroughly cleaned out the oil galleries etc before the rebuild. He had fitted a brand new oil pump too. He was at a loss to explain what was happening as we replaced all that was needed save sending the head away to be checked over, that is.
It was at that point I first heard of this fact that the cams ran on seats as opposed to shells and when I checked this out on a TT forum, I found that this could be responsible for the loss in oil pressure as it is known problem ( not to me ) with this type of set up.
I've no idea whether the oil coolers are in the right place or not, and I can only assume that the thermostats are opening as she drives lovely in normal conditions. There's no mixing of oil and water and I'm assuming again that the cam covers are in good condition as the advice given to me was either strip the head off and send it away to be tested ad repaired if necessary or just as cheap (i laugh) get another engine (VEGE) AND HOPE THAT SORTS IT OR PLAN B WALK AWAY.
I do trust the mechanic as he is a personal friend and he has looked after my vehicles for about 18years. He did say that normally he wouldn't have advised me too rebuild the engine he would have opted for a new lump but he knows my financial situation and this has been done at cost. Not in hindsight ideal as I can't very well say fix it you built it. Which is why I'm here trying to get some guidance on what is going on.
Thanks again for taking the time to give advice it's most welcome. Rob

[937carrera]

That's helpful, so the problem is real as oil pressures have been checked.

When you are talking about temperatures, are you talking oil temperature or water temperature.

At what engine speed was the engine producing 60 psi ( 4 bar for me ), what' s the oil pressure when cold at idle and hot at idle

If you start the car and just leave it idling will the problem appear.

What oil are you running ?

As an engine gets hot the oil gets thinner. Thinner oil means less pressure. In some engines you can have a situation where an oil pressure light comes on / flickers at idle after running at high temperatures, though this is not normal. An extra 200 rpm knocks the light off.

Do you know what condition the water pump is in. I assume with a TT it has plastic vanes and there are problems with the vanes coming loose on the shaft

Has your mechanic checked the correct operation of the oil pressure relief valve ?

[skysurfin09]

With regard to tempretures I'm only referring to water temp as I've no idea as to oil temp in the car.
I believe that the oil pressure was recorded at 2500 revs but I'm not certain.
The oil in the TT is a 5-30 fully synthetic oil. Today I took her for a short drive approx 5miles to the shops and then on the way back the oil can flickered on again and I had to stop put the heater on full chat and let her cool down just to get home. I can't vouch for whether the mechanic has checked the oil pressure relief valve or the water pump. I can only assume that the water pump is working as the engine temp is constant when normal driving. The thermostat opens as it should and you can see this operating via the gauge. I'm sorry that I can't be more precise with the information you ask for but at a certain point when all you hear is bad news the eyes glaze over and I reach for a razor blade.. Thank you for your interest. Rob

[937carrera]

OK, here's what I would be looking at:

1. Coolant system - seems to be overheating, need to find out why, water pump, thermostat not opening, fan not operating ? You haven't mentioned coolant loss, so I assume there isn't any
2. Oil pressure relief valve. I had a quick read around after my earlier post and someone else had similar problems with rapid pressure loss, ORV sticking was suspected

If it's those items then the good news is you don't have an expensive fix. Have a word with your mechanic friend and see what he thinks.

[937carrera]

Hi, Oil press should be.....Idle 1.0 bar/14.5 psi......3000rpm 3.5Bar/4.5Bar..51-65 psi @ 80 degrees C.

Copied from an Audi TT forum - so yours is close to spec until it gets hot / sudden loss.

I didn't say so before I believe the cooling problem triggers the oil pressure problem. Fix that and the oil pressure problem may disappear.

The water pumps were plastic, now modified by VW and aftermarket with metal ones also available.

Seems that the oil strainers also get clogged a lot I suggest you get that checked again and make sure there are no cracks in it which can admit air.

Finally, make sure you are using a good / VW spec oil filter. I'm not normally one for saying that only OE stuff is good, but I have seen a situation where a Cayman had an oil pressure problem. This was eventually traced to a bad batch of filters (made by a top quality German manufacturer).

[937carrera]

Just wondering if you have managed to make any progress with this ?