Audi A4R4 450HP CBEA (CR) Build

Looks great. Are you using regular rubber(viton?) o-rings for the coolant ports? What are you doing about the oil feed port to the head? It looks like an o-ring groove around only the port from the filter housing to the top of the block, does the CR head use the head bolt to port the oil to the head like previous motors do?

JFettig said:

Looks great. Are you using regular rubber(viton?) o-rings for the coolant ports? What are you doing about the oil feed port to the head? It looks like an o-ring groove around only the port from the filter housing to the top of the block, does the CR head use the head bolt to port the oil to the head like previous motors do?

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yes viton seals.

If there is a head bolt involved..I have missed that. I will have to double check that now..its been almost two years since I worked out the machining paths. thanks for the heads up.

If it is the case (oil delivered through cap screw) which I suspect is still correct, the oil pressure could possibly be delivered through the threaded Alan screw on the back of the head. It is the main oil galley for the head I believe.

In the worst case just run a small external line and tap a plug in the existing hole in the head and block

See the keyhole shaped head bolt hole between the cylinders on the far left toward the top of the photo? That is the part of the gasket that feeds the head bolt which feeds the head.


I don't see why you can't re-cut that O-ring groove to go around the bolt hole, It will only have a little extra geometry which shouldn't matter

JFettig said:

See the keyhole shaped head bolt hole between the cylinders on the far left toward the top of the photo? That is the part of the gasket that feeds the head bolt which feeds the head.
I don't see why you can't re-cut that O-ring groove to go around the bolt hole, It will only have a little extra geometry which shouldn't matter

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I see it. Thanks for catching that. I will weigh out cutting a new oring path around that bolt verses the external line. The dry sump adapter I have (it bolts on where the oil cooler/oil filter assembly bolts) has a pressure circuit in it to limit pressure to the head. If I go with an external line I will have to try and tap into that circuit on the adapter or add some other external pressure limit. Any further thoughts on that Ruben?

Look at the bottom of the head, I believe there is a groove to port the oil into the bolt hole so you might have to block the port in the block if you feed it externally.

I can't think of a reason that you couldn't just cut the groove around the stud and leave the extra part of the groove like this


It probably won't disrupt the flow much.

JFettig said:

I can't think of a reason that you couldn't just cut the groove around the stud and leave the extra part of the groove like this

It probably won't disrupt the flow much.

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somebody has solidedge or inventor. yes, I can do that. It just a matter of creating the path and taking the block back. The set-up will cost more than the cutting. Then tank it again or do a really good tape and seal job.

if there is enough capacity in the pressure stage of the dry sump pump, would there be a need to limit oil pressure to the head?

TDIsyncro said:

somebody has solidedge or inventor.

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Solidworks
I'm a Machine Design Engineer so its always handy

A good read on common rail injection systems:

http://www.yildiz.edu.tr/~oisin/Dersler/Dersnotlari/0653611/dinjection.pdf



Wanted to captrue the link to the 8V Common Rail Project discussion started by TDIMeister since there is good information on common rail systems being discussed in there.

http://forums.tdiclub.com/showthread.php?t=353770

Bump for a TDIFest appearance. Let's get the cylinder head, brake caliper and other outstanding odds-and-ends shipped. I can't wait!!

TDIMeister said:

Bump for a TDIFest appearance. Let's get the cylinder head, brake caliper and other outstanding odds-and-ends shipped. I can't wait!!

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thanks for the moral support Dave. working hard to try and get there.

JFettig said:

I can't think of a reason that you couldn't just cut the groove around the stud and leave the extra part of the groove like this

It probably won't disrupt the flow much.

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does anybody have the bolt hole diameter in the head at that location?

TDIsyncro said:

thanks for the moral support Dave. working hard to try and get there.

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Scott promised me he is shipping your caliper by next Monday. Let's get the car buttoned up.

Minds will be absolutely blown when the car is done and introduced in its final form. So much not even discussed on the forums....................

TDIMeister said:

So much not even discussed on the forums....................

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Please share

I'll try to get that measurement for you today or tomorrow if I remember. it'll be off of an AHU or ASZ head though.

.515-.520" on my AHU head.

JFettig said:

.515-.520" on my AHU head.

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thanks,

I brought the block back to the machine shop yesterday. I had verified that my head gasket has the same path. It is going to be really hard to fit an oring path in between the space left between the oil return passage and the bolt hole. I will have to come up with some sort of non standard compromise or bail on the block supply and feed with sepparate line as Ruben suggested.

There's always RTV, the duct tape of gaskets...

Can you not pocket out the area?

akafred said:

Can you not pocket out the area?

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the oring ultimately needs backing on the outside edge to hold it in place with oil pressure on the inside area.

Dave...I know silicone is an option...it might come down to that.

A pocket should give you just that, and path for oil

akafred said:

A pocket should give you just that, and path for oil

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thanks for pushing me on this a bit. I agree with you. I think that can work and will just fit the oring in with may be .5mm of backing matrerial between the pocket and the oil return port..enough to hold an oring in place.

Valves have been lathed down to 1.266" and 1.346". Final sizes will be adjusted with a valve grinder if needed.

Whitbread said:

Valves have been lathed down to 1.266" and 1.346". Final sizes will be adjusted with a valve grinder if needed.

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nice to see Matt. That is plus 6mm on OEM as it sits right now. How do the faces look? I am wondering how much of the recess cleaned off when we went to the smaller dia. I am hoping most of it.

TDIsyncro said:

nice to see Matt. That is plus 6mm on OEM as it sits right now. How do the faces look? I am wondering how much of the recess cleaned off when we went to the smaller dia. I am hoping most of it.

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The faces are still recessed unfortunately. I only took ~.100" off both.

Whitbread said:

The faces are still recessed unfortunately. I only took ~.100" off both.

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it looks like the valves could be alot thinner but its hard to say for sure by a picture. What are you using for reference on edge thickness? The thicker they are, the deeper the seats are sunk into the head which equals more valve shrouding.

Does anybody else have some opinions on valve thickness? Ruben? TDImeister?

Don't worry, Louis, it appears like the seat chamfers haven't been cut yet. Some thickness is required to prevent a sharp edge that will overheat and burn out the valve, but the amount required is not large. Too much (valve seat chamfer deeply recessed in the head) and like you said, you will unnecessarily shroud the flow. Here's a guideline from Heywood:



1mm should be sufficient, especially since we're talking about Inconel valves here.

Also, and any experienced head machinist knows this so I'm probably rehashing old news here, there's supposed to be a very small difference in the angle between the valve seat and the valve itself. The idea is that this differential angle results in a line contact on the OD of the seat when the valve closes but under cylinder pressure the valve head will flex and seal on the whole width of the seat for better sealing under both conditions. Values vary depending on OEM, seat/valve manufacturer and even machinist preference/philosophy, but the picture shows 20 minutes, i.e. 0.3 degrees. Also, the contact face should follow the 1/6-2/3-1/6 rule as shown below.

Optimizing the seat and valve angles helps the flow alot more than modifying the runner/port in a VE/PD head.. (exh valve)

On a side note, anyone has more infor about the strength of the newer style engine block?
http://www.ebay.de/itm/VW-T5-Motor-...528145247?pt=DE_Autoteile&hash=item2560391b5f
here are some good pictures of the CR180 style block, and here are some of the earlier engines with round exh ports:
http://www.ebay.de/itm/VW-AUDI-2-0-...675180270?pt=DE_Autoteile&hash=item2314f0caee

I wonder why they again put freeze plug in there, and why the webbing looks thinner. also the oil outlet for the turbo is now at the rear side of the engine block with a M12 or M14 banjo