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AAZ Head Rebuild
by
TonyTDTruck
on 26 Feb, 2012 11:43
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What else can be done to an AAZ rebuilt cylinder head for better performance other than port and polish? The engine will have an intercooler and oil cooler with a Giles pump and stock K14 turbo.
Thanks
Tony
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#1
by
R.O.R-2.0
on 26 Feb, 2012 11:59
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a cam, bigger valves..
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#2
by
TonyTDTruck
on 26 Feb, 2012 18:32
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The machine shop that is working on the head says they can't put bigger valves in it. What p/n for the valves and cam?
Maybe if I brought it to them they could do it.
Thanks
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#3
by
CrazyAndy
on 27 Feb, 2012 05:49
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There was a guy either here or on another forum that got more lit from a stock cam by machining down the cam base circle. It's a little tough (for me at least) to find any diesel performance camshafts. Maybe find a shop that could do that?
And where in the system are you running the oil cooler, just wondering?
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#4
by
R.O.R-2.0
on 27 Feb, 2012 07:14
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The machine shop that is working on the head says they can't put bigger valves in it. What p/n for the valves and cam?
Maybe if I brought it to them they could do it.
Thanks
i wouldnt even worry about valves..
theres only a couple guys running big valves on here, and one of them is CONSTANTLY breaking things..
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#5
by
TonyTDTruck
on 27 Feb, 2012 08:14
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OK no big valves. Don't want to brakie anything.
CrazyAndy I am going to run the cooler to the front of the truck. It's a long way but it works I hear.
The cooler mounts where the oil filter housing is. The oil filter then screws onto the cooler and hoses run to the radiator in
front of the car.
Here is an example.
http://www.summitracing.com/parts/FLX-3953/?rtype=10
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#6
by
RabbitJockey
on 27 Feb, 2012 08:40
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any good machine shop should be able to get you custom valves or cut some down that are too large, they're not cheap like the stock valves are but not horrible either. if i ever get my car together, and go to move on to a stage two build, i would like to try larger valves in my 1.6 head and do the small valve gasser sizes of 38mm intake and 33 mm exhaust, the big valve size would be sweet, 40mm and 33mm but in an engine with a 76.5mm bore, that would not leave much material between the two valve seats and between the valve and cylinder wall. also diesels can't really rev over 6k so i don't know at what point larger valves become pointless. they sell an oversize valve kit for tdis i think its 37mm and 33mm i can't remember, tdis start having an issue where the valve seat gets very close to the injector hole and cracking becomes very likely. this is something i've been discussing with a machine shop, they also make off set valve guides so u can position the valves nearly where ever you want. either way it's not something that has been experimented with much on here, but it can definitely been done.
1.6td: 34mm and 31mm
aaz&tdi: 36mm and 31mm
tdi has different stem length tho.
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#7
by
CrazyAndy
on 27 Feb, 2012 08:54
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TDI has diff. stem length than the AAZs? I thought they were the same, which was why you could run 7mm stem TDI valves in an AAZ. If true, then that's another mod that might be a good idea, if you're looking for less stuff in the way of incoming and outgoing gas charges. Just make sure to get 7mm guides.
Not sure if It'll make noticeable gains though; would 1mm extra in the intake valve head diamerer make any difference, too?
And that oil cooler looks nice, just make sure the line fittings are crimped well. Might be advisable to get a hydraulic shop to press-crimp some female threaded ends on that hose for security.
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#8
by
R.O.R-2.0
on 27 Feb, 2012 08:55
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OK no big valves. Don't want to brakie anything.
CrazyAndy I am going to run the cooler to the front of the truck. It's a long way but it works I hear.
The cooler mounts where the oil filter housing is. The oil filter then screws onto the cooler and hoses run to the radiator in
front of the car.
Here is an example.
http://www.summitracing.com/parts/FLX-3953/?rtype=10
he breaks things because he has a compound turbo'd 300hp AAZ variant..
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#9
by
RabbitJockey
on 27 Feb, 2012 09:42
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OK no big valves. Don't want to brakie anything.
CrazyAndy I am going to run the cooler to the front of the truck. It's a long way but it works I hear.
The cooler mounts where the oil filter housing is. The oil filter then screws onto the cooler and hoses run to the radiator in
front of the car.
Here is an example.
http://www.summitracing.com/parts/FLX-3953/?rtype=10
he breaks things because he has a compound turbo'd 300hp AAZ variant..
thats kind of my thought there are alot of changes to that engine to blame valves for any failures not specifically related to valves. but there is definitely a point where the port design becomes the restriction and not the valve as well as a point where is no point in going any bigger haha.
yes tdi has different stem length, and later aaz's actually had 7mm valve stems so they are easily available. for gas engines some companies have 7mm valves that are cut down to 6-6.5mm just above the head of the valve. i think they even make oval stems?
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#10
by
R.O.R-2.0
on 27 Feb, 2012 09:53
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OK no big valves. Don't want to brakie anything.
CrazyAndy I am going to run the cooler to the front of the truck. It's a long way but it works I hear.
The cooler mounts where the oil filter housing is. The oil filter then screws onto the cooler and hoses run to the radiator in
front of the car.
Here is an example.
http://www.summitracing.com/parts/FLX-3953/?rtype=10
he breaks things because he has a compound turbo'd 300hp AAZ variant..
thats kind of my thought there are alot of changes to that engine to blame valves for any failures not specifically related to valves. but there is definitely a point where the port design becomes the restriction and not the valve as well as a point where is no point in going any bigger haha.
yes tdi has different stem length, and later aaz's actually had 7mm valve stems so they are easily available. for gas engines some companies have 7mm valves that are cut down to 6-6.5mm just above the head of the valve. i think they even make oval stems?
what im getting at, is you dont NEED big valves unless you are striving for those insane power levels.. stock valves are good for 250hp or so..
big valves need big seats, and big seats need bigger holes in the head, so that leaves less material between the seats, so cracking is basically a guarantee at some point..
these engines spin 6000 revs TOPS.. they are only going to move soo much air, and they only have soo much space in the cylinder.. too big of valves and you get valve shrouding, and then you are going backwards, in terms of flow..
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#11
by
Alcaid
on 28 Feb, 2012 00:44
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what im getting at, is you dont NEED big valves unless you are striving for those insane power levels.. stock valves are good for 250hp or so..
250hp on stock valve size? Maybe, but with insanely high boost pressure
The 6k rpm limit is a limit given by the VE pump, an inline pump happily revs higher, just look at what the MB IDI builds are capable of.
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#12
by
TonyTDTruck
on 28 Feb, 2012 06:50
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Thanks for all the help. From the looks of things I can stay with the stock valves. The fuel pump is being set for max 20psi . I'm not planning on racing this truck just hoping for a bit more power. Porting the head sounds like it would improve on things, but a cam should help with the flow. Where can I find this cam? Anybody have a p/n or store? I've installed cams on gasoline engines from mild to racing cams but never a diesel. Nobody I've checked with knows of a cam for this AAZ.
Thanks
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#13
by
rallydiesel
on 28 Feb, 2012 08:54
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The 6k rpm limit is a limit given by the VE pump, an inline pump happily revs higher, just look at what the MB IDI builds are capable of.
I wonder what it would take to use a MB inline pump on a vw. Do they even turn the same direction?
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#14
by
Thezorn
on 29 Feb, 2012 20:37
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Thanks for all the help. From the looks of things I can stay with the stock valves. The fuel pump is being set for max 20psi . I'm not planning on racing this truck just hoping for a bit more power. Porting the head sounds like it would improve on things, but a cam should help with the flow. Where can I find this cam? Anybody have a p/n or store? I've installed cams on gasoline engines from mild to racing cams but never a diesel. Nobody I've checked with knows of a cam for this AAZ.
Thanks
Used to be Dr diesel on this forum, last I heard he past all his know-how onto giles who now sells the cams. try giving him an email