Aaz based mtdi cam selection

[blackdogvan]

So I'm looking for educated info on this subject. There have been a few on here who have run the aaz cam in their mtdi builds, some say it's fine & others who feel there is the potential for valve contact. I'm in the final run here for mine, the aaz cam is in now & it turns over just fine, not contact. One comment I did hear was it's as near to zero clearance so it might clear by hand but make contact at higher rpm. I'm not smrt enough to know how to calculate it & adjust for timing, at this point without some concrete science I'm inclined to pull the aaz cam & run the Tdi. The benefits are mostly word if mouth so it might not even be really a huge benefit anyway... thoughts?

[410]

A fairly easy way to measure this is use some clay or plasasine.  It requires removing the head but that really doesn't take too long on our engines.  Place a small amount of clay on the piston and reinstall head.  No need to retorque head fully, 70-80% of full torque is fine.  Install timing belt and rotate engine slowly two full turns then dismantle.  You can now measure the thickness of the clay left on the top of the piston which is your clearance.  It's a bit timie consuming but relatively easy and very accurate.  If you have  .030" clearance it should be fine.  I'm running the ahu cam in my mtdi.

[Rabbit on Roids]

there are people selling TDI and IDI performance cam shafts on here in the vendors selection..

i would buy a Dr. Diesel cam tho, he is much nicer to deal with, over the other vendor selling cams and warez, who shall not be named..

[burn_your_money]

He hasn't tested his yet for a TDI has he?

If you are using the clay idea I think it would be a good idea to spin the oil pump while turning the engine over to make sure that the lifters are fully pumped up

[Rabbit on Roids]

oh yea, he has only done IDI testing with that camshaft hasnt he?

but if you can use a AAZ cam with a Mtdi, why wo... never mind, im just gonna answer my own question i guess...

the Dr. Diesel cam is an improvement over the stock AAZ.. so it probably has more lift, and more chance for bending a valve.

[oldskool rich]

havent read the whole thread so forgive me if im repeating

my big power 1Z is running a brand new AAZ cam, its runns fine and is very fast, however after 10k it dropped a valve which killed the block, head and piston, after we took it apart we found the vales had hit every piston, i believe at high RPM the valves hit, which isnt a massive problem in the short term but eventualy one will snap. we are now going ALH for a stronger block and we have machined 1mm out of the valve resses on the pistons to stop them from hitting

ive also done the same on my own 2.0 BKD VE project

[MJF]

Rich: what valvesprings?

[oldskool rich]

stock, sheet never thort of that tbh, can you recommend any?

audi 5 pots have 2 spings per valve, wud that work?

[MJF]

Stock dual springs are a little better. At last time I used 1,9 outer spring with 1,6 inner, thatīs a little stiffer than stock duals. But I need stiffer than that, Iīll order a set from Rosten Performance. 8v gasser performance springs will fit.

[Rabbit on Roids]

Stock dual springs are a little better. At last time I used 1,9 outer spring with 1,6 inner, thatīs a little stiffer than stock duals. But I need stiffer than that, Iīll order a set from Rosten Performance. 8v gasser performance springs will fit.

they make some stiff dual spring sets for gassers too!

[theman53]

havent read the whole thread so forgive me if im repeating

my big power 1Z is running a brand new AAZ cam, its runns fine and is very fast, however after 10k it dropped a valve which killed the block, head and piston, after we took it apart we found the vales had hit every piston, i believe at high RPM the valves hit, which isnt a massive problem in the short term but eventualy one will snap. we are now going ALH for a stronger block and we have machined 1mm out of the valve resses on the pistons to stop them from hitting

ive also done the same on my own 2.0 BKD VE project

I have talked to a guy that makes cams and the opening and closing ramp of camshafts is critical. He told me if you are making a cam or swapping one from one to another be very picky about that. His cam on one of his gassers he had made is VERY hot, but they figured it will not last 50,000 miles without dropping a valve and killing the piston. I am only bringing this up because you have said that it happend to you and if you never found out the cause of it then this might be worth checking into.

[oldskool rich]

so is valve dropping a result of being too hot?

i will happily spend money on a cam if anyone can tell me what spec will be rappid and reliable

[theman53]

I think he was meaning the ramp angles being too steep when he said hot.

[blackdogvan]

Well it was ran for 2 min on the floor before the pump went to Giles, I'm going to pull the head & have a looksee when I change the cam back to the ahu cam. Report back then even tho it's not really enough to go on.

[rolo]

Built an aef/ahu mtdi with new aaz cam. Had alook after about 200 miles as it would rev past 5. inlet valve contact on 2&3. Measured lobes IDI cam 0.6/7mm more lift, replaced ahu cam.  --Rich, just picked up an alh for the pistons, you reckon its a stronger block than afn? Got acouple of early 1.9 girdles on the way will one fit the alh?