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Engine Specific Info and Questions => Diesel Swaps => Topic started by: lord_verminaard on October 26, 2011, 01:16:34 pm

Title: IDI to TDI, a few questions
Post by: lord_verminaard on October 26, 2011, 01:16:34 pm

Say I have an AAZ block, and I acquire a 1z TDI head, would I be able to use ALH TDI pistons in the AAZ block?  Or would 1z pistons be my only choice?

Thanks-

Brendan

Title: Re: IDI to TDI, a few questions
Post by: 410 on October 26, 2011, 09:47:18 pm

You can use the alh pistons but there is one issue.  Since the top ring groove on the alh piston is higher than the aaz piston, the ring can catch the ring groove in the cylinder wall.  Even the ahu or 1Z pistons have a higher top ring groove than the aaz but not quite as high as the alh pistons.  If there is no ring groove in the cylinder wall or you've bored to the next size then your fine.  I'm sure you know this but you also need tdi delivery valves, injector lines and valve cover to make it all work. 

Title: Re: IDI to TDI, a few questions
Post by: rallydiesel on October 27, 2011, 01:03:08 pm

This is all assuming you are going mtdi. If you want to run an ecu, you will need a tdi block as it has the casting to accept a crank position sensor.

Title: Re: IDI to TDI, a few questions
Post by: lord_verminaard on October 28, 2011, 11:56:44 am

Awesome.  Just the information I was hoping for.  Thanks!

So rods.  Some use AAZ rods with the TDI pistons, can I use TDI rods on the AAZ block?  Since I have a set of those too that I won't need for my Scirocco TDI build.  ;)

I do plan on MTDI for the AAZ to-TDI conversion, not aiming for a ton of HP, just double what the car came with in the 1.6.  ;)

Thanks folks-

Brendan

Title: Re: IDI to TDI, a few questions
Post by: MJF on October 29, 2011, 03:31:04 am

130+hp PD rods has larger big end, so those won't fit, but all othes will.

Title: Re: IDI to TDI, a few questions
Post by: jimfoo on November 23, 2011, 07:22:55 pm

And if you don't use TDI delivery valves???

Quote from: 410 on October 26, 2011, 09:47:18 pm

You can use the alh pistons but there is one issue.  Since the top ring groove on the alh piston is higher than the aaz piston, the ring can catch the ring groove in the cylinder wall.  Even the ahu or 1Z pistons have a higher top ring groove than the aaz but not quite as high as the alh pistons.  If there is no ring groove in the cylinder wall or you've bored to the next size then your fine.  I'm sure you know this but you also need tdi delivery valves, injector lines and valve cover to make it all work. 

Title: Re: IDI to TDI, a few questions
Post by: 410 on November 24, 2011, 02:42:34 pm

Quote from: jimfoo on November 23, 2011, 07:22:55 pm

And if you don't use TDI delivery valves???

I don't know what happens if you don't use tdi delivery valves but I do know they are different.  The tdi ones have a bleed port and the idi ones are designed to leave a bit of pressure in the injector lines.  I remember reading about it in my Bosch manual but I lent it to a friend so I can't reference it right now.  The other issue is if they are a different length, so the lines don't fit so nicely!

Title: Re: IDI to TDI, a few questions
Post by: oldpoopie on December 02, 2011, 08:56:56 pm

I think I've got a set of TDI delivery valves lying around.

Title: Re: IDI to TDI, a few questions
Post by: jimfoo on December 12, 2011, 01:00:52 am

Well, I guess I have been running mine with AAZ delivery valves since '07, although my pump never has become a full M-TDI pump yet. I got a kick out of reading my original IDI to TDI thread, although it made me realize I have forgotten a lot! Well, now that the overheating is finally fixed, maybe I can slowly return to where I left off on my pump mods, where ever that was.....

Title: Re: IDI to TDI, a few questions
Post by: jimfoo on December 12, 2011, 07:25:06 pm

Good to hear. That way I have one less thing to worry about