1.6 cy TD bottom end 1.9 aaz head project

[NintendoKD]

In respect to rebuilding the head, I may need a number of things we will have wait and see, gonna pick up the block today, pics to come soon.

[NintendoKD]

will a fuel cooler from a 300 HP blown turbo v6 detroit diesel work as an oil cooler for our cars?  It's made by "Behr" sp? and is all aluminum  these units have been removed because of an upgraded part modification to the motor.  In case you are curious they come from a military lav's engine and have been just thrown away.  Not adequate for a V6 but adequate enough for us I wager.

edited for content now reads 300 instead of 30

[Rabbit on Roids]

will a fuel cooler hold up to 200 psi? if it will, why not use it.

[maxfax]

I would also try to find out how much flow they are rated for..   Restrictions in the oiling system = Boom...

[NintendoKD]

I don't think that restriction will be an issue because I am using a dry sump system, and extra pickup pump.  Also, if there was a restriction of any kind, I think that the 300 HP v6 would likely not run at 300 HP under load, and lemme tell you something about the vehicles they are in, they weigh at least 12 tons plus armor, plus personell, plus gear.... need I go on.

[Rabbit on Roids]

yea, but you are using a FUEL cooler. they never cooled oil in there intended use. and 300 hp worth of diesel fuel doesnt take much flow. now that i think of it, it very well could be too restrictive to be useful for an oil cooler.

[NintendoKD]

hmmmmmm...... good point.  seen the passages on the inside didn't look too restrictive, but...... you're probably right.

[NintendoKD]

Ok, so I have a question, how do I go about welding an aaz cast aluminum head?  I have been told that I need to have a rod with the same mixture of aluminum as the cast does, how do I find that out?  Where can I get said rods?  I know what has to be done to repair just not sure if it will work, and everyone tells me that It's a tossup 50/50 at best maybe Arb would know.  I will have to heat the head to about 450F and then weld it with a special rod, then heat it back up to facilitate good heat distribution, wrap it in a blanket and let it cool in a wind free place.  I have also been told that I will need to prep the head before surgery, as in taking out the precups and the valveseats and cutting the cracks to find the roots, and thats is where the weld should start.  I lack the skill to do that kind of welding, and a lot of knowledge is missing as well.   It just kills me, I wanna know how, and I wanna do it.   Anyone out there can help me, I'll PM Arb.

Thanks,

Kevin

[arb]

Hi Kevin, thanks for the PM. Are you looked to weld these cracks just to see if you can ? I agree with some of the others, I would not use this on a daily drive if I didn't destroy it welding it, and it could be resurfaced. This head looks abused. Those cracks look like some might breach the coolant jacket, all between the valves looks rather deep too. The problem with a crack is if you can't repair it all the way in, it will become a stress raiser and likely return. Now we get into the problems with welding them. Yes, all aluminum welds better if you preheat it. The problem with preheating this head design, is every time you heat a part close to the austinite state (spelling - its when the crystal boundries dissolve but it is still sold. )
You can look up the specs for cast aluminum if you know the alloy - different for each flavor. Any way, at the elevated temp, the part WILL distort. When I was a machinist, we always did the heat treatment before the final machining operations otherwise it would not be to spec, the problem with this head design in this area is the head is the bearing for the cam, so if that distorts the line bore of the cam in the head, you can't easily have it line bored and use over sized bearing backings like some other engines.

Another problem with welding between the valves is they go deep and to the valve seats. You don't want that steel alloy dissolving into your molten aluminum when you are welding. Al - Fe is not useful for anything I know of. I've never tried to replace these seats as they I've never seen them bad enough where I couldn't cut them. If you can pull them, just as welding at the precup you'll have to have the bore of the seat and precut machined as the metal will flow a little into the bore. It can be done but you might make it too big for the seat / precup, but to get the weld deep enough  you really need some heat, and that will certainly distort things locally. The nice thing about TIG is you don't need those special rods and you can concentrate the heat very locally and w/o the preheat.

The bad thing about those special rods and stick welding is you don't have nearly the heat control as TIG.  So, I'd only go to all this trouble if it was to see if you can and to learn new skills. Still, I would not use it as a DD.
-dave

[NintendoKD]

I believe that maxfax is the one with the welded block with copious amounts of JB in it as well, although I also understand that this is a cyl. head, and not a block.  I like what someone said on his post "it takes a great person to know when to cut their losses and just get a new one, but a much greater person to endeavor and repair what most would deem unrepairable..... or something to that effect" I will not be using this as a daily driver, and it will be pressure tested before all is said and done.  Point taken, mig is the way to go to fix this, I'll be sure to post the results here.  My trusted Machinist is doing the work, not me.  This is the reason why I wanted to ask the oldest and wisest of all of us, I got this head earlier and the money was refunded, as opposed to selling it for aluminum scrap I think I'll give this a try, could be fun, and a good leaning experience.  It will not be installed in a daily driver, and is "just for the hell of it" thing.  Thanks ARB, and everyone else who contributed.  Should I have the valve seats replaced? or can they be reused?  I am replacing the valve guides, they have quite a bit of slop, where can I get those for the AAZ?  I also need new freeze plugs, valve stem seals, and injector seals"unless they are universal"  I am currently looking for 1.6 turbo injectors, or someone that wants to swap for some REALLY! CLEAN! AAZ injectors.

Kevin

[maxfax]

If I had to pay someone to do all that work that cracked engine would have been scrapped, end of story.. If you're not sinking big bucks into it, weld 'er up and see what happens..  I wouldn't worry about getting any parts for it till it's pressure tested though... 

 AS far as your valve seals, it may be best to just get an engine gasket set..  These typically do not come with a head gasket, but it'll have everything else, including valve seals.. No sense in buying them twice..   The Freeze plugs are just plain ole 36.5mm (?).. Available at most autoparts vendors..   I'm sure one of our vendors on here can get valve guides, I typically just them from my machinist since their  doing work on the head anyhow ..  Make sure to measure your valve stems..  Rare that I've seen those wear, but it could happen...

Do you still have your 1.5 injectors??   IIRC I've heard they can be rebuilt to turbo spec, but you'll need access to a pop tester... Otherwise I think I still have a set from an '84 TD jetta laying around here somewhere..  They'll be dirty, and will probably need rebuilt.. 

[NintendoKD]

max fax, you don't want to trade for a set of awesome aaz injectors??  Good to know, I'll go ahead and order both, so that he can put them in.  He will plug the return oil passage too, to recap that is weld cracks, install return oil plug, resurface, pressure test, install new valve stem seals, valve seats, and valve guides, all for about $300.00 not bad huh?

[macka]

Kevin, 

  I've seen a welded up block running. It was a stovebolt 6 IIRC, and it was welded up in 60's, and has been running since. It has to be done right, or its a waste of time and money. A good welder can do miracles with metal.

[NintendoKD]

Now this is where it gets complicated, I want a lower gasket set, because I have the 1.6 bottom end, and I want the upper gasket set because I have the aaz head.  Where can I get the upper gasket set?  Any aaz owners to chime in here?  I don't plan to use this head for the build but it will kill some time till the newer one gets here, and give my machinist time to see what this thing is, before he sees the other one.

[arb]

... "This is the reason why I wanted to ask the oldest and wisest of all of us..."
Kevin

:-)  Thanks Kevin, as my recently departed Dad used to tell me - "Its HELL growing old" and since I was born at the begining of the 1960's I guess I'm older than many on this forum :-( or is it :-P ? Anyway, point being since its not your DD and you are not paying big bucks to the machinist, Best of Luck and  look very much forward to hearing how it went. Like I said, I have never had to replace a valve SEAT on one of these heads, so I have no advice on if you can reuse them.

-dave