262's 85 Fiero SE LX9 F23 swap thread lots of pics

[ericjon262]

quick update, did a pneumatic test of the cooling system, went to 22 PSI, and was at 20 PSI in 2 minutes, took about 23 minutes to go from 22 psi to 12 psi. not sure how much (if any) was test rig leakage vice system leakage. I'm going to fill the system, and start the car to see how quick pressure builds, if it immediately jumps, probably the headgasket, if it doesn't, probably not. . If it doesn't point towards that, I'm gonna back the car out of the garage, clean the floor, and lay down some paper, refill the system with water and dye, and re-pressurize to see if I can pinpoint a leak location.

radiator cap tested fine, so that can be checked off the list.

[ericjon262]

well, the aluminum fill/thermostat housing performed about like I thought it would, just not as good as I hoped... leaked like crazy. 1 pinhole leak from a weld, and from the entire cap. I either warped the cap, or it's cheap junk I'm guessing its a combination of the 2. I reinstalled the neck I had with a bleed, and finished a high point fill that fills at the suction of the water pump, much more discrete, and should be just as effective. I took it for a spin again, seemed to still want to overheat, not as bad. I'm going to pull the rad and inspect for foreign material or signs of clogging. as well as try to flush out the cooling tubes and see if anything comes out.

[Xnke]

Another no-no for aluminum is autogenous welding-don't do it. It might look like it works but you ALWAYS have to add filler rod to get a strong joint.

[Will'sFiero]

A grinder and flapper wheels are not the best choices for prepping aluminum for welding. Aluminum is soft and when using those types of item will actually roll the dirt into the metal. It is better to use stainless wire brushes, files and carbide burrs. A mild acidic cleaner can also help. Also as you noted, a pre-heat sometimes helps.

Ditto on the stainless wire brush. I was going to suggest that. Also, set your SS wire brushes aside for aluminum only and do not use them for anything else. I keep mine in a big ziploc bag to keep it clean. (I'm not yet a welder, but when I prep a piece of aluminum for welding, I like to be able to to it right).

[Xnke]

Best is to file it down to get the cast finish off, then clean with a stainless wire brush that you only use on aluminum. Don't use that brush for anything but degreased aluminum, and once you brush it, do the weld within an hour or re-brush it.

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[45es]

No particular brand of cleaner although the citric acid based cleaners can and do work well especially with the degreasing. For something more aggressive, check with your welding consumables supplier. They should have something on the shelf. A final rinse (and dry) with clean water also helps to remove any residue the cleaning agent my leave. As Xnke noted, clean both sides of the parts.

When welding aluminum, I can not stress how important cleaning and joint prep is. Case in point, I remember mig welding a part for the Navy. I didn't notice a spot of dirt about the size of a pin head that was in the weld joint area. During welding when I came to that spot, the weld puddle literally split apart and recombined as I moved past that spot. I had to cut out the weld and spot of dirt to repair.

[ericjon262]

thanks cor the tips. I'm a bit new to aluminum. the advice makes sense. got a cleaner you would recommend?

[45es]

the outside was worked over with a grunder and flap wheel, inside was bare as cast. next time, I'll try cleaning the inside as well, thanks!




LOL, busted... didn't do it on purpose. I really need a small welding table, trying to control a foot pedal standing at the bed of my truck, and trying to keep the work piece where I want it can result in unexpected movement...



it'll be easy to spot if it's there. thanks.

I think the only thing that wasn't mentioned that would have also helped. was a mild pre-heat.

A grinder and flapper wheels are not the best choices for prepping aluminum for welding. Aluminum is soft and when using those types of item will actually roll the dirt into the metal. It is better to use stainless wire brushes, files and carbide burrs. A mild acidic cleaner can also help. Also as you noted, a pre-heat sometimes helps.

[ericjon262]

Scrub that aluminum down better next time-it's cast and so it's gonna come up dirty like that but you can get it cleaner. Take a file and remove the sand-cast finish from the surface, both inside and outside, and it will help considerably.

the outside was worked over with a grunder and flap wheel, inside was bare as cast. next time, I'll try cleaning the inside as well, thanks!

Also looks like you've dipped the tungsten

LOL, busted... didn't do it on purpose. I really need a small welding table, trying to control a foot pedal standing at the bed of my truck, and trying to keep the work piece where I want it can result in unexpected movement...

Those welds may be fine, but a lot of times with dirty aluminum it'll seep through the porous weld over time. If you have a mysterious coolant leak in the future, you might find it there.

it'll be easy to spot if it's there. thanks.

I think the only thing that wasn't mentioned that would have also helped. was a mild pre-heat.

[Xnke]

Scrub that aluminum down better next time-it's cast and so it's gonna come up dirty like that but you can get it cleaner. Take a file and remove the sand-cast finish from the surface, both inside and outside, and it will help considerably.

Also looks like you've dipped the tungsten

Those welds may be fine, but a lot of times with dirty aluminum it'll seep through the porous weld over time. If you have a mysterious coolant leak in the future, you might find it there.

[ericjon262]

depends, how much external circuitry do you want to deal with? with limited inputs that can read period and pulse on-time measurements, I would suggest just the MAF be used for it. if you wanted flex-fuel capability, I would run its signal through a frequency-voltage converter to make a 0-5V signal that could be read on a plain a/d input. wouldn't be able to read fuel temp, but that seems less critical.

sounds like a plan.

[robertisaar]

do you think it will be possible to integrate MAF, and flex fuel? or is it going to be a one or the other type deal?

depends, how much external circuitry do you want to deal with? with limited inputs that can read period and pulse on-time measurements, I would suggest just the MAF be used for it. if you wanted flex-fuel capability, I would run its signal through a frequency-voltage converter to make a 0-5V signal that could be read on a plain a/d input. wouldn't be able to read fuel temp, but that seems less critical.

[ericjon262]

Cool. Do yourself a favour though and add a support bracket from the rad cap fitting to the head or front cover, so that when you push down on the cap too install or remove it, you won't break the thermostat housing.

it's a good idea, but I think I'll just put my other hand under it while I do it. and if I break it... I'll weld it up again.

[ericjon262]

assuming my new job doesn't keep kicking my ass, I may finalize MAF support for both the nAst1 and P66 V6 projects at some point.

do you think it will be possible to integrate MAF, and flex fuel? or is it going to be a one or the other type deal?

Cool. Do yourself a favour though and add a support bracket from the rad cap fitting to the head or front cover, so that when you push down on the cap too install or remove it, you won't break the thermostat housing.