Can I mig weld my pitted exhaust plate mating surface

[Bigabe82]

Hey guys, new here and really love this site! First off, The motor is a 1998 force 120 outboarb 4 cylinder two carb. I have searched and searched, but to no avail, for the probability of mig welding(have a lincoln promig-140 w/spoolgun ) the exhaust plate mating surface which I have dang near completely decimated(with my other welder):redface:. I decimated it by utilizing the mig approach to removing a broken tap. It took 8 sessions of building up the weld!! I take photos and videos of everything I work on so I'll attempt to attach at least one photo. Now with my first post kicked off, I can't wait to contribute any hard lessons learned and try to give back. If y'all want to see video, let me know. And thanks in advance for any time invested into reading and replying....

Well it's telling me that the file is to large :facepalm:

I'm going to go ahead and post and try to figure out how to make it smaller


I got it!! Pic's up! Had to chop it down drastically

 

[CharlieB]

Re: Can I mig weld my pitted exhaust plate mating surface

Ouch!

The damge is already done, so now you just have to repair it. Take your time and be sure to keep the heat under tight control. Fill in only what is necessary and file/machine to a good flat surface, redrill and tap using the cover as a guide to maintain your center.

Sounds like you know what you are doing, just need a bit of encouragement to reinforce your plan.

I'd say 'Good Luck' but luck has little to do with it. Patience, welding skill, steady hands, will get it done.

 

[Bigabe82]

Re: Can I mig weld my pitted exhaust plate mating surface

Sir I am 28 and at an age where still I need to keep an open ear. Thanks! Just wasn't sure if it was feasible. I've heard of building up the surface with several "chemicals" that mix and harden(which I've used on several applications, none like this) but nothing beats metal melting!! So just tack it up and sand it down huh? I'll do It and report results. Thanks again!

 

[sschefer]

Re: Can I mig weld my pitted exhaust plate mating surface

Heres the trick with that junk cast al. You have to get it really, really clean. As clean as if you were going to TIG it. Hit it with a map gas torch to bring the oils and dirt to the surface and then clean them off with Acetone. Tacking cast Al with MIG is tricky because you go in cold so make sure you pre-heat to 200 degrees. No more than that though. You won't be doing an actual tack but rather a short weld and you'll come back over the top at the end to avoid crater crack. The preferered method would be TIG with a 50ar/50he mix (aka heliarc).

 

[Bigabe82]

Re: Can I mig weld my pitted exhaust plate mating surface

Well I did exactly that and it came out great. Just didn't use tig. Now its time to see if all of this worked. I started with 16 of 27 bolts broken on the chase of a water fouling problem. Now I have 27 threaded holes. Thanks for the advice fellahs!! I will post results as soon as gaskets and plate arrive tomorrow. The pictures I'm loading are of the hole before after and the old exhaust plate crack.

 

[Bigabe82]

Re: Can I mig weld my pitted exhaust plate mating surface

Well guys, I finally did it! I initially did not get the welded one right. I was forced to pull it back apart, remove the helicoil and insert a new one that was seated correctly. The weld held up fine but the coil wasn't seated from the beginning.Now its on to the real problem(as if losing my rear on $300 for 8 DAYS and 16 snapped bolts isn't enough!!). The cylinders were being water fouled and I did find the cracked exhaust plate. So, a cracked exhaust plate wil leak water back into the cylinders, correct?

 

[j_martin]

Re: Can I mig weld my pitted exhaust plate mating surface

If a crack lines up with an exhaust port, it can shoot some water into the cylinder. Happens on V6 mercs all the time.

 

[Bigabe82]

Re: Can I mig weld my pitted exhaust plate mating surface

If you click that photo I have, you can see that the largest chamber is the main exhaust port for all cylinders. It was in this chamber, around the 2nd cylinder height, that this three and a half inch crack formed. Would that water foul every cylinder? I thought that it would but my ears are open. And thank you for the reply! I've seen quite a few of your posts for the past year and a half!

 

[79Merc80]

Re: Can I mig weld my pitted exhaust plate mating surface

This really should be in the Force/Chrysler forum. A Force engine is NOT a Mercury engine.


********************************MOD's, Please move to the Force/Chrysler Forum. Thanks.***************************************

 

[Bigabe82]

Re: Can I mig weld my pitted exhaust plate mating surface

Still uses quite a few parts from the mercury's. Mercury built this motor. It's a MERCURY FORCE and there wasn't a category for it. I chose this one. It truly is funny how much this seems to itch you. If it needs to be there, it needs to be there.