Welding Aluminum Block

**leon phelps** · 12-14-2009, 04:21 AM

Hello,

I recently bought a LS1 with a rod through the block. The engine was running and was shut off as soon as the bang. It was being revved by the previous owner. I have not disassembled everything, but am thinking of trying to weld the hole myself.

The hole is 1"x2". You can see it is in a window only and nothing too involved. I have welded aluminum before. I was figuring on getting a piece of flat stock 1/4" and making a patch to cover the hole then welding the perimeter of the patch to the block. I can weld it from both sides, since I will probably take the complete engine apart.

I have a Miller Spool gun for mig welding. I have read a few cases where people have even epoxied patches in with success.

Being an intermediate welder, do you think I would be biting off more that I can chew with this? The way I look at it, if I fail then no loss because the block would need to be replaced anyway since it would cost the same as a block to fix.

Any suggestions or resources would be appreciated.

**Smittro** · 12-14-2009, 04:33 AM

I think you may have issues with welding non-cast plate aluminum to cast aluminum. Not worth messing with IMHO. The entire block structure maybe compromised after that type of damage as well..

**Skippy** · 12-14-2009, 10:40 AM

Aluminum doesnt respond to welding like steel. You can weld cast to forged with no problem. The main problem youll have is getting all the oil out of the block. When it comes to welding aluminum cleanliness is key. I would say try it and then have it checked by a machineshop, like you said what do you have to lose?

**pajeff02** · 12-14-2009, 11:14 AM

We've welded up lots of stuff through the years -- sometimes it works, sometimes it does not. I think that with all the labor and expense that goes into assembling an engine that the potential for further problems outweighs the benefits of a repair in the manner you wish to attempt. Let us know what you do though as I am curious.

**Smittro** · 12-14-2009, 11:28 AM

Originally Posted by Skippy

Aluminum doesnt respond to welding like steel. You can weld cast to forged with no problem. The main problem youll have is getting all the oil out of the block. When it comes to welding aluminum cleanliness is key. I would say try it and then have it checked by a machineshop, like you said what do you have to lose?

I do metal fab for a living but I've honestly never mastered aluminum so I don't mess with it unless I have to that's what employees are for lol.. My biggest concern realy would be structural integrity of the rest of the block after a failier such as that.. To each their own I guess..

**Skippy** · 12-14-2009, 11:41 AM

I do fab work as well and have spent many years welding alum. The structure on the block is around the outer edges of the windows. Its kindof like a top alky drag block. They are designed to knock out a window if a rod fails. Sure you can kill the structure if you weld it wrong but hey, the block is junk now so he cant make it worse. The least he will get is a little practice welding alum. Thats why I suggested getting it checked after repair, to insure it wasnt overheated when it was welded. Thats just my views on it though. I dont wanna push anyone in a direction they dont wanna go. As long as the none of the stiffening ribs on the block got damaged it SHOULD be ok. I wouldnt build alot of HP with it, but for a driver or bolt on car I dont think there should be an issue.

**TransAm11973** · 12-14-2009, 12:28 PM

if you do try to weld it, good luck to you, and try to keep the ground as close to your weld area as possible

**Hi-Po** · 12-14-2009, 12:36 PM

My Opinion,

A LS1 block goes for anywhere between 150-350 bucks. Obviously, when you get the welding done, your going to pay someone to check it out correct? At a shop charge of 80-90 dollars, I would add that towards getting a nice, used block. Then you still, Have a block that was once very badly damaged and was band aided back together. So you spend at least 1000+ dollars on a rotating assembly, plus money for heads and hardware. What if that spot is weakened ( Not really what if, its... How much is it weakened? ) and the block lets go again, ruining all this money, time and effort again.

IMO, saving 250 bucks is not worth that slight chance of it letting loose again. Hand it in for scrap metal so we can all have more Pepsi cans to drink out of.

**leon phelps** · 12-14-2009, 01:33 PM

Why would I pay to have it inspected if it is in an area where only oil and exhaust gases are? A rod went through the part, not anything that is critical.

I have been looking for a block for a couple weeks. Have not seen any that cheap or else around.

**Hi-Po** · 12-14-2009, 01:39 PM

Originally Posted by leon phelps

Why would I pay to have it inspected if it is in an area where only oil and exhaust gases are? A rod went through the part, not anything that is critical.

I have been looking for a block for a couple weeks. Have not seen any that cheap or else around.

Your not looking hard enough then. In 5 minutes I have this,

LS1 Block

Another LS1 Block

Another

Another

**Hi-Po** · 12-14-2009, 01:43 PM

Another

That one is 450, and still for sale. Obviously its overpriced slightly.

Another

Thy are out there. I wasnt telling you what to do what so ever. I was just putting my opinion in on the subject, and I hope every thing works out for you whichever route you decide to go.

**TransAm11973** · 12-14-2009, 03:49 PM

Originally Posted by Hi-Po

My Opinion,

A LS1 block goes for anywhere between 150-350 bucks. Obviously, when you get the welding done, your going to pay someone to check it out correct? At a shop charge of 80-90 dollars, I would add that towards getting a nice, used block. Then you still, Have a block that was once very badly damaged and was band aided back together. So you spend at least 1000+ dollars on a rotating assembly, plus money for heads and hardware. What if that spot is weakened ( Not really what if, its... How much is it weakened? ) and the block lets go again, ruining all this money, time and effort again.

IMO, saving 250 bucks is not worth that slight chance of it letting loose again. Hand it in for scrap metal so we can all have more Pepsi cans to drink out of.

i would say this is the best opinion I have read so far.....Hi-Po has some good words

**Skippy** · 12-15-2009, 08:09 PM

Wow, I never searched to see how cheap an ls1 block was. If it were me Id buy a diff block. You could weld all over that one for practice.

**leon phelps** · 12-20-2009, 02:38 PM

Well, the latest news is that the block was junk anyway. There was a hairline crack on the corner, I am guessing from vibration before the rod let loose.

Thanks for the advice guys. I think I am gonna get a complete power plant now.