When people talk about filling a block, they talk about using the concrete-like products on the market. To me, it seems like concrete isn't the best material to use because it's less dense and probably not-too-flexible.

I would have to imagine that somebody makes an epoxy that would be stronger, more flexible, and would expand at a rate closer to that of iron, and would be nonporous, unlike concrete. Best of all, it wouldn't take a month to cure.

Am I missing something?

 

I suppose the only people who know are those who have tried it. But I would answer your question with a question: on what basis do you think that epoxy "would expand at a rate closer to that of iron"? Also, the stuff that is used is not porous, at least that I can tell. Always good to try to think of something better, but unless it has been tested we are just speculating.

Rich

 

Yep Devcon works pretty well for this. Rich knows something about that.

bret

 

That's true. I must confess to doing a little advocacy for the devil. I have used a couple of different Devcon products for block related repair. The one block ended up as a partial fill job, but the original intent was to plug a leak. If it weren't a leakage issue I would just use one of the regular "concrete" type block fillers as they are a lot cheaper and proven.

This product http://www.devcon.com/devconfamilypr...124.0&catid=34 can be very useful, but it too thick to fill a block with and far from inexpensive. This stuff http://www.devcon.com/techinfo/108.pdf can be used as a fill.

But as to any advantage over the other stuff??

Rich

 

We've had some unpleasant experiences using epoxy materials for fill. In some cases the epoxy has had a tendency to separate or to lose contact with the cylinder walls. When that happens the cylinder goes severely out of round and can be the beginning of serious problems with the piston/wall relationship. Of course, perhaps we didn't do the mix and fill process correctly with the epoxy. Since there haven't been the same problems with the powder/water type fills I tend to go with a priority system: that which gets the job done, that which is simplest to use, that which is least costly.

 

Maybe I'm missing something. I thought the idea of a block filler was to stiffen the thing to keep things like the cylinder walls from flexing and making them think they are part of a billet block (no water passages at all).

If I had to fill a block because I couldn't or wouldn't use a Bowtie or good aftermarket block, I'd like to fill the water passges with cast iron, but since that's not practical, something stiff with a lot of solids seems to be the next best thing. Epoxy doesn't appear to be the best.

As far as thermal expansion goes, block temps run about the same as cooling water temps, so that's maybe 150* F above normal room temp. Not a huge expansion problem. Look up concrete and cast iron coefficients of expansion (COE). You might be surprised.

FWIW, by the time most well built engines get to run in anger, a month from block fill day probably has elapsed. You do fill before block machining, right?

My $.02

 

Well I've never been afraid to step on it, so here goes.
Back in the day, before there were bowtie and after market blocks, I seem to recall filling the dragster motor with some Aviation type epoxy stuff. So how long has this concrete filler been around?

 

Forever.... makes me wonder how long you've been around!

Just busting on ya.

 

I would think the epoxys would be more expensive and from what I've seen thicker and harder to fill a block with. The concrete would be cheaper and easier.

 

Don't think we want to go there. You know what they say about memory being the second thing to go. This was back in the early 70's, and I wasn't the one who did it, so I'm probably wrong. The second hand dragster was almost as old as I was at the time.

 

Youngster!

What's the first thing to go? I forget...

Nope, not that.

The answer is probably the same one as for the question: "What's left on the floor after a good bar fight?"






Answer: Teeth, hair and eyeballs.

 

[QUOTE=rskrause]That's true. I must confess to doing a little advocacy for the devil. I have used a couple of different Devcon products for block related repair. The one block ended up as a partial fill job, but the original intent was to plug a leak. If it weren't a leakage issue I would just use one of the regular "concrete" type block fillers as they are a lot cheaper and proven.

This product http://www.devcon.com/devconfamilypr...124.0&catid=34 can be very useful, but it too thick to fill a block with and far from inexpensive. This stuff http://www.devcon.com/techinfo/108.pdf can be used as a fill.


So is this stuff best for a block repair? Whats the proper way to do it?

I just had a machine shop fix a whole in my water jacket. They said they have done it many times. It looks like they braised it. I was told for extra insurance to put about 1" of block fill in But I've talked with a few people who have had this fail.

I don't really want to lose this block since it's all ready to go.

 

If it's already patched, use fill for reinforcement. If you want the technical info., call Devcon. That's what we did. I can't say I remember the detials other than that it was winter and it was difficult getting the block warm.

Rich

Rich

 

Thanks

Have you repaired very many blocks and have you had any fail?

 

Sucess with 2/3. What I meant in my previous post: if it's already patched, just use regular bllck filler to reinforce it.

Rich