Why would Gil Manifolds crack?
 

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I need one more set of Gils to complete the parts list to fit two BBCs into my 28' Checkmate. I found these on eBay, and wondered why they would crack in the first place?

Is this normal for Gils?Anybody had this happen to them?
http://cgi.ebay.com/ebaymotors/ws/eB...ayphotohosting

That is a common problem I have had several of our engines full of water over the years with cracked manifolds. If you look at that picture of the manifold you listed it was already repaired on the inside. It looks like bubble gum on there.

I've seen more than one set of Gils fail in that area.

I would look for some stainless marine manifolds.

http://cgi.ebay.com/ebaymotors/STAIN...QQcmdZViewItem

Thanks for the advice, but next time. I've invested in Gil for tails and one set already, otherwise I'd by these from Bad Enough.http://www.offshoreonly.com/forums/s...d.php?t=175626
Here in Ontario, the most common reason for cracking is frost - typically water left in the exhaust maifolds and freezes over the winter.
Do Gils (or any cast) have have a habit of cracking? What stress causes this? The weight of the risers vibrating?

I had two manifolds crack/leak in that area. Don't know why. I still have two sets of old manifolds that I will part out for much less than the ebay add. Maybe shipping plus 100 or so. I will ship the best pair. If you are going to take a crap shoot on old Gils at least get them cheap. I bought new ones from Douglas marine. PM me.

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PM away to Thunder - thanks. Merry Christmas.:cheer:

My Merc/Gil manifolds cracked in the same place.

I lost a motor in my old Fountain because of a failed Gil manifold. Cracked in the same place.

Any idea why? And from the eBay posting it looks like the crack is on the engine side, running on a 45 angle down from the flange...
Must be the stress from vibrating those risers.. anybody ever braced the risers? Anybody cracked Gils while running the Silent Choice pipsqueak, snub risers?
Too bad, as they look like a good option for aftermarket marine exhaust. I'm still going ahead and installing them because of the parts I've already paid for, but I am disappointed they have this reputation.

You live and learn...:mad:

I bought 2 sets used that had beenrun in salt. 1 cracked in the same spot the second year I ran them. I had it fixed and have had no more troubles in 3 years. Irun in fresh water.
I wonder if salt or fresh water makes a dif.