Cracked block question RV8 3.9...

Blackflag533 · Post by **Blackflag533** » Thu Jul 07, 2011 10:07 pm

Evening all,

Just filled up the cooling system on the car to find all the hose joints nice & tight, but an unhealthy flow of water out a crack between the two core plugs on the right hand side of the block.

Silly question time: is ally welding an option or am I digging the 3.5 out and putting that in instead...?

Thanks in advance.

davemgb · Post by **davemgb** » Thu Jul 07, 2011 11:29 pm

Alloy welding is probably more of an option than a similar repair on an iron block but if there is a crack externally then what chance of other defects in the block casting?

Is the crack between the forward or aft pair?

Dave

DaveEFI · Post by **DaveEFI** » Fri Jul 08, 2011 7:47 am

It's a strange place to crack? Any chance it froze up in the last hard winter?

I'd be inclined to try JB Weld. Not much lost if it doesn't work.

Blackflag533 · Post by **Blackflag533** » Fri Jul 08, 2011 8:01 am

Cracked horizontally between the forward pair.

The car sat inside without any coolant in it over the winter but there would have been something remaining in the block.

unstable load · Post by **unstable load** » Sun Jul 10, 2011 7:10 am

Strip it down, have it chemically cleaned and then give it a good look over for internal damage, maybe even a dye penetrant check. If it looks good, clean out the crack and JBWeld it from inside and out and you should be good to go.

JSF55 · Post by **JSF55** » Sun Jul 10, 2011 7:49 am

I've had one cracked block repaired by welding, this was between the rear pair and that was fine, i had a similar smaller crack on my last 3.5 and added kalimex. Worked the rest of the engines life including be thrashed up the strip and saves pulling the engine out !
http://www.kalimex.co.uk/index.html

bigaldart · Post by **bigaldart** » Sun Jul 10, 2011 6:34 pm

We fixed one of the rear wings back on the block after the flywheel spacer let go and blew it off. Cut a piece from a scrap block and glued it in place using perforated metal and Belzona. Belzona is expensive but will do a great job as long as you clean everything thoroughly. I would have no qualms about welding either if I had the facilities.

Alan

Blackflag533 · Post by **Blackflag533** » Tue Jul 12, 2011 12:24 pm

Thanks for the replies all.

I'm going to clean it up and use some sort of two part to seal the crack.

And, i'll let you know how it holds (or not)