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Tech, Repairs, Upgrades => Capri N/A 89-94 => Topic started by: 1991---Capri---AT--NonTurbo on November 05, 2008, 11:03:00 AM

Title: Cracked Valve Cover - JB Weld It or What?
Post by: 1991---Capri---AT--NonTurbo on November 05, 2008, 11:03:00 AM

Whilst replacing the rubber valve cover seal and grommets today I managed to crack the aluminum valve cover due to over-torque...partly not my fault as the factory Service manual states ~70-95 ftlbs, which for our information is not correct. At about 14 ftlbs I heard a "crack" sound and sure enough, the aluminum valve cover cracked around the side of the bolt head area.

Any ideas?

I was considering replacing the cracked valve cover with a new un-cracked used cover from the local junkyard however I got to thinking...

Gee Whiz...the head is aluminum, all the other bolts were at about 14-15 ftlbs when I heard the "crack"...if that's the case, then the threads in the head for the valve cover bolts are most likely stripped or near stripped! Yikes! Better just JB Weld the crack now at its most open position, then while the JB Weld is still liquid, back off the torque on the adjacent bolt and evenly on all the other 10 bolts as well. Then let cure.

I'm concerned that the JB Weld may not expand and contract properly along with the aluminum valve cover once it's completely cured...you know, engine at normal operating temperature and all. From my understanding, JB Weld's characteristics act more like "Steel" than "Aluminum".

A friend swears by "Honda Bond" but never has had this particular issue pop up before. I'm used to "JB Weld." Anybody got a better idea?

I don't want to have to remove my head! Please Help!

Title: Cracked Valve Cover - JB Weld It or What?
Post by: Rocketman on November 05, 2008, 03:14:00 PM

Midco Mustang usually has a good valvecover up on ebay...and they usually have em cleaned up nice.

Should have been 70-95 INCH POUNDS not ft-lbs...just about what one might call "snug"

It would not be expensive to replace the valvecover. You may have stripped the head, you'll have to find out. Like i said you only need the bolts 'snug' you probably still have enough thread left to grab.

Title: Cracked Valve Cover - JB Weld It or What?
Post by: CapriTypeR on November 05, 2008, 07:48:00 PM

........Or I could ship you a decent valve cover for $20 + shipping!

Cougar1prod@comcast.net
---Russ

Title: Cracked Valve Cover - JB Weld It or What?
Post by: 1991---Capri---AT--NonTurbo on November 06, 2008, 05:28:00 AM

Thanks Rocketman for your correction...

Everybody take note:

The 11 Valve cover bolts are to be tightened to a torque of 71-97 LB-INCH...that's INCH...not FT!

In short, as Rocketman suggested:

About "Snug/Hand-Tight"

Russ, thanks for your offer on that spare valve cover, I may take you up on that...

Still...anybody still think JB Weld is worth a shot...or would you suggest another type/brand of "cold bond goop?"

Title: Cracked Valve Cover - JB Weld It or What?
Post by: dennis on November 06, 2008, 03:45:00 PM

J&B Weld should work.  They sell a 'fast cure' type but don't use that.

I used J&B Weld on an aluminum outboard engine about 1 inch from the exhaust port to seal a hole in the water jacket.  The J&B Weld discolored from the heat but after two years it was still holding.

You'll have to clean all the oil off to get a good seal.  When you tighten the valve cover you might crack it again so just buying a replacement valve cover is better fix.

Title: Cracked Valve Cover - JB Weld It or What?
Post by: 1991---Capri---AT--NonTurbo on March 15, 2009, 04:31:00 PM

Update...It's been about 4 months now and the JB Weld is still holding strong.

Title: Cracked Valve Cover - JB Weld It or What?
Post by: 1991---Capri---AT--NonTurbo on November 17, 2009, 03:30:00 PM

Update...It's been about 1 year now and the JB Weld is still holding strong.