Installed new vitreous enamel coated exhaust manifolds about 2 years / 1,500 miles ago. Followed recommended heating / cooling cycles to reduce likelihood of blistering. Also checked that car was properly tuned - timing / fuel mixture and all. Manifolds have since blistered and lost large portions of coating.

I'd like to replace the manifolds, show the car and still be able to drive it occasionally. Any suggestions would be appreciated.

Submitted by dkrolik@rcn.com on Fri, 09/20/2013 - 16:54

Sam,
I've done the job many times, but am embarrassed to admit I do it by feel and don't know of a torque figure. They don't have to be terribly tight. I would try snug, but on the lower torque side and then check periodically for loosening.
Day

Submitted by dkrolik@rcn.com on Tue, 09/17/2013 - 22:20

Sam,
That's the good and bad news. I had an XK 150 for 48 years. When I stopped driving it hard in the wet, a set of vitreous manifolds still looked great after 15 years. I've researched this pretty thoroughly and have concluded, as Michael says, "there's not much you can do" except avoid water until, hopefully, someone comes up with a vitreous enamel that will survive a bath. Some folks go so far as keeping two sets of manifolds, one for show and one for driving. I think covers under the louvers is worth a try if you want to experiment . I suspect that the louvers are
cosmetic, except perhaps under the most extreme conditions.
Day

Submitted by ssmith7000@sbc… on Tue, 09/17/2013 - 18:31

Day,

It's sure encouraging to know that, without rain, the manifolds may have a great deal more longevity. My wife, Julie and I encountered a torrential rain storm on our first trip in the E- from Indianapolis to St. Louis. That may have been the beginning of the end for those manifolds.

I would be hesitant to cover the louvers because of the considerable heat generated. I'll do my best to avoid rain.

Thanks greatly
Sam

Submitted by dkrolik@rcn.com on Tue, 09/17/2013 - 16:54

I followed the same protocol, and the two years and 1500 miles are the same for me and my manifolds from Barratt are still perfect. Unfortunately, it's water or rain on them when hot that does them in. I was able to keep my manifolds pristine for a number of years on my XK 150 by keeping them dry. Of course ÔÇô no louvers. I've heard of some people fabricating rain shields which they attach temporarily to the underside of the bonnet with magnets. So far I've just managed to avoid the rain, but this is a difficult problem.