My MGB has never suffered from overheating problems and I have not found it necessary to fit an electric cooling fan. The engine temperature gauge does creep up when moving slowly in traffic, but does not go much above 190 degrees F, even on a hot summer’s day. However, when stuck in traffic my MGB can be difficult to drive as the engine gets “lumpy” when crawling along. But when the traffic clears a little and I can speed up, normal engine running quickly resumes as fresh cooling air enters the engine bay.
My thought process leads me to think fuel was vaporising in the carburettors when stationary in traffic. The carburettors sit directly above the hot exhaust manifold, and when stuck in traffic on a hot day, there is little air moving through the engine bay to dissipate the hot air from the exhaust system.
With this in mind I researched ceramic coatings for exhaust manifolds, which claim to reduce heat loss from the exhaust system and protect surrounding components. The ceramic coating process is a spray-on finish that’s infused with heat-insulating ceramics. It is not something that can be done at home and requires the manifold to be sent away to a professional.
Good used manifold purchased ready to have ceramic coating applied by Zircotec
I found a good used exhaust manifold so decided to have it ceramic coated, with the aim it would reduce under bonnet temperatures and improve engine running in traffic. My hope was this would reduce any fuel vaporising in the carburettors. There are other advantages of ceramic coatings like more power, which is a consequence of hotter exhaust gases inside the manifold, which then expand and want to escape more rapidly through the exhaust. But more power was not my primary aim.
To get advice and support I contacted Zircotec to see if they were willing to apply a ceramic coating to a MGB manifold. Daryl Butler, from Zircotec, was extremely helpful and advised a finish that would match the factory cast iron manifold finish from the factory. Incidentally, Zircotec are based on the old MG factory site at Abingdon, Oxfordshire, UK.
Zircotec required the removal of the old studs from the manifold. A lot of heat was applied to get the area around each stud cherry red before attempting to remove the stud. Even with heat, stud removal proved a challenge as 2 out of the 6 studs broke off. The 2 broken studs then had to be drilled out. Fortunately, no threads in the manifold were damaged during this process. Once the studs were removed the manifold was sent off to Zircotec.
The Zircotec ceramic coating process starts by sandblasting the manifold to remove any dirt and grime, and to create a surface for the bond to stick to. The metallic based bond coat is then sprayed onto the manifold, which ensures the ceramic coating adheres to the surface. The ceramic coating is then applied with a plasma jet, which fires zirconia ceramics at the surface at high speed. Finally the colour is applied over to ceramic coating. The manifold is then inspected for quality before dispatch.
MGB manifold receives the final colour layer
MGB manifold receiving final inspection before dispatch
Ceramic coated manifold ready for dispatch
Installation of the manifold followed normal procedures and was straight forward. The hardest part, as always, is working underneath the car to start the nuts and washes on the threads of the exhaust studs before tighten them up. Access is very limited with a 1/2 inch socket and extension bar, and it takes a lot of patience with a universal joint in the socket system to get the job done. Anyone that has done this will know what I am talking about!
Old manifold (left) removed and new ceramic coated manifold (right) ready to be installed
Ceramic coated exhaust manifold being installed
First impressions are good. My MGB appears to run more evenly than it did before if stood stationary for some time with the engine running. This has made the car much easier to drive in traffic. I only have anecdotal evidence for this claim, but the only thing that has changed is the introduction of the ceramic coated exhaust manifold. While I don't have any before and after temperature readings from the engine bay, it would appear the ceramic coating has reduced heat from the exhaust system, which is preventing fuel vaporising in the carburettors. Certainly the engine runs more evenly than it did before when hot and the car is stationary. However the real test will be this summer when getting stuck in heavy traffic, which is an inevitability on UK roads. I will keep you all posted………..
Update: 9 June 19. Over the weekend I attended MG’s in the Park at the Cotswold Wildlife Park. Fantastic event and recommended. However, I got stuck in heavy traffic trying to get through Burford, Oxfordshire. I am pleased to report the ceramic coated manifold made a big difference. My MGB ran much smoother in the very slow moving traffic, and it was much easier to drive.
Job completed! Unfortunately the exhaust manifold is hard to see now it’s buried underneath the carburettors, inlet manifold and heat shield.