Exhaust Leak
Hello, I own a '94 Minnie Winnie that's on a Ford E350 frame. I have the 460CI gas engine. I have an exhaust leak on the passenger side. From what I've read, this is a common issue with the 460,...
Forum Discussion
Common issue.
They've been done with and without gaskets. The idea of No Gaskets was to try and keep Head and Manifold expansion/contraction dimensions together. Using a gasket, at least in theory, insulates Manifold from Head and leads to leaks.
Yes, some have replaced Manifolds with Headers. In theory they make your doghouse hotter. Some have insulated their headers and been happy with them. You need "torque" headers with long tubes (Doug Thorley Tri-Y used to be popular), NOT "Shorty" headers for high RPM HP.
Problem in these repairs is getting the original bolts out. I was blessed to get all 16 out on our 1983 460. I then had the manifolds machined back into flat and reinstalled using stamped steel gaskets with Never-Seez on both surfaces, and new bolts.
On advice from an old mechanic who had a 460 I did NOT torque the manifolds down tight. Only enough to crush the stampings in the steel manifolds so they'd seal. Kent's idea was that the expansions would never be equal so let the parts slide. Make it easy for them to do so.
Our engine used "heat shield" gaskets. They protected the sparkplug boots, and were stamped steel. I don't think the "waffle" versions would hold up in RV use, but both were available.
What I'm told is 460's like to run with headers. The gains seem to be in lower temperatures and more power, not much better mileage. That's probably due to driver's enjoying the extra punch.
They've been done with and without gaskets. The idea of No Gaskets was to try and keep Head and Manifold expansion/contraction dimensions together. Using a gasket, at least in theory, insulates Manifold from Head and leads to leaks.
Yes, some have replaced Manifolds with Headers. In theory they make your doghouse hotter. Some have insulated their headers and been happy with them. You need "torque" headers with long tubes (Doug Thorley Tri-Y used to be popular), NOT "Shorty" headers for high RPM HP.
Problem in these repairs is getting the original bolts out. I was blessed to get all 16 out on our 1983 460. I then had the manifolds machined back into flat and reinstalled using stamped steel gaskets with Never-Seez on both surfaces, and new bolts.
On advice from an old mechanic who had a 460 I did NOT torque the manifolds down tight. Only enough to crush the stampings in the steel manifolds so they'd seal. Kent's idea was that the expansions would never be equal so let the parts slide. Make it easy for them to do so.
Our engine used "heat shield" gaskets. They protected the sparkplug boots, and were stamped steel. I don't think the "waffle" versions would hold up in RV use, but both were available.
What I'm told is 460's like to run with headers. The gains seem to be in lower temperatures and more power, not much better mileage. That's probably due to driver's enjoying the extra punch.
