Working on a 454...

[Hank70SS]

in a motorhome is not like working on one in a Chevelle. You would think as big as a motorhome is there would be all kinds of room. It's like working on one in a van. The engine is under the flip up doghouse inside. Valve covers are below floor level. The floor comes up close to the sides of the engine so you can't even see the spark plugs or exhaust manifolds.

Both the 454 and the Ford 460, in a MH, were notorious for snapping passenger side exhaust manifold bolts/studs. For whatever reason, direction the fan rotates maybe, there is less airflow on that side. Ours had snapped off the rear bolt and of course it leaked. I ordered a new manifold and started taking off the old one, reaching over the front tire from underneath. The front stud snapped right off, not too bad. I can put a nut on it and weld it on. all the other bolts/studs came out okay and I pulled the old manifold off.

Rear bolt was snapped off just below the head surface . I drilled through it with a few different size reverse twist bits, didn't budge. Tried an easy out, not too much pressure, didn't budge. Heated it, soaked it with PB Blaster, no luck. I'm afraid to drill it out more because the hole is not perfectly centered. Maybe work on it some more tomorrow.

Just to give you an idea how hot these manifolds get. The new ones have slots cut in between each exhaust port. Originals were a solid flange like the flange on a header. This lets the lower part of the manifold expand and contract without over stressing the bolts. I saw slots in mine and said shit, it still snapped the bolt. After removing all the bolts/studs the slots closed up. I looked closely at both sides of the manifold and it wasn't a clean cut, it snapped in 3 places!

Also destroyed the dipstick tube pulling it out from behind the manifold. The heat had burned the tube, had a few pinholes in it. I used a couple of 3/8" brass unions, a piece of 3/8" steel tubing and rebuilt it. It's like 4' long, goes all the way out to the front and you can't get a replacement. Maybe at a dealer if they can find one and you want to pay $100.

Anyway, that's been my fun the last few days, along with some yard work. I know nobody gives a shit, but tough, I'm telling you anyway. Oh, we did take the Chevelle to CVS, the hardware store, the DQ and the pet store so it wasn't all bad today.