So my 71 mav has a 200 inline 6 and Its been having some problems lately. First off, when I turn the car off I can see it leaking gas from where I believe to be the throttle body shaft on the carburetor. This also makes me think there is a vacuum leak there. How would I fix that? And also I know my car burns oil, but just recently it seems to be getting worse. The car has stalled a few times and I can feel an occasional misfire at idle. I pulled the plugs from cylinders 3 and 4 and they were both coated in oil. I've replaced the valve seals so I know its coming in through the rings. any way of maybe fixing that without taking the engine apart?
I've rebuilt the carb many times with no improvement. and I just don't think the engine is worth rebuilding since its just a 200 six and I have plans to eventually swap in a 302.
rebuilding will not fix worn out throttle shafts and the carb must be taken in to have the positive type seals/bushings installed. as for the oil leaks.. only way to totally cure that leak is to redo the guides and machine for positive type seals. Even new umbrella seals can have little effect sometimes since they quite literally act as mini oil pumps as the hot oil gets spalshed/runs under them. I have however used a combo of both seal designs without having to remove the head. Once on a 351W and the other an old 170. You simply cut the positive valve seals top section off so you have a mini umbrella type seal(but without the umbrella). Ends up being more like a little disc type seal. Then you use the umbrella type seal over that one. Was an old heavy equipment mechanic working around me for quite a while and we talked about a lot of these old low budget tricks that he and hid father had used. I only used that trick twice but the oil consumption and plug fouling improved considerably. Just need to keep in mind that it only works on low-po/low-lift type cams where there is more than sufficient retainer to guide clearance to work with, is all. Plenty of room on this motor to do it. Not saying that the rings aren't bad too.. but these old motors really like to eat the old cast iron guides and pump oil like it's only a quarter a quart. Which it probably was when they designed it. The hardest part is you'll still need to remove the springs which requires the old stuffed rag/rope trick or compressed air at TDC/compression stroke per cylinder to keep the valves tight on their seats while you do it. Still a bit of work.. but sure beats pulling the topend to fix it.
You better get the fuel leak stopped or you won't have anything left after the fire to put a 302 into.
