Engine Diagnosis Q's - 400cid

[Bullitt390]

So the machine shop installed a new seat, but you still had to go to an autoparts store to get your own valve? Josh

[Furyus1]

Originally Posted by Bullitt390

So the machine shop installed a new seat, but you still had to go to an autoparts store to get your own valve?
Josh

Well, the parts store I went to owns its own machine shop which is a block down the road from the parts store. They tend to be higher-priced than Autozone or Checker but they seem to have high-quality parts and they have a fairly large warehouse full of parts on hand so I don't mind paying a little extra... Been going to them for years...

Originally Posted by mark a.

I'd find out what caused this in the first place or you probably will end up right back where you started from. Check valve train geometry. Something is really messed up to tear those guides out so quickly, assuming they were in there & sized right in the first place.

You're probably right as there's no telling what shortcuts the rebuilders took on this engine... I've got the old guide and valve here and I don't feel too much "slop", but the machinist apparently did... His feeling was that the rebuilder reamed out the original guides +15 rather than putting new ones in then put in valves with +15 stems. I'm thinking I'll probably just eventually look into replacing the entire engine with a good used 351/400...

This truck is only source of transportation at the moment and I don't have the time or the money to tear the engine completely apart and do a complete rebuild... I need to get this back on the road before Monday so, I'm in the process of putting it back together now and hope it holds together for a few more miles until I can figure out what to do next...

[Bullitt390]

The cheap way to do a valve job is to knurl the guides and then smooth up the valve stem, which actually makes them smaller. Lasts about 1000 miles then the engine starts spewing smoke out the pipes.

Josh

[Furyus1]

It's Alive!!!

And it idles sooooo much smoother now...

After I got it back together and got it running, I took it out for a test run - I took it slow at first - just around town for a bit - then I took it out on some back roads at no more than 40-50mph... After some 35-45mph driving, I got brave and took it out on a 55mph highway and went for a drive...

The difference is unbelievable... The idle doesn't rock the truck around at a stop anymore and having compression in that eighth cylinder certainly helps with the power output

I started running Lucas Fuel Treatment in the gas - It says it helps lubricate the valve seats and it "should definitely be used in vehicles that require leaded fuel because it actually replaces the benefits of lead in gasoline without causing harmful emissions." - I figured "Why not? - what could it hurt?" - other than it is a bit pricey, but I found getting a quart was a better deal than the single-shot bottles...

I think I may have also finally come up with a name for the ol' beast - "Patch"