Guys, I hope that someone can enlighten me on a baffling issue. I just replaced a 400 V8 in my 82 F350 wrecker with a used 400. I buttoned everything up with a new melling HV oil pump as well. Did not put new rod or main bearings in the motor; just a new clutch. Upon initial startup, everything went fine...motor ran great. However, the next morning, nothing but backfires--wouldn't even run. Upon closer inspection, I found that the rotor in the distributor was messed up. The indexing button on the inside of the rotor (the part that keeps it tight to the shaft), had sheared off leaving the rotor unable to rotate correctly. After I installed a new rotor, it fired right up but it was running like a V4! New plugs, fuel filter and duraspark module later, I still had a V4 on my hands. On a whim I pulled the dome covers and Voila! almost all the intake pushrods were bent like a pretzel. The exhausts were OK. I replaced all the pushrods and pulled the coil wire to turn it over and almost immediately, the same exact pushrods bent again. Next, I pulled the valve springs and seals from the offending valves. Although I had no air pressure at that moment to hold up the valve, the valves were really, really tight in the guide. A few hard raps with a piece of 4x4 moved them somewhat but I am not so sure that this 'stiffness' is normal. Never replaced the timing chain on the engine; I assumed that it was OK. BTW, this truck was sitting for a LONG time prior to me putting in this engine and the gas was really really stale; it had that RANK smell; the exhaust even smelled of it. I just dumped 10 gal of FRESH gas in with 2 cans of gas line antifreeze to the old stuff then fired it up. It ran FINE until the rotor issue arose. I don't know what to do next. I don't want to pull the heads/manifold if I don't have to. How can I tell if it a bent valve versus sticking valves? Would sticking valves cause bent pushrods? When this thing ran like a V4, I heard NO clanking noises like the pistons hitting the valves. Remember, ONLY the intakes were affected....strange indeed! Ideas anyone? Thanks in advance and sorry for the long post!
Ben

 

my best guess is that the engine needed to be refreshed before putting it in. The surfaces between valve and guides oxidized like all dissimilar metals will..possibly with the help of rank chems. The idea would be to yard out the heads, disassemble and put back together with some fresh parts. You can get the book that will show you how to check for tolerences to save money where you can or you can be more complete and replace springs, valves or just have them rebuilt. I like putting them together and lap myself but have to triple check everything.

or you could get some sea foam, penetrating oil, blow torch (ha ha) and clean up the parts as best as you can to free them up without removal- moly them up real good, recheck the valve train geometry and give her another go. Not sure what the prob is with distributor...rotors usually get hurt when not installed correctly...not that i would know from multiple experiences...

I imagion that the valves moved freeley enough to run at first but could not get enough lube to clear the gunk and metal matter and thus took the opportunity to nearly seize with the heat then sitting...or for all intense purpose they did seize up pretty good.

I take it you checked out the bearings etc...it's a pretty big risk of wasting a round of installation and removal time putting a rank engine in like that but maybe you can still get it to run for a while eh? I am encouraged by your courage...i'm so friggin **** i would have to ck and replace eveerything if I actually had the engine out....then take a few weeks getting it 'buttoned up' and put back in.

 

As for checking the bearings, I did not. I never had luck replacing inserts on a worn engine. I did this on 2 or my 390's when they were in the truck. They both had a warm knock at idle and I replaced the rod inserts with clevite tri-metal to no avail. SOO, I figured to leave this engine alone and just pick up any slack with a melling HV pump. When she ran, it ran really, really well and sounded good. Its disheartening to see it all disassembled again sitting in the engine bay. As for the penetrating oil idea, I sprayed the stems liberally with PB blaster. I am going to put 150 lb air to the cylinder today to see if the valve 'pops' back up; if it does not, I will most likely have to do some surgery. BTW, this 400 came out of a 74 Ranchero. Does anyone know if I can replace the ranchero valves (the keepers have 3 or 4 grooves) with the regular truck 400 valves (those have 1 groove in the keeper) Are they the same valve except for the keeper grooves? THe casting code off the top of my head for the ranchero heads is something like D4AE-AA and the codes for 400 truck heads that I pulled were D2TE-AA
Thanks again

 

Suggest checking your distributor gear to make sure the high volume oil pump did not break it.

 

Also check the dizzy to oil pump shaft. I use a hardened shaft with a HV pump. The stock shafts can bend/break.

 

OK
I decided to pull the heads and manifold after a long debate. What I found is really, really odd. All the intakes were stuck. There appears to be this thick, black tarry substance all over the underside of the valve head and in the combustion chamber. As a matter of fact, in one chamber, there looks to be 1 inch of thick goo sitting under the valve head!!!! It is NOT oil either; this stuff is black, tarry and sticky. Remember, the truck gas tank had rank gas in it when I fired the motor. There wasnt much; maybe 1.5 gallons or so? I added 10 gal of fresh gas with 2 cans of gas line additive before I fired it up. I am wondering, would bad gas do this? If I knew how to post pics, I would post them so everyone here can see the damage that was done. I guess now I am going to clean everything up, re-lap the valves and give it a whirl again.
FYI
When I put in the HV pump, I bought a hardened shaft from summit racing as well; I ALWAYS use hardened shafts when swapping in HV pumps! Thanks for all the replies!

 

Sounds very interesting and I've run into that (i think) decades ago when I was the engine dismantler at a rebuild shop., sometimes I'd swear the oil and gas would go back to fermenting dino gook of some sort. at least you should have an easier fix...clean and go maybe. I'm pretty sure you can use the ranchero valves...from the research I've done i have found different springs but not valves.

So you ran the rank gas through the engine after diluting with the good gas?

 

Could someone have pickled the motor with something for storage?

 

I diluted the bad gas in the tank with roughly 10 gal of new gas. It ran well for awhile, then the backfiring and bend pushrods occurred after it was thoroughly cooled down. I guess the gook got liquidy when hot and real sticky & thick when cold? Today I am going to clean everything with gas and strip it good with my pressure washer. I'll keep everyone posted with my progress