Hello all. As I posted a few weeks back, I was eyeing an 86 F250 w/ the 351 W HO, 4x4. Guy was asking $1500, but beyond the cosmetic items that need addressed, the hood latch was broken and the guy couldn't get it open. The truck fired first try. It was idling hard, but drove. I could hear air sucking an figured a really bad vac leak. I offered him $750, knowing I was taking a gamble not being able to look under the hood, but the tires are brand new so I figured worse case I just bought tires for my 6.4 power stroke. The guy took my offer. I got the truck home, hood opened and was presently surprised. No major leaking, cleaner than I expected.

1st thing I did was tear into the carb. After a can of carb cleaner and adjusting the idle, the engine is running pretty good. It still wants to die when I reverse and when I first go into gear, but if rev it, I can keep it going. The one obvious thing I found that I, assume, is causing the staling is the PCV valve is sucking air through the top port. It looks like it was attached to a hose at one point, but have no idea where to. The larger, primary port of the PCV is attached to the carb inlet, which I know is correct. My question is where does that 2nd PCV port need to be attched to? An does the sucking mean that the PCV is bad? Any info would be great.

 

At this point and time I would plug that open port. Not all engines used that smaller port, so if you buy a new PCV valve, that port is there but is plugged over with the plastic. If your particular engine uses that port, you take cutters and cut the plastic off.

You may be able to figure out from the hose diagram on the radiator support if your truck even used that port. Some engines used it to evacuate the charcoal canister, some used to for other things. The vacuum systems on these engines can get complicated, and it seems no two were the same. So I would plug it and move on to bigger and better things.

 

Thanks for the Franklin2. I went ahead and covered the port. It looks like the previous owner pulled a lot of the original emissions out. Trying to follow the vacuum diagram under the hood is proving to be impossible as most the components are not there. . . I guess my 1st order of business will be to get all the vacuum lines and components back in place.

On a side note, do you know a good place to find reference, diagram and/or manuals for 7th gen F-series. I found a Chilton's manual on Amazon, but I kinda hate those manuals since they cover such a broad range of year (80 - 97 for all F Series vehicles).

 

Thanks for the Franklin2. I went ahead and covered the port. It looks like the previous owner pulled a lot of the original emissions out. Trying to follow the vacuum diagram under the hood is proving to be impossible as most the components are not there. . . I guess my 1st order of business will be to get all the vacuum lines and components back in place.

On a side note, do you know a good place to find reference, diagram and/or manuals for 7th gen F-series. I found a Chilton's manual on Amazon, but I kinda hate those manuals since they cover such a broad range of year (80 - 97 for all F Series vehicles).

 

I ordered my Ford Shop Manuals through Rock Auto. I bought the CD-ROMs offered by Dave Graham, and I've been very happy with them. Very detailed engine schematics, and good instructions. Just my $0.02...

Unfortunately I don't see a CD-ROM available for the 1986 F250 on RockAuto. But my 1981 manual does have the 5.8L 351 CID covered in it. I'm not sure how different 1981 and 1986 might be...

If you want to have a peak, let me know. Might help you to better judge if it is similar enough before you purchase.

 

Is there a reason you want to put everything back in place? A aftermarket 4bbl and intake will wake that engine up, and lessen the need for any emissions, unless you have smog inspections.

 

 

If you have the cash, I would recommend a matching intake to your Edelbrock. My 460 has an Eddy carb but the intake is stock. Sure I could get some more juice out of the old boy with an intake upgrade but I am starting an engine build anyways so I may never know.

 

Always try to put a 4bbl carb on a 4bbl intake manifold. I know they sell adapters, but they never work very well.

 

x2 If you want to stay with the factory stock v2 intake but still want a boost look at the Holley 2300 v2 carb.
They come in 350 CFM & 500 CFM sizes and use all the same tune up parts as it's big brother the v4 carb just half of them.

I have run a Holley 2300 v2 500 CFM on an AMC 304 CID motor using the stock v2 intake replacing the Motorcraft 2100 carb.
It was a totally new motor with the power it had with the carb swap.
Dave ----