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86 F-250 460, lacks power

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imcqueen

86 F-250 460, lacks power

So I lost oil pressure the other day and now have a light knocking from the bottom end and extremely low power.
Oil pump is able to be spun by hand or run with a drill.

I have ordered a new long block and will R&R the engine once it arrives next month.

The truck still runs and fires up immediately (when I need to move it to work on it), but barely goes up my driveway - and pumps out white smoke.

Would a spun bearing cause such a lack of power? Or is there something else at play here that I need to address so the new engine runs right. (I’m guessing I have a fueling issue - clogged or dirty pickup socks).

1986 F-250, 4x4, 7.5L 460, C6, SCLB.

Pete Whitstone

Re: 86 F-250 460, lacks power

imcqueen wrote

- and pumps out white smoke.

That makes me think that coolant is getting in the combustion chamber, if it's truly white. If it's whitish blue it could be oil in the combustion chamber. Either would not be good. But if you're replacing the engine then it's kind of academic.

I haven't thought of a way to equate lack of oil pressure with a breached head gasket or head or cylinder wall though. So I'd be interested to see what you find on teardown.

81 F150 Flareside, Edelbrock Pro Flow4 FI, hydraulic roller 351W, E4OD, 4x4, BW1356
92 F150 RCLB 351W E40D BW1356 mostly stock

imcqueen

Re: 86 F-250 460, lacks power

It’s burning oil. The smell is unmistakable. And there’s oil residue in the snow next to the exhaust pipe.

Coolant and oil are both clean and non contaminated.

I’m looking forward to the tear down as well.

I’m guessing it spun a bearing and has bad valve seals (unrelated), and a clogged fuel pump in the front tank.

1986 F-250, 4x4, 7.5L 460, C6, SCLB.

Gary Lewis

Re: 86 F-250 460, lacks power

Administrator

In reply to this post by imcqueen

Welcome to the forum. But, as said in the email I sent you, your first post was supposed to be an introduction in the New Members Start Here folder.

One reason for that is because when you open that folder you'll see our guidelines, which are really requirements as we require everyone to abide by them. So we want everyone to have had the opportunity to have read them. Please confirm that you have.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

mat in tn

Re: 86 F-250 460, lacks power

puffing white smoke sounds more like steam then oil. but you may have just lined up a series of wear across a few things. how many miles? what temp did it fail at? pumps don't usually just fail. it's more likely for them to get run low and even out with high mileage engines whether from consumption or leaks. that kills bearings etc. but oil also cools .

imcqueen

Re: 86 F-250 460, lacks power

In reply to this post by Gary Lewis

All caught up. Read email, I had already read the forum rules.
I’ve now posted in new here.

1986 F-250, 4x4, 7.5L 460, C6, SCLB.

Gary Lewis

Re: 86 F-250 460, lacks power

Administrator

Thanks. Glad you've read the rules.

Gary, AKA "Gary fellow": Profile

imcqueen

Re: 86 F-250 460, lacks power

This post was updated on .

In reply to this post by mat in tn

Nah. Burning oil. The smell, the oily residue in the snow by the tailpipe, oil consumption, smoke (not steam) lingering in the air….

I’m guessing a history of abuse (assuming no oil changes, plow truck, sitting for years after plowing, etc), all took its toll and finally caused the engine to let go.

Here’s the sound of her knocking.

https://youtu.be/TOyD6C_MVg0

Temps were normal when I lost oil pressure. And never overheated.

Mileage is 107359…. Or 207359… I believe it’s 100k.

1986 F-250, 4x4, 7.5L 460, C6, SCLB.

mat in tn

Re: 86 F-250 460, lacks power

uuuuhhhh. stop that!

imcqueen

Re: 86 F-250 460, lacks power

Lol. New engine is on the way!

1986 F-250, 4x4, 7.5L 460, C6, SCLB.