81 ford bronco knocking 351w

I have a 81 ford bronco that when started in the morning or after a long sit has a knocking sound but when it warms up it the sound goes away and there is no loss of power. I was wondering if anyone could give me some help in this matter.

Reply to
charles mays
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Check the oil first. Sometimes the lifters make a little noise when they run low on oil. If the oil level and pressure are fine, you may have a rod knock, which means you need new rod bearings and maybe a rod, possibly a crank, not easy or cheap. Best of luck to you, hopefully it turns out to be something easy and I was wrong! Erik D. '94 white lightning

Reply to
Erik D.

This usually is because of oil drain-down during extended periods of rest. Oil drains from the lifters, which will cause a sharp rapping-type knocking sound. A deeper/throatier sounding knock will come from the crankshaft, because of the oil drain-down. This knock is more 'meaningful' and could be a sign of the upcoming need for a bearing job. As long as it disappears once the engine reaches normal operating temp, I wouldn't be overly concerned. It's also possible that the oil needs to be changed, or the weight of the oil being used is too light or too heavy. High-mileage engines eventually begin having these types of worrysome noises.

Dave S(Texas)

Reply to
putt

On Thu, 30 Oct 2003 14:31:43 +0000, charles mays rearranged some electrons to form:

Don't worry about it. You didn't say how many miles were on it, but as long as you have decent oil pressure, keep running it until it scatters.

Reply to
David M

"David M" wrote in news:pan.2003.10.31.11.29.30.324158@sled351:

It is quite common to have some piston colapse and slap problems on higher milage ford small blocks. It is exaclty these symptons. It will usually last a long time this way. KB

Reply to
Kevin Bottorff

Oooo... that how most do it but I've never really liked that method for myself. I drove mine to a friend's place (Willcox) and we pulled the engine and took it to the engine re-builder. It wasn't running so good, but turns out it was mostly the heads/valve seats. (148K)

Same with my A/C, it got weak from a leaking compressor seal, so I pulled the belt off before it melted down (died from "black death" the A/C guys call it) where the temperature gets high enough for the freon to separate into F and Cl and attack the aluminum like it means business! Why wait for that and have to replace everything, instead of just the compressor and the receiver/dryer?

My engine (clunky ol' 360;) is still going with most of the original parts. The original parts I already owned, see? So there's where the advantage is to me.

Cool. :)

The trick, from my point of veiw, is to catch it -just before- "it scatters ;)".

What kind of tests can the OP perform that would pin point what's wrong, so he can know when it's going to "scatter;)" and so catch it just before? :)

Like I remember my dad (farmer's son) saying something like "when you let off the gas, if it's a rod bearing, that's when it knocks loudest" "If it puffs blue smoke only when you let off the gas it's the valve seals and not the rings" and a bunch of other stuff like that.

Alvin in AZ (no TS#;) '75 F150

Reply to
alvinj

I had one do this, and it turns out that the oil pickup screen on the oil pump was slowly getting clogged. Over a few months it got worse and then finally died a nasty death. fried main bearings. It goes away because the oil thins as the engine warms up and it can get more pressure through. Catch it before it scatters and decides to let you walk home. Good luck.

Reply to
nobody_special

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