Replacing a Piston with Engine in the Truck ??

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Ok, best that I can determine, the noise in my Engine is Piston Slap. It's kinda loud (during Accelleration). BTW, the 2nd Piston from the Front is the culprit.

My goal here is to get my truck running, be reliable for the LEAST amount of $$$ output. Given these goals, a complete rebuild/engine swap is out of the question (for NOW anyways :-X07 )

I guess a few questions I have of the bat are;

  • 1) Anyone here done this procedure before
    2) Where to buy an Oversized (like .002/3 or whatever the size needs to be) ??
    3) What other Tips can you'all give me for a First Time Pan Puller ?? :-X03

Someone did post this WONDERFUL site and I found the Procedure in detail! Oo. Oo. Oo.

-->> Piston Replacement How-To Article <<--
 
8) the only problem in replacing one piston is the pistons are a matched set in regards to weight. replacing one changes the weight on one piston causing an imbalance that will only damage the engine do to severe vibration. best to run a thicker oil or even better would be to rebuild the bottom end.
 
rbohm":3lcxdbxo said:
8)best to run a thicker oil or even better would be to rebuild the bottom end.

How thick of a Viscosity Oil ??

Where can one find an INEXPENSIVE rebuild kit ?? How much ??
 
8) run 40wt oil. as for an inexpensive rebuild kit, what do you consider inexpensive?
 
I suppose there are ways to deal with this one, if you have a brave machinist and want to inflict a slow death on a block.

A rebuild kit will not alleviate piston slap. That requires bigger holes and bigger pistons. I had a piston shatter in a 2 stroke once. What a mess.

Start saving your pennies.
 
We seem to have created two near-parallel threads, each with some useful input. I can't merge them...
 
I have seen several engines with one cylinder bored oversize that ran just fine for a long time. Stock engines, not 7000 rpm engines. You will never know the difference in a 3000 rpm 300-6 with 7 main bearings. Remember, this is on the reciprocating mass, not the rotating mass. The reciprocating mass is very unlikely to have identical forces applied except at idle or constant speed and load due to the varying combustion chamber filling. Think about it.
Joe
 
IF, and I stress IF, it is piston slap, then you can't bandaid it. You either punch out the hole and put in an over size piston...or don't.

Unless you actually opened up the engine and seen the sloppy piston, my first guess would be a broken piston/skirt/etc. In which case you can give the cyl a quick hone and drop in a stock size piston. Will it be loose? Of course, and so will the other 5. Your not rebuilding it, you're just replacing a piston.

Or, it's not piston slap at all. :shock:


Oh yeah, and I agree with lazy, one "heavier" piston will not be noticed in a 3000 rpm stock street engine.
 
goinbroke2":3e3vqthz said:
IF, and I stress IF, it is piston slap,
Or, it's not piston slap at all. :shock:
I wish I knew BEFORE I disassemble the engine!

There was a Ford Line Mechanic here the other day (looking at another car I have For Sale) and I let him listen to the engine noise.

He seemed to concur that it was In-Fact Piston Slap. It's making the noise at 1/2 the frequency of the valve train (rules out lifter issues).

He said "Back-in-the-Day" that they could get SLIGHTLY oversized Pistons to match the worn cylinder bore. Say .002,.003, .004 oversized.

Can Slightly oversized pistons still be bought anywhere ??
 
Standard pistons here came in "Grade Red" and "Grade Blue"; one was a smidge larger. Often 2 thou over are available but don't quote me.

To make the finicky types cringe, workable wear limits are 5 thou out of round and 10 thou taper in a bore. If it's there now, start saving and button it back together...

Why would one piston/bore slap more than another?

Adam.
 
It could "slap" because it is rocking in the bore, because it is missing a skirt.
Been there, done that.
Ever pull a 351W apart from '78 on....and NOT find at least 3 or 4 pistons broke/cracked?

I've done quite a few 351's for the local stock car crowd, and I think every one tore down with pieces of skirt in the pan. :shock:

You will HAVE to tell us what you find!

Oh yeah, and why would one piston break? Detonation/overheating/piston hitting valves during valve float, all kinds of reasons.
 
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