Topic: Piston Slap

[ccannon222]

My 22r makes a knocking/piston slap type sound when it cold and put under load.  When in netrual, at idle or reved up, no sound.  Only when put under load. 
Does this sound like piston slap or a bearing knocking?

ccannon

[Mike D]

you might need to adjust you valves

[79coyotefrg]

it sounds more like detonation to me,  which WILL cause piston problemo real quick, check your timing,  how many miles on your timing chain??

[MidgetMike]

What year is your 22R, I had a simular problem and it turned out to be my timing chain guide 84 and up 22R's and 22RE's have a plastic guide that will break and allow t-chain to slap the t-timing chain cover, pull you valve cover and look at the guide if you have to look hard to see it, it's broke. It should sit just below the t-chain pully.   

[BigMike]

FYI, you will ALWAYS get some rattling on any "aged" 20R/22R/22R-E/22R-TE engine. This is because not only is the oil pressure low during cranking, but also the timing chain tensioner runs off of the oil pressure, so while the oil pressure is building up, you'r timing chain is rattling all over the place.
That's why you should never ever ever never ever ever! rev up an engine really high when it first starts, and also while its cold.

The best way to listen for piston slap is when you rev it to any rpm and then quickly let off, right at the instant that the load is inbetween "power" and "coast" the internals are in a free-play and that's when you notice the piston slap.

But when you say that you don't hear the noise during reving then its most likely not piston slap.

Is it an exhaust leak under load?

[BigMike]

it sounds more like detonation to me, which WILL cause piston problemo real quick

Now that is great advice. If your timing is advanced say 15 degrees, then it will detonate simply under starting, and will of course make a racket while driving

[ccannon222 [OP]]

Thanks for the help.  I didn't think that is normal 4 banger noises.  It's an 85 with 150,000 miles.  My 85 efi runner has 173,000 miles and does not make the same sound.  I haven't check the timing.  I'll do that next.  The prevous owner said he changed the timing chain recently.  I can see new gasget material.  However, I do plan on replacing it with metal guides.  Also, I am going to replace the tensioner and the oil pump while I have it apart.  When I changed the chain on my 4runner, the drivers side plastic guide was broken. Also, my truck does have an exhaust leak.  I didn't know it could cause that noise tho.

ccannon

[79coyotefrg]

just adjust your timing befor you do anything drastic,  i'll bet it clears it up, to much advanced timing will make it sound like a diesel under load

[ccannon222 [OP]]

What is the timming supposed to be on these motors?  Mine was set at 15 degrees.  I dropped it down to 12 and the motor runs better.  However, the sound didn't change any.  I am going to adjust the valves this weekend.
Any other ideas?

ccannon

[MidgetMike]

My 22R only had 40k on it and I lost the T- chain guide and was on the verge of losing a headgasket, but I also hammer my engine when I'm playing, in that change my oil sooner and check for leak's and adjustments   

[Skinny_Pedal]

What is the timming supposed to be on these motors?  Mine was set at 15 degrees.  I dropped it down to 12 and the motor runs better.  However, the sound didn't change any.  I am going to adjust the valves this weekend.
Any other ideas?

ccannon

mine was at 15degrees and wouldnt pass smog. put it to 7degrees and it passed. 5-8 degrees is stock timing. advance for engine mods

[79coyotefrg]

850 rpm about 8*,