Engine?

[trainguy1989]

My engine has some piston slap until it warms up and I had plan to invest more money into the engine (BBB, rod bearings, and other things). I have already have done both the front and upper 60Ks. It has 180K on the clock. My question is whether I should look for a new engine because I have no tools and facilities to rebuild an engine or just live with it. How much damage can this cause? Is it fixable without yanking a engine?

Thanks,
David

 

[zblackbeast]

Yo were going to do rod bearings and intake stuff, and you did 2 60k's and you dont have tools to rebuild and engine? Did you loose the tools you had? No, if you have piston slap you need to remove the piston.. i recommend a motor swap!

 

[trainguy1989]

Man!! I already put $800 into the engine. I did a cylinder balance test and I got a 90 meaning all cylinders are contributing equally. I borrowed all those tools and said people I borrowed from disappeared. Sniff....

 

[St Louis SHO]

Drive it....

 

[trainguy1989]

Am I going to hurt the thing by driving it?

 

[zblackbeast]

AKA, your block is not happy...

Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.

 

[trainguy1989]

Sticky Rings? The heads seem very clean with valve covers off....

 

[SHOtimer]

What makes you think it is piston slap?

Doug

 

[SHOtime2511]

WTF is Piston Slap?
you think you piston is hitting the bottom of the head?

that chatter you hear on cold start up can be caused by many things.
Some as simple as a cheap oil filter (Fram) with a failing anti drainback valve.
Could be rod bearings are about due also.

 

[trainguy1989]

The car has a slight knock when cold. After the car warms up, said knock disappears. The engine builds great oil pressure. I used a screw driver to try to locate the noise and the noise is not from the valve covers or the timing covers. Crank bolt is as tight as can be. The sound is coming from the rear bank. It can heard best near the firewall and under the car. After the car warms up, sound is gone. Rod noise would get louder as the car is warmed up as the oil would be thinner. I suspect piston slap because that would explain why the noise would disappear after the engine warms up. Piston expands in the cylinder.

Thanks,
David

What makes you think it is piston slap?

Doug

 

[zblackbeast]

WTF is Piston Slap?
you think you piston is hitting the bottom of the head?

that chatter you hear on cold start up can be caused by many things.
Some as simple as a cheap oil filter (Fram) with a failing anti drainback valve.
Could be rod bearings are about due also.

obviously you didnt read my previous post...... :angelnot:

 

[SHOtime2511]

If your hearing the noise from the driver side of rear bank id suspect the timing chain tensioner is worn or has some crap in it preventing it from expanding with oil pressure like it needs to.
if you pop off that valve cover and you find the pad on top of the tensioner is in good shape you should be able to clean out the oil passages with brake cleaner.

Edit: I highly doubt "piston slap" is your issue.
unless your dumping blue smoke everywhere you drive.

 

[raff18]

older hondas i knew had pistion slap because the cylinder was oval when cold and would alow the long side of the pistions to slap the block. but it would only last seconds and would soon go away
ive never heard of a ford engine yet a yamaha
id take SHOtime2511's advice and look at the cam chains

 

[rubydist]

There is a good chance that a 180k mile SHO engine has rings that are sticky enough that there is audible piston slab when cold, that goes away warm. trainguy's conclusion is a reasonable one.

I have gotten at least one SHO engine to quiet down with AutoRx treatment, so that would be a good place to start. I have not had as good of success with SeaFoam, so I recomment AutoRx. If its not too bad, it will loosen the rings up enough to quiet the engine down. If not, the pistons need to be removed, the rings taken off, and the pistons physically cleaned up to get all the carbon gunk off them. Some guys have done this and reinstalled original rings with no honing of bores and made an engine that lasted a long time, so that is a thought.

The problem you have with picking up another engine is that you don't know if it will have the same issue or not. You have some history with this one.

 

[sperold]

302's were notorious for having piston slap, perhaps because half the piston skirt is hanging out the bottom of the block when the piston is at the bottom of the stroke. This eventually cracked the skirts. The SHO motors don't have that issue. Wrist pins can make a noise too. All these noises are the result of turning out motors with high tolerances for the masses.
The SHO motor was low production and has the tolerances of a Formula 1 engine. You just don't have those issues.
Work with the motor you have and go ahead with the changes you were planning to make.
In the old day while going to school (and working for that matter) I had cars with both piston slap and wrist pin noise, as they were well past their due date. In all cases, there were never any failures (in over 100,000 miles), in fact the noises never got worse. And that is with the old, high tolerance junk that was designed to fail.

 

[zak]

WTF is Piston Slap?
you think you piston is hitting the bottom of the head?

My vote for QOTW

 

[sho_shane]

There is a good chance that a 180k mile SHO engine has rings that are sticky enough that there is audible piston slab when cold, that goes away warm. trainguy's conclusion is a reasonable one.

I have gotten at least one SHO engine to quiet down with AutoRx treatment, so that would be a good place to start. I have not had as good of success with SeaFoam, so I recomment AutoRx. If its not too bad, it will loosen the rings up enough to quiet the engine down. If not, the pistons need to be removed, the rings taken off, and the pistons physically cleaned up to get all the carbon gunk off them. Some guys have done this and reinstalled original rings with no honing of bores and made an engine that lasted a long time, so that is a thought.

The problem you have with picking up another engine is that you don't know if it will have the same issue or not. You have some history with this one.

I agree 100%, You can do a leak down test to find out witch one it is. Im a SeaFoam gunky myself. I would try parking the car for a few days. Pull the plugs and pore some SeaFoam in everyone of the holes. Let the car sit for 2 days with the plugs out rags in everyone and the SeaFoam in everyone. Then on the 3rd day turn the motor over a few times with the pulgs out to blow any seafoam still left in the holes, dran the oil, replace it and crank up the car and see where you are.

I bought a SHO a few years ago that smoked really bad becuse of sticking rings. I did this and the smoke all but disapired...

Sidenote: You car might smoke a little till it burns all the SeaFoam out.

 

[yamahaSHO]

TBH, you're probably getting rod knock at start-up.

Rod noise will not always go away when the engine warms up. Cold oil with excessive clearance on start-up is your biggest issue when this occurs. Warm oil will flow better and warm parts will expand.

I vote for changing your rod bearings. You could try some AutoRX afterwards as well.