Motor UPDATE!!! It aint pretty

Status
Not open for further replies.
BRENT in 10-uh-C said:
Not any more!!
LOL.gif
Click to expand...

I got a good chuckle at this
 
I'm with James and Brent on the the rods and pins. Also, you need to find a
qualified engine builder...some of this mess could be your fault.

From the quick look that I did, the engine was assembled dirty....trash in the
bearings. Also, whats with the Helicols in the main bearing bulk heads??
No through bolts?
 
d.j. moordigian said:
I'm with James and Brent on the the rods and pins. Also, you need to find a
qualified engine builder...some of this mess could be your fault.

From the quick look that I did, the engine was assembled dirty....trash in the
bearings. Also, whats with the Helicols in the main bearing bulk heads??
No through bolts?
Click to expand...

Dudley, please consider this engine was run for XXX amount of miles with galled aluminum on the walls. The "dirt" or "trash" you see likely has been scraped off by the rings and knocked into the pan where it was picked up by the pump or rod dippers and thus circulated into the oil. This could be confirmed by looking in oil galleys, main bearing tubes, and imbedded into the oil pump gears.

Also, the thread inserts into the main webs is done as a way to use a stronger grade of bolt to clamp the main cap instead of using an original bolt. I have seen this used effectively in the past on other engines. This engine was never intended to be a stock-type rebuild.
 
In the initial post Logan mentioned that a rod would not drop when a piston/rod assembly was held parallel to the floor. Sounds to me that the problem stemmed from dry wrist pins at assembly. Without knowing anything about the pistons and wrist pins used if the pins were in the pistons right out of the box then I would expect that thumb pressure would be enough to push a pin from a pin bore. If gages are available I'd look for .0002-.00025 clearance in a new wrist pin bore.
There is a lot of blue coloration to the rods, looks to be much more than necessary to install the wrist pins. I think the pins were never lubed prior to firing the engine and there was almost immediate galling of the pins in the pin bores. The heat generated was transferred to the pin bosses and then to the skirts resulting in the aluminum deposits on the cylinder walls. Logan mentioned a pin had been hot enough to turn purple, again indicating to me that much heat was generated from galling.
 
There are only 4 things that will take out pistons, some stated already.

To tight of fit.

Wrist pin to tight a fit.

Top side of the piston hitting the head on the edge above the ring, and that gets the ball rolling. When it is on the side like that, you would never hear it. But you can see it taken apart.

Antifreeze on the cylinder wall, and that doesn't take to long.



The pitting in your bearings, that is all the Aluminum off the pistons.
 
You would have to mic the pistons, and bore to determine if the pistons were to tight first. Only the pins that were still free are the ones that you could mic for clearance of those.

The wrist pins can take out the pistons, or the pistons can take out the wrist pins.

As far as wrist pin clearance, I can only comment on stock Model A rods, but the wrist pins should be fit with .000-50 thousandths clearance. at .001-00 the bushing are all ready wore out.

Ford Spec's on wrist pin clearance is .000-30 to .000-50, but 1/2 thousandths is by far the best.
 
IIRC, the field expedient rule of thumb on new wrist pin fitting was if you could hold the rod out straight (horizontal) and give it a little push, (or a jiggle) it would drop to the bottom of travel by its own weight without stopping.

Logan's description of how tight it was seemed incorrect (and prone to problems) although we don't know if he's talking about the other three probably o.k. rods or the one that seized.

Joe K
 
My 2 cents. It looks like it got real hot to me. That is a lot of build up on the cylinder walls. I bet that it was 3and 4 that got the build up.

After looking closer, I think maybe that piston was not getting oil. Looks like it was running dry. That is why I was thinking it got hot. Also the one main was running dry. I can see what looks like copper, like it was worn through the bearing metal, It also looked dry.
 
Last edited:
One other thing if you use Chev 283 piston, they have off set for the wrist pins built in to them. The Model A motor already has a lot of off set. They work the best if you put them in with the front of the piston to the rear.You will end up with the right amount of off set. If you don't do that they will have a lot of load on the thrust side of the piston. That will cut your power and could cause scoring.
 
Russ/40 said:
I don't understand your way of posting measurements?
Are you saying .0003 to .0005"?
Click to expand...

Yes Russ, I work with these kind of Mic readings every day, all day long.

The reason for it is, in many years gone by, if I write down say,

3.0045, or 3.00450, when I glance at the numbers, I have mistaken the same numbers for 3.045, or 3.0450, and so on.

If I write them as 3.004-5, or as I normally do 3.004-50, I don't mix the true figures up, and I can tell at a glance what the true number is, with out making a mistakes on the tenths.

I am not saying that anybody should do this, its just me, and I think you had it figured out anyway.
 
d.j. moordigian said:
I'm with James and Brent on the the rods and pins. Also, you need to find a
qualified engine builder...some of this mess could be your fault.

From the quick look that I did, the engine was assembled dirty....trash in the
bearings. Also, whats with the Helicols in the main bearing bulk heads??
No through bolts?
Click to expand...
Dudley, I think you are correct but I believe instead of some it is most. ;)
 
I consider this another problem...too what you have already.

If you Helicol the mains as in this block.....what registers the main caps? Nothing!
In the original set-up the bolt shank does it....very little cap movement

In my "B" I have billet main caps with high dollar bolts, it is set-up for inserts.
It also has hollow dowels around each main bolt too register the cap. This equals
repeatability.

If you look through Logan's photobucket and double click too super enlarge his
engine gives you a better idea of what happened. Only one piston got backsided,
that kinda eliminates a heating problem. It wasn't down the center of the skirt,
but more on the sides(more material too expand) and no place to go. It's not
a pin problem at this point.
 
Was it only one piston that was bad? I thought all 4 were pictured as bad.:confused:

I'd still like to see pictures of the strange shape of the counterweights.:)
 
D J.
How can you say this or some of this may be his fault??
If the builder assembled the engine, where or how can you determine that Logan /Jordan had any fault here at all?
Huh?
 
Last edited:
Kahuna said:
D J.
How can you say this or some of this may be his fault??
If the builder assembled the engine, where or how can you determine that Logan /Jordan had any fault here at all?
Huh?
Click to expand...

Because all we are is young and stupid. Don't you know that by now? Logan could've just went ahead and put a small block Chevy in it for little under 2 grand, but he dumped $4500 and a lot of faith into an engine builder so he could keep his grandpa's prized possension just like it was before he passed. (and I personally know he'd never do that anyways) Is it really that terrible that he is upset that he got a bad motor TWICE? The first time he never mentioned any names, to give him a second chance, even though he had EVERY right to from all of the stuff the builder tried to screw him out of. I've noticed before Logan ever even mentioned a word about the motor, people always constantly trying to prove him, and Jordan wrong, even when they weren't. I guess that's just what you get when people hide behind the internet. Some of the comments I've seen are absolutely ridiculous. Cussing at a 20 year old over the internet? You look really cool. No model a people I have ever met have acted the like the big bunch 5 year old I've seen lately. Maybe I should just chop mine up and make a hot rod so I don't have to deal with these arrogant people anymore.
 
Kahuna said:
D J.
How can you say this or some of this may be his fault??
If the builder assembled the engine, where or how can you determine that Logan /Jordan had any fault here at all?
Huh?
Click to expand...

I'm not saying this is what happened but, what if someone ran an engine hard at a constant high RPM like one would on a highway before everything was broken in? Would the engine fail in the same way this one did? When my engine was done years ago I was warned not to drive above 45 and to vary the speed of the engine for the first couple of hundred miles. I was also told to change the oil a couple of times during that break in period. Maybe insert engines are different than poured engines but I think a hard ride before a proper break in "could" cause what we see here.

Once again I'm not saying he did this, only that I was warned about it in the past.
 
Mike V. Florida said:
I'm not saying this is what happened but, what if someone ran an engine hard at a constant high RPM like one would on a highway before everything was broken in? Would the engine fail in the same way this one did? When my engine was done years ago I was warned not to drive above 45 and to vary the speed of the engine for the first couple of hundred miles. I was also told to change the oil a couple of times during that break in period. Maybe insert engines are different than poured engines but I think a hard ride before a proper break in "could" cause what we see here.

Once again I'm not saying he did this, only that I was warned about it in the past.
Click to expand...

The car is at Logan's house so I can't validate with the book we keep all the mileage in, but I would guess it had 1,500-2000 miles on it. I would assume it's well broken in by then. We had gone on several trips in it.

I wouldn't think that it would matter if it had inserts or babbit bearings. In this case, the bearings weren't the problem. It was the piston.
 
Status
Not open for further replies.
Back
Top