Vintage Mustang Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
705 Posts
Discussion Starter #1 (Edited)
Hello VFMers once again I'm here seeking knowledge, this time about pistons. Popped the pistons out today. So much fun!

Now that my project is happily running and driveable on it's rebuilt 74' 302 it came with I've been tearing down it's 289 that it also came with. I'm trying to ascertain if the 289 is rebuildable (less than .030 bored over) in the next couple of years.

I was quite happy to find that it's a VIN numbers matching engine. From digging up old threads on here (thanks Woodchuck lol :) ) I found the block VIN location under an inch of muck. It's only a C code Coupe but still it's nice to find that.

While I'm awaiting proper tools for measuring the bores I was wondering if anyone knows how to ID those Ford 289 Pistons. The entire assembly looked pretty good inside, rotating nicely and surprisingly clean. I'm sure it's at least had head work done on it in the past if not more....but I see hints and signs of very OE parts.

I'm focusing on the pistons and here's what I've observed:

1) Have FoMoCo stamped inside; numbers I see are TPL21 on one side of the inner skirt, and C80E on the other. Latter matches the heads casting number.
2) I do not see any written indication they are oversize....doesn't mean they might not be.
3) Rod Bearings also stamped with FoMoCo and have 5 68 and then the part number. I mention this because per the VIN this car was built in July of 68. Maybe that's May 68? Some of them were showing quite a bit of wear on certain spots.
4) Rod Bearing in picture says C5OE-6211 AB which from Google I understand to be an original size bearing.

Is there any way to tell if the piston is a standard size or over size? I'll update when I get my dial indicator and measure out the bores.

Also maybe I don't know where to look but I could not find a full part number on the inside piston skirt. Just what I saw in #1

Thanks for reading!

Jonathan
 

Attachments

·
Registered
Joined
·
35,922 Posts
Replacement pistons were typically marked on their face with the oversize, eg. ".030". You probably have the original pistons since it appears the bearings haven't been touched.

When searching for a replacement piston, in the oversize determined by bore measurements... it'd be nice to get away with 0.020", if possible... I'd suggest a flat-top hypereutectic (high silicon) piston with valve reliefs such as the Silv-O-Lite 3101HC. It is very close in specification to the 289 HiPo piston, with .005" more compression height, and a 3cc valve relief. With your 63cc '68 2V cylinder head you should be between 9.0-9.1 to 1 static compression ratio... quite a bit better than the actual (not "advertised") compression ratio of around 8.1-8.2 to 1.

If you decide to go with a cylinder head with a smaller combustion chamber, like a 58cc aluminum head you should STILL be okay as the aluminum head has better tolerance to compression and the small quench distance will be better for detonation prevention than buying a "destroked" piston.
 

·
Registered
Joined
·
705 Posts
Discussion Starter #3
Woodchuck....I'm beginning to think you're a supercomputer that answers all times of the night and "knows exactly what the facts is". Thanks again!

Yeah the puzzle pieces are beginning to look like an OE lower block. I will be OVER the moon if this block has never been bored up and only have to take it up to .020 this would be a dream.

Not quite ready to build it yet but life is short why not enjoy it :) when I do I will make sure it is at least in the HiPo kind of range for gross power....and smacks the living tyrrany out of the 302 motor that is now in there. That thing has some superb torque and a nice growl but the P.O. intended it for a truck and not a Mustang.

I did scrub away the top of one piston with a can of brake clean. Could not find any signs of writing or even melted writing on it. Nothing remotely resembling .020 .030 etc on the sides or anywhere.
 

·
Registered
Joined
·
801 Posts
If you're really lucky, sometimes a stock block can just be ridge reamed, honed, cleaned, and stock bore pistons can be used too. It's not too common for a carbureted engine of this vintage, but when it's time, see what the machinist says. The extra cubic inches and 'power' added by boring are negligible, especially with stock valve sizes. Removing less metal just means stronger cylinder bores, better sealing, and in the future, 'one more rebuild' if necessary.

When it comes to rebuilding, extra money spent on balancing will make a big difference in longevity and smoothness. Your car will spin to higher RPMs without worry or fuss, but even just driving down the highway, you will notice. ALWAYS get your engine balanced if you're replacing pistons or rods.

Zero gap rings will usually get you somewhere between 2-4% more horsepower. and they're kind of a no-brainer, unless you're just trying to save every last dime. Not that much more expensive, and you will probably pick up an easy 10 hp from them.

Thermal coatings for the pistons, heads, and ports can net you about the same power increase - though for the price it's not always worth it. If you go with coatings, don't get cheap, because 'badly done' just means they'll flake off at some point. Swain Tech would be my first choice, and they charge $350 for a set of heads, I believe. For a fun street car that isn't going to be racing or see super heavy use, I'd probably skip coatings (excepting pistons, because they usually include it these days).
 

·
Registered
Joined
·
3,131 Posts
engine build

Grim, where on earth are you getting this ? NO, you can't ridge ream and then use new standard size pistons. Not ever. If there is so much ridge that you think you need a reamer, you HAVE to bore because of wear. Our shop teacher showed us a ridge reamer back in the 70s. He wanted us to see what it looked like. Then he told us to to never to use one. I have seen LOTS of people ruin their own block with a ridge reamer. Don't do it.
And the 'gapless' ring thing is just an advertizing scam. They don't do a damn thing for you. Plenty of folks with more experience than me have tested them, and they don't gain you anything. LSG
 

·
Registered
Joined
·
271 Posts
the vin says the build date is July 68 with a c code? I thought 289s were only the first few months of 68 model production
 

·
Registered
Joined
·
895 Posts
the vin says the build date is July 68 with a c code? I thought 289s were only the first few months of 68 model production
I have a build date of June 7th on my 68 C-Code.

Even though they ran out of 289 blocks, they kept building 289's using 302 blocks.
 

Attachments

·
Registered
Joined
·
705 Posts
Discussion Starter #8 (Edited)
@LSG and @68Hildago thanks for the comments, it is indeed an actual 289 and not one of the 302 blocks with 289 internals. Was hoping it would be! You can see it is stamped 289 in the lifter valley. I did decode the block casting number and it's a block from 1966. More research reveals that sometime into 1968 they were running out of 289s so substituted the 302 block. However, at some point during this they found a cache of stored 289 blocks and so those reappear for a time. This perfectly explains the 1966 casting on my 289. My heads show actual 68's by the casting #. As I said earlier VIN on the block matches my car and you can tell it was etched by Ford OE tooling at the time of assembly.

I'm fairly aware of the requirements to build a new engine right. If I had the equipment at our auto shop I could machine it myself and reassemble (I work in IT now but once was a trained auto mechanic in my early days and yes we did train to bore and hone). I will have a good machine shop build the entire long block though as it will then have a warranty. If they machine and I build I'd be on my own. I know some guys in VA/MD who are OLD school and are doing that for vintage cars for decades. This thing is not going back to stock pistons at 51 years (it ran at least 45 and was well cared for considering how clean it is) The taper and out of round will be too much. Will verify when I get my dial gauge :0) and do the math.
 

·
Registered
Joined
·
801 Posts
Now that I am not up at 4:30 in the morning wishing I could sleep, and thinking more clearly, I DID offer some poor advice. I was putting several thoughts together and managed to come up with something pretty dumb. You're right about the ridge reamer. If your cylinder's worn enough to use one, you definitely need to bore your engine and true it up. You CAN sometimes use stock bore pistons on an old engine though, and if it's in good enough shape to make that happen, you should.



However, there *IS* a demonstrable improvement made by gapless rings, and while small, it does apply to all engines, be it street or dyno queens. I'm not saying that I've personally done back to back runs to prove it, but people like David Vizard have, and I tend to believe their information. If you want to argue that the power gain for it isn't worth the cost, then you go right ahead. Reducing blowby to near 0% has always seemed like a good idea to me. It's especially true for blown or nitrous engines, because you can run more clearance, giving the rings more room to expand, while not allowing more blowby.
 

·
Registered
Joined
·
35,922 Posts
the vin says the build date is July 68 with a c code? I thought 289s were only the first few months of 68 model production
289-2V ("C" code) were available throughout the complete '68 model year. Interestingly enough, you could get a 302-2V in a Cougar ("F" code, base engine), but not in a Mustang!
 

·
Registered
Joined
·
705 Posts
Discussion Starter #12
Guys....I think I did this right after following the instructions for the tool calibration and zeroing out. The part of the measurement calibration that really Put me at ease was that when I put it down in the bore part past the ring travel area Which is still crosshatched it came back to my calibrated zero which is the 4”

Pics 1-3 are setting up calibration and 2nd to last is the bore past ring travel...last is how it looked at top (and bottom) of ring travel.

The 4” - 5” micrometer came with a 4” calibrating bar. These bores are 4” bores we know this.... the dial tool too came with a 4” measuring bar.

Inthink my bore dial tool days each line is .0005! Range is .0005 to .25 it says. This does not quite add up.

Each cylinder was consistently showing no more than the 5 line to the left from top to bottom of ring travel which is 10 increments times the value so 10 x .0005 = .005

So my bores are 4.005 inches? How is that even possible. Or is it 4.05. I’m confused there.

The increments on the gauge are really hard to understand. Can anyone verify what those are?
 

Attachments

·
Registered
Joined
·
271 Posts
That's interesting about the 289 all the way through the year. I didn't know that. There is a lot of conflicting data out there.
 

·
Registered
Joined
·
705 Posts
Discussion Starter #14
So getting back to this image.....I think I've figured it out with fresh morning eyes, coffee and a co-worker motor-head. If each tick mark is .0005 than each two is 1/1000th of an inch. So my bores are reading solid all around at 4.005.

This is half way to 4.010 which would be at the "10" mark on this gauge. This is INCREDIBLE for a 51 year old engine. Wow!

So I'm good to have it bored to 4.010. I'll have to look at the Ford shop manual to see if this incredible 4.005 deviation is even out of spec. Original pistons, bearings, crank and maybe cam and matching VIN....I'm awestruck by my luck here.

@Woodchuck, @GypsyR what do you guys think? Good measurement? Bore it or leave it. I'll remeasure this weekend just to be sure. But I didn't see any deviation from this .005 in any cylinder at any angle. Plus the area below ring travel zero'd out to my 4" calibration precisely.

@Israel I'm not quite ready to build this motor it's an unexpected GEM. Maybe in a year or two. But I could do a build thread on all of my restoration work with the 302 and interior so far!
 

Attachments

·
Registered
Joined
·
35,922 Posts
Yes, each "tick" on your dial indicator is .0005" so what your dial is showing, in the picture, is .005". Now, bear in mind that you should have taken approximately 12 measurements per cylinder (top, mid, bottom and 3, 6, 9 and 12 O'clock at each level). Then you compare these against maximum out of roundness (.005"), maximum taper (.010"), maximum diameter (4.0024").

Now, it's been a long time since I did any machine work, but there is typically a MINIMUM amount of material that can be cut which, IIRC, is around .005", so what you're probably going to end up with is a .020" overbore, as a .005" cut will increase the diameter by .010" overall. Run this by your machinist and then provide him with the pistons and rings so he can match the finished bore size to your components.... He (or she) is going to bore first, shy of the finished size, then hone to finished diameter to match your piston/wall clearance and plateau hone to match the surface roughness needed by your particular ring package.
 

·
Registered
Joined
·
3,131 Posts
engine build

Js, so, you have .005 wear. No problem. You could hone it and go. We don't like to see new rings if the taper is .008 or more so, you are under that limit, but it wouldn't be perfect. But, you DON'T bore to 4.010, at least not with out spending MAJOR dollars on custom pistons. it really isn't cost effective.What you should do is get new pistons, Silvolite 3101HC, in .020 over, an off the shelf size. Your rings should be Hastings 2M139, also in .020 over. And your machinist needs those pistons in his or her hands BEFORE you bore. If somebody suggests boring first and then getting pistons, take your stuff and run the other way ! LSG

Grim, plenty of guys have tested the gapless stuff on engines on the stand. The big money guys have also found nothing is gained over normal rings, when tested on the dyno or the racetrack. Its an ad gimmick. Some of the raceguys spend more than you & I make in year on one engine, and they say normal is better
 

·
Super Moderator
Joined
·
10,054 Posts
So getting back to this image.....I think I've figured it out with fresh morning eyes, coffee and a co-worker motor-head. If each tick mark is .0005 than each two is 1/1000th of an inch. So my bores are reading solid all around at 4.005.

This is half way to 4.010 which would be at the "10" mark on this gauge. This is INCREDIBLE for a 51 year old engine. Wow!

So I'm good to have it bored to 4.010. I'll have to look at the Ford shop manual to see if this incredible 4.005 deviation is even out of spec. Original pistons, bearings, crank and maybe cam and matching VIN....I'm awestruck by my luck here.

@Woodchuck, @GypsyR what do you guys think? Good measurement? Bore it or leave it. I'll remeasure this weekend just to be sure. But I didn't see any deviation from this .005 in any cylinder at any angle. Plus the area below ring travel zero'd out to my 4" calibration precisely.

@Israel I'm not quite ready to build this motor it's an unexpected GEM. Maybe in a year or two. But I could do a build thread on all of my restoration work with the 302 and interior so far!
Please do, I’d like to follow.
 

·
Registered
Joined
·
705 Posts
Discussion Starter #18 (Edited)
@Woodchuck, @LSG. Good to know! I forgot that .010 isn't standard so it sounds like .020 is the way to go. Then the engine can probably be rebuilt at least 1 if not 2 times more for future generations. No plans or budget yet but I'd like to do some tried and true hipo type of work and get it to a reliable 270 - 300 hp. I think only the crank will go back in most likely. Will keep some of the OE FoMoCo stamped stuff from 68' as heritage pieces.

Yeah I was wondering if just honing alone could do since the cylinders seem very uniform. This could not have been a very high mileage engine. I'm now wondering if the 64000 ish where my odometer went bonkers was actual mileage. I'd assumed it was 164k or more. B

I did measure many angles (top bottom, center and rotated 360 in each position and none of them were any more than the 4.005. It was a fairly cold night 45 degrees I'll re-calibrate, and redo the all proper measurements and record them this weekend in high 60 degree weather.

The ONLY time I actually bored and honed was on a junk block in auto school circa late 90's. So I will not be machining or honing anything myself :p
 

·
Registered
Joined
·
705 Posts
Discussion Starter #19
Final Measurements

So I discovered something I’m guessing most engine rebuilders know....I very accurately calibrated the tool today.

You get to the little area right before (like maybe 1/16th an inch) the top ridge of the cylinder bore. At that point the wear mushrooms out a bit.

If you measure by hooking the tool right on the lip edges of the ridge at top of each cyl wear will show to ‘mushroom’ out to nearly 4.010. I think in most cases the exact measure on my dial was 4.008-9 or so.

That must be where normal ignition detonation occurs while the piston is at TDC.

Well at least now I know that it’s going to bore out to 4.020 ?

But this wear level is still amazing for a 50+ year old motor. Must have been some quality iron block composition made in 66’ to 68.
 

Attachments

1 - 19 of 19 Posts
Top