351w block needs honing?

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Tataocb

Well-known member
Joined
Jul 11, 2016
Messages
67
Reaction score
0
Location
Houston, TX
My Car
1973 Mustang Convertible 351C 2v, auto.
A guy is offering this 351w roller block as part of a trade. He's like an hour and a half away so I have not seen it in person. All I got is some pics and was wondering if you guys can tell based off the pics, if the cylinders need honing. The guy says he builds engines for a living and this block would not need any machine work.

Thanks,

1a491429f65042534b3cfd948aacc899.jpg


f7929605ffc4e569e32560bcdb3bfe3c.jpg


39a9974b1788d9bde8c0c4a0cb0d8353.jpg


Sent from my SAMSUNG-SM-N910A using Tapatalk

 
They look like they could stand to be honed (not bored) Overall it actually looks pretty good, but pictures are not a reliable way to go!

Measuring taper of the cylinder bores would really be the only way to tell.

Honing is barely machine work ;) You can do it yourself if the bores are not excessively worn.

It is very clean-I'd be curious about that.

 
If you do not intend to put rings in or do anything then you don't need to hone but you should use a bore indicator to check for taper and out of round along with size. You can use telescoping gauges but you need to be experienced in using them.

The reason for honing the cylinders is when new rings are installed to allow them to break in. if you put new rings in a glazed over bore they will not seat and if there is any ridge the new rings can go up and bump the ridge and crack the ring lands on the pistons.

I personally take no opinions from people selling anything. I have seen some sorry engine work come from experts in the past.

 
I agree with Jeff. You can pick-up a cylinder hone from a local auto parts store, or even Harbor Fright, and run it through the cylinders (after the engine's been taken apart, with the pistons removed).

It does look pretty clean, but the surface rust pattern on the top cylinder of the first picture tells me it was sitting for awhile with that piston at TDC (the rings coincide with the piston rings & gaps).

If nothing else, and if you don't trust the guy, have a machine shop check it out for peace of mind. A little surface rust is no big deal - putting that engine back together and firing it up would remove that little bit of surface rust within the first few minutes of running - it's amazing what heat does for that. But, I'd want to know for sure what I had before going to the time, effort, expense, and hassle of putting something unknown together... I'm just not that trusting.

 
A quick way to check to see if it needs to be bored (and from the pics, I'd say it does), is to see if you can catch a fingernail on the ring ridge. That top cylinder looks like someone already honed it or ran a ridge reamer on it. You have to check cylinders that haven't been honed or reamed for the fingernail trick to work. Of course, an inside mic or dial bore gauge to check taper on the entire cylinder is the way to go. I agree with prior poster(s) that it looks like at least one cylinder sat with water in it for some time.

 
I discovered a broken skirt on the #4 piston of my Jeep's 4.2L I-6. Everything else was fine, otherwise. I wound up pulling it out, but not before I ran the ridge reamer in the #4 cylinder (it wouldn't come out, otherwise). Cleaned it up, ran the cylinder hone, got a new piston mounted with the appropriate rings, and put it all back together. It still runs great, 12-13 years later.

The absolute best way forward would be to have a machine shop go through it and adjust whatever needs to be done - no arguments there. But if you can check out the bores, clean up the cylinder walls and ridges (if any), and put it all back together while still getting good compression, that could be an inexpensive and quick way to get it running.

My point: don't write it off just because it's had or needs the ridge reamer taken to it. Just like anything else, figure out what you have and go from there. ::thumb::

 
Eric,

My point is that if it has a ridge large enough to catch a fingernail (that equates to ~.008" or more taper), the cylinder is worn beyond recommended limits.

...and I totally agree...I've been amazed at the various fixes that will run and for how long. When I was 19, I was at the track, jetting my 850 holley....I didn't bring enough fuel and had to go to the local gas station (on an air force base)...they only sold unleaded, so I put unleaded premium in it.....Evidently, there was enough difference in the fuel I was running and the premium to lean the engine out just enough....I ended up smoking a piston on the second pass.....I found a used std bore OEM piston and knurled it to proper clearance....that piston ran hard for at least a year.....it finally gave up after 7 or 8 races against a 930 Porsche....I had no idea until I tore it down, but it had knocked the skirt off of the knurled piston....at 7300 RPM and 135MPH (presumably)

 
Eric,

My point is that if it has a ridge large enough to catch a fingernail (that equates to ~.008" or more taper), the cylinder is worn beyond recommended limits.

...and I totally agree...I've been amazed at the various fixes that will run and for how long. When I was 19, I was at the track, jetting my 850 holley....I didn't bring enough fuel and had to go to the local gas station (on an air force base)...they only sold unleaded, so I put unleaded premium in it.....Evidently, there was enough difference in the fuel I was running and the premium to lean the engine out just enough....I ended up smoking a piston on the second pass.....I found a used std bore OEM piston and knurled it to proper clearance....that piston ran hard for at least a year.....it finally gave up after 7 or 8 races against a 930 Porsche....I had no idea until I tore it down, but it had knocked the skirt off of the knurled piston....at 7300 RPM and 135MPH (presumably)
Don't get me wrong, I wasn't trying to argue against your advice - ring ridge definitely indicates wear... however, I wasn't aware that acceptable number was so low. :chin:

I think the ridge on my Jeep was somewhere in the .5 - .7 mm range, actually - it was quite significant. :whistling: That's why I was thinking there was more room to wiggle (since I had success with mine).

Knurling - LOL. Yeah, I had some wheel bearings go South in the rear axle one time - so bad, that I had to knurl the mounting surface and the outside of the race itself for it to stay put and seated. I've since swapped out that axle. :whistling:

Good stuff, here! ::thumb::

 
The Ford manual is rather stringent...more so that I feel is necessary...they recommend no more than .001" out of round and .005" of what they call "wear" and .001" of taper. Piston to bore clearance is another factor to consider.

As a rule of thumb, you can catch a fingernail on .004-.005" ridge...that equates to .008-.010 on a diameter... well outside of recommended limits.

I've done the knurling trick on a wheel bearing bore, as well. :) One case turned out badly...it was on a customers Jeep Cherokee...it had tapered rollers on the rear wheel bearing...the owner didn't want to spend the money on a new axle housing...so the boss had me knurl the housing....the customer lost the wheel & axle on his way up the mountain going home...thank God nobody was hurt.

Sorry for digressing from the OP's post.

 
I agree with basstrix, it appears to need boring. There is something weird with #5, it has a double ridge, which means to me that the top compression ring was broken, plus the discoloration may mean it had a bad head gasket. Antifreeze and water increase cylinder wear. Plus, you don't know what #4 & #7 cylinder look like.

This is one where buyer (trader in your case) needs to be aware.

 
Thanks for the help guys. The guy is pretty "motivated" to get the deal and is throwing in more parts on top of the block. I think I'm going to ask him for other parts as this block will most likely need some machine work.

Sent from my SAMSUNG-SM-N910A using Tapatalk

 
Back
Top