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Boring a 351c


71ponymaster
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My sons car is a #s matching m code

Motors been rebuilt before to .040 an is wore to .045

Im sure yall have heard bout the inconsistancy in these

Blocks an far u can go. I have access to a sonic tester

An am goin to my machine shop this eve. Just lookin to

See if any yall have got any experience w this an

Got any advice. Any will b very appreciated. Thx. Steve

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Weve discussed sleevin. I have no experience there an am concerned bout reliability an longivity

Were plannin on it bein his daily driver

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If keeping #matching is important then sleeve it. I cracked a bore and the machine shop sleeved it and the bore next to it. It works fine and I am running high compression and rev it pretty good.

 

New blocks might be available soon.

'Mike'

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

 

Pics of modifications included in: [button=http://www.7173mustangs.com/thread-1973-convertible--3335]My Garage[/button]

 

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If done properly there is nothing wrong with sleeving but in the situation it is not cost effective. The M codes simply aren't that valuable. If it were a Boss or an HO it might be a different story. I would source a used standard bore block and bore it the minimum amount necessary to clean it up. Keep the old block in storage and let the next guy worry about it.

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.

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Find a machine shop that has, and knows how to properly calibrate and use, a sonic tester to see how thin the walls are (particular attention to the thrust sides). Even for a mild build about .080-.90 is a minimum for me. Sleeving all eight is a task for only the best machinists and is expensive (about $100 per hole labor, about $35-50 per sleeve, plus re-deck the block and check crank line bore). If done properly it will be better than new (less bore distortion and better ring seal). An option is a quasi-custom piston at +.045 or +.050. Diamond piston will do this and others as well. Still not cheap but less than sleeving all 8. Not matter what you do the the quality of the machine work must be spot on. Good luck on the build, Chuck

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Thx to all. Were gonna sonic test all cylinders tonight

If we can verify theres still .100 all around we will have options maybe

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Mine 351C-2V is bored out to .060" - no worries. I've let the engine run during cam break-in, ran it idling and all sorts of other tests to bring the temps up, and it hasn't seen anything over 200 yet (laser thermometer shooting in just about every place imaginable on the block, heads, water pump, intake, temp sensor, etc.). No forcing out of coolant, although I do have a burp bottle.

 

I also went with everything new - I'm sure the roller-everything options I went with have helped reduce friction (and friction-generated heat) greatly. The monster 7-blade fan probably hasn't hurt, either. The ceramic-coated headers is what gets me - I haven't seen any temps higher than 300 on the headers themselves - probably has something to do with the ceramic-coating, I'm sure. Things I've read about headers says this is not normal... but again, just idling vs. actual driving.

 

However, I have not yet had the car on the road (under load) with the engine compartment 100% sealed up (hood closed during normal driving conditions) - so I'm sure there will be a difference in temps when it's finally on the road.

 

If/when the engine's time comes due, I'll sleeve it then [if possible] as I trust my machine shop (so far, so good). If the engine grenades, I'll come up with another 351C block, and most likely will go with the exact same 2V set-up I have now - might go with Edelbrock heads though.

 

My opinion: I'm not entirely done formulating my opinion on .060" bores with my set-up, but I hafta say, "so far, so good." It seems like the overwhelmingly popular opinion is that Clevelands have are too thin-walled to survive anything over .040" - to which I say, "It depends on what you are going to use the engine for." If .060" was such a bad thing for the Cleveland's survival, then why do they have such a large selection of .060" parts for the Clevelands? I didn't have to "special order" my pistons or rings, after all - got 'em straight "off the shelf" from Summit Racing (no back-order... shipped the same day).

 

My theory is that the people with those opinions are wanting to race their Clevelands, so yeah - .060" might only be for short-term survivability in racing conditions... and makes perfect sense. But, just putt-putting down the road going to work or an occasional weekend outing - I'm willing to roll the dice. Worst case scenario: my 44-year-old engine that was seized up when I bought the car finally grenades - oh well. I'm not a racer... the car probably will never see over 100mph (well... maybe once or twice)... and I currently only roll about 6-7,000 miles/yr on my current daily driver. I like my odds. ;) :D

Eric

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All,

 

Just out of curiosity, I had to look up to see what the average cost would be to prep and sleeve the entire 351C engine block.

 

Machine Shop Prices source: http://www.simonsbalancing.com/hpv8.html

Cleaning block = $50.00

Inspect for Cracks=$20.00

Pressure check=$50.00

Check line Bore=$30.00

 

Installing sleeve and finish to size (most cases) up to 4.060= $110.00 x 8 $880.00 ?? ****

 

Torque plates on blocks (add) (if available)=$70.00

Block decking (milling head surface) Square on BHJ Fixture= $125.00

Line Hone Block with original caps (unless burned, loose, or mismatched caps) =$90.00

Install cam bearings (plus parts) =$30.00

Install freeze plugs (plus parts) =$15.00

 

So far $480.00 to do the basic machining to ready for re-build. Now, I would assume that each cylinder is $110.00 for a total of $880.00 to re-sleeve the entire block?

So, are we looking a potential of $1360 to bring this cylinder Block back to standard bore and ready for rebuild?

 

 

 

Aussie High Nickel 351C Standard Bore =$499.00

http://www.ebay.com/itm/Aussie-Ford-351-Cleveland-block-/271621905038?_trksid=p2054897.l4275

 

1971 72 73 351C COBRAJET 4 BOLT MAIN SHORT BLOCK in Pennsylvania -E-Bay= $1499.00

 

http://www.ebay.com/itm/1971-72-73-351C-COBRAJET-4-BOLT-MAIN-SHORT-BLOCK-D2AE-GA-1K29-PANTERA-MUSTANG-/390892322819?pt=Vintage_Car_Truck_Parts_Accessories&hash=item5b02ff8003&vxp=mtr

 

More input!

 

mustang7173

Thanks,

mustang7173 🇺🇸

"Courage is being scared to death but saddling up anyway" -- John Wayne

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Well from what ive read theres inconsistancy in the castings which variates how much u can bore w/o hitting a jacket. Ive read where jackets were hit at .040 over

Read where many are .060 over an runnin fine

Personally i agree w an earlier comment. Not sure an m code block is worth $1000 of machine work (at least at this point). If he redoes it later years he can decide to sleeve it

 

Either way were gonna sonic test it tonight an see what meat it has. How centered up all the casting is

Cooling wise im not too concerned. Gonna run an aluminum radiator an large 7 blade fan since daily driven. Hes young so i know shell see sum rrr's when cavin to pier pressure. Lmao

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Well from what ive read theres inconsistancy in the castings which variates how much u can bore w/o hitting a jacket. Ive read where jackets were hit at .040 over

Read where many are .060 over an runnin fine

Personally i agree w an earlier comment. Not sure an m code block is worth $1000 of machine work (at least at this point). If he redoes it later years he can decide to sleeve it

 

Either way were gonna sonic test it tonight an see what meat it has. How centered up all the casting is

Cooling wise im not too concerned. Gonna run an aluminum radiator an large 7 blade fan since daily driven. Hes young so i know shell see sum rrr's when cavin to pier pressure. Lmao

 

Let us know what you find out and decide how to proceed. Chuck

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Just like to add as well about the Australian blocks, that add is the biggest load of crap I've heard about these blocks. The only difference I have heard and been told about Aussie blocks is, apparently the Australian engineers modified the castings so that there was more "meat" in the bores and main bearing webs. Never ever heard that they are supposed to be higher in nickel content (maybe true, but doubt it) and no one else I know has either. The only thing you need to worry about with Australian blocks is the later blocks (79-82/84) had a smaller distributor shaft bore , from 13mm (early blocks) to 12.5mm in the later blocks. It's no big drama though just need to bore it out before assembly (have seen this done more than once) or use the smaller shaft dizzy. Also I have personally bored Australian blocks to .030 that have gone through to the water jackets, so just because it's an Australian block means sweet f/a. Sonic testing (as long as the operator is competent) is the only way to go on Clevo blocks now as they are at the very least 30 years old now. As for sleeving a block, absolutely nothing wrong with it ( as long as it's done correctly) and as c9zx has said it will your block better than new, but the costs involved are quite high ( bore and fit sleeves, hone to finished size, line bore mains, deck block to square) If your block can go to .060 safely then don't worry to much about it, as I have seen .060 blocks used as burn out engines and lasted for ages and didn't split a bore either. As long as your block tests ok then go .060 and you should not have any problems, especially in a daily driver that won't be revved hard all the time.

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We sonic tested all 8 cylinders in all spots next to a jacket. Smallest number we found was .133. Any thoughts?? My machinist says should b good

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I agree with 4VForever never heard of Aussie blocks being higher in nickel than any other Clevo. Lots and I mean lots of 60up Clevo's around in AU

He has all the vices I admire and none of the virtues I despise

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We sonic tested all 8 cylinders in all spots next to a jacket. Smallest number we found was .133. Any thoughts?? My machinist says should b good

 

I'd agree with your machinist then. If he's a competent engine machinist and the thinnest area is .133 and you're already at .040, then an increase of .020 overbore is still giving you a minimum of .113 and as someone else has said (c9zx I think) a minimum of .080 thickness is sufficient, then punch your block to .060 and you still have your matching numbers engine in the car. As I have said previously I have seen many clevo's bored .060 and have had no dramas, but then again I have seen them split bores on anything from a standard bore to .060. There is a big misconception about boring Clevo blocks past .030 as they are to thin, but to be honest I have personally seen more chev's bored .060 that have had dramas than clevo's. So mate if it's just a daily and it's not going to be revving it's ring out all the time, then all should be sweet.


I agree with 4VForever never heard of Aussie blocks being higher in nickel than any other Clevo. Lots and I mean lots of 60up Clevo's around in AU

 

Exactly right Luke, this guy is trying to make these blocks out to be something they are not. It's not like we had anything like with chev with the 010 020 high nickel content blocks, they were just standard cast iron blocks and this guy is just trying to dupe people into believing his B/S. The only thing I will say that we made stronger over here would be the crankshafts. Ask anyone that grinds them and they will tell you that sound of them being ground (heard this myself as I used to grind them and use to say back then about the sound) and the extra time it takes, because they are so hard.

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I agree. Should b fine. Gotta lot better thoughts on it now that its been sonic chkd. Not just boring into the abyss

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Haha. I have an AMC jeep and belong to several jeep clubs. There is the same rumor about the AMC 401 vs the AMC 304/360/390 that the 401 had a higher nickel content.

 

Anyways, sounds like you are good to go. Your machine guy knows older engines?

'Mike'

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

 

Pics of modifications included in: [button=http://www.7173mustangs.com/thread-1973-convertible--3335]My Garage[/button]

 

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I sure hope so. Gonna give him plenty of $$$ to get started tomorrow. Ya an his dad (72) has been machining for over 30 years an still wks in the shop a few days a week


Mustang7173. Thats def input!


I appreciate all u guys input. Ty

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the only advice I would offer is sending a request for information on the finished product by email. Not a face to face conversation...because people tend to tell you what you want to hear. If by email they commit to a tolerance/performance/reliability standard, you have it in writing vs a "hearsay" conversation. With that said I've always been lead to believe the 351 has thin walls and .30 to .40 is the most reliable. In addition it gives you "tolerance" opportunities if changes need to be made. Go .60 and your DONE!

 

67 Diamond Blue Vert

 

images?q=tbn:ANd9GcRveIaRU6OAzTfd2Mv6ypGH49BZcPU7MS_7PBKhiOmpmJJrHJ_B_Q

 

DUDE

 

LOL even my sig line offended somebody!

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The thing I'm having a hard time getting my head around is the idea that .020" - the thickness of 2 or 3 sheets of aluminum foil - makes such a huge difference in the survivability of an engine.

 

I get it that "more metal is more better." I'm not disputing that, or the trend of engines being more prone to blowing up with larger bores. It's just mind-boggling to me that with consideration to all of the pressures, friction, heat, stress, et al, that engines go through, 3 sheets of aluminum foil can make all the difference.

 

Another question: if .113" is "good to go" for milling off another .020", then what is the absolute engineered minimum tolerance for cylinder wall thickness? If it's less than .093", then I think it's safe to say from an engineering perspective that Clevelands indeed do not have "thin" walls and is just another unfounded altruism propagated most likely by some Camaro guys. ;) :D

Eric

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I would just like to point out that when you bore a cylinder .020" over you are only reducing the wall thickness of the cylinder by .010".

 

Also, my understanding of the term "thin wall casting" is it refers to the modern casting technique developed in the 40's and 50's to manufacture cast iron blocks. It is not a direct reference to the cylinder wall thickness of a particular family of blocks. The thin wall casting technique was developed to improve the quality and accuracy of the castings while making them lighter at the same time.

 

The anecdotal evidence regarding Clevelands is that .040" is the max safe over bore. That doesn't mean a Cleveland can't be bored larger with good results. As Chuck pointed out it is all about the wall thickness on the thrust side of the (thinnest) cylinder.

 

This has been discussed at length over the years on the FE forum as well as the 460 forum. The advice with regard to a 460 is that .060" is the generally accepted safe max overbore but many blocks when sonic checked can go .080 while some can go as far as .120".

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.

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I would just like to point out that when you bore a cylinder .020" over you are only reducing the wall thickness of the cylinder by .010".

 

Also, my understanding of the term "thin wall casting" is it refers to the modern casting technique developed in the 40's and 50's to manufacture cast iron blocks. It is not a direct reference to the cylinder wall thickness of a particular family of blocks. The thin wall casting technique was developed to improve the quality and accuracy of the castings while making them lighter at the same time.

 

The anecdotal evidence regarding Clevelands is that .040" is the max safe over bore. That doesn't mean a Cleveland can't be bored larger with good results. As Chuck pointed out it is all about the wall thickness on the thrust side of the (thinnest) cylinder.

 

This has been discussed at length over the years on the FE forum as well as the 460 forum. The advice with regard to a 460 is that .060" is the generally accepted safe max overbore but many blocks when sonic checked can go .080 while some can go as far as .120".

 

Good points, Tommy! ::thumb::

 

I'd forgotten that boring .020" diametrically only yields .010" of material from the radius of the bore. So technically, the thinnest the material will get on 71ponymaster's block is .103", rather than .093".

 

Still amazed that 1/10th of an inch can still stand-up to the hellish environment inside our engines, though. :-/

Eric

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