Why did Ford change the small block offset balance?

[cjshaker]

It's been 30 years since I've messed with small block engines, so my memory is pretty foggy on this stuff.
Why did Ford change the offset balance on small block engines in '82 (it was '82, correct?)? Did they change crank designs, piston weights or what?

I'm asking for a friend who has an '82 Capri with a 302 and standard shift. The car has had lots of backyard mechanic stuff done to it over the years and he's trying to undo all the crappy work that has been done. After having to pull the tranny, he discovered a 28oz imbalance flywheel, when it supposedly should have a 50oz balance. When he talked to the previous owner, he was told that he just used parts that he had laying around. I've been trying to help him out as needed. He needs to verify the engine year, but I'm trying to remember why Ford changed the imbalance in the first place. 22oz of difference is huge.

[WConley]

It was a weight reduction effort, to eke out a bit of vehicle fuel economy in the dark early 80's.  The 302 block and crank had several pounds of weight taken out. 

This was fine for the low stock power levels of the day, but these early 80's short blocks should be avoided for performance builds.  The mid - late 80's HO blocks and cranks were much improved.

Some discussion here:

https://www.cartechbooks.com/techtips/rotating-assembly-parts-interchange-for-small-block-ford/

[machoneman]

Yes, Bill has it exactly correct.

Interesting btw to see 60's-early 70's blocks and cranks next to the later lightened parts. I think starting in 1987 (could have been a tad earlier) and later Ford added back material for stronger blocks and cranks. Still, the '69-'74 series of 302 and 351 blocks are the most valued for strength as Ford didn't add all that much metal back for what became (302 Windsor at least) the very popular 5.0 Mustang engines.

[cjshaker]

Thanks for that link, Bill. It jarred some of my memory, which obviously needed it, considering all the info in there that I had forgotten.

I do recall Ford having issues with early '80s blocks. They were actually twisting under heavy loads and seizing up rotating assemblies. I remember my Dad and one of his friends, who worked in hot test at the Lima plant, having talks about the tests that they were doing in hot test, to figure out what was causing the problems. Apparently, they had removed a little bit too much weight (strength) from the castings.

[gt350hr]

   Actually Ford had 50oz flywheels in '63 , though NOT production. I have two "ASK" numbered , high nodular flywheels from an experimental "325" engine project built in '63. The crank rods pistons all had sequential ASK (or Advanced Engineering ) numbers on them. The added external weight was needed to counteract the increaded rod weight and stroke increase without redesigning the crankshaft counterweights. The 3.250 stroke was machined onto a "stock" cast iron raw casting crankshaft.
     As Bill mentioned the move to 50oz external balance in the '80s with the dramatically lightened crankshaft. Rpm was limited so the lightening worked until "racers" began getting big power numbers . This also compromised the "lightened" blocks causing them to split in half in many cases. As stroke and RPM increases neutral balance becomes a "must be".
      Randy

[WConley]

Funny how lightening campaigns sprang up from time-to-time.  One of the reasons I left Ford was the emergence of the bean-counters in the early nineties.

I was ordered to take a bunch of weight out of a four-cylinder crankshaft.  Never mind the fact that the dyno data showed that the crank was at its absolute minimum.  It would fall in half if we did anything else to it.  In fact, our group was pushing for a fully counterweighted internally balanced version of the engine.  The prototypes revved wonderfully and at least were a step in the right direction towards creating a Honda rival.

Aww hell no!  That would cost money and add weight.  Never mind ...    Meanwhile they were packing more five pound stereo speakers in the car (to cover up the terrible powertrain noise???)

[cammerfe]

   Actually Ford had 50oz flywheels in '63 , though NOT production. I have two "ASK" numbered , high nodular flywheels from an experimental "325" engine project built in '63. The crank rods pistons all had sequential ASK (or Advanced Engineering ) numbers on them. The added external weight was needed to counteract the increaded rod weight and stroke increase without redesigning the crankshaft counterweights. The 3.250 stroke was machined onto a "stock" cast iron raw casting crankshaft.
     As Bill mentioned the move to 50oz external balance in the '80s with the dramatically lightened crankshaft. Rpm was limited so the lightening worked until "racers" began getting big power numbers . This also compromised the "lightened" blocks causing them to split in half in many cases. As stroke and RPM increases neutral balance becomes a "must be".
      Randy

I had a '325' short-block back in the day. Mine used connecting rods different from any production piece. A later discussion with another owner disclosed that his iteration used a yet different rod in which the parting line was not at 90 degrees to the shank of the rod, but substantially at a different angle.

The engine in an MG-A I kept running when I was in school in Indiana had rods with that same layout. I discovered them after a loud 'bang' out on a road East of town and a tow back to the station that let our Rod club work on our cars in off hours. I pulled the head and couldn't see anything wrong until I discovered that one piston wasn't connected to the crank. Found another rod---cost five bucks---and had the crankpin turned while still in the block, and in the car. Patent machining gizmo belonging to a local parts store. They did it in the alley behind the store. New bearing, and new pan and head gaskets and we were ready to go. Can't get 'em like that any more.
KS

[gt350hr]

   KS,
      "My" 325 had the off set "tounge and groove" rods with a capscrew bolt. The cap was offset so the rod would clear without bore notching. Cast iron 1M crank "made" with a 3.25 stroke. 5 bolt bell housing , HiPo caps, Hipo counterweight, no balancer , HiPo cam , hand stamped ASK "assy" numbers. Should never have sold it LOL.
   Randy

[Dumpling]

Maybe those early, weakened, 80's blocks were what drove people to search for the (mythically?) better Mexican blocks during that time?

[Heo]

I dont know Mexican or mythical or what. I had a -74 302
i think it was
Probably came out of a Van .Ridicusly long dipstick for
the trans. One exh manifold looked like a 271 hp
 Beefier mains  bigger oil chanel from the
filter, bigger than it was recomended to bore it out to
in some book i had, bigger rodbolts,spotfaced not broached
 dont remember size now

[machoneman]

I dont know Mexican or mythical or what. I had a -74 302
i think it was
Probably came out of a Van .Ridicusly long dipstick for
the trans. One exh manifold looked like a 271 hp
 Beefier mains  bigger oil chanel from the
filter, bigger than it was recomended to bore it out to
in some book i had, bigger rodbolts,spotfaced not broached
 dont remember size now

Heo, turns out the Mexican blocks superiority was a myth. By weighing an uncleaned, used bare block next to a cleaned-up 302W block of the same year (or within 1 year IIRC) the Mexican block weighed a whopping....less than 5 lbs. more. Close inspection also showed the same architecture of the mains, cam tunnel, side rails and main caps. The Mexican Ford affiliate did get the molds for the 302 right form Ford USA so tha makes sense for sure.

Interestingly enough, when I ran the old 'Net 54 SBF Winsor 221-260-289-302-351 Forum as the moderator, lots of great info was posted for it's 17+ year run until that stupid TapaTalk bought out the old site. I factoid we all learned from a guy in Mexico was that when Ford lightened up the crank, block, etc. (as mentioned in the first post here) the Mexican Ford management never did adopt this change. Point is, even until recently Mexcio Ford was cranking out lots of 'old style' 302W blocks and cranks that mirrored the '69-'74 engines that were of a stronger and heavier construction than what we came to know in the 80's as the later 5.0 engines.

The 1974 block you mentioned was and still is highly sought after as the strongest iteration of the '69-'74 302W blocks.

[FElony]

The 1974 block you mentioned was and still is highly sought after as the strongest iteration of the '69-'74 302W blocks.

What about pre-'69 blocks?

[machoneman]

Easier to explain through this link: http://www.mustangtek.com/block/Block.html

Early 3.80 bore Windsor are a no go unless one sticks to the small bore size. Any true 289 Hi-Po block, all 4.0 bores, are good to go but virtually impossible to find these days as Tiger, Shelby Mustang and Cobra restorers sucked them all up some years ago.

In the list, any other 4.0 bore block is fine as well. Yet, the '69 to '74 up to blocks are the most produced, somewhat better and still somewhat plentiful.

[FElony]

Mustangtek doesn't really go into structural differences year-to-year. I was wondering why you used 1969 as a cutoff, as '68's should be identical. The story is that the bore length was slightly shorter on the 289 blocks, but otherwise same same.

Bottom line is I have about 20 '64-'71 engines, in and out of cars, about an even split between 289's and 302's. If the blocks are worth more than later roller castings, then how would I go about selling them for the extra bucks? Bare, built short blocks, complete?

What would be the best SBF forum these days?

[Heo]

Easier to explain through this link: http://www.mustangtek.com/block/Block.html

Early 3.80 bore Windsor are a no go unless one sticks to the small bore size. Any true 289 Hi-Po block, all 4.0 bores, are good to go but virtually impossible to find these days as Tiger, Shelby Mustang and Cobra restorers sucked them all up some years ago.

In the list, any other 4.0 bore block is fine as well. Yet, the '69 to '74 up to blocks are the most produced, somewhat better and still somewhat plentiful.

When i see that link, For some reason my Van engine had boss 302 rods. No heho en Mexico on the block and
not those round nobs pointing forward. I think i have the rods somwere at my dads place must look for them
some day

[machoneman]

Mustangtek doesn't really go into structural differences year-to-year. I was wondering why you used 1969 as a cutoff, as '68's should be identical. The story is that the bore length was slightly shorter on the 289 blocks, but otherwise same same.

Bottom line is I have about 20 '64-'71 engines, in and out of cars, about an even split between 289's and 302's. If the blocks are worth more than later roller castings, then how would I go about selling them for the extra bucks? Bare, built short blocks, complete?

What would be the best SBF forum these days?

No, they don't go into detail as do most any other site. Many engines installed in 1969 cars were actually cast in late 1968 by casting I.d. number (model year versus actual casting date). And yes, wall length does count for stroker applications. And I never mentioned value as that's up to the seller and buyer.

Nope, nothing worthwhile on a pure SBF engine site. Good stuff on car related (i.e. Cobra, Shelby) sites.

Never recommend any and won't. Kinda' like sending your pals to your fav restaurant and then they have a sucky meal!     

[gt350hr]

     Heo,
       The last 289 hi po "service" short blocks Ford sold were in fact the Mexican block ,289 crank, Boss rods, and cast pistons. A friend of mine bought one from the local dealer and was surprised when he went to use it and found the block and rods. The "myth" about the block being superior has been around for over 40 years and is NOT true. The caps are thick like a HiPo and that is it.
    Randy

[Falcon67]

I also recall some late or middle 68 289 production used the new 302 blocks.  I've had several emails over the years with pics of the 302 in the valley with the question "I thought it was a 289?". 

I have a 72 351W block with .020 over bores (needs touch up) saved in the shed.  I can pick up a 351C block, not far but a little.  I can't pick up the 351W block.  They are technically not supposed to be that much different but the double arm lift with your legs test says they are by a bit at least. 

LOL, file the Mexican block thing with all the "high nickel block" deals. 

[machoneman]

I also recall some late or middle 68 289 production used the new 302 blocks.  I've had several emails over the years with pics of the 302 in the valley with the question "I thought it was a 289?". 

I have a 72 351W block with .020 over bores (needs touch up) saved in the shed.  I can pick up a 351C block, not far but a little.  I can't pick up the 351W block.  They are technically not supposed to be that much different but the double arm lift with your legs test says they are by a bit at least. 

LOL, file the Mexican block thing with all the "high nickel block" deals.

Yeah, the 351C block (and engine design) was a great one save for thin bores. Had too many where at a .030 bore one could push a sharp ice pick right through some weird, dark looking areas on the lower cylinder walls, especially #5. I surmised long ago in casting, the oil filter mount somehow pulled away the poured cast iron, leaving the non-thrust walls on #5 really thin. The 351C Pro racers of the era did all pretty much have all eight sleeved, a big expense even back then. Too bad Ford never cast up a batch of much heavier-walled blocks for the racer set....they never did. 

[gt350hr]

  Bob ,
    Ford did in fact make some "good" 351C blocks for racers using SK numbers. The "366" blocks had 4.080 bores and were used in Nascar only. The last "good ones" were made in Australia ( all the patterns went there) at the Gelong foundry. The "good ones" have an SK or XE number instead of the normal DOAE  or D2AE casting number. "Production" blocks as you mentioned were horrible for core shift on #5 cyl. Yes THE BEST blocks were the "furnace brazed" as you noted.
   Randy

[machoneman]

  Bob ,
    Ford did in fact make some "good" 351C blocks for racers using SK numbers. The "366" blocks had 4.080 bores and were used in Nascar only. The last "good ones" were made in Australia ( all the patterns went there) at the Gelong foundry. The "good ones" have an SK or XE number instead of the normal DOAE  or D2AE casting number. "Production" blocks as you mentioned were horrible for core shift on #5 cyl. Yes THE BEST blocks were the "furnace brazed" as you noted.
   Randy
[/quote

Randy you are correct and yes, that I knew plus the Aussie connection. 

But, only factory sponsored NASCAR teams here in the USA got them or race major teams (read: long-time drag racing teams like Nicholson , Schartman, et al. Heck,even some nascent Can-Am and FIA teams got a few) that had a pipeline for those special blocks. The 351C runners in drag racing at least knew Ford only make a handful of these non-production blocks and I was told even they were used up damned quick as so many (in drag racing only) had to revert to furnace-brazed sleeves to OEM 351C blocks near the end of the less-than-500 CID Pro Stock era.

We knew a few of those 351C Pro Stock runners then here in the Midwest and the had those highly prized those blocks which btw they could hardly give away (Hi-Ported steel heads, complete engines, etc.) once the NHRA switched to the 500 CID rule. Had offers to buy complete or parted-out 750hp or so Pro engines for a song then but I didn't bite as we had all our bucks in Boss 302 engines.   

Yeah, what I should have said was the for mere mortals, a thick-walled OEM block available to all would have helped immensely to slay all those Chevys.  Imagine too a world-beater tall deck 400 CID stock thick-bore bore Cleveland engine that coudl easily go to 454 CID or so. Killer!   

[gt350hr]

    Ford at that time was desperate to make quality blocks. I have at least 7 different SK numbers for 351C blocks ( revisions) They tried "square" casting cores for the cylinders and multiple changes to the round cores . They tried slowing down the flow rate of the molten iron in order to stop "moving" the cores around during casting. The scrap rate on Cleveland blocks was the highest in Ford's history.
    Randy

[babybolt]

Only the first year or two of the Mexican block had "normal" 302 hardness in the iron, after that those blocks used soft junkier iron, must have been remelted SBC's.  You can see it in the bore wear, most the Mexican blocks worn out and needed at least 0.040" to clean them up way back in the day.

Then Ford made some 302 Versailles blocks with the HD caps around 1976.

After 1985, around 5 lbs or more was added to the 5.0L block, not sure if this happened in 86 or 87.  5.0L blocks have a bad tendency to crack outward from the front left #5 head bolt hole.  351W roller blocks have cracked in the lifter gallery.  Both 5.0L and 351W roller blocks are harder than previous blocks and usually don't have much bore wear.

A Ford engineer told me that in 1994 Ford built a new machining line for the 302 and 351W and those blocks made off that line have significantly more accurate tolerances.

[machoneman]

    Ford at that time was desperate to make quality blocks. I have at least 7 different SK numbers for 351C blocks ( revisions) They tried "square" casting cores for the cylinders and multiple changes to the round cores . They tried slowing down the flow rate of the molten iron in order to stop "moving" the cores around during casting. The scrap rate on Cleveland blocks was the highest in Ford's history.
    Randy

I had heard that (lots of revisions). Very strange though that Ford kept demanding (they must have) that even those special 351C blocks had to have water jackets between the cylinders! Heck, today one can even buy siamesed Windsor-based SBF's right from Ford! I guess they were trying to appease all the potential users where a NASCAR/FIA sports engine I guess they figured had to have full coolant circulation around each cylinder.

[pbf777]

Very strange though that Ford kept demanding (they must have) that even those special 351C blocks had to have water jackets between the cylinders!  I guess they were trying to appease all the potential users where a NASCAR/FIA sports engine I guess they figured had to have full coolant circulation around each cylinder.

     Yes, because when in service, functioning, this results in the most progressive dimensional growth change in response to the heat experienced by the casting throughout the cylinder's circumference.   And ideally one needs the cylinder wall thickness to remain constant about it's circumference also; this was a drawback to the "squared" cylinders as they did/don't remain as round when heated, but perhaps better than the "siamesed"-cylinder block castings.   The siamesed-cylinder casting configuration is such due to no other choice of chosen cylinder bore diameter vs blocks cylinder bore spacing limitations.   

     Scott.