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