Scat 221 stroker cranks
 

I know not many of you guys play with 21 stud engines, let alone hot them up, but....
a wee word of advice about the Scat 4" stroker crank for 221, part # 9000-221-4000-2000.
I purchased one of these some months back as I acquire parts for my next build, a 255 cu in 37 block with pumps in heads. It is winter down here in New Zealand, been a cold damp one. I've had the crankshaft 'stored' on my wooden workbench sprayed with rust preservative, and its rusted on some of the webs. I've caught it in time, but interestingly, I've got a pile of old Ford cranks stored on steel shelving 2" off a concrete floor that are as good as the day I filed them away down there. Chinese cast iron definitely different to Fords.
Anyway, I went to trial fit this Scat crank into a 37 block; no go! The front and centre main bearing journals, whilst ground to the correct dia, are too short. Obviously Scat have followed the later crankshaft dimensions [which have larger dia/shorter lengths].
I have advised Scat of this error, hopefully they'll reply, but in the meantime, anyone considering one of these cranks; be warned- they don't fit and you'll need to undertake further machining operations in order to make them fit.
Brianhttps://www.fordbarn.com/forum/images/icons/icon8.gif

Re: Scat 221 stroker cranks
 

My son-in-law worked for a major can manufacturer who outsourced their can blank manufacture to a Chinese company. The rejection rate was so bad, that they had to go to 100% inspection and found the rejection rate was 50% or more.

Re: Scat 221 stroker cranks
 

Ahhh just gets better hey Brian... That crank would have cost you big bucks too. They had better come good on this! ��

Re: Scat 221 stroker cranks
 

Brian, would that crankshaft have been a better fit in an earlier babbitted mains 21 stud, 221ci block? I know in the past those stroker crankshafts were special order from Scat, maybe made only as needed, and this one was incorrectly machined.
I have also thought about building a higher performance 21 stud engine, maybe using a special Merc 4" crank machined to fit, or possibly placing an order for one with Scat.
Let us know how this plays out for you with Scat.

Re: Scat 221 stroker cranks
 

Our buddy 'Gosfast' always speaks of assembly of later blocks with four inch cranks. His findings are the SCAT crank is a pain to fit. He always uses Eagle cranks, with SCAT rods. The Eagle rods also require machining to make work. So for him its got to be Eagle crank, Scat rods.

Re: Scat 221 stroker cranks
 

I installed an 8BA crank in a 37 block back a few ears ago.It was a test fit for a 4" merc crank. The shop that did it had a very good machinist and as you say the crank didn't drop right in. We didn't have a 37 crank to measure but the interference was the length of the center and front journals. He took a smal amount of material off the sides of the center and fron main journals, and the crank dropped right in. This could have been done in a lathe. Unfortunately we never did put a Merc crank in the block, but now we know how to do it. The engine went into Paul Howards Roadster.

Re: Scat 221 stroker cranks
 

I have used the SCAT cranks in later engines with no fitment problems. The only problem is either adding tungsten or doing weight removal at the throws, or both, to achieve balance. This is made more simple if using a 1.999 journal.

I am wondering if Brian's crank was in the wrongly identified box?

Re: Scat 221 stroker cranks
 

No, in all other respects the crank is right; all journals are ground to correct diameter, but the front and centre mains are of the same length as the later large journal [post 1939] cranks. This Scat crank has the double slingers on rear main to suit the 221 configuration. The other difference [no big deal- just use 81A 6211 bearings], is the width of the rod journals which mimic those of the post 39 cranks, which again are narrower than the earlier versions which ran flanged floaters. Rod journals are double drilled, probably to permit running Scat rods and Buick bearings, but I'll run 21A rods and 81A floaters.
I'm off to work today to machine in the required clearances. This machining would have been required had I adapted a 'real' Merc 4" crank, along with considerable grinding down of all journals, dealing with rear main seal [again no biggie- use 19B 6336 and 91A 6335 positive seal holders in the block/cap], along with purchase price and cost of shipping, total cost difference wouldn't be much.
But better material that doesn't rust the same!! Oh well, live and learn, it's off to work I go! Brian

Re: Scat 221 stroker cranks
 

Good info Brian, I was thinking of one of those cranks for a spare 37 block,
let us know how you get on.
I,m about to change out the engine in my 34(36LB) for the original 33 babbit eng,its the smoothest eng I have and went like a rocket in the 33,as you know ,they are nice engines.
Lawrie

Re: Scat 221 stroker cranks
 

Lawrie, Don't buy a scat crank! Crap of the highest order. I've just popped home from work, where I've been machining up the crank to suit a 37 block. Next problem is; the front main journal, after machining the back of it to fit the block is too short by about 1/8" at the front. This means the timing gear and everything forward of that journal is gonna be in the wrong place. Only way I can think of fixing this problem is gonna be to machine that journal smaller and shrink a sleeve the correct length onto it and finish grind sleeve to suit [after drilling oil passages etc].

Re: Scat 221 stroker cranks
 

Begeesus Brian what a fxxxup, you need to get a new no stress hobby like needle point or flower arranging. I know your the right man to get it sorted. Cheers Tony.

Re: Scat 221 stroker cranks
 

Thanks for the heads up Brian, I will drag the 37 block out and look at a ford crank to fit,
We have a scatt crank in the dragster (8ba) and in the 99a eng in the 33,both seem OK.
But obviously not the 221 one.Thanks Lawrie

Re: Scat 221 stroker cranks
 

Yeah, obviously Scat use the same casting for the 221 crank as the later cranks. The throws certainly resemble the later castings, not at all like the nice light 221 crank. And they're obviously unaware the front and centre main bearings need to be machined wider. All good now; I machined up a 1 millimetre wide spacer to go behind the timing gear, that will space it out the correct distance, and will drop the crank off at my machinist to just kiss the faces I've machined with his crank grinder and put a nice radius on each end of the appropriate journals. I spent a bit of time with a die grinder and fettled that casting; it is now a lot smoother. I'm a bit happier than I was yesterday when I discovered this problem.

Re: Scat 221 stroker cranks
 

Well at least you're moving along Brian. Im still screwed and cant find a decent 37 crank around here that hasn't had more than .022 of the mains already .. Really need a set of .040 flanged floaters to move on ..oh yes and there is the problem as you know of my machinist than cant find my bearing caps ..pfft!

Re: Scat 221 stroker cranks
 

You're probably already aware of this, but will mention anyway, a '36 LB crankshaft and/or an early 38 crankshaft, from a 21 stud engine, will also work in that '37.

Re: Scat 221 stroker cranks
 

The crank from a 1938 only 24 stud will also fit. The larger mains and longer crank started in 1939.

Re: Scat 221 stroker cranks
 

Yes boys , been eyeballin' plenty , long snout , short snout, damn Im sure I even saw a large journal one with double slingers..!

Re: Scat 221 stroker cranks
 

And just to complicate matters a bit more...Pilot crank has long snout, double slingers, double oil holes on rod journals, and will fit that block too!

Re: Scat 221 stroker cranks
 

Thanks for the information - damn shame these manufacturers don't just pickup ONE block for the years they are claiming they fit - to test/validate all of this stuff BEFORE they offer up products for sale. This is complete CRAP that anybody has to deal with stuff like this. And to make matters worse, you're way across the big pond - so "sending it back" isn't much of an option either. I'd make them pay for the work you had to do - it is the least they can do.

Re: Scat 221 stroker cranks
 

The Tex Smith flathead book had an article about a 37 engine that was modified for the Great American Race (GAR). They used a late 255 Merc crank with a lot of mods to work in a 1935 coupe. They wanted 3 3/16 standard 255 pistons and 4-inch stroke all in a little 221. They bored through the cylinder walls to get larger sleeves to fit. I know they turned the crank and it seems like that had to clearance somewhere else to get the 4-inch assembly to work but I'm not sure where. These things become apparent after you get a rotating assembly in there and start turning it though. It wouldn't take long to find any other clearance problems at that point.