4.375 Cranks, are they gone?

[Joey120373]

I’ve read here, and confirmed trying to buy one, that the Chinese 4.375 is pretty much out of stock everywhere.
Does anyone know if it’s going to be produced again?

As an alternative, I guess scat will custom grind a forged unit, wondering what that might cost? Guessing it’s around $2k?

Thanks

[blykins]

The last I heard from RPM, he was concerned about placing orders for crankshafts because he didn't know what the tariff situation was gonna be.   He basically let his warehouse supply in the US dwindle down.   Not sure if they'll be made again, I would assume so, he's just waiting for everything to die down. 

Scat can make you one, as you say.  The price is in the ballpark.  I do a few this way, as you can customize the stroke, rod journal size, extra options, etc.  They are nice pieces.

[427HISS]

I have to sell my new 4.375 MAHLE's if you find a crank.

[CaptCobrajet]

I really think that tarriff excuse is just that.....an excuse.  They ran out of 3.98 forgings before anybody mentioned taffiffs.  25% extra on the raw materials alone would not be a deal breaker for the market.  It would not be 25% of the cost of the finished crank, only the steel used in it.  That tarriff deal is so overblown, and the Chinese are smart enough to play on our politics.  Not the venue to discuss this I realize, but making them play fair is long overdue from our nation's standpoint, regardless of a person's political preference.

I think there was a very large batch made of each of those forgings, several years ago, and I think they are selling out at different times.  At some point, there will be more..... even if it isn't the RPM folks, someone will do it.  Tom Molnar has mentioned doing FE cranks to me.

As suggested, the Scat customs are nice.  More money, but a nicer product.  I am pretty sure 4.350 stroke is all you can go on their forging with a 2.200 journal size.

Most folks won't do it, but I sell quite a few Crower custom billets.  We can get anything made that will fit in a block, and they are absolutely perfect.  I just ran a 4.500 stroker yesterday.  Longest stroke ever in a non-SOHC that I have run.  It may be the longest stroke that has been run by anyone, but I don't know everyone who might have tried it.  It takes a 2" crankpin and about 6 hrs of rod clearance duty, but it cleared a .820 lift cam with mid 280s at .050 with the largest base circle that will fit on a standard cam core.  I'm rambling.....but a person building a serious piece for the long term should weigh the cost.  There are more American crank people like Moldex, Bryant, and others, but my experience with Crower has been 100% great.  It takes a while sometimes, but I have never seen a nicer crank.

[country63sedan]

Blair, I'd love to hear about that 4.5 stroke engine. I'd be interested in any details you're willing to share. I'm most interested in clearance between the rods and the cam. Thanks, Travis

[CaptCobrajet]

Blair, I'd love to hear about that 4.5 stroke engine. I'd be interested in any details you're willing to share. I'm most interested in clearance between the rods and the cam. Thanks, Travis

I actually had two of them made.  One is still on the operating table.  Billet Crower rods with 2" bearing size took almost exactly the same amount of clearance work as a 4.375 with 2.200 journals.  The back four rods needed clearancing.  Didn't even hit the screen windage tray....

[country63sedan]

How big is the bore? Any dyno numbers? Probably made diesel like torque 

[Joey120373]

Blair, I'd love to hear about that 4.5 stroke engine. I'd be interested in any details you're willing to share. I'm most interested in clearance between the rods and the cam. Thanks, Travis

+1

Blair, I would love to hear/see more details on these two builds. seems like a lot of extra money for an extra 30 cubes
but that's an extra 36-40 foot pounds of torque across the entire rpm range I suspect.
Sounds like an interesting build for sure.

*edit* Just popped over to Crowers web page, they list the FE custom billet at $3977.89 for those who are stuffing the piggy bank saving for one. That's a lot of cash per cube. Somehow I had it in my head that a billet crank was in the $2500-$3000 range, looks like I was way off. Definitely puts it in the cubic dollars category for me. 

Hows that quote go? "the only substitute for cubic inches is cubic dollars" how about, cubic inches AND cubic dollars! 

[CaptCobrajet]

If you ever want a billet Crower,  I could help you.  That is their price for a "standard" billet crank.  I am WD with them, and can get all kinds of options and can still sell one for that kind of figures.

Scat also does billets, just not quite as high of quality as Crower.  All the bells and whistles on a Scat billet approaches 3K now.

The custom forged Scat is probably the best bang for the buck if the budget is tight. JMO.

I don't want to say too much about the engines we put them in.  The folks that own them read here.  I'll leave it to them if they want to give any info on their engines.  Safe to say you can see 800+ ft lbs of torque if you attack it the right way.

[fekbmax]

X2 on the custom forged Scat crank. Very nice piece and a fairly quick turn around. 

[Joey120373]

Safe to say you can see 800+ ft lbs of torque if you attack it the right way.

well, there goes my retirement fund.......

 


   

[CaptCobrajet]

Safe to say you can see 800+ ft lbs of torque if you attack it the right way.

well, there goes my retirement fund.......

Just remember......you can't take it with you!  LOL

[jayb]

Blair just helped me get a 4.750" stroke Crower crank for my big SOHC.  Took 13 slugs of Mallory metal to balance it LOL!  Uses 2.100" rod journals.  This crank will be replacing the 4.600" stroke Crower crank with the 2.200" rod journals that I've had in that engine previously.  With the spread bore spacing and 4.500" bore it will be 605", biggest FE ever I'd imagine.  My last one made 830 foot pounds, this one should make  860+.  Hoping for 1050 streetable HP when I get it all finished up and ready for Drag Week (next year).

I ordered the crank in November, and just got it a couple weeks ago.  Crower sure takes their time, but the product is top shelf.

[Heo]

605",  5" short of 10 liters Im not worthy Master , Im not worthy (kneling and facing towards Minesota)

[CaptCobrajet]

I think your crank was a special case Mr. Jay.  I ordered those other two at that same time, and they came in March.  Your short rods and small counterweights required all that heavy metal.  The 4.500s have 6.700 rods and they balanced with zero heavy metal, and no drilled holes.  The wedge pistons are also much lighter than the SOHC.  We made 15:1 with only a .047 flat dome.