Moparts

BPE 4.250" Crank/OEM Block

Posted By: BPE

BPE 4.250" Crank/OEM Block - 04/24/11 02:25 PM

I've had several questions concerning clearance issues that
may be encountered using the BPE 4.250" stroke crank. I mocked
one up in a +.030" 340 block using both the Compstar 6.200" and
Oliver 6.200" rod.

A mile to the pan rail.

Attached picture 6600259-BPE4.250OEMBlock003.jpg
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 04/24/11 02:28 PM

Compstar rod will require minimal clearancing at the bottom of the bore(4.070") for rod bolt.

Attached picture 6600261-BPE4.250OEMBlock001.jpg
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 04/24/11 02:29 PM

As does the Oliver.

Attached picture 6600262-BPE4.250OEMBlock005.jpg
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 04/24/11 02:33 PM

Clearance to the oil pump and Milodon pick-up was checked with both
rods in standard and HV Melling 72 oil pumps. Over .100" in all instances.

Attached picture 6600266-BPE4.250OEMBlock017.jpg
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 04/24/11 02:36 PM

Not a concern with this block but, something else to check for.......to the dipstick boss.

Attached picture 6600274-BPE4.250OEMBlock018.jpg
Posted By: DavidDean

Re: BPE 4.250" Crank/OEM Block - 04/24/11 03:07 PM

Thanks for the post & pics !!
Posted By: Quicktree

Re: BPE 4.250" Crank/OEM Block - 04/24/11 03:08 PM

good tech be interesting how long a stock block lasted and what kind of power it made with that crank.
Posted By: Streetwize

Re: BPE 4.250" Crank/OEM Block - 04/24/11 03:27 PM

Looks like a lot less clearancing than I needed to get a 3.55 aluminum rod crank in a 318!!

Speaking of which, I'm thinking about using the 4.25 as a torque monster in a 318 block (since I already have one) Something with about 525 lb/ft at 3200 rpm to use as a tow rig.
Posted By: HEMIDARTS

Re: BPE 4.250" Crank/OEM Block - 04/24/11 03:55 PM

That looks great!!
I can see 1 of these combos in my future!!
Thanks again for trying to make the S/B market affordable, but still quality!
Posted By: S/ST 3040

Re: BPE 4.250" Crank/OEM Block - 04/24/11 04:28 PM

Quote:

good tech be interesting how long a stock block lasted and what kind of power it made with that crank.



Rod insisted on checking clearances in a stock block.
We could have used my R-block but, he wanted to show
what the average guy might have to work around.
Posted By: Dunnuck Racing

Re: BPE 4.250" Crank/OEM Block - 04/24/11 04:46 PM

Vic,
What are you waiting for? put one in your R block and go fast.You told me you could not find a decent stock crankshaft anyway.
Just
Let me know if you still need a crank and I will make some calls on Monday.
Keith
Posted By: Quicktree

Re: BPE 4.250" Crank/OEM Block - 04/24/11 04:56 PM

Quote:

Quote:

good tech be interesting how long a stock block lasted and what kind of power it made with that crank.



Rod insisted on checking clearances in a stock block.
We could have used my R-block but, he wanted to show
what the average guy might have to work around.

I understand, but I was wondering how the stock block would hold up under the extra stroke. build one and let us know.
Posted By: Dunnuck Racing

Re: BPE 4.250" Crank/OEM Block - 04/24/11 05:10 PM

I would not be too concerned with a stock block,properly prepared and depending on it's use.My 4.125 BPE crankshaft is in a stock 360 block and has been being abused for a long time with no issues.
I run mine to 6500 every pass,and used to wind it to 7000.People worry about longevity but how many of us would run something like this for 100,000 miles anyway?
Big block guys run strokes this big or bigger all the time.The lightweight parts that tend to go with the longer strokes really help IMO.
Just my
Keith
Posted By: Quicktree

Re: BPE 4.250" Crank/OEM Block - 04/24/11 05:26 PM

Quote:

I would not be too concerned with a stock block,properly prepared and depending on it's use.My 4.125 BPE crankshaft is in a stock 360 block and has been being abused for a long time with no issues.
I run mine to 6500 every pass,and used to wind it to 7000.People worry about longevity but how many of us would run something like this for 100,000 miles anyway?
Big block guys run strokes this big or bigger all the time.The lightweight parts that tend to go with the longer strokes really help IMO.
Just my
Keith

Posted By: S/ST 3040

Re: BPE 4.250" Crank/OEM Block - 04/24/11 05:33 PM

I filled your block.

I wouldn't hesitate to build a stroked SB that sonic checked good though.

BTW, the problem I'm having finding a stock crank is, all of them
are .010"/.010", .010"/.020", etc. H-bearings are only available
in standard or .010" and I'm too picky with my clearances to buy
one already "turned".

That or they want stupid money for them.
Posted By: Leon441

Re: BPE 4.250" Crank/OEM Block - 04/24/11 05:48 PM

I would not anticipate any issues with steel rods on that crank. A little nip in the bottom of the cylinders and you should be fine. Be careful not to cut into water getting greedy with the grinder. Guys need to remember though, a stock 340 4.040" bore. A 318 is only 3.910". The diiference in bore .130". You only need to know half of that .065" when clearancing. This should not be an issue, but something to keep in mind. And unless you plan to run with bent rods or worn out bearings .015 is all the clearance you need.

Something else I have ran into big differences in rod length can change cause a clearance issue if you were already really close.

I have heard people cringe at the XR2 blocks worried about the cam tunnel. I wouldn't get too exited as it is nowhere close on an A engine block.

I have run BIG alluminum rods in the past and the internal oil pump was the only item that took extra work to clearance. Would run an external in the future on any build like this.

Now if someone wants to give away a XR2 with the lifters done and no oil leaks I will be glad to show you how a back yard hillbilly can make a huge engine on the cheap. LOL

Leon
Posted By: 1Fast340

Re: BPE 4.250" Crank/OEM Block - 04/24/11 07:10 PM

Quote:

I

BTW, the problem I'm having finding a stock crank is, all of them
are .010"/.010", .010"/.020", etc. H-bearings are only available
in standard or .010" and I'm too picky with my clearances to buy
one already "turned".

That or they want stupid money for them.



cant even find a stock forged 273 or 318 crank for good money? everytime i dont need one i seem to run into them in piles,its a shame i could have had a whole pallet of those cranks stached away for no money at all by now i think 318 poly engines have good cranks aswell.
Posted By: all spooled up

Re: BPE 4.250" Crank/OEM Block - 04/24/11 08:13 PM

rod do you have a list of compression hight on your pistons ??
i like to get a 4.125 or 4.250 crank i all ready have a set of 6.300 h beam rods 2.000 b end .927 s end
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 04/25/11 12:22 AM

There really isn't a specific compression height on the pistons I offer. What I do is have pistons made for your build. After the engineering costs we only need to stay within a few perameters. I currently offer a -17cc dish and a flattop for the 4.125". We can adjust for rod length, deck height, bore size, ect. So, it's like getting a custom piston without all of the costs associated with it. We are currently working on the 4.250" stroke combo's.

Rod
Posted By: all spooled up

Re: BPE 4.250" Crank/OEM Block - 04/25/11 12:34 AM

thanks
Posted By: gremlinsteve

Re: BPE 4.250" Crank/OEM Block - 04/25/11 12:58 AM

wow...if you guys had had this crank out a few years ago i woulda gone this route...
now i gotta decide hemi or build me one of these big inch LA motors.

steve
Posted By: 1Fast340

Re: BPE 4.250" Crank/OEM Block - 04/25/11 01:12 AM

Quote:

There really isn't a specific compression height on the pistons I offer. What I do is have pistons made for your build. After the engineering costs we only need to stay within a few perameters. I currently offer a -17cc dish and a flattop for the 4.125". We can adjust for rod length, deck height, bore size, ect. So, it's like getting a custom piston without all of the costs associated with it. We are currently working on the 4.250" stroke combo's.

Rod




cool stuff and very nice to see that its so close to just drop in!
just a few Q: im faar from going to start the next enginebuild since im not done with the engine at hand but would these rotating assemblys be capable of withstanding the forces of a twinscrew blower at 20pounds of boost and could a piston for this be designed within these parameters that are set? im starting to get some bad ideas about another 100cui in the future
Posted By: DJVCuda

Re: BPE 4.250" Crank/OEM Block - 04/25/11 01:19 AM

thanks for posting Rod - Good info right there!!
Posted By: Hitman340

Re: BPE 4.250" Crank/OEM Block - 04/26/11 02:49 AM

Rod, with the quality of parts you offer and the well thought out kits you have put together to make it almost fool proof for the DIY er. Not to mention the best value anywhere in the market place for kits made up of the same quality parts that you offer.Its easy to see your out to help people and not just not line your pockets.
I sure hope that any of you guys out there who are thinking of stroke n your SB be sure to take the time to do your research and then give Rod at BPE a call.
Posted By: DJVCuda

Re: BPE 4.250" Crank/OEM Block - 04/26/11 03:00 AM

Quote:

Rod, with the quality of parts you offer and the well thought out kits you have put together to make it almost fool proof for the DIY er. Not to mention the best value anywhere in the market place for kits made up of the same quality parts that you offer.Its easy to see your out to help people and just line your pockets.
I sure hope that any of you guys out there who are thinking of stroke n your SB be sure to take the time to do your research and then give Rod at BPE a call.


Rods first class to deal with & well said!
Posted By: cheapstreetdustr

Re: BPE 4.250" Crank/OEM Block - 04/26/11 03:16 AM

now if you would get on the deal with more gen III hemi cranks...that would be great...
cheapst
Posted By: Five9Dak

Re: BPE 4.250" Crank/OEM Block - 04/26/11 04:03 AM

Quote:


Q: im faar from going to start the next enginebuild since im not done with the engine at hand but would these rotating assemblys be capable of withstanding the forces of a twinscrew blower at 20pounds of boost and could a piston for this be designed within these parameters that are set? im starting to get some bad ideas about another 100cui in the future



I actually have the same question, looking to build an R block bottom end for some ported eddies huffed by a big twin screw. I would like to purchase the assembly from BPE since I appreciate the support they are giving the SBM crew.
Posted By: MattW

Re: BPE 4.250" Crank/OEM Block - 05/29/11 07:36 PM

Any news if the BPS 4.250 Crankshaft is being offered with the 360 main?
Posted By: HotRodDave

Re: BPE 4.250" Crank/OEM Block - 05/29/11 10:50 PM

I asked the same question a couple days ago...



"I plan to at some point but not sure exactly when it's going to happen. I have 4.125" for 360 mains if you are interested.

Rod"
Posted By: BPE

Re: BPE 4.250" Crank/OEM Block - 05/29/11 11:16 PM

As some of you guys may know I am a one man show and trying to get this deal going to benefit all of us. I have a fulltime job besides trying to do this smallblock mopar thing. The reason the first 4.250" were based on 340 mains is most available race blocks are available in this size. I do not want send the wrong message and I will not lead someone to believe something that is not going to happen, just to keep them on the hook. When it does happen Moparts members will be the first to know, just like always.

Rod
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