Question about HPE 4mil stroker crank

[bored&stroked]

Ok so I found the thread for HPE's 4mil stroker kit, really sweet kit for the price and whats included. I like the no case mods. My question is the port timing aspect. It said it was designed with 760's in mind, does it alter the 760's port timing or does it just not change it compared to before stroking? I ask because I want to run it with a 61x cylinder if possible and don't want to mess up the port timing. Not even sure if thats possible so I thought I'd ask haha.

 

[madd_dips]

@holeshot

 

[CD155MX]

Prob lots of good info here.

http://www.x-h2o.com/index.php?threads/hpe-4mil-bolt-in-stroker-kit.174406/

 

[bored&stroked]

I read threw that thread and wasn't sure on the answer. I pm'd him but haven't heard back, figured somebody on here would know off hand since the kit's been around for a bit now.

 

[CD155MX]

I think you are good with your 61X Cylinder.

http://www.x-h2o.com/index.php?threads/hpe-4mil-bolt-in-stroker-kit.174406/page-2#post-1858563

 

[bored&stroked]

son of a b....how did I miss that?????? Such a newb.

 

[Just4Fun]

It will work on 61x but im was designed for the TCylinder. Matt strongly urges using one against a X cylinder..

 

[x2mafia]

Yeah that ^^^

 

[bored&stroked]

It will work on 61x but im was designed for the TCylinder. Matt strongly urges using one against a X cylinder..

Dammit so now I'm back to my original question: does the stroker kit alter the base timing of whatever cylinder its used on, or keep the timing the same as original?

 

[x2mafia]

I think the combination of the drop domes and spacer plate effectively lower port timing on 62t and 760 cylinders. Plus for complete motors getting built there is "more meat on the bone" to port a 62t or 760 cylinder for more potential.

 

[ajmps1]

He likes the 62t cyl better because they are stronger than the 61x cyl. Tons of fun things to use those 61x jugs for still

 

[holeshot]

Sorry ive been a bit busy. I like the 62t cylinder MUCH better. The transfer allignment is dramatically better, auxillary transfer windows are 2mm wider than the x, exhaust and transfer timing are great even for stock stroke on the 701 62t but 760 a touch too much blowdown for stock stroke to feel as strong off idle as you would expect it to. Total loss can help there and hpe 4 or 5 mil kits wake the 760 dramatically down low. The 62t 701 and 62t 760 do not have the same port timing or transfer angles by the way. 760 has more exhaust timing about 4 degrees more, and 33 degrees blowdown compared to 31 on the 62t 701. The 62t cylinders are stronger but do require timeserts or heli coils so they can accept the 61x m8 exhaust bolts. I do think a slight amount if torque might be lost to the larger exhaust passages on the 62t compared to 61x but the benefits outweigh that quite a bit.
When Porting its very inportant to keep roof angles the same on opposing windows and trade pros know to avoid changing roof angles unless absolutely last ditch necessary for this reason. The 62t roof angles can go undisturbed for the most part when porting but the 61x has to be moved considerably due to factory misallignment a big plus for the 62t. We want minimal turbulence leaving the port window and a clean collision or merge between opposing transfer charges to minimize fresh charge from mixing with residual exhaust gasses to avoid as much charge dilution as possible. Turbulence in the dome is an entirely different situation.

 

[holeshot]

as far as stroker cranks and the different cylinders.
760 is great stock or ported with either 4 or 5 mil hpe kits.
The 62t 701 is best with 4 mil non ported and great with 4 or 5 mil hpe when ported.
The stock 61x will benefit from a 4mil hpe kit for sure. But due to transfer misallignment either a properly ported 61x or a swap to 62t cylinder is where the gains get serious. The 4 mil kit on the 61x will keep transfer timing within 1 degree of stock and exhaust timing will stay within 2 degrees. Blowdown will go down about 1 degree. So the stock 61x cylinder will possibly lose just a touch of peak rpm as in 100 rpm and gain hp from idle to peak rpm noticeably. Youll gain case volume and lift the sleeve up out of intake port and transfer cups so stock cases behave ported, youll gain dwell as the piston leaves tdc making better use of combustion, youll pump the cases better due to less dwell at bdc, and youll have added leverage at the crankpin, and you will increase displacement. All adds up to nice gains you will feel everytime you grab throttle. By the way 90% of flow in the reed duct is at the port roof so lifting the sleeve there is good good.

 

[holeshot]

You guys are always welcome to pm me on messenger "matt holeshot hobson" or visit my facebook page same name as above. If you want to discuss tech in a forum invite me in im happy to talk like anyone else im never claiming to know it all these are just my points of view and your not allowed to debate them lol just kiddin.

 

[bored&stroked]

Between the PM's and here you've answered every question I could come up with plus another or two. Thank you.