Major Hot Rods Stroker Crank Issue

[rablack21]

My friend and I both had to do a small notch on our 370's with +4 hot rods.  The notch is toward the top front of the crank case. The rod hits halfway between the piston and main rod bearing. It can be notched without separating the cases if you want to risk it.  Use a vacuum to suck shavings as you grind.

I get what you are saving. However, what I am getting at is Hot Rods is advertising this crank to not need any case machining or clearancing. And according to Eddie, previous style ones have not needed it. If I purchased the stroker crank and their directions said to machine the cases, then I would be ok with that. But that is not the case here. People need to be aware of this issue.

[jfwyatt1]

the crank +4 hotrods crank i used when i put my cousins motor together a couple of years ago didnt need any machining and when he switched to a prox cylinder the following year he never said anything about having any problems then either.

[jcs003]

mine also needed notched to clear cases.

John

[jason_bolton355]

I had to massage rod and cases on mine just did this 2 weeks ago

[udontknowme]

When using a stroker crank or a aftermarket connecting rod, experienced builders install the piston in the cylinder on one case half with the crank installed and check for this common problem.

yep its always a good idea when using nonstandard parts (longer rods, heavier duty rods, longer strokes) to chuck the crankshaft assembly in one case half and install the cylinder and piston to see if theres any clearance issues

I have been where you are now.

been there myself. although i feel the better option is to take the material out of the case (if theres sufficient material) rather than cut down the rod big end

 

Hot rods will probably tell you should have checked for clearance before final assembly.  

if they use the same rod on a standard stroke and +4 it doesnt suprise me of this clearance problem. they simply had a brain fart and probly forgot the +4 needed the rod machined in order to be considered a drop in component.

[rsss396]

Hot rod does machine the bigend down to save you from machining the whole case bottom, but you have to remember the pin is now 2mm farther away from the crank center line and it is not a smart move for them to machine even more of the rod for the needed clearance.
They should have been more informative of what is needed when installing there crank for sure but IMO you are building a stronger setup than one with the rod ground down even farther for the upper case clearance. I have built probably 6 stroker 250r's and every one had the cases clearanced.

[rablack21]

According to Eddie, none of the previous hot rods cranks #4107 have needed additional clearance. He said that he noticed that they just recently changed how they were machining the crank rod end and it looked different. So clearly they were producing a drop in stroker crank that does not require clearancing of the cases.

The simple fact is , this is false advertisement and a design failure on their part. Just trying to pass this information on to other potential future buyers. I will get my engine taken care one way or another, just making people aware of this issue. Hopefully, they will recognize their mistake, fix this, and go back to their original process or alteast stop advertising these as drop in cranks with no machining required.

[Jerry Hall]

...............you are building a stronger setup than one with the rod ground down even farther for the upper case clearance.

Yes, Yes Yes,

Leave the big end of the con rod alone and clearance the cases.  Machining the big end of the con rod reduces the RPM where the big end distorts enough to stop the rollers from rolling.  

The new rods (copper coated) are a better rod than the old (non copper coated) rods.

[Tbone07]

Sounds like they updated the product without updating the documentation

[rablack21]

Here are some pics of the culprit crank rod and machining. If you look closely, you can see the high point of material they left on the crank rod that is causing it not to clear correctly. If they would have smoothed out the transition on the rod just a little more, the crank would have cleared like it was designed to. It is possible that this is just a machining error. Perhaps the cnc program was not set to transition enough of the material off. I still haven't heard anything back from Hot Rods yet.

[Burns363R]

FYI i have never notched my cases for my +4 hot rods cranks. they are roughly 1-2 year old cranks.  But still.

[Jerry Hall]

Some guys have their cases machined for the big bore cylinders and some guys hand grind their cases.  This fact may help explain some of the inconsistency why some guys have to notch their cases on the old rods and some do not.

..........and all shops do not machine the cases so there is the same clearance between the sleeve and cases.

[rablack21]

Some guys have their cases machined for the big bore cylinders and some guys hand grind their cases.  This fact may help explain some of the inconsistency why some guys have to notch their cases on the old rods and some do not.

..........and all shops do not machine the cases so there is the same clearance between the sleeve and cases.

The way the cases are machined for big bore cylinders is not the variable here, the way the crank rod is machined is. If a person was using an OEM cylinder, no machining of any sort would be required to the cases for the Hot Rods stroker crank, according to Hot Rods.

[F-Red]

That's definitely a quality controlled issue. Hot Rods needs Process Engineers, to eliminate any issues when changing a process. You have my luck, Ryan. These things always happen to me. Good luck. I hope you get some compensation.

[rablack21]

That's definitely a quality controlled issue. Hot Rods needs Process Engineers, to eliminate any issues when changing a process. You have my luck, Ryan. These things always happen to me. Good luck. I hope you get some compensation.

Thanks Fred. My middle name might as well be "Murphy". LOL