Stroker worth the "trouble" ?

[oletshot]

Agreed with the reconditioning. But if the aftermarket bearing doesn't have some type of clearance, the oil will never get to the groove. Again, I'm not sure this condition exists, I find it hard to believe that a reputable bearing company could overlook this detail. Stranger things have happened though.

[Alex22]

My set of bearings from Engine Pro are from CLA (made in Australia) and they do have the squirter holes in them. The Primary source for oil on the cam is the oil passage that is drilled through the lifter holes from front to back. The oil is pumped into that passage and makes its way down the line as the lifters move up and down a little oil will get past for the next lifter and so on. I have to double check on the exact passage from the pump to the cam and mains tomorrow.

I'm sure if you started a pole in each jeep forum about whether or not your strokers cam failed you wouldn't have many yes answers. It only takes a few to cause a stir.

~Alex

[Flash]

I forgot one. I was just recently reading somewhere (here or the yahoo group) that some or all of the rod bearings don't have notches cut in them for the oil squirt hole in the side of the rod. That squirt hole provides the cam with oil. I'm not sure how true this situation is, but block off that hole and your setting yourself up for failure, unless you supply your cam with oil some other way.

I also believe the gains are worth the cam change. I just tried to choose a cam that didn't have so much more lift that it required stronger valve springs.

I remember reading the same thing.
When a rod is reconditioned, part of the process is resizing the large end. In use, the large end has a tendency to stretch, or become slightly oval. This is remedied by removing a small amount of material from the mating surface of the cap, reassembling the rod, and honing the bearing surface to a round condition. The process does make the rod slightly shorter, but if done correctly it should be limited to a few thousandths.

On the oil squirter...
The groove that the oil follows from the bearing and out to squirt on the cam is milled into the rod, not the cap. Reconditioning rods should nave no effect on the oil passage. The only time this passage may become blocked is if little care is taken in preparation, such as a defective or incorrect bearing, or possibly a burr or other debris in the passage after replacing rodbolts.

So... Although it is important to check the passage during engine assembly as it is important to check many things, reconditioning a rod and replacing a bearing "should" have no effect on its oil passage...


im hoping to spend some time with myy engine today. Ill see if I can get some pictures of a rod and squirter and get them posted if no one else has any... Yes, please do, as i don't thing there has been any pic with the focal point in this area of our rods


Q...
Has anyone considered cross-drilling the mains ? I have heard of cranks braking but not main caps......


k.

Are you taking about oil passages? or a 4 bolt main cap?

As i haven't pulled a rod out of my spare block, a picture would be grate!


Flash

[kris]

Im talking about cross drilling the oil passage inthe main journal. Its a popular race mod as the most oil is transfered from the oil hole in the block/upper 1/2 of the bearing while the hole in the crank is in proximity of that hole. Cross drilling the main doubles the potential flow of oil to the rod journal.

I went out an looked last night and judging by the location of the oil passage in the rod journal of my 258 crank, the rod journal hole is in line with the rod squirter hole when the rod is half down. Its several inches below the cam. It would need to be squirting when the piston is around tdc to actually hit the cam.

Ill take pix now...

k.

[kris]

Here ya go...




The mark on the cap is a stain. The passage in the cap is visible. On this journal the hole lines up with the squirter around BDC. Go figure. The groove in the upper shell would provide some pressure to the squirter until TDC, but I cant see it being that much.

Id have to think that the squirter has little to do with cam oiling and nothing to do with cylinder oiling. Youd get much more oil that high up from slinging off the crank in general than from the hole.

k.

[Flash]

Am i the only on that can't see this pic?


Flash

[John]

Yes. Switch settings on yer decoder ring. It does take a little while for the image to come up.
John

[Flash]

Haaaah, that better, took a will to find it .........is a decoder ring supposed to be black

I though that it was a passage that was drill upward and came out next the the H part of the rod beam.
That makes more sence

Flash

[kris]

I though that it was a passage that was drill upward and came out next the the H part of the rod beam.
Flash

Nope. It comes straight out the parting line of the cap. Squirts on the side of the pan and block well under the cam.

k.

[John]

From Mopar Jeep Motors 3rd Edition
Galleys extend downward from the main oil gallery to the upper shell of each main bearing. The crankshaft is drilled internally to pass oil from the main bearing journals (except No. 4 main bearing journal) to the connecting rod journals. Each connecting rod bearing cap has a small squirt hole. Oil passes through the squirt hole and is thrown off as the rod rotates. This oil throw off lubricates the camshaft lobes, camshaft position sensor drive gear, cylinder walls, and piston pins. (Slinger operation, not direct spray)
The hydraulic valve tappets receive oil directly from the main oil galley. Oil is provided to the camshaft bearings through galleys. The front camshaft bearing journal passes oil through the camshaft sprocket to the timing chain. Oil drains back to the oil pan under No. 1 main bearing cap.
The oil supply for the rocker arms and bridged pivot assemblies is provided by the hydraulic valve tappets which pass oil through hollow pushrods to a hole in the corresponding rocker arm. Oil from the rocker arm lubricates the valve train components and then passes down through the pushrod guide holes in the cylinder head, past the valve tappet area, and returns to the oil pan.( This provides most of the oil our cam lobe see's)
John

[John]

You might find this a good read. http://www.hesco.us/forum/forum_posts.a ... rill+crank
John

[Alex22]

Back to the OP,
Just something to keep in mind when building a stroker. You can't turn chicken shit into chicken salad, no matter how much mayonnaise you add. If you want to build a stroker and have reasonable expectations for it and want to keep it in the stock RPM range then you have nothing to worry about. You should also build your stroker knowing that the stock drive train components were designed with a 190hp engine and 28 inch tires. My local transmission re builder told me that he has seen a few AX-15's with the input shaft shaped off because the owners put in medium built 350 that just had too much power for the little thing.

Its a inline 6 jeep, not an indy car.

~Alex

[AaronJ]

So can the standard 4.0 crank be cross drilled?
would this be worth the cost?

[kris]

So can the standard 4.0 crank be cross drilled?
would this be worth the cost?

Yes they can. Its not that expensive. I'm not sure there is a benefit though.


On the ax15, its a medium duty transmission. Its input torque rating is around 280-300lb/ft with a GVW of around 7000lb. It uses the same 1.125" 10 spline input size as transmissions like the nv3500/3550, and the nv4500. Although inputs can break (its not a drag transmission) the real weak spot in an ax15 is the 3rd gear syncro hub. JeepSpeeders regularly break it.
A "medium built" small block will be putting out around 300-350lb/ft or tq. If you're doing hard launches or running +37" tires on a trail rig with a heavy foot, its gonna break. I wouldnt hesitate to run an ax15 behind a v8 for general trail or daily driver use. It is a good transmission.

k.

[John]

Here is a pic from the web of One of the crankshafts from Barney Navarro's racing motors. 1967 single turbo 550 hp 6000 rpm. And it is a factory casting.
John