Top End Rebuild on 2006 117 (got tips/suggestions?)

[SMCT]

They very well could have been straight when it was new, but the way it appears it's engineered, is that there is not enough support around that sleeve, to keep it nice and straight over time. It's not uncommon at all, for a race team to take a new block that is bored and honed perfectly, assemble the entire engine, dyno it through out the day, take it back apart, re-hone the cylinders straight again because they moved around, and pick up 6-10 HP. Not uncommon and it's done often. New blocks are always expected to move around, even if the tune up is perfect, but once it has it's second hone through it, they usually stay straight, unless the tune up has them banging around from detonation.

 

[SMCT]

The bottom of the cylinders have definitely moved around, but my findings that I mention in my post where not down past the middle to the bottom. It's nice to have the whole darn cylinder straight, but I am really just concerned about the portion that is from 3.0 and up because that's where it really starts to require the rings to stay perfectly round. When I do engine blocks in the shop, the entire cylinder is finished perfect and within .0001 everywhere. You can't fight something that is not engineered properly. It's like a catch 22. You can't make the sleeves overly thick because it won't dissipate the heat well and then the piston will fail. You have to find that happy medium with these air cooled cylinders.

Just to give you an example. When we talk about a cylinder that has been "really kicked around" we are talking about bore distortion that is .0020 to .0030. I've seen on a very, very bad tune up bores that where kicked really hard and where .0035-.0045 out of round. At .0015 my stones will start skipping and you can feel it without even getting into it with a dial bore gauge.

P.S. These engines should have been designed with 7/16th studs. What the heck where they thinking? On a bore that is 4.125 and a stroke that is 4.375, standard is always no less than 4 studs per cylinder and at least 7/16th. If each cylinder is making 55HP, that's 440HP at 8 cylinders. The factory 3/8th studs are of no special material either, and that makes it even worse for the ability to mechanically clamp.

 

[Th3InfamousI]

The bottom of the cylinders have definitely moved around, but my findings that I mention in my post where not down past the middle to the bottom. It's nice to have the whole darn cylinder straight, but I am really just concerned about the portion that is from 3.0 and up because that's where it really starts to require the rings to stay perfectly round. When I do engine blocks in the shop, the entire cylinder is finished perfect and within .0001 everywhere. You can't fight something that is not engineered properly. It's like a catch 22. You can't make the sleeves overly thick because it won't dissipate the heat well and then the piston will fail. You have to find that happy medium with these air cooled cylinders.

Just to give you an example. When we talk about a cylinder that has been "really kicked around" we are talking about bore distortion that is .0020 to .0030. I've seen on a very, very bad tune up bores that where kicked really hard and where .0035-.0045 out of round. At .0015 my stones will start skipping and you can feel it without even getting into it with a dial bore gauge.

P.S. These engines should have been designed with 7/16th studs. What the heck where they thinking? On a bore that is 4.125 and a stroke that is 4.375, standard is always no less than 4 studs per cylinder and at least 7/16th. If each cylinder is making 55HP, that's 440HP at 8 cylinders. The factory 3/8th studs are of no special material either, and that makes it even worse for the ability to mechanically clamp.

Good to know thank you for sharing your knowledge.

I recall someone in the past mentioning they did use a different stud. One of better quality. If memory serves me right it's Carlos and he has a history with racing cars back in the 80's so uses some aftermarket studs that he preferred. I can't for the life of remember the brand but I remember looking them up and you could order them from Summit or the likes.

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[Big Daddy 72]

That's a big piston with a long stroke. How long are the rods? I believe if memory serves me that is a sbc 400 bore that crank is only 3.75" with a 5.565" rod (factory length rods) everyone pitches those in the trash. 6.0" rod for that set up is pretty common now. Just curious on v-twin rod length. I know absolutely nothing about v-twins so the piston size was shocking but cool to know in comparison Where is the pin location to the ring lands?

 

[Big Daddy 72]

Very cool thread!!

 

[SMCT]

Yes, the pin is in the oil ring groove, so it uses what is known as a "ring groove spacer"

I'm not sure of the connecting rod center to center length, although it definitely looks long. If I was to take a guess at it, I would say it is somewhere between 6.800 to 7.000

 

[SMCT]

One of better quality. If memory serves me right it's Carlos and he has a history with racing cars back in the 80's so uses some aftermarket studs that he preferred. I can't for the life of remember the brand but I remember looking them up and you could order them from Summit or the likes.

ARP Fasteners?

 

[woodbutcher]

ARP Fasteners?

can't go wrong with them.

 

[SMCT]

Stumbled on this. Interesting read.
https://www.rbracing-rsr.com/113orca.htm

 

[john sachs]

That's a big piston with a long stroke. How long are the rods? I believe if memory serves me that is a sbc 400 bore that crank is only 3.75" with a 5.565" rod (factory length rods) everyone pitches those in the trash. 6.0" rod for that set up is pretty common now. Just curious on v-twin rod length. I know absolutely nothing about v-twins so the piston size was shocking but cool to know in comparison Where is the pin location to the ring lands?

Evo style rods = 7.440".
Rare to ever see a Harley stud break. They will pull out of the aluminum case.(case threads are the weakest link of the chain).
John

 

[Th3InfamousI]

Stumbled on this. Interesting read.
https://www.rbracing-rsr.com/113orca.htm

Interesting article...i don't how that motor would be streetable..but cool.

I have no idea what clutch could hold up to 400HP on an MC... Wow cool though

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[Big Daddy 72]

Evo style rods = 7.440".
Rare to ever see a Harley stud break. They will pull out of the aluminum case.(case threads are the weakest link of the chain).
John

Wow!! What a difference from a v-twin design to v8 I think 632 ci bbc isn't even that length!! Makes sense on the Alu threads though..I actually had a bike that did that.

 

[SMCT]

Today it was all about making a ring compressor tool. I have quite an arsenal of ring tools but since the oil ring ends up in the wrist pin area, it requires the pistons to be on the rods with it's rings in place, prior to dropping the cylinder down.

 

[SMCT]

Sunday 1/29/17

I was very disappointed to see that the factory assembled these engines, well at least mine, with oil rail end gaps that where close to .060. This is excessive and over the years there has a been a move towards reducing the normal .025-.040 spec. to that of .017-.020. They are finding that there is less oil getting past the rails at gaps of this amount. They refer to the tighter gap rails as "wc" or otherwise known as winston cup rails. Now with that said, .060 is way beyond any tolerable spec, not to mention that my rail gaps where lined up from the factory, which is double the trouble. In ordering new top and second rings, I did not order any rails and expanders as I was just going to re-use them until I found out that the current rails used from the factory are wrong. I stock a lot of ring packages and this 4.125 bore is common, so to my inventory I went and had a ring package that had the correct rails in it. Now the gap is .025. I did not have the wc rails for a 4.125 in stock, but regardless .025 is a heck of a lot better than the incorrect .060. I also decided to do a polishing as well as I was going back together.

 

[SMCT]

Now that the cylinders are on, I can focus a bit on the cylinder heads. A little shaping of the intake port and bowl.

 

[Th3InfamousI]

Now that the cylinders are on, I can focus a bit on the cylinder heads. A little shaping of the intake port and bowl.
View attachment 39653 View attachment 39654 View attachment 39655

Very cool! Knocked that edge down a little?

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[Jwooky]

Very impressive

 

[Hirter6Pack]

Very impressive

We have a lot of very impressive people and skills here and I hope they all stick around as long as I have a BigDog.
I know that last part sounded a little selfish but what can I say.

 

[Hirter6Pack]

Being selfish is what makes ya the #1 new

I'm still not on the list

 

[Big Daddy 72]

Your talking about the oil support rails due to the bottom ring land and the piston wrist pint sharing the same location. The 496 I just built had srp pistons double spiral locks and the oil support rails. My hands and fingers felt like raw hamburger after preping and installing all 8 pistons on the h-beam rods with the rings. The spiral locks are awesome when you slip and one slides up under your fingernail. Cool to see one going together! You do very clean work bro! Head looks nice!