Carillo Rods - Worth the expense??

[al_roethlisberger]

Well, I asked this question some time ago, but thought I'd revisit it before the bike goes into the shop, and I order the parts.

 

MGNA finally(some 9 months later) <_ .....has gotten around to sending the replacement cases for my lemans and i intended add some fast bits while engine was apart.>

 

(As an aside: Although the cases came in, as per the previous sets shipped to Moto Italiano, they were just thrown together in a box with a little bubble-wrap and some shredded paper. And you guessed it, they are damaged. Fortunately they aren't actually broken like one set they received, but the starter bell apparently has some paint chipped off. I am to go up there tomorrow to inspect the cases and decide whether to accept them or not, or make MG send another set, properly packed. I suspect that unless the cases are really messed up, and it is only this one little chip, I'll just accept them instead of waiting another eternity for another set to show up, possibly damaged just as bad or worse in shipping MI told me that they complained to MGNA about the substandard shipping after two sets of cases showed up damaged, and then one subsequent shipment did show up packed better, with no damage. But then my cases showed up next, back to the old shipping method )

 

 

Anyway, along with Mike Rich 10:1 pistons, Megacycle Cam 620x9(x10 requires sinking the valves, and I'm not shipping my heads off again), and new valve springs(for the cam).... I was considering adding Carillo connecting rods to the mix.

 

The inclusion of the rods would add about another $600-700 to the cost of the project(rods' price, installation, engine balance)..... so I'm trying to gauge the real "seat of the pants" benefit, if there is much, from others that have ridden bikes with these rods fitted.

 

If on a street bike, that isn't ridden terribly aggressively, I'm trying to get a feel for if the reduced rotating mass will be that noticeable for the money spent(again, "is it worth it" other than "gee whiz" factor)... and also making sure that it's not a tradeoff, such as making the idle more finicky, or maybe making for a "less smooth" engine.

 

 

Also feel free to comment on the other modifications if you wish

 

My goal all along has been to get a true 90 well-behaved HP at the rear wheel, then I'm done. BTW, I have no logical reason why 90HP is my goal, other than that's about what my FJ1200 had before I bought the LeMans .....but there ya go.

 

Thanks.

 

al

[Guest vkerrigan]

Al,

 

From my car days past, the main reason people went to those types of rods were to handle a drastic increase in cylinder pressure and rpm. Since this doesn't seem to be the case, I would think its effect on horsepower would be minimal. But everyone floats their boat a different way. If you want the "uber" rods as a base for later mods or if its just exclusivity you desire, it may very well be worth it to you. From a power standpoint, I've never seen a thread here on running nitrous, and with the stock compression ratio, nipples already on the throttle bodies, etc., I would think it to be a relatively easy way to get a conservative 20 rwhp. With the nitrous though, one may need the higher performance rods.

 

Hope this feedback isn't too off tangent. I guess the bottom line is only you can decide what best suits your tastes. ................vk

[gthyni]

Balancing as part of tuning the engine is a good thing

in it's own right. So the costs of balancing and new rods

perhaps should be considered indepentently.

[al_roethlisberger]

Correct on both points:

 

- Balancing is indeed a good thing, but I probably wouldn't bother unless I changed the rods. It isn't necessary with Mike's pistons.

 

- WRT to power, perhaps I should clarify that I realize changing out the rods offers no benefit to power production, but does lighten the rotating mass, making for faster "spin up". Actually if power is simply the concern, the stock(heavy) Guzzi conn-rods are pretty bullet-proof from what I hear

 

 

Thanks, and looking forward to the thoughts of anyone that has personal experience comparing bikes equipped with the rods versus those not so equipped.

 

al

[al_roethlisberger]

An interesting perspective from Will Creedon, definitely food for thought:

 

 

The reduced rod mass wouldn't be detectable, nor will the change to Carillos have any effect on driveability, idle quality etc. Carillo rods are very uniform in weight, which makes it easier to balance the engine, but that is no advantage if the crankshaft, rods and pistons are sent to the balance shop anyway.

 

A good reason to use Carillo rods would be because you have an expectation that the originals are going to break in service. If that is not the case (depending on the rpm and power output you use) then I would tend towards getting the crankshaft and existing rods balanced to match the new pistons, and leave it at that.

 

Carillo rods are beautiful and reliable, but unless you expect to break the originals they won't have any practical advantage in your situation.

 

Will

 

[Baldini]

Al,

 

Get the engine parts balanced, you'll notice the difference, a smoother motor. from what you say I can't see how you would need Carillos - I've not had them but my understanding is they are strong rods for stressed engines. There's probably better ways to spend the money...brakes, wheels,chassis ... unless you're planning on one day pushing the motor much harder.

 

KB

[Guest dkgross]

ya know..it's getting to where you should have just bought the Ghezzi-Brian Furia instead.

 

[pete roper]

I'd have to say Al that since I haven't heard of any rod problems, (Apart from the recalled ones ) unless you are planning to start reving it to 10 grand on a regular basis I'd agree with Will and say don't bother. I have 4mm over Carilos in the hot-rod and they *are* beautiful but I got them because I was short stroking it and because I *did* rev it to 10 grand At which point it started torching its big ends lavishly and with gusto due to oil pump cavitation .

 

The gains you get from over-reving a Guzzi big block come at a price. At the end of the day it is still a hemi-headed, 2 valve, air-cooled shitbox and quite simply, even with the best porting job in the world, the volumetric efficiency will drop off as the revs rise. Yes, you can play with cams and pipes and stuff to make it work much better at the top end but it will make the motor a peaky, unrideable, pig apart from when you're going flat chat!!!

 

A few years ago one of the Oz bike magazines gave away a Carb Sport. They sent it to Barry Jones with express instructions that he should turn it into the most hairy-chested Sport imagineable. He tried to talk them out of it but they were adamant. So he built them a 100+ HP Sport C. It was won by an idiot in Bungendore and it wouldn't really pull below 5,000 and was a pig to get off the line. To get it to carburette up top the accelerator pumps on the Keihins had to be setwith the decay springs so firm that if you twisted the throttle with the engine off your boots filled up with petrol! It was an absolute shocker . Needless to say the owner, an *expert* reckoned he could make it run better, (Than Barry? I think not!) and it got progressively slower and less rideable until it munted it's gearbox, (The then, second, owner *fixed* this by putting some Nulon 'Wonder Snot' in the box ). Last I heard it was sitting in a chook shed in Goulburn covered in guano with a blown box, (Gosh! What a surprise!!!!). The original owner who won it traded it in on a BMW 'Funduro', quite possibly the most boring motorcycle ever built. I found that somehow apt

 

Basically, what I'm trying to say is its probably not worth it. Give it a lairy paint job instead and buy it some bling!

 

Pete

[al_roethlisberger]

OK, well it sounds like you guys have just about got me convinced to "save some $$"... which is a good thing

 

 

Thanks for all the feedback

 

al

[Steve G.]

I can understand basic hop up stuff, but Al, if you want to go real fast, push a squid out of the way and get a ZX10R. This is a air cooled pushrod 2 valve twin. As an engine is basically a self powered air pump, maximum efficency does not come with this kind of package.

Ciao, Steve G.

[andy york]

agreed with all of the above. If you want faster spool up, take the boat anchor, known as a flywheel on a Guzzi and have a pound or two taken off the outside .

I think something was wrong with your old FJ. I still have mine but shes rather burley now after the hormone treatments!

 

cheers andy

[al_roethlisberger]

....understood, and I'm not looking to make the bike into something it's not, just a little more oomph since I'm already "in there"

 

But I don't want to throw good money after bad if the benefit is negligible, hence my question about other's experiences, and thoughts about the "correct" application for these rods.

 

WRT to the FJ, you may be right. It had about 80k miles on when I sold it, and I never put it on a dyno.... so who knows how much power it was producing at the end But the ~90rwhp(maybe around 100 on a good day) figure was based upon what I'd read on various FJ reviews over the years

 

http://www.visi.com/~charlesr/fj/cycle_89.html

 

Anyway, I just set ~90rwhp as a goal a while back... no real solid reason, just a general target

 

al

[Guest Fonzarelli]

Anyway, along with Mike Rich 10:1 pistons, Megacycle Cam 620x9(x10 requires sinking the valves, and I'm not shipping my heads off again), and new valve springs(for the cam)....

It is my opinion that "sinking the valves" is not an effective way of gaining piston to valve clearence. Basically, this operation will hamper your intake flow due to the decrease in curtain area of the valve to seat. I'm surprised that his was reccomended to you. Maybe it was not.

 

How much piston to valve clearence do you have? How much do you expect the lift to increase?

 

I would consider a custom piston or machining the valve relief pockets for your needed clearence.

 

As a side note: I would strongly consider (while you have the engine apart) setting the piston deck height to ZERO. If you are currently running a negative deck height, a zero deck height will promote better combustion and more importantly, help prevent detonation. Even with a increased static compression ratio, your detonation will be less or possibly eliminated.

[al_roethlisberger]

Anyway, along with Mike Rich 10:1 pistons, Megacycle Cam 620x9(x10 requires sinking the valves, and I'm not shipping my heads off again), and new valve springs(for the cam)....

It is my opinion that "sinking the valves" is not an effective way of gaining piston to valve clearence. Basically, this operation will hamper your intake flow due to the decrease in curtain area of the valve to seat. I'm surprised that his was reccomended to you. Maybe it was not.

 

How much piston to valve clearence do you have? How much do you expect the lift to increase?

 

I would consider a custom piston or machining the valve relief pockets for your needed clearence.

 

As a side note: I would strongly consider (while you have the engine apart) setting the piston deck height to ZERO. If you are currently running a negative deck height, a zero deck height will promote better combustion and more importantly, help prevent detonation. Even with a increased static compression ratio, your detonation will be less or possibly eliminated.

 

 

Yeah, Mike is aware of all of this. The sinking of the valves for the x10 cam is not to accomodate valve/piston clearances, it is to keep the valves themselves from tangling.

 

His pistons are engineered with many of the issues in mind that you point out, as well as an improved squish-band and crown to reduce detonation and encourage a better burn.

 

I could go on, but then I get out of my depth to some degree.

 

Mike does this for a living, headwork, etc for race cars, bikes, and Guzzi's are near and dear to his heart apparently. After all, he does the work for the "Cooked Goose" LSR team

 

 

If you have more questions about his work, he loves to chat, so just give him a call:

 

http://www.cookedgoose.org/sponsors/richmotorsports.htm

 

 

al