Another long term engine results

Post your R&D threads here, what are you working on?
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wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#1 Post by wistech »

Here's an original Nacs unicorn engine I updated 2 years ago. Its in for a freshen up and inspection.
When I first saw this one it had a piston pin access cover bolt fall into the metal oil pump gears. They finished the days last few races with no oil pumps.

More good news to the valve spring shimming update and cam bucket mods.. The cams are still perfect. No floating .

From the cleanliness of the piston its obvious she was starting to use oil. This piston was the original. It was actually wore out a few thousanths . Its got a mirror finish on the skirts . Thats rare . Usually they are galled all to heck from the crank bearing rip saw . This is just normal wear and tear . Or would it be abnormal wear. rolleyes.gif

The decomp was a powdered metal one . It will need just a little tightening but is much better than most.

Here's the 2 year old z400 bearing. The cage still has the coating on it.

This is nice . ZERO wear on the rod . I wasnt going to split the crank because of my confidence in the z400 bearing but curiousity got the best of me.

Sorry if the pics are not that great . Its the camara phone.

This will make the owner happy that just a piston and sleeve,new valves and back out on the track.

cannondale27
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Joined: Wed Mar 10, 2021 10:41 pm

#2 Post by cannondale27 »

How about the spring retainers?Gold aluminum or Ti

yamadjs08
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Joined: Wed Mar 10, 2021 10:41 pm

#3 Post by yamadjs08 »

Yeah!!! This is my motor! Im glad everything looks good! I was good about frequent oil changes and it looks like it shows. Im going to give you a call tomorrow (Thursday) and see whats up. Im still debating on head porting, I just need to talk to you about it. Thanks for posting pics and stuff, very cool!

fig
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Joined: Wed Mar 10, 2021 10:41 pm

#4 Post by fig »

Great, this shows you guys are improving our bikes. Nothing but good news!

Thanks for taking the time to share your knowledge.

kdeal
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Joined: Wed Mar 10, 2021 10:41 pm

#5 Post by kdeal »

Wistech,

The wear on the piston is a rare sight, because most non-updated Cannondales never get to that many hours of use before something else (usually the crank) would wear out. The piston wear is standard for a piston that is so short and lacks the support of a full skirt. But, that's one of the things that make the new breed of 450cc class motors so powerful. This should be the normal wear item, not the crank! Good work!

wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#6 Post by wistech »

Yes it is kind of wierd to just do a "standard" rebuild. I feel like Im missing something not having to weld holes in the cases and scraping the destruction out of the bottom of the crankcases. MMMMM good times. wacko.gif

wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#7 Post by wistech »

Another nail in the coffin for the idea that cams fail because of lack of oil. When I built the engine for Animalscannibal I found that one of his intake cam oil squirters had not been drilled into the oil gallery. Since then I have been checking many other heads for this problem and found none. Now on this engine both squirters were not drilled and feed zero oil to the intake cam. So the whle topend has only been getting oil from the exhaust cams and wouldnt you know it. No wear at all on these cams as well. The buckets were all perfect and slid free in the bores as well. Just something that should be checked by all builders no matter how rare it is.

cannondale27
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#8 Post by cannondale27 »

I agree.Rid the motor of the sticking bucket and shim springs to spec along with even proper hardness cams and the newer retainers we are good to go in valvtrain.It is amazing the difference in the wear pattern on the cams no more wierd crossways wear at all.Best of all some of the coatings Wistech has been getting show real promise even with lower hardness cams.Now the fun part can begin with different profiles and such for MORE POWER!

wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#9 Post by wistech »

Steve you asked about the retainers. They were titanium. No wear.

wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#10 Post by wistech »

It amazing how long you can ride with updates. No worries mate.

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