BLACK BEAST BUILD Slicktop R-Spec

I was just stating that it was definitely the same gear on both cams that broke and I know this because it wasn't the one he repaired.

Originally Thought it was the repaired one on both occasions but it wasn't

Could be something to do with that gear or just bad luck

Time will tell



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Why not go back to stock gears and enjoy VCT? That's what I did and the car is so much more drive able.

 

S2's ..my bad

 

Shit I knew that..I had jun cam gears lol...

 

Amazing...I'll post dyno graphs of the new runs when I cbf lol

 

Have you checked the intake cam bolt length? I've a few intake cams snap due to the bolt being too long and when tq'd down will bind inside the hole and cause fracture and it will snap the front end of the cam off. Nissan used 2 different length bolts so I'd double check that as well. I didn't know this until I started really checking parts I had on the shelf and in my bolt bins. Thankfully my bin that I keep all cam gear bolts for the intakes had 1 of each length and thats when I knew something was wrong.

My view is that you just stick with mechanical gears and run another set of exhaust cams and cam gears on the intake side. Better bolt pattern for keeping things fitted to the cam and much lighter mechanics for components. VTC is cool and all but a headache of sorts with sensors and specific cam gears. You can certainly gain the power or set up your relative curve with phasing which honestly is a better way of doing things from my experience. Good luck

 

Thanks for that .. will check the bolts
Why would they make 2 different lengths, ? (cams being the same)

I agree with the 4 exhaust cams but you are not going to get as wide a power spread as I have .
One of the objectives was to get fastest spool vs top end power .
The average with these turbos is 300kw at 4500rpm .I have 400rwk at 4500rpm

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power curve is speculative to the build design and work put into it. Not all builds are the same obviously but I wouldn't flat out say that someone couldn't have your power curve like you have.

As for the bolts...I've no idea either man. I went through all my intake cam bolts and some are longer than the other. Must be something they did with either the cam gear thickness at the bolt hole or the depth of the threads they ended up tapping in the snout of the crank.

 

could it be series 1 cam gears/cams and series 2 cam gears/cams using slighty different bolt lengths?



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more than likely. Its the only thing I came up with when I ran into the issue.

 

New BDE gears are in .

Definitely getting these balanced at machine shop and will see if I can reduce some weight .

 

Interesting, I also had a camshaft snap while using BDE cam gears.








However I want to make it clear that these cams were well used, they had been in the previous two race engines and were 20+ years old and had been re ground/built up at some stage in the past.

So they had seen a lot of race miles in their life and they snapped down a weak point, where the oil gallery for the VCT is.

I also run the BDE cam gears in my street Zed and have for years with no trouble.

But reading Rob's post and considering the weight difference between the non VCT Tomei gears and the BDE cam gears I wonder if there is something contributing. The gears have a lot of downward pressure from the cam belt and maybe the extra weight of the VCT gears has some impact.

No real conclusions, other than my old cams broke and I was super lucky as it happened just before the pit lane and didn't destroy the engine.

Did end up putting in some new billet cams and valves/lifters etc. So bit of a bonus as got to upgrade the cams.

 

I definitely think this is a contributing factor .




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This begs the question ??? Should one be concerned if utilising the gears OR is it also tied in with the cam shaft?

 

No definite answers Procky .

Time will tell

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What engine mounts do you and mikec run in the racecars? If solid maybe the extra vibration compounds with the weight thing.

 

...waits for mine to snap ...
Lol