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89 EF 4wd sedan
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Discussion Starter #1
Hi D series.org

I want to get people opinions/thoughts on something my engine builder pointed out.

I'm running bisimoto cams, and with the (standard) valves adjusted to take up the reduction in the base circle of the cam profile, the geometry is such that the cam hits the rocker quite high on the contact patch which is resulting in more lift than what is on the spec card that came with the cams.

We contacted bisimoto and we've been back and forward, but it sounds like something they haven't seen before. They've said that their cams in an otherwise stock head should be producing the specs that are on the card they provided.

It would probably run with no problems, but i'm worried that the point where it's contacting on the rocker isn't ideal and might result in faster wear.

I think longer valves will allow the geometry to be closer to ideal, but how much longer we're not sure.

Is anyone running bisi cams in their ZC and have had a similar experience?

TIA.
 

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Classic Man
Civic
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They are a joke, that company. My suggestion is that if they dont know their own product, how can you expect it to work correctly? I would sell it all before its used, as a new product, and move on.


I was able to sell my junkimoto parts, thankfully. Moved on to Colt cams and never looked back.
 

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89 EF 4wd sedan
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Discussion Starter #3
That's a fair question. That would really suck to have to sell the parts, but i see what you're saying. What's your bad experience with the companies parts?

I had thought people had reviewed these cams positively before i bought them. I think i had researched them on thezcr though, and i can't find anything anymore now that the site has gone belly up.

I think i had tossed up between the colt cams and the bisi cams, but just leaned towards bisi because it was a brand i felt more familiar with.

Even still, the lift isn't huge on the cams i have, so the 'problem' i'm having mustn't be uncommon. What are other people doing with their valve adjustments on reground cams? Are your colts regrinds?
 

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95 civic coupe
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1,358 Posts
I've used Rocket billet cams for about 3 seasons and have had good results. It helped carry the power up high which was crucial in drag racing and i didn't have to deal any rocker wear issues. As for bisi cams, I think the first batch was good as I know a one person that had good luck, but the rest all ended up with wiped out rockers.

Anyway, we are exploring with another custom cam for my next build. This one has never been tested and will have a bit more lift on both intake and exhaust as well as higher LSA to support the overall bigger induction of the new set-up. Danz also had great results with Colt cams although I've never had any personal experience with them. It might be worth asking Rocket and see if he can help and suggest a camshaft that could possibly meet your expectations.
 

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89 EF 4wd sedan
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Discussion Starter #5
I've used Rocket billet cams for about 3 seasons and have had good results. It helped carry the power up high which was crucial in drag racing and i didn't have to deal any rocker wear issues. As for bisi cams, I think the first batch was good as I know a one person that had good luck, but the rest all ended up with wiped out rockers.

Anyway, we are exploring with another custom cam for my next build. This one has never been tested and will have a bit more lift on both intake and exhaust as well as higher LSA to support the overall bigger induction of the new set-up. Danz also had great results with Colt cams although I've never had any personal experience with them. It might be worth asking Rocket and see if he can help and suggest a camshaft that could possibly meet your expectations.
Are you running longer than factory valves, or just factory length with rocker adjusted to suit?

In hindsight i probably would have gone with Colts, just so i don't have to dredge through countless soap opera style bisimoto related threads. It's hard to find any real useful info about them.
 

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95 civic coupe
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I had stock valves, but I went with ferrea now +1 intake std exhaust.
 

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Classic Man
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Yeah the Colt cams I have run have all been regrinds and I have never had an issue setting valve lash or with cylinder head components wearing out. Thousands of daily driven KM and hundreds of passes at the strip, maybe thousands.
 

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Discussion Starter #8
Yeah the Colt cams I have run have all been regrinds and I have never had an issue setting valve lash or with cylinder head components wearing out. Thousands of daily driven KM and hundreds of passes at the strip, maybe thousands.
Just to be clear, the lash can be set on my head also. It's just that once they've been adjusted, the valves will now lift more than what the cam card shows because of the angle they now contact the rocker due to how much adjustment is required.

Maybe i'm wrong, but is it common for the ACTUAL lift of the valve to be different to the lift that's listed on the cam card due to geometric changes that occur when you're reaching the end of adjustment on the rocker?

If that's the case, all reground cams would experience this issue? (listed lift vs actual lift)
 

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Discussion Starter #9 (Edited)
So just keeping this thread updated. I've contacted Bisimoto, and i should have an answer to this tomorrow.

An update on the problem though, i didn't realise that the concern is actually that the cam starts hitting the pad of the rocker off the edge with the OEM valve adjusted correctly. The OEM cams hit the rocker pad about 2mm or so from one edge, and leave the pad 2mm before the edge.

The bisi site doesn't mention the need for aftermarket valves so that's a bummer.

My options are to get longer valves, or sell these cams and go with fresh cut cores and not regrinds. Either way it looks like the cost will be about the same.

I'll keep this thread updated with a response from bisi for anyone else having similar issues in the future.

@FarmerD, out of interest, how much were your Colt cams? They don't have a price listed on their website.
 

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Classic Man
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My custom cam which I wanted power from 6000-9000rpm was expensive. But it was also LEGIT!! haha. Never had a bad thing to say about that puppy.

If you want pricing, I know, its not what you want to hear... Pick up the phone and call :)
 

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Discussion Starter #12 (Edited)
Lash caps + clearance on the rocker arm?
Supertech LC-65 should be suitable.
I suggested this to my builder and apparently lash caps do not suit the DOHC ZC valvetrain. He said the spring retainer/rocker is not compatible?... I'm going over to have a look tomorrow.

My custom cam which I wanted power from 6000-9000rpm was expensive. But it was also LEGIT!! haha. Never had a bad thing to say about that puppy.

If you want pricing, I know, its not what you want to hear... Pick up the phone and call :)
Yeah i understand that. I thought you might have had 'off the shelf cams' that are listed on their website, in which case it would've been easier for you to tell me rather than wake up early, call internationally and try and understand your crazy american accents :p

So i got in contact several times with Bisimoto and after a week of back and forward i eventually got an email (the 'techs' are never around to talk) that said "If you're concerned with the rocker geometry, lash caps are a method we have used with good success"... Which i personally find a bit of a cop-out. They're not saying that they acknowledge that their cam requires other aftermarket parts to work correctly... Also they mentioned they would be happy to help source lash caps... As i mentioned before, my engine builder said the retainer type on the DOHC ZC is incompatible with lash caps. Any thoughts on this? I'll be taking a look for myself tomoz.

Anyone recommend off the shelf valves that are 2mm longer than the factory valves? I don't want to have to dish out $$$ for custom cut valves.
 

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ED6&7. EE4&5, MB1
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I suggested this to my builder and apparently lash caps do not suit the DOHC ZC valvetrain. He said the spring retainer/rocker is not compatible?... I'm going over to have a look tomorrow.
Self-made lashcaps and modification on rockers.
Regrind "required" more length 1.2-1.4 mm on intake and 0.8-1.0 mm on exhaust valves.
No problems so far running two seasons "stock car race" with 8500 rev limit.



 

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Discussion Starter #14
Self-made lashcaps and modification on rockers.
Regrind "required" more length 1.2-1.4 mm on intake and 0.8-1.0 mm on exhaust valves.
No problems so far running two seasons "stock car race" with 8500 rev limit.




Awesome post, thanks! I came here to post up these pics of the rocker thinking, how are lash caps going to fit in here?





Also here's the smear pattern on the rocker pad.

 

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ED6&7. EE4&5, MB1
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Awesome post, thanks! I came here to post up these pics of the rocker thinking, how are lash caps going to fit in here?
You widen the slot at the end of the rocker so that the lash caps fit in them.
Your quick and dirty method was angle grinder combined to a stable hand but there are more sophisticated methods. ;)

 
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