Custom cam regrind specs? - Mazda MX-6 Forum
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post #1 of 19 (permalink) Old 8-22-15, 3:00 Thread Starter
 
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Custom cam regrind specs?

Anyone with a custom cam regrind have specs theyd like to share? Just seeing what other people use
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post #2 of 19 (permalink) Old 10-19-15, 23:41
 
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for an F2T?

You would do get more answers if you had the mods move this to 1gen other performance.

My personal opinion:

These Regrinds never made sense to me, i know it can change the torque curve, but don't you want more lift and more duration and not less. No matter what they do it will always be less and not more.

Logic tells me you would loose power, but what do I know.

Have I ever had one? no. Do I have a dyno sheet? no. Will I ever get one? I got something better: the carb f2 which from the top of my head has same lift as stock but more duration.

I think people get their cams reground for only 2 reasons, change torque curve or to add something to their "mod" list.

best of luck
happy HP hunting.

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post #3 of 19 (permalink) Old 11-20-15, 23:05 Thread Starter
 
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Colt cams has two options for their regrinds, both add lift and duration. One of their regrinds I think gained 10-20 hp on a stock engine at 12lbs. The other which was using their tri flow design they didn't have any dyno proof but said its better. Idk I got the one with the proven gains.
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post #4 of 19 (permalink) Old 11-21-15, 8:19
 
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Quote:
Originally Posted by juanpac_tupac View Post
One of their regrinds I think gained 10-20 hp on a stock engine at 12lbs. The other which was using their tri flow design they didn't have any dyno proof but said its better. Idk I got the one with the proven gains.
I offer to pay give anyone $50 who can proved that those cams regrind makes a different in HP on f2/f2T 3-4 years ago. nobody bite, no single dyno #, no prove whatsoever, yet they post pic .

I do agreed with Darkmx6, it doesnt make any sense, you have to add metal to gain more lift, grounding something down changes the profile. but hey , what do i know, since i never use anything than stock cam, and will stay that way. and still makes power.

use that money you going to spend on that regrind on a more sensible mods.

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post #5 of 19 (permalink) Old 11-21-15, 16:22
 
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post #6 of 19 (permalink) Old 11-21-15, 21:16
 
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Now how many of those guys that got a reground cam actually got the supporting mods to take advantage of it.

How would you adjust our lifters? They are HLAs. Yes they are self adjusting, but will that be enough? they are only made to extend so far.

Another thing to think of is how the cam is made.

What if our cam is cast, machined, and then the surface is hardened so that it can rub against the rocker.

If that is the case, when they grind on that cam they are taking off that hardened layer; Leaving the soft under layer exposed and soon you will have a cam with no lift and no lobes.
Or at least that is what an old-timer told me.

just some things to think about.

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post #7 of 19 (permalink) Old 11-21-15, 23:38
 
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^All good points to think about. I just posted that pic to dispel the myth that the lobes are ground on a regrind cam. its just the base circle that gets reduced. I don't know if shims under the HLAs would work. They would obviously need modification to allow oil to pass through or swap to manual adjusters. If I were to have a cam reground, I would certainly have it re-hardened.

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post #8 of 19 (permalink) Old 11-22-15, 2:39
 
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I'm glad you posted that picture. For real, because I totally failed to understand how it worked.
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post #9 of 19 (permalink) Old 11-30-15, 10:10 Thread Starter
 
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Ima try it out and see how it works. I have dual valve springs and new valves so if I have any problems valve train wise I know its going to be cause of the cam. I have a spare stock cam so if it gives me a lot of shit then I'll just stick the stock cam in but not bad gains for the $$
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post #10 of 19 (permalink) Old 11-30-15, 10:11 Thread Starter
 
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I got the c.444.h cam regrind
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post #11 of 19 (permalink) Old 11-30-15, 10:42 Thread Starter
 
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They're on holiday until dec. 10th so I'll try and get my hands on the actual dyno sheet then
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post #12 of 19 (permalink) Old 12-1-15, 14:10
 
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Quote:
Originally Posted by Darkcyde View Post

Am I missing something in the explanation here?
The peak of the lobe or lift represents the valve opened as far as it will go.
The Base of the cam lobe is the valve completely shut.

If you remove the rocker arm the valve wont be any more closed.

If you cut the whole low side off a cam and install it with the peak of the lobe up then installed the rocker arms that valve would be opened the same distance it was before grinding down the other side.
Does the HLA magically make up the low lobe gap and carry it through the valves opening, when it collapses on a stock cam?
I can see changing profile and duration but overall valve travel with our HLA's I can't see it. If the HLA's would stay fully extended at all times then yes, maybe increased oil pressure might reduce their travel but by increasing valve spring stiffness the HLA will most certainly completely collapse when the valve is opened.

I know with the triflow cam regrinds (colt I think), people ran tiny washer in the rockers as spacers for the HLA's to make up the ground cam gap or the rockers would rattle, with the shims the rockers tapped the valve cover baffle...

And if you don't think the HLA's collapse on every valve stoke. The HLA's sucks in and squirt out oil, pull the valve cover of with the engine running, everytime the valve opens and the HLA collapses oil is squirted out the rocker top, when the HLA extends oil trickles out the rocker top.

If you had the 5 bearing sections of the head machined and shimmed to physically raise the complete cam the amount the low side was ground to make up the gap then you would increase lift and have trouble with front and rear housings fitting.

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post #13 of 19 (permalink) Old 12-2-15, 1:06
 
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Quote:
Originally Posted by Mazda Carnage View Post
I know with the triflow cam regrinds (colt I think), people ran tiny washer in the rockers as spacers for the HLA's to make up the ground cam gap or the rockers would rattle, with the shims the rockers tapped the valve cover baffle...
That's how it's done. You have to take up the space left behind by the reduction of the base circle.

Here is a better picture:



Quote:
Originally Posted by Mazda Carnage View Post
And if you don't think the HLA's collapse on every valve stoke. The HLA's sucks in and squirt out oil, pull the valve cover of with the engine running, everytime the valve opens and the HLA collapses oil is squirted out the rocker top, when the HLA extends oil trickles out the rocker top.
I know how HLAs work.

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post #14 of 19 (permalink) Old 12-2-15, 17:37
 
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I actually did miss something when I read "Cam regrinding explained" and it was the whole reason for my post.

"you have to adjust the rockers to now reach lower"
Don't know how I missed that part of the explanation.
Somehow my brain registered -By removing material at the base of the cam lobe, you have adjusted to rockers to reach lower and increased the valve travel into the cylinder.
My whole post referred to not adjusting the rocker reach, which wasn't what the explanation said.
Sorry about that.

I had a cam all boxed up and ready to ship to crower cams, with a cross section of head with valves and cam caps and rockers, Larken and I chopped up for porting research. The owner wanted it for grinding research, we talked a couple times on the phone, when he told me about the HLA washers and valve cover tap I cancelled that idea.
The way I see it is a professional company that knows what they are doing covers all the bases, even for a car with solid lash adjusters any cam regrind should fit the functioning engine or made to. Sell a valve cover spacer and HLA shims with the grind or a custom valve cover even. The idea of trying to find the right size washers in a hardware store or to shave down the baffle plate support evenly (and it's effect on oil/air in the baffle), or run without it and burn lots of oil or make a custom plate or put a ford probe part on a Mazda engine made me feel it wasn't meant for these cars.

I looked into colt or comp cams system of adding material to the top of the lobe, to increase lift without changing rocker dimension or effecting valve cover clearance. But at 25$US per lobe and then the grinding fee I found it to expensive.

Was always curious about the cam regrinds performance on an F2T putting out decent power, I don't recall anything but stock IHI dyno's with custom cams. On this forum.
It usually seems to be the bone stock internal engine guys making high power and the 3angle valve job, custom cam, high compression pistons, forged rods, decked head... guys running more conservative sized turbo's or boost, possibly to protect their investment . (Ademan excluded)
Or a really expensive engine build and lots of forum activity, then they just disappear, I figure they blow the engine in the first few days due to lack of tuning and don't want anyone to know.

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post #15 of 19 (permalink) Old 12-3-15, 14:54 Thread Starter
 
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Does anyone have any actual experience with the lifters not performing the same with a reground cam? Colt said that it's a direct drop in so I'm just kind of curious if all of this talk about the lifters on this engine just theory or have any of you guys actually tried one out and had the lifters fail or anything of similar nature. Thanks for all the info though none the less.
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