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Old 08-11-2014, 02:59 PM   #601
Mitsu
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re read what i said, the resonance will cause the bucket to spin, but i do stand corrected, i should not have said the valve HELPS it spin, but actually the spring. Most of the rotation is from the resonance.
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Old 08-11-2014, 05:01 PM   #602
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be that as it may, why do some of these shots show wear that is consistent with NOT spinning?
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Old 08-11-2014, 05:07 PM   #603
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I know its nothing we can change, but I wonder if the oil passage could be cast at an angle to promote spinning
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Old 08-11-2014, 06:07 PM   #604
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If the oil sliding across the side of the bucket imparts enough force to make it spin, I suspect there's something wrong with that oil.

Unless you pair that idea with buckets that have a band of ratchet steps around them...
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Old 08-11-2014, 09:40 PM   #605
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Quote:
Originally Posted by ride5000 View Post
be that as it may, why do some of these shots show wear that is consistent with NOT spinning?
those pics that Funk posted look like debris was washed over the bucket as the cam lobe was rotating, causing pock marks/gouges on the face of the bucket.

The buckets also look like they were spinning somewhat as the marks are fanned out. He also said the lobes were smooth, so at this point its a guessing game.

There is no definitive answer, other than don't use aftermarket cams unless you are going to pull your covers after a few hundred miles and inspect.

Since other vendors on here do sell or service other types of vehicles, are there failures with GSC/Kelford cams, say on Honda, Mitsu or Nissan cylinder heads?
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Old 08-11-2014, 10:05 PM   #606
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This is the response I got from Supertech

"From the photo, we can determined, that the wear on these could be cause by one of the following reasons:
- Too much concentrated pressure due to misalignment between bucket and cam surface (not parallel).
- Lubrication issues: if pressures on the bucket are very high it is recommendable to use a better racing oil after using a good assembly lube at the time of installation (see “drivenracingoil.com”. I think DT40 would be a good choice for your engine but it is better to get their expert advice)
- Make sure the billet cams are Nitrided. Billets cams that are not nitrided are not compatible with the nitrided surface of the bucket and will damage the surface"

I have used Rotella T6 since the motor was broken in.

GSC cams are not nitraded (I don't think most are)
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Old 08-11-2014, 10:10 PM   #607
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Quote:
Originally Posted by Flat 4 Motorsport View Post
those pics that Funk posted look like debris was washed over the bucket as the cam lobe was rotating, causing pock marks/gouges on the face of the bucket.

The buckets also look like they were spinning somewhat as the marks are fanned out. He also said the lobes were smooth, so at this point its a guessing game.

Ya I was kind of thinking that also but I would expect some type of damage to the lobes also would I not? and it is on multiple buckets on one side and just 1 on the other side of the motor..
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Old 08-11-2014, 10:30 PM   #608
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Quote:
Originally Posted by funk32 View Post
This is the response I got from Supertech

"From the photo, we can determined, that the wear on these could be cause by one of the following reasons:
- Too much concentrated pressure due to misalignment between bucket and cam surface (not parallel).
- Lubrication issues: if pressures on the bucket are very high it is recommendable to use a better racing oil after using a good assembly lube at the time of installation (see “drivenracingoil.com”. I think DT40 would be a good choice for your engine but it is better to get their expert advice)
- Make sure the billet cams are Nitrided. Billets cams that are not nitrided are not compatible with the nitrided surface of the bucket and will damage the surface"

I have used Rotella T6 since the motor was broken in.

GSC cams are not nitraded (I don't think most are)
From the way they worded that sentence, it's not clear whether nitriding is a requirement for all cams to work properly with their buckets, or if nitriding is only a requirement for billet cams.
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Old 08-12-2014, 09:18 AM   #609
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I just saw this thread yesterday. Boy did this get out of hand. lol. Not that my thoughts matter, but here is just one engineers perspective:

1) Surface finish on a cam lobe is paramount. You better see yourself in that surface. Mirror level microfinish.
2) Cam to bucket offset is more important than I think most folks are getting. It's not simply a re-lubrication issue. You're moving from a sliding action to more of a rolling action. This simple tweak in geometry is a "poor man's roller rocker." Lubrication aside, it's reducing friction, and therefore, wear and heat.
3) Hardness needs to be matched or something is going to wear.

If I was placing bets, I would guess that if these cam manufacturers dealt with these three specifications, all would be well.
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Old 08-12-2014, 09:40 AM   #610
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as i said before I have a set of cams going into a car that have been WPC treated. All the buckets are brand new.

I'm going to pull it after 5-600 miles to recheck the lash.

Given the surface finish post above has anyone had a set of GSC or Kelford cams REM polished?
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Old 08-12-2014, 10:05 AM   #611
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Quote:
Originally Posted by thefoos View Post
I just saw this thread yesterday. Boy did this get out of hand. lol. Not that my thoughts matter, but here is just one engineers perspective:

1) Surface finish on a cam lobe is paramount. You better see yourself in that surface. Mirror level microfinish.
2) Cam to bucket offset is more important than I think most folks are getting. It's not simply a re-lubrication issue. You're moving from a sliding action to more of a rolling action. This simple tweak in geometry is a "poor man's roller rocker." Lubrication aside, it's reducing friction, and therefore, wear and heat.
3) Hardness needs to be matched or something is going to wear.

If I was placing bets, I would guess that if these cam manufacturers dealt with these three specifications, all would be well.
But it can't be the cams... It must be the builders/installers...

Sorry lots of sarcasm from me here.

-- Ed
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Old 08-12-2014, 10:21 AM   #612
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Quote:
Originally Posted by thefoos View Post
I just saw this thread yesterday. Boy did this get out of hand. lol. Not that my thoughts matter, but here is just one engineers perspective:

1) Surface finish on a cam lobe is paramount. You better see yourself in that surface. Mirror level microfinish.
2) Cam to bucket offset is more important than I think most folks are getting. It's not simply a re-lubrication issue. You're moving from a sliding action to more of a rolling action. This simple tweak in geometry is a "poor man's roller rocker." Lubrication aside, it's reducing friction, and therefore, wear and heat.
3) Hardness needs to be matched or something is going to wear.

If I was placing bets, I would guess that if these cam manufacturers dealt with these three specifications, all would be well.
I think the biggest one personally is the lobe being offset. With proper lubrication hardness should not be as paramount but still important. Mirror finish would also be good to have, OEM are mirror as well.
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Old 08-12-2014, 10:25 AM   #613
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Quote:
Originally Posted by Turn in Concepts View Post
as i said before I have a set of cams going into a car that have been WPC treated. All the buckets are brand new.

I'm going to pull it after 5-600 miles to recheck the lash.

Given the surface finish post above has anyone had a set of GSC or Kelford cams REM polished?

I have not done a set of aftermarket cams yet, we have done some oem cam shafts as well,but I have been doing the oem buckets as I get more of a collection of them. Typical surface finish on a new bucket is going to be very, very close to 1 Ra in microinches, and sometimes our profilometer doesn't even come back with a number.

What I would love to do, is have everything REM ISF treated, and then sent off for a DLC treatment as well.

If there is an professional engine builder that can use this as data, and that has a set of cams ready to go, we can make you pricing in the interest of finding a solution to this problem.
PM me for more info.

These are stock cams in a bugeye



stock cam buckets







Cam follower from a briggs motor



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Old 08-12-2014, 10:39 AM   #614
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how is the friction when turning the engine over by hand?
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Old 08-12-2014, 10:56 AM   #615
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Quote:
Originally Posted by MPS-Dom View Post
how is the friction when turning the engine over by hand?
Less... This isn't an engine that I built, I'm not an engine builder, nor do I pretend to be, but I do know the data on REM ISF and how effective it is.
And I do believe that it is very,very applicable in this situation.
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Old 08-12-2014, 11:31 AM   #616
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^ I can attest to this. We use it too. It works well. Even better with WPC.
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Old 08-12-2014, 11:50 AM   #617
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Quote:
Originally Posted by KillerBMotorsport View Post
^ I can attest to this. We use it too. It works well. Even better with WPC.
We used to do camshafts for roush-yates, and a few for penske before the nascar teams all went and bought their own machines so they didn't have to send their secret cam profiles out the door.

Like I said before, if there is an engine builder that wants to have a set of cams and buckets treated, and that engine to be used as a data point for some testing, we can accommodate some very good pricing.
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Old 08-12-2014, 12:06 PM   #618
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Here's a study regarding valve train friction (and wear) reduction via polishing and thin film coatings.

http://www.stle.org/assets/document/..._Polishing.pdf
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Old 08-12-2014, 01:04 PM   #619
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TL;DR:

In a direct-acting mechanical bucket tappet–type valvetrain,
the cam and tappet contact is responsible for about 85% of
the total valvetrain frictional losses. Because this contact operates
primarily in a mixed lubrication regime, it offers an opportunity
for friction reduction through surface engineering.
The friction reduction potential of thin Mn-phosphate coating,
diamond-like carbon coating, and polishing on the bucket surface
was explored using a motored valvetrain rig equipped with
3.5L V6 engine head. The durability of tappets and cam lobes
was also evaluated using a different motored valvetrain rig consisting
of a single lobe and a single tappet. The polished buckets
demonstrated substantial friction benefit over current production
buckets at all speeds investigated. The diamond-like
carbon coated buckets did not show any additional friction reduction
benefit. The wear data demonstrated much less wear
with polished buckets and also for cam lobes when in contact
with polished buckets compared to current production buckets
and cam lobes.


CONCLUSIONS
Tappets with Mn-phosphate and DLC coatings as well as
polished tappets showed reduced friction compared to the current
production tappets at all engine oil temperatures investigated.
The DLC-coated tappets showed similar friction reduction
to that of the polished tappets, suggesting that improved friction
is more due to improved surface finish and not the coating
itself.
The wear rate of polished tappets in contact with a cast iron
cam lobe was significantly lower than that of the current production
tappets.
The wear of the cast iron cam lobe in contact with a polished
tappet was lower than that of the production tappet. The wear
of steel cam lobes was also lower in contact with polished tappet
than that of the production tappet. The wear of the steel cam lobe
was similar to the cast iron cam lobe in contact with the current
production tappet.
The wear characteristics of the steel cam lobe in the presence
of engine oil containing soot and fuel from dyno tests was no
worse than that of fresh oil.
The composition of the tribofilms that formed on contacting
components did not change significantly with variations in cam
lobe material or tappet surface finish.
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Old 08-12-2014, 02:38 PM   #620
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^ there are many white papers on this. Any engine builder worth a salt should be on the up and up with the latest and greatest benefits technology has to offer.
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Old 08-12-2014, 03:46 PM   #621
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just when u think building a ej couldn't get anymore complicated
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Old 08-12-2014, 04:43 PM   #622
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Quote:
Originally Posted by Mitsu View Post
In a subaru, the cam is flat and the lifter is flat. The only thing that provides rotational force for the bucket is the location of the cam lobe.
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Old 08-12-2014, 08:30 PM   #623
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This
\/


Quote:
Originally Posted by Delphi View Post
I think the biggest one personally is the lobe being offset. With proper lubrication hardness should not be as paramount but still important. Mirror finish would also be good to have, OEM are mirror as well.


The lobe and bucket surfaces need the oil film just as much the soft main and rod bearings need it to protect them from the crankshaft. There is a HUGE difference in hardness between those and yet the oil does the trick. While I can see there being hardness issues with the aftermarket cams, the offset of the lobe would seem more important. Also consider the jagged sharp edges of the aftermarket cam lobes and how they can affect oil shedding on the lobes.

Last edited by 2slofouru; 08-12-2014 at 08:35 PM.
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Old 08-12-2014, 09:36 PM   #624
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i wonder if a quick chamfer on those sharp 90* edges would help?
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Old 08-12-2014, 09:54 PM   #625
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Quote:
Originally Posted by 2slofouru View Post
The lobe and bucket surfaces need the oil film just as much the soft main and rod bearings need it to protect them from the crankshaft. There is a HUGE difference in hardness between those and yet the oil does the trick.
Apples and oranges. Cam/bucket interface is similar to a point load vs a bearing load that is massively more distributed.
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