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Discussion Starter #1
sent this letter to Delta cams today...

Hello Ken,

I am sorry to report this but I am experiencing a significant problem with the Subaru cams you reground to your delta 1500 profile. See the attached pictures of the assembled valve train.

On the intake side, you have taken off so much meat off the intake lobes that my brand new tappet adjusters are completely out of adjustment capability. I have carefully measured the cams, and all the intake lobes require that I move the adjusters 0.070 to 0.080 inches (1.81 mm to 1.97 mm) farther into the rocker arm (i.e. towards the valve relative to the stock cam). The new tappet adjusters are the same length as the old ones.

As a result, there are only a few threads of the adjuster locking nut engaging the adjuster screw. There are NO threads exposed above the locking nut. If I have any wear at all on the adjuster tips, rollers, or cam I will be unable to adjust them further.

I do not have as large a problem with the exhaust lobes. Since the exhaust rocker arm ratio is smaller I have only had to move the adjuster screw 0.059" to 0.063" (1.50 mm to 1.62 mm) towards the valve, and this leaves about zero to 1 thread of the adjuster screw exposed above the adjuster locking nut.

The intake profiles have had 0.015 to 0.020" removed (up to 1/2 mm!) from the max lift point, and the base circle has had 0.041 to 0.043 inches removed relative to stock.

In comparison the exhaust lobes have had 0.004 to 0.007" removed from the max lift point, and the base circle has had 0.038 to 0.041 inches removed.

The extra material removed from the intake lobes is compounded by the larger rocker arm ratio for the intake rockers.

If you had controlled the amount of material removed from the intake profiles more closely, these cams might have been useable, but as it stands now I would be very uncomfortable proceeding with the engine assembly.

I think you owe me some new cams. If these cams are typical of your regrind tolerance/practices then you will have this problem in the future as well.

John Banks

Intake adjuster

intake-adjuster.jpg photo by 5322009 | Photobucket

exhaust adjuster

exhaust-adjuster.jpg photo by 5322009 | Photobucket

cam profile measurements

cammeasurements.jpg photo by 5322009 | Photobucket
 

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2001 VDC/SC One of a Kind
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I hope he's a fair guy. Is the machine shop a local one? How long you think before he answers or delivers your cams? I would follow up with a phone call.
 

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OBW H6 VDC, Tribeca, XT6
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How long you think before he answers or delivers your cams? I would follow up with a phone call.
agreed. fantastic measurements, wow, very keen! did you try calling them first? that is generally a better first step?

I hope he's a fair guy. Is the machine shop a local one?
No it's not, they are a well known aftermarket cam supplier for Subaru's in Washington state, I've installed a few of their cams. they've been building stuff for Subaru's for a long time, used to (still do) old school 80's EA and ER platforms as well.
 

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"I think you owe me some new cams"

Not exactly the best stance to take on the first letter of complaint to a company. Give them time to research the problem - he may offer you a new set anyway without immediately pointing fingers.
 

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DIY-Turbo 2.2l OBS 12.89s 1/4mile @ 106.17MPH
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Could this be the reason cars with delta cams sound like midgets with baby-sledge hammers are actuating the valves...?...
 

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Discussion Starter #6
a little perspective....

I do hope that this issue resolves well. However, I have been building engines for over 4 decades using new billet and reground cams and I have never had this particular problem crop up before.

I have watched Delta's youtube video of how they set up a cam for a regrind and I have to tell you...their set-up process appears pretty hit-or-miss to me when showing several tries being necessary to get the cam indexed properly to the grinder. That alone may be the source of the extra material loss off the lobes.

There is an indexing pin on the end of the cam, so it should not be necessary to move the cam back and forth as shown in the video to get the lobe properly indexed to begin grinding.

But what do I know....I'm an aerospace engineer with 45 years of experience and a dozen patents.
 

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Discussion Starter #7
Issues resolved....

Took a new set of valves, but I got the needed threads appearing above the lash adjuster screw locking nut. Turns out the guy that did the valve job also took a little too much off the intake stem tips. So be warned if you are doing a valve grind along with the 1500 cam install.

FWIW, Delta was willing swap me out for any other of their cams, including stock ones...but it would have cost me shipping both ways.
 
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