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Old 01-12-2022, 11:18 PM   #51
rb92673
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IPD billet turbo cam purchased 11/2020 and has 6 days of racing on it:

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Old 01-13-2022, 02:08 AM   #52
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Both my failed cam and the one that's been in the car for years had that black coating on them.
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Old 01-13-2022, 02:11 AM   #53
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Originally Posted by rb92673 View Post
IPD billet turbo cam purchased 11/2020 and has 6 days of racing on it:

Holy shiz! Dude it looks pretty dry also no oil residue?
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Old 01-13-2022, 04:15 PM   #54
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Interesting Sam, if memory serves, the worst of mine were exhaust as well.
leftover combustion pressure adding to the opening effort?
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Old 01-13-2022, 05:43 PM   #55
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^^^ yeah, but that would be when the valve opens, not at the tip of the lobe, and the spring isn't pushing so much yet.

If it's binding on the valve stem seals, it would be intakes (redblocks only have an intake seal, needed to prevent sucking oil thru guide during intake stroke - exhaust always has positive pressure when open)

If it's floating the valves, assuming similar lobe profiles and accelerations, the intakes would loft first due to bigger size and more mass (F=MA).

So, damage more on the exhaust side and just past the lobe tip seems weird.
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Old 01-13-2022, 07:42 PM   #56
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Some solid-lifter flat-tappet engines are more prone to eating cams than others. The metallurgy between the cam and lifter (in this case shims) needs to be compatible, and the 2 parts wear together. I know some engine builders who will even not move cams and lifters from 1 engine case (or head) to another because any differences in castings could cause the cam and lifters to sit and wear differently than they had in the previous motor. Now that may an extreme case, but it's a practice based on experience.

When breaking in a new cam, there is a delicate process. I've had good results with a break-in lube and high zddp oil, hold the engine at 3k rpm's for 15 minutes immediately after start up.

The rule of thumb is to never use a new cam with old lifters. The lifters (shims here) may have a concavity and have been worn in with a previous cam. Using a used cam with new lifters I believe is acceptable, as long as the lifter's aren't already poorly worn.

Similar to resurfacing a flywheel, it is common practice to resurface lifters

And the last thing I have to add, is that the lifter rotates in its bore as the cam spins. If the lobe is centered directly over the center of the lifter, it may not spin the lifter, and the cam will dig a groove right into the shim. It may be the case that the lifters were binding in the bores of the head.

I know many of you have gotten with breaking every one of these rules, but I just wanted to add my 2c.
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Old 01-13-2022, 10:53 PM   #57
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FWIW heres a kg2t cam I got quite a while ago, been in the engine for several thousand miles. Looks like it is a cast part and has the parkerizing. It looks like most of that is intact, some appears to be wearing/flaking off the edge of the tips of the lobes. I think these were an "A" intake and "K" exhaust lobe, but maybe longer duration and altered lobe separation? I've never had one of the ipd turbo cams.

No specific break in was done, thought that was more of a thing on ohv engines. Just filled the troughs with oil and some grease only on the bearing journals. New/late b230 springs, retainers, and keepers. Original/used buckets, and mix of new and used shims. Gets spun to 7k regularly. Click the link for a giant version of images.


https://a4.pbase.com/o12/81/744881/1..._014556875.jpg


https://a4.pbase.com/o12/81/744881/1..._014908073.jpg


https://a4.pbase.com/o12/81/744881/1..._015105387.jpg
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Old 01-17-2022, 09:22 AM   #58
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Originally Posted by leecatd8209 View Post
That looks awfully similar to what I had happen with mine. User Mikezohsix also had a similar experience.

When did you buy the ipd cam?





I am running an IPD Turbo cam which i bought new from IPD around 5(?) yrs ago. It cam with the black coating. Ran for years on reused shims with in spec clearance for years, no issues. B230F+T using na manifold, JPipes, EVO8 turbo 15 psi.

Then i upgraded to 531 ported head with 40mm exh vlvs, 3" TB, KJet manifold & due to increased flow (but same exh manifold setup) EGTs went through the roof (1000 DegC+).

I now have better exh manifold & bigger turbo & egts are back to sensible levels.

However, since the EGT issue my exh vlv clearances keep closing up & when they reach 10 thou the cam eats a shim.

I stripped the head & found vlvs were 'cupping' (valve head sinking into the port), found when measuring as the underside of the vlv head is no longer flat, but sunk in the middle.

For now im putting this down to having softened the vlvs. The tempering temp for the grade of stainless used is around 800deg.

Im currently replacing the valves.

Point to note, is my #2 exh was the one which sinks quickest & eats the shim, same as your clearances show, coincidence??

Make what you will of my own findings & thoughts, but wanted to chip in and share the similar issues im having & working to resolve.
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Old 01-20-2022, 11:04 AM   #59
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I drove the car to work all week and decided last night to check the valve lash and just inspect things. Still not thrilled with the way the shims and camshaft are looking. Not sure whats going on here but I think I'm just gonna start new and get another head from somewhere. I've had this head for a long time and its been abused and neglected enough.
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Old 01-20-2022, 11:47 AM   #60
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Why not try throwing in a doorstop...er...T cam just to see what the wear pattern looks like, keep from ruling out the head? Same pattern for me, old/known VX went in while waiting on the Turbo cam, new shims, and it was just fine.
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Old 01-20-2022, 12:20 PM   #61
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Originally Posted by gsellstr View Post
Why not try throwing in a doorstop...er...T cam just to see what the wear pattern looks like, keep from ruling out the head? Same pattern for me, old/known VX went in while waiting on the Turbo cam, new shims, and it was just fine.
A lot of work to setup the head for another camshaft. I have had my reservations about this head for a long time so its really an easier decision than you would think

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Old 01-28-2022, 11:32 PM   #62
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If used shims were used during installation. Maybe the hardened surface was compromised?
You can definitely reuse shims if they're in good shape. I've been running a head like that since I installed an IPD turbo cam back in 2013.

For one thing those lash numbers are all over the place, and I wouldn't expect them to magically get tighter without the valve seat wearing down. Did you just slap it in there for a dyno sesh or did you actually adjust it and break it in?
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