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Need help with degree timing Isky Cam


madkaw

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Did you recently buy this from ISKY or is it an "isky regrind" that you got from someone else?

 

Also, did you set you valve stem heights exactly equal? Without equalized stems, or even with them and slightly not-right lash pads, each valve runs on a different cam profile...

This is a regrind I bought.

I thought the whole idea of the lash pads is to even things up? If all the lobes are swiping the same pattern on the rockers, aren't they close enough? I guess it would be ideal to have exactly the same stem heights, but you know it doesn't work out the way.

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This is a regrind I bought.

I thought the whole idea of the lash pads is to even things up?

Yes they can be used for that, but this presumes that you know the height of each valve stem and also have a sufficient selection of various lash pad thicknesses  to do the "evening up" with.  Generally it's assumed that the stem heights are all the same and the lash pads are then used to compensate for the size of the base circle of the cam.

 

 

 

 If all the lobes are swiping the same pattern on the rockers, aren't they close enough?

Sure, probably...

There are those that would argue that you've already gone way past "close enough" already.  Others might ask once you've come this far, why not do the rest?  

In reality if the wipe patterns are pretty similar you are probably close but that's kind of a crude measurement.  Stem heights aren't that hard to check, especially if you are already set up for degreeing the cam.  If they come out within a few thousandths of each other then you are done.  If they don't then you can always degree the outliers and see if there is much of a timing difference for those lobes...

 

The detail stuff is always tedious.

Edited by TimZ
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Thanks for the info. What I had going on is 2 different valves. Stock Nissan intakes and aftermarket exhaust. Tried to get them as close as possible to each other . Just running 2 different lash pad sizes. The machinist didn't want to sink valves much more and or only take a few off the stems. Without knowing how deep the hardness is on the stem tips it would be risky for more than a touch.

Learned a lot from doing this head- TWICE

 

Nissan stuff is good enough for my power levels. Find a machinist that is knowledgeable about Nissan solid lifter geometry.

Next head will be new enough to have steel guides and seats so that battle will be done. Then order a cam kit from Rebello with lash pads and springs complete.

Looking forward to my MN47 /L28 with newly earned knowledge.

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Steve, I had issues as well when trying to degree my Isky cam on my old L28ET build.  I wound up with piston to valve impacts (slight) on #1 and #6 while rotating it by hand.  I could not, for the life of me, get the cam degreed to the numbers I was given as well.

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I hope you said something. The bad is that everyone at Isky says "datsun!, you need to talk to Ron". So I lost a day and a half waiting to contact an owner over such a trivial question. Happy to talk to Ron, but if Isky modern enough to send info in a PDF file, then the data should be accessible to someone for verification.

 

I was 30 degrees off, lucky no Collison there.

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  • 1 year later...

Dragging up an old thread . Buddy got a 280/280 Isky . We went to degree it and same issue- wrong numbers . Pretty sad if you ask me. To make matters worse we found the balancer that Damper Doc rebuilt was off TDC by at least 15 degrees .

Don't assume anything guys

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