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Old 03-27-2011, 08:57 AM   #101
olov
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Originally Posted by B-dub View Post
Jonathan is in the process of doing it to my head. I have a very aggressive cam and I spit a shim because of that. Going to the under shim system is the way to go, and it's lighter. I would call RSI to see if they are ready to ship a kit.
aren't you using a stage V from RSI? so this info isn't 100% correct

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Originally Posted by towerymt View Post
Pretty sure it's a lot higher than that, but I'm not sure of the magic number.

edit: says 14mm lift, still with stock buckets
http://yhst-26451710505916.stores.ya...vturbocam.html
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Old 03-27-2011, 10:05 AM   #102
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Originally Posted by Gabe244 View Post
Anyone on here sell the stuff to do that? I'm keen on a doing a nice base circle reduced regrind if its not cost prohibitive.
we have had them available for well over a year, they are designed to work with stock or larger base circles. we are working on shim under buckets for reduced base circle cams.

the hard part with the shim under buckets is getting the lash set correctly. the lash caps can be supplied two ways long and trim to fit or in a kit with them in 0.25mm increments.
with the trim to fit method it is very important that they are ground short very precisely, with say a centerless valve grinder or a grinding attachment on a lathe. i have seen it done by someone with a standard grinder and they were not ground square, which caused the caps to cut into the lifter, lifters bound in there bores and whipped the cam out in several hours of use.
with the kit its much easier to set the lash as you would have every size on hand, but the hard part with that is the deposit on the kit, there are hundreds of lash caps in it and make it quite expensive.
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Old 03-27-2011, 01:11 PM   #103
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Originally Posted by fidel View Post
, but the hard part with that is the deposit on the kit, there are hundreds of lash caps in it and make it quite expensive.
So sell the kit with the shortest lash caps, have the customer measure the clearance and order what they need and exchange the short ones...
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Old 03-27-2011, 01:28 PM   #104
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go look at a fiat twin cam ......

im pretty sure you would only need to setup on old buckets /shims , measure twice , order once .

ive also seen buckets machined down to spec with longer valves .

H section lash caps that have little button shims .

while this may be a wild guess that parner sells cams that need a big diameter tappet, he must have according buckets in the correct increments . or at least he used too , altho he is a dirty word too now....
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Old 03-27-2011, 05:53 PM   #105
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1. The three Fiat two-sticks that I know tolerably, that is to say the 1592 cc, the 1608cc and the 1792 cc (in the slightly different guises) were the simplest things in the world to change the shims. You needed a thing ilke a bent fork (preferably a special tool but you could do it with a couple of table knives or even an actual bent table fork) slid it between the cam and the bucket, that depressed the valve on its springs and the shim popped out in your hand - big thing about the size of a 2p piece (sorry, no idea what that is in US dollars) but thicker and you slipped in a new one and measured again. Most Fiat nuts had a biscuit tin full of different thicknesses! If you were sensible and greased one side of the cam cover gasket but used red hermetite on the other you didn't need a new cam cover gasket and there were only two retaining collars to undo and replace.

2. In the world of simple swappery, it seems that an unmodified 531 (and sodium filled valves) with an A or V cam (surely VXs are rare as rocking horse doodoo) will outrun an equivalent (N/A or turbo, using stock turbos) by a street. The high lift cams from the specialist suppliers are hundreds of pounds in the UK, and the number of tuning shops who can properly port and re-valve a head with bigger valves must be under 10 in the country.

3. I'm not that bothered about idle (so long as I pass emission control) nor indeed about torque since I quite like changing down. I think that (memories stirring from the past) that velocity is largely about droplet size and wall wetting, so so long as you rev it's of little relevance.

4. No, I have no tested these ideas other than the FIAT shims since about 1967 when I did have some BMC A series heads with very modified squish areas (Somender Singh did not exist then) and the habit of producing sheets of flame on a closed throttle, but a nice noise on an open one - up to about 8,000rpm, quite a lot for a BMC A series crank!
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Old 11-06-2019, 06:03 PM   #106
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Yes, I am bumping this old thread.
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Originally Posted by Stereophile33 View Post
I just want to post this up so hopefully it will become internet lore.

We've been doing alot of head stuff and for turbo and NA folks using camshafts under 12.5mm of lift and for that matter stock unported intake manifolds, the 531/405 head is a waste of your time as it won't make more power, especially under the curve.

A well ported/filled 530 will make more power than a 531 anyday with a cam under 12.5mm. If going to a bigger cam, you bet, make the jump for the 531/405 heads, but you should also consider one of Nathan Kahler intake manifolds at that point.

Cheers.
Jonathan
So, how about that more info/graphs, Jonathan? I know that info is well out of your hands now and lost forever, which is a damn shame.

Also, what is likely most relevant to a lot of people on here, is how these differences show up in the real world with unmodified 530 and 531 heads, instead of just looking at a well ported/filled 530 head, which is much more rare than even a 531 head.
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Old 11-06-2019, 07:04 PM   #107
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Call Bergen. He has all of the proprietary knowledge now.
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Old 11-06-2019, 09:24 PM   #108
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Yes, but the computer is a mess and I doubt he's dug into it any or that the computer still lives.
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