Derek Posted September 17, 2009 Share Posted September 17, 2009 I'm going to be doing the shave .080" P90 trick and I need to shim up the cam towers. My plan is to machine out the spacers from some 6061 T6 .080" sheet I have. I measured the sheet with my Starrett high precision mike and there is virtually no difference in thickness. I'm also thinking the thermal coefficients will be more equal as they're similar metals just a different alloy as opposed to aluminum head, steel shim, aluminum cam tower. Am I missing something? Thanks Derek Oh and does anyone have a DWG or DXF of the cam tower shims? (Dreaming) Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 17, 2009 Share Posted September 17, 2009 valve stems need to be longer to acconodate different cam height and still use a decent thickness valve lash pad... Quote Link to comment Share on other sites More sharing options...
Derek Posted September 17, 2009 Author Share Posted September 17, 2009 valve stems need to be longer to acconodate different cam height and still use a decent thickness valve lash pad... Hi Tony I was wondering if I was missing something in my analysis of using aluminum as shim material as opposed to steel. Believe me there's a lot I'm missing on the entire project! Derek Quote Link to comment Share on other sites More sharing options...
johnc Posted September 17, 2009 Share Posted September 17, 2009 Aluminum is fine but I would use 7075 or 2024 instead of 6061. Quote Link to comment Share on other sites More sharing options...
Xnke Posted September 17, 2009 Share Posted September 17, 2009 I would be worried about compressing the softer metal, but 7075 or 2024 should work out ok. Tony, to compensate for the length difference, He'll need to use the 0.080" longer N42 valves. Not only that, but He'll have to make sure that the valvesprings can handle the longer valves, too. I *MAY* have the drawing you need, I'll have to look. Quote Link to comment Share on other sites More sharing options...
Derek Posted September 17, 2009 Author Share Posted September 17, 2009 Aluminum is fine but I would use 7075 or 2024 instead of 6061. I was just getting ready to reply that Mcmaster only has .080 in 6061 (which I already bought) and decided to check again. They have 2024 in .080. It's 33.00 for a 12" x 12" sheet. Are you sure that 6061 won't work:o Derek Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted September 17, 2009 Share Posted September 17, 2009 You will probably be fine with 6061. I would be surprised if the cam towers were made out of anything much stronger than that. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted September 17, 2009 Share Posted September 17, 2009 As long as you're not yeilding the 6061, 7075 isn't really necessary. They both have the same modulus of elasticity, so they should compress the same amount. Quote Link to comment Share on other sites More sharing options...
Derek Posted September 17, 2009 Author Share Posted September 17, 2009 As long as you're not yeilding the 6061, 7075 isn't really necessary. They both have the same modulus of elasticity, so they should compress the same amount. He used the biggest words so he wins!!!!! Plus it was what I wanted to hear. 6061 it is. I hate to be cheap but every dime has to count in this economy. The head and cam towers are a casting alloy and I doubt that the heads been heat treated. The cam towers probably are though. so the shims will probably be stronger then the base. Derek Quote Link to comment Share on other sites More sharing options...
SHADY280 Posted September 17, 2009 Share Posted September 17, 2009 i used .075" steel for mine, and yes longer valves would work, but ive also used .120 lash pads to take up the slack, but i also have a re-ground cam, not new billet Quote Link to comment Share on other sites More sharing options...
Derek Posted September 17, 2009 Author Share Posted September 17, 2009 I'm going with Stainless N42 valves http://www.sivalves.com/ocforeign_valvessp_nis.html and a Isky regrind on a nissan cam. Derek Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted September 17, 2009 Share Posted September 17, 2009 Hey derek mind me asking how much your getting those valves for? Quote Link to comment Share on other sites More sharing options...
zcarman1259 Posted September 17, 2009 Share Posted September 17, 2009 Derek, for an option, you could go with a Kameari cam tensioner set. If I build another engine with a P-head cut, I'll use it. Now, the cheapest source for it, don't know. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 17, 2009 Share Posted September 17, 2009 Derek, for an option, you could go with a Kameari cam tensioner set. If I build another engine with a P-head cut, I'll use it. Now, the cheapest source for it, don't know. That's a great alternative, the Kameari tensioner and an adjustable cam gear. It's also about $800 for just those two parts, but it is a great alternative if you have the $$$. Quote Link to comment Share on other sites More sharing options...
Xnke Posted September 17, 2009 Share Posted September 17, 2009 Yeah, SI valves are a real deal. Stainless, swirl polished, they actually supply NISMO. I payed $10.50 per intake valve, in 2mm oversize, and had them cut down to .5mm oversize to fit my head. Stock replacement is $8.50 per intake valve, last time I checked, which was a few months ago. I wonder if they will cut a set of valves 2mm longer for the same kind of mod on a N42 head....hmmmm Quote Link to comment Share on other sites More sharing options...
Derek Posted September 17, 2009 Author Share Posted September 17, 2009 I wanted one of those Kameari units from the first time I saw one. Then I saw the price........ $8.50 per valve was what I was quoted as well. For that kind of money I don't see any reason not to use them. Derek Quote Link to comment Share on other sites More sharing options...
letitsnow Posted September 18, 2009 Share Posted September 18, 2009 I wanted one of those Kameari units from the first time I saw one. Then I saw the price........ $8.50 per valve was what I was quoted as well. For that kind of money I don't see any reason not to use them. Derek Damn, I wish I knew about them when I replaced some valves in an n47 that I ended up not using, 4 intake valves were ~$70 from msa. Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted September 18, 2009 Share Posted September 18, 2009 I wonder if they will cut a set of valves 2mm longer for the same kind of mod on a N42 head....hmmmm Probably deserves it's own thread, but I have a lot of interest in the N42 shave concept after reading Babalouie's mystery engine thread http://forums.hybridz.org/showthread.php?t=141159&highlight=mystery+engine Have not been able to determine the approximate shave to make the N42 a "closed chamber" head, but I don't think finding a usable length 8mm stem valve is the hard part. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted September 19, 2009 Share Posted September 19, 2009 That's a great alternative, the Kameari tensioner and an adjustable cam gear. It's also about $800 for just those two parts, but it is a great alternative if you have the $$$. Any setup which keeps the proper tension on the timing chain will be ok... cam tower shims or the Kameari setup. Cam tower shims restore the original distance between crank and cam centrelines, whereas the Kameari setup will not do this. Just don't forget all this work is necessary to keep cam timing as close to spec. as possible. I would invest in an adjustable cam sprocket, an eight holer is my preference but the other 'loosen adjust tighten' jobby is acceptable (Either sprocket is necessary if using only the Kameari setup without shims.) Cheers. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted September 19, 2009 Share Posted September 19, 2009 I wanted one of those Kameari units from the first time I saw one. Then I saw the price........ $8.50 per valve was what I was quoted as well. For that kind of money I don't see any reason not to use them. Derek The Si valves are great. Been using them for a while, best deal around Quote Link to comment Share on other sites More sharing options...
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