cd1105 Posted August 18, 2009 Share Posted August 18, 2009 I'm in the process of rebuilding a l28et with p90 head. I'm not really up grading internals just refreshing the motor with new parts and machine work. I ordered the msa performance spring set just to substitue for the oem springs and didn't read the part that said "for use with performance cam only." will i cause harm to the head if i use my stock cam or am i forced to upgrade to use the springs? Quote Link to comment Share on other sites More sharing options...
smokeybear Posted August 18, 2009 Share Posted August 18, 2009 I'm in the process of rebuilding a l28et with p90 head. I'm not really up grading internals just refreshing the motor with new parts and machine work. I ordered the msa performance spring set just to substitue for the oem springs and didn't read the part that said "for use with performance cam only." will i cause harm to the head if i use my stock cam or am i forced to upgrade to use the springs? I cannot answer your question but if you are doing all this work, $150 for a cam goes a long way. Just my $.02. Quote Link to comment Share on other sites More sharing options...
cd1105 Posted August 18, 2009 Author Share Posted August 18, 2009 I cannot answer your question but if you are doing all this work, $150 for a cam goes a long way. Just my $.02. I appreciate it. I still want to know if i can use stock cam though. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 19, 2009 Administrators Share Posted August 19, 2009 I cannot answer your question but if you are doing all this work, $150 for a cam goes a long way. Just my $.02. If is he using the stock EFI, a cam is the wrong advice to be giving! Been covered many times on the forum about how the stock EFI does not play well with aftermarket cams! Aftermarket EFI or carbs, then yes, a cam can improve performance. I appreciate it. I still want to know if i can use stock cam though. Yes, you can use the aftermarket springs on a stock cam. 3 issues. 1) You’ll take a slight hit in power overcoming the extra spring pressure. 2) Stiffer springs expedite valve train wear. For stock cam on and engine that might see 50,000 miles before the next rebuild, it’ll be fine. 3) Those spring should come with their matching retainers have deep pockets for taller lash pads, (typical of aftermarket cams). The stock lash pads will ride low in those pockets and the tip of the rocker could contact the edges of that retainer pocket, not good! Hope that helps, Paul Quote Link to comment Share on other sites More sharing options...
cd1105 Posted August 19, 2009 Author Share Posted August 19, 2009 Thanks i think i'll be returning the springs. Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted August 20, 2009 Share Posted August 20, 2009 May a good alternative would be a set of the Robello outer springs for about $80, keeping the stock inners and the stock retainers. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 20, 2009 Share Posted August 20, 2009 Why bother with any aftermarket springs on a stock cam? The stock springs should run the cam up to any reasonable redline without any trouble at all. Spend money where it will make a difference. Quote Link to comment Share on other sites More sharing options...
cd1105 Posted August 21, 2009 Author Share Posted August 21, 2009 Thanks for everyone inputs. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 21, 2009 Administrators Share Posted August 21, 2009 Why bother with any aftermarket springs on a stock cam? The stock springs should run the cam up to any reasonable redline without any trouble at all. Spend money where it will make a difference. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted August 21, 2009 Share Posted August 21, 2009 (edited) Hey Paul, What's your thoughts on this- I found out that Schneider cams make two different versions of the same cam http://schneidercams.com/l-series6cylinder.aspx 1.) For carb application it is 107 LCA 2.) For stock EFI application it is 112 LCA Same lift, same duration Make any sense?? Jeff Edited August 21, 2009 by MONZTER Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 21, 2009 Administrators Share Posted August 21, 2009 (edited) Hey Paul,What's your thoughts on this- I found out that Schneider cams make two different versions of the same cam http://schneidercams.com/l-series6cylinder.aspx 1.) For carb application it is 107 LCA 2.) For stock EFI application it is 112 LCA Same lift, same duration Make any sense?? Jeff Yeup, makes sense. The cam with the tighter LSA, (Lobe Seperation Angle), of 107 degrees has more valve overlap. They call the other cam an EFI cam as it is more friendly for "FACTORY EFI", (less overlap for more idle vacuum and comparable VE curve which the factory EFI is tuned to) That and it might be the internal oiled cam vs the external. With aftermarket EFI or carbs, choose the cam specs that best fit your performance needs, not necessarily whether the cam is labeled as EFI or Carb. This should help when choosing a cam. Tight LSA is generally more peak power and more peak torque, peakier power bands at the sacrifice of low RPM drivability, smoothness, mileage, emissions. Wider LSA for a given lobe profile will generally be smoother, more street friendly, have a broader power band with a flatter torque curve, but not as much over all peak torque as the tighter lobe separation variant. 104-110 degrees LSA is more performance oriented, the 104-108 range is generally race oriented. 112-118 is generally moderate performance, and modern 2 valve OE LSA's are in the 115-118 range. There is a LOT more to it than just this. Cam design and valve event timing as applied to 2 valve internal combustion engines could be a 2 year degree program in itself! This is just generalizations of how LSA affects power production and drivability. Depending on the lobe profile, mild vs radical, differing LSA figures can exaggerate those tendencies, or vice versa. Like most everything performance related, it's all a compromise. Finding the least compromise for that particular application is what separates the ho-hum power plants from the magical torque producing monsters. Ps. I've said this a thousand times and will probably say it again. I don't care what the cam manufactures claim, NO aftermarket cam that specs at any appreciable more lift/duration than stock, will play well with the factory DATSUN EFI, period! So for you guys reading this that are contemplating a cam swap and using the stock EFI, "leave the stock cam in your engine", until you are ready to install aftermarket EFI or carbs! Trust me on this! Seen and dealt with that scenario in the past far too often. This applies the old L-jet EFI as used on the S-30 and S-130 cars. Edited August 21, 2009 by BRAAP Typos. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted August 22, 2009 Share Posted August 22, 2009 Thanks for that Good Info Quote Link to comment Share on other sites More sharing options...
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