blueking Posted May 6, 2009 Share Posted May 6, 2009 I recently obtained a camshaft that is supposedly, "streetable," but am not sure if it has to high of spec's for my stock 1983 280zx, it has a stock ecu, and a p79 head, i cant recall off the top of my what block but here are the spec's on the cam. Intake Exhaust Valve Lash .008 .010 Valve Lift .450 .450 Duration 260 & 260 degrees Duration @ .050 238 & 238 degrees Lobe Center 108 & 111 degrees Intake Opens 11 Degrees B4 TDC Exhaust Opens 50 Degrees B4 TDC Intake Closes 47 Degrees after BDC Exhaust Cloases 8 Degrees after BDC The car has trouble staying, even when i give it gas on but i have a feeling it could be the timing on the ignition or improperly adjusting my rocker arms. i adjusted my rocker arms to .010inch and .012 inch, like the dealers manual says but it says you do it HOT, and obviously the car has to be cold to put the cam in. the timing between the cam and crank is dead on as I took off the cover to do the timing right.... Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted May 6, 2009 Administrators Share Posted May 6, 2009 All aftermarket cams are 'too big' for the stock ECU. You may be able to ban-aid it into being drivable, but it will always be compromised. Quote Link to comment Share on other sites More sharing options...
blueking Posted May 6, 2009 Author Share Posted May 6, 2009 All aftermarket cams are 'too big' for the stock ECU. You may be able to ban-aid it into being drivable, but it will always be compromised. its .010 smaller the msa's stage 1 Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted May 6, 2009 Administrators Share Posted May 6, 2009 In my opinion, it doesn't matter. The stock ECU is not adept to compensating for any torque curve changes. I'm not saying you can't make it run... I'm saying it will never be 'ideal'. By the way, you mention LSA at 108 & 111. It can only be one number. Which is it? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted May 6, 2009 Administrators Share Posted May 6, 2009 As already stated ANY after-market/performance cam other than stock is too big for the stock ECU! And with any cam other stock you will need matching springs! Stock springs are barely adequate for stock cams when they are fresh. Being 30 years old and 100,000 miles on them, valves start to float before ideal shift point with the stock cam. More cam exaggerates this problem. All of this has been covered in depth on this forum including the results from others that have tried it! If you want more performance, there are a few other areas to gain performance if you have to retain the stock ECU, and not have make so much of a compromise in power vs drivability. Quote Link to comment Share on other sites More sharing options...
PalmettoZ Posted May 6, 2009 Share Posted May 6, 2009 Hey Blueking- One way you could check to seee if your camshaft timing is correct is to do a compression check on each cylinder. If it is way down then perhaps the timing is off. Did you check ignition timing? How about your air flow meter and hoses, make sure you don't have any vacume leaks. Make sure you are adjusting your valve lash with the cam lobe in the correct position. I would double check for the basics to be correct first, that cam is fairly mild. Although this is not to undermine what Braap and RTz said, they are right that the ECU is primitive. I recently obtained a camshaft that is supposedly, "streetable," but am not sure if it has to high of spec's for my stock 1983 280zx, it has a stock ecu, and a p79 head, i cant recall off the top of my what block but here are the spec's on the cam. Intake Exhaust Valve Lash .008 .010 Valve Lift .450 .450 Duration 260 & 260 degrees Duration @ .050 238 & 238 degrees Lobe Center 108 & 111 degrees Intake Opens 11 Degrees B4 TDC Exhaust Opens 50 Degrees B4 TDC Intake Closes 47 Degrees after BDC Exhaust Cloases 8 Degrees after BDC The car has trouble staying, even when i give it gas on but i have a feeling it could be the timing on the ignition or improperly adjusting my rocker arms. i adjusted my rocker arms to .010inch and .012 inch, like the dealers manual says but it says you do it HOT, and obviously the car has to be cold to put the cam in. the timing between the cam and crank is dead on as I took off the cover to do the timing right.... Quote Link to comment Share on other sites More sharing options...
evildky Posted May 6, 2009 Share Posted May 6, 2009 stock ecu sucks in general, if you want to make any power eitehr swap to carbs or megasquirt or similar stand alone Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted May 6, 2009 Administrators Share Posted May 6, 2009 stock ecu sucks in general, if you want to make any power eitehr swap to carbs or megasquirt or similar stand alone Quote Link to comment Share on other sites More sharing options...
blueking Posted May 6, 2009 Author Share Posted May 6, 2009 Hey Blueking-One way you could check to seee if your camshaft timing is correct is to do a compression check on each cylinder. If it is way down then perhaps the timing is off. Did you check ignition timing? How about your air flow meter and hoses, make sure you don't have any vacume leaks. Make sure you are adjusting your valve lash with the cam lobe in the correct position. I would double check for the basics to be correct first, that cam is fairly mild. Although this is not to undermine what Braap and RTz said, they are right that the ECU is primitive. can you send me a link for adjusting lash? I've read how to modify your datsun ohc a few times and it still doesnt seem clear.... maybe ignition but shouldnt be too out of faze..... no vac leaks Quote Link to comment Share on other sites More sharing options...
1 fast z Posted May 6, 2009 Share Posted May 6, 2009 Before my MS days, I ran a stock ECU and electronics. I ran a 13.9 in a full 280z car, at 1300 feet of elevation. I ran turbo injectors, a WB, and a turbo converted AFM. I had a .470" lift and 270 in duratin, and 280 ex duration. When I went with MS and ITB's I got it down a few more tenths. IMHO, MS, should be the FIRST mod on any car. Quote Link to comment Share on other sites More sharing options...
blueking Posted May 7, 2009 Author Share Posted May 7, 2009 The car runs now I did the ignition timing to the factory 10 degrees and the motor idles incredibly rough at 500 i cant get it to go any higher, but once it hits 1,000rpm there is no stopping it, the sad part is..... i have to take it apart again seeing as how there is now water in my oil and i have a feeling its the timing cover... FML Quote Link to comment Share on other sites More sharing options...
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