ThaPimpShrimp Posted March 19, 2014 Share Posted March 19, 2014 I am planning on building an L28 for my '72 240z. I've done lots of reading, and of course have discovered the information on DatsunZGarage. I am planning to follow his setup on a P90/F54 (Which I already own) pretty much exactly. It is a pretty moderate build, and I'm not going to go overboard into performance. I try to daily drive the Z when I can, which includes a 100 mile commute. My main concern is pinging. Shaving the head 0.080" brings me up to around (Probably a little over, I don't know what size pistons I need yet) 10:1. With the P90's head design this shouldn't be an issue, but I am in California so I really only have access to 91 octane and I don't plan on using any octane booster. If this is CR even an issue, I'd rather just get the compression a bit lower from the start, than retarding timing and potentially losing performance that way. I understand how the camshaft and valvetrain geometry is kept in line with his setup, what I don't know is if I want to lower it a bit, how to go about that the best way (Say shaving just 0.060" instead). Like I said, I have done lots of reading, and have searched on here and haven't quite found my answer. This is probably more a question of general engine building than specific to the L series, but you guys likely know best and I figure it should be a fairly short and sweet answer. I'll try to get a thread together showing my progress with the car soon too, it's been a lot of work but I enjoy it, and I love my Z. Thanks! Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 21, 2014 Share Posted March 21, 2014 (edited) Here is a config I built last year for a friend. He uses it on the street and for track days. It runs just fine on 93 pump gas with 34 degrees of advance. P90 head: Head was only resurfaced. Less than .005 removed Stock valves, and springs Fresh valve job This cam: http://schneidercams.com/260-70F_L6.aspx Correct lash pads F54 block: ITM 87mm flat top pistons Felpro head gasket Full balance. SU carbs with SM needles. The engine pulls strong to 6000RPM. I figure the CR is around 9:1. Edited March 21, 2014 by z-ya Quote Link to comment Share on other sites More sharing options...
clarkspeed Posted March 21, 2014 Share Posted March 21, 2014 That's a good set up. I built one to drive 140 miles a day with a P79. Just fresh engine, blended the ports into the valves, port matched the manifold, weber big throat, headers, 2-1/2 exhaust with cheap 3" Catalytic converter. Ran like hell on 87 octane. 23mpg. Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted March 21, 2014 Author Share Posted March 21, 2014 (edited) Here is a config I built last year for a friend. He uses it on the street and for track days. It runs just fine on 93 pump gas with 34 degrees of advance. The engine pulls strong to 6000RPM. I figure the CR is around 9:1. Thanks for the tip there. Is 93 octane really necessary on that engine? Or just a precaution. The reason I was worried about getting near 10:1 is I only have access to 91. Not to mention my cam selection is pretty mild so that won't help much with the dynamic compression. I need to look into SM needles, I have stock rebuilt ZTherapy SU's on currently. That's a good set up. I built one to drive 140 miles a day with a P79. Just fresh engine, blended the ports into the valves, port matched the manifold, weber big throat, headers, 2-1/2 exhaust with cheap 3" Catalytic converter. Ran like hell on 87 octane. 23mpg. Sweet! I'm going to do some port work as well. I've got the full MSA exhaust system (6-1 headers) and an N36 intake w/ SU's. 23mpg isn't bad. Would you believe me if I told you I was getting up near 30mpg with my L24? 5 speed + stock gearing ratio helped out a bunch there I'm sure. Edited March 21, 2014 by ThaPimpShrimp Quote Link to comment Share on other sites More sharing options...
clarkspeed Posted March 22, 2014 Share Posted March 22, 2014 I was running stock efi and cam in an 82 ZX with a ported out 75 manifold. Everyone who drove it was amazed at the power it had. I would keep the compression low and run cheap gas for daily driving. Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted March 22, 2014 Author Share Posted March 22, 2014 I was running stock efi and cam in an 82 ZX with a ported out 75 manifold. Everyone who drove it was amazed at the power it had. I would keep the compression low and run cheap gas for daily driving. Hmm alright thanks for the advice. I keep going back and forth on that topic. I even spoke for a while to Rebello (Since he's in CA) about what he would do. Tough decisions to make! I'm using ARP Studs anyway so I suppose if I want to, I can go back in and raise compression later. Technically I'll get better fuel economy with higher compression anyway Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted March 23, 2014 Author Share Posted March 23, 2014 So the final plan is just leaving compression alone, just using flat tops to get me up into the 8's . Later on though, I am going to boost it when I get all the pieces together. Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 24, 2014 Share Posted March 24, 2014 You can run 91 on the setup I posted above. OEM rod, main and head bolts are fine for all street applications. With an 87mm bore, Felpro gasket, and flat top pistons you should be around 8.9:1. Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted April 5, 2014 Author Share Posted April 5, 2014 You can run 91 on the setup I posted above. OEM rod, main and head bolts are fine for all street applications. With an 87mm bore, Felpro gasket, and flat top pistons you should be around 8.9:1. I'll end up pretty close to this setup, though I may be using 86mm pistons. I've been reconsidering cam options.. and I'm not sure what to go with. When I compare Webcamshaft's 94a to stock cams it seems pretty similar.. so I don't see the point in spending the money to "upgrade" to it. Even the 91 looks to be less racey than MSA's stage 1. Am I reading the specs wrong? Do you guys have any suggestions as to what would work best for me? Car will see the rare track day but mostly daily driving and fun runs, I do a good amount of spirited driving so I'm not afraid of losing a little but I don't want to go overkill either. Quote Link to comment Share on other sites More sharing options...
steve260z Posted April 8, 2014 Share Posted April 8, 2014 I am planning on building an L28 for my '72 240z. I've done lots of reading, and of course have discovered the information on DatsunZGarage. I am planning to follow his setup on a P90/F54 (Which I already own) pretty much exactly. It is a pretty moderate build, and I'm not going to go overboard into performance. I try to daily drive the Z when I can, which includes a 100 mile commute. My main concern is pinging. Shaving the head 0.080" brings me up to around (Probably a little over, I don't know what size pistons I need yet) 10:1. With the P90's head design this shouldn't be an issue, but I am in California so I really only have access to 91 octane and I don't plan on using any octane booster. If this is CR even an issue, I'd rather just get the compression a bit lower from the start, than retarding timing and potentially losing performance that way. I understand how the camshaft and valvetrain geometry is kept in line with his setup, what I don't know is if I want to lower it a bit, how to go about that the best way (Say shaving just 0.060" instead). Like I said, I have done lots of reading, and have searched on here and haven't quite found my answer. This is probably more a question of general engine building than specific to the L series, but you guys likely know best and I figure it should be a fairly short and sweet answer. I'll try to get a thread together showing my progress with the car soon too, it's been a lot of work but I enjoy it, and I love my Z. Thanks! Isn't the general idea about that mod is that .080" is also the difference in valve stem length? Steve Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted April 8, 2014 Author Share Posted April 8, 2014 (edited) Isn't the general idea about that mod is that .080" is also the difference in valve stem length? Steve Yes sir you are correct, I was wondering if there was a way of shaving less off (perhaps .060") to keep the compression a bit lower since I only have access to 91 octane.. but I've since decided to just not do any shaving anyway. Too much hassle, and my compression will be good enough for a street car with the bigger pistons/thinner gasket. Edited April 8, 2014 by ThaPimpShrimp Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 10, 2014 Share Posted April 10, 2014 MSA cams are Scheider cams. My suggestion is not to cut the head 0.080. You can get very close to 9:1 CR without cutting it. It will run very nicely on 91 octane. Quote Link to comment Share on other sites More sharing options...
ThaPimpShrimp Posted April 22, 2014 Author Share Posted April 22, 2014 MSA cams are Scheider cams. My suggestion is not to cut the head 0.080. You can get very close to 9:1 CR without cutting it. It will run very nicely on 91 octane. I am getting a ton of conflicting opinions on Schneider vs. Isky vs. Webcams and also tons of conflicting opinions on regrinds versus new billets.. What's your opinion on all of this, and how is that cam holding up thus far? I'm looking for a grind very similar to the one you used. Quote Link to comment Share on other sites More sharing options...
Dkyle Posted October 2, 2014 Share Posted October 2, 2014 i have the same question.. & I also have a similar build.. P90 NA,with SM needles; but went with custom "domed" pistons (.040" over) instead of shaving the head. With a 1mm gasket I should have a bit > 9.5 CR. I polished the ports. i'll be using a 3.95 differential. I had decided on the Schnieder 17033 cam (215/215 dur .480"/.480" lift) but the cam is not avail with a 107 lobe seperation. Schneider has convinced me that their regrind of my old "Turbo" cam would be good.. the core is a better material than those new cams.. higher nickel content. After the regrind, they should be telling me what lash pad I'll be needing to order. My only decision now is what spec to regrind it. I want the car to be quick; to be able to jump, accelerate quickly, whether i'm going 30mph in 3rd, or 70mph in 5th. I'm not sure I'll be taking the car much over 100mph very much. I would want the Powerband in the low-mid range? I also do NOT want it to ping. I don't know how a 220/230 dur .460" lift would be different from a 215/215 .480" lift. Do i seperate the lobes a bit more to help mitigate pinging? ..108, 109? Any ideas? Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 3, 2014 Share Posted October 3, 2014 I am getting a ton of conflicting opinions on Schneider vs. Isky vs. Webcams and also tons of conflicting opinions on regrinds versus new billets.. What's your opinion on all of this, and how is that cam holding up thus far? I'm looking for a grind very similar to the one you used. Without Data to back it up, discard the "opinion"... I believe it was W. Edwards Deming that said "Without data, you're just another person with an opinion." Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 3, 2014 Share Posted October 3, 2014 I ran the 274f Schneider grind and it had very good low end. Power band was as advertised Quote Link to comment Share on other sites More sharing options...
Dkyle Posted October 5, 2014 Share Posted October 5, 2014 yes.. the 274f schneider is 215 deg @ .415" lift. Did you install it straight up? or advance it #2 ? What size lash pad did you end up using? Quote Link to comment Share on other sites More sharing options...
madkaw Posted October 5, 2014 Share Posted October 5, 2014 I have an adjustable sprocket , but the numbers came out slightly advanced when I was done. I couldn't get it dead on the specs-probably because of head shave and block shave, so I leaned towards numbers that advanced intake. Quote Link to comment Share on other sites More sharing options...
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