PapaSmurf Posted November 15, 2007 Share Posted November 15, 2007 Ok guys I'm still tryin to get a runnin motor in my Z, the l26 I tried to swap in was doa and now I've got me a nice re-manned dipped l28 to stick in. She's got flat top pistons standard bore as far as I know though it may have been bored by the po I'll have to compare with the other l28 anyways I got an n42 head with it, it's been gone through valves replaced etc and I'm wondering wether it would be better to go with it or the n47 or e88 I got in the driveway. It's been gone through and it looks perty nice but as long as she's apart I'm lookin into some options. I checked it out on l6 engine builder 0.1 from zcar club australia and from what I'm seeing the n42 is identical to the n47 in every way except that the exhaust ports on the n42 are square ports vs the n47s round ports. I'm also seeing that my n42/47 both get slightly better compression ratios than the e88 with my block. I'm thinking I'm gonna go with the n42 since it's all nice and shiny but I just wanted to hear some opinions from the guys that know, is it a good head is it a bad head as far as reliability and performance. Lemmie know what ya think. Also What head gasket should I go with? According to this program the felpro gasket raises my compression ratio 10.08:1 rather than 9.82:1 for the standard. I like power power is good... vroom vroom baby Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted November 15, 2007 Administrators Share Posted November 15, 2007 Papasmurf, PLEASE oh please read the links below before you commit to this combination you proposed. Your combination of a flat top piston L-28 and N-42/N-47 head for a street pump gas L-28 is a very poor combination. Read on… 1) For a reman L-28, you will see absolutely NO difference in performance between a stock N-42 and stock N-47 head. Depending on what your exhaust manifold/header is, (in this instance anyhow), would be the deciding factor as to which head to choose, i.e. square or round exhaust port. At that, both are a very poor choice for that short block in a stock to mild L-28 application! 2) OE flat tops in an L-28 with an N-42/N-47 head, stock application, even with premium pump gas is far from ideal. That combination is notorious for being detonation sensitive, even with the highest quality premium pump gas available, this is a bad combination. You would be MUCH better off with either a P-79 or P-90 head on that short block. With the N-42/N-47, your compression ratio will be TOO high for an "open chamber" L-series on Pump gas. To get that combination to run “safely” and produce ANY power, you will have to retard the ignition timing to the point the engine is VERY inefficient, and be VERY soft power wise. The P-79 or P-90 with those pistons, will run circles around the N-42/N-47 head on that same short block with pump gas hands down! Trust me on this one. In short, your shooting yourself in the foot trying to put an N-42/N-47 head on a Reman flat top piston L-28 for street duty with pump gas, PERIOD! This topic has been covered ad-nauseum here on HybridZ. Here are those links… L-series heads, the good, the bad, the ugly! A very in-depth review… http://forums.hybridz.org/showthread.php?t=104420 L-series cylinder heads… http://forums.hybridz.org/showthread.php?t=105653 Bonus thread.. Valve unshrouding… http://forums.hybridz.org/showthread.php?t=110269 Hope that helps, Paul Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted November 15, 2007 Author Share Posted November 15, 2007 Haha thats why I got this block/head for so cheap $200. The guy was tring to run it with regular at normal timings and he decided it must be a devil engine because it wouldn't freakin run. I was in racing mode forgetting that this is ALSO my daily driver, I was thinking premium isn't that much more if I'm payin 3.00 a gallon any way lol but premium wouldn't really have the juice I'd have to retard her and she'd have no power when I wasn't splurging on race fuel. I could always run a thicker gasket on there 2-3mm any problems there? Quote Link to comment Share on other sites More sharing options...
naviathan Posted November 15, 2007 Share Posted November 15, 2007 Papasmurf, 2) OE flat tops in an L-28 with an N-42/N-47 head, stock application, even with premium pump gas is far from ideal. That combination is notorious for being detonation sensitive, even with the highest quality premium pump gas available, this is a bad combination. You would be MUCH better off with either a P-79 or P-90 head on that short block. With the N-42/N-47, your compression ratio will be TOO high for an "open chamber" L-series on Pump gas. To get that combination to run “safely†and produce ANY power, you will have to retard the ignition timing to the point the engine is VERY inefficient, and be VERY soft power wise. The P-79 or P-90 with those pistons, will run circles around the N-42/N-47 head on that same short block with pump gas hands down! Trust me on this one. Paul BRAAP...How did I miss this????? Now I understand why I couldn't get my car to run right and why it kept detonating!!!! When pulled my P-79 head off and it was horribly warped from overheating I decided to grab a head from the shop and get it cleaned up and throw it on the car. I pulled a N-42...Wow...I put an N42 head on a stock F54 N/A block with flat tops and the gas in the car was 87 octane with stock injectors. First time the valves impacted the pistons and I had a whole slew of non related problems. Second time everything was great except I couldn't get the damned thing to quit detonating and it finally blew the head gasket at the number 5 piston pouring coolant into the one piston. Wow...This thread has just opened my eyes A LOT. Thank you BRAAP. Quote Link to comment Share on other sites More sharing options...
PapaSmurf Posted November 15, 2007 Author Share Posted November 15, 2007 lol naviathan sorry to hear about that. I think I'll just run a 2mm gasket on the n42 and premium if that gives me problems at normal timings I'll try some lead additives or get drastic with it. Though my elevation is only 75 feet... maybe a 3mm gasket lol Quote Link to comment Share on other sites More sharing options...
naviathan Posted November 15, 2007 Share Posted November 15, 2007 If you don't mind me asking, where are you getting your gaskets from? I've been wanting to get a MLS 2mm head gasket, but I'm not sure where the best place to buy one is. MSA I think charges way too much. Quote Link to comment Share on other sites More sharing options...
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