fraz Posted April 18, 2017 Share Posted April 18, 2017 I have a few 05L heads from the l20et that I was hoping to use for an l28. I will cut 1 of them up to see how much material there is in the port walls. Is it worth cutting every port? I put cylinder 6 through the bandsaw this morning and it looks promising. Quote Link to comment Share on other sites More sharing options...
WhitleyTune Posted April 18, 2017 Share Posted April 18, 2017 I'd say just one cut each through an inlet and exhaust port will give you a good idea of how much material can be removed. If you are going 10/10ths then you could do the lot, but you'd probably be better investing in a good sonic thickness tester in that case. Any chance you could put some photos up? Have a few 05L heads myself here. Quote Link to comment Share on other sites More sharing options...
fraz Posted April 18, 2017 Author Share Posted April 18, 2017 Yip I will put some photos up when I have some more free time. Quote Link to comment Share on other sites More sharing options...
fraz Posted April 20, 2017 Author Share Posted April 20, 2017 Quote Link to comment Share on other sites More sharing options...
fraz Posted April 20, 2017 Author Share Posted April 20, 2017 Quote Link to comment Share on other sites More sharing options...
fraz Posted April 20, 2017 Author Share Posted April 20, 2017 Cylinder 6 exhaust Quote Link to comment Share on other sites More sharing options...
fraz Posted April 20, 2017 Author Share Posted April 20, 2017 Cylinder 6 inlet Quote Link to comment Share on other sites More sharing options...
fraz Posted April 21, 2017 Author Share Posted April 21, 2017 sorry photos are currently a bit average. i posted them from my phone. Will delete them next week and re-post some better ones. I measured the chamber at around 37cc, which will probably end up being maybe 40 with some bigger valves fitted and some de-shrouding I want to put it on a l28 with +030 flat tops. On the various compression ratio calculators i get around 10.5:1 We have 95 and 98 octane fuel available locally which is equivalent to 91 and 94 US octane. I should be ok for knock with a mild cam right? Quote Link to comment Share on other sites More sharing options...
WhitleyTune Posted April 23, 2017 Share Posted April 23, 2017 Cool, thanks for that. Looks to be plenty wall thickness for the larger valves. Will you have to put new seat inserts in or are they large enough to fit the L28 valve sizes? Knock wise you will be fine at 10.5:1 with a mild cam on our 95/98 pump gas. The chambers on the 05L have a decent amount of squish so you won't have the issues that a 10.5:1 N42 would have. Good luck! Interested to see how you go, the 05L seems a good starting point for a nice head to me. Quote Link to comment Share on other sites More sharing options...
fraz Posted April 24, 2017 Author Share Posted April 24, 2017 Quote Link to comment Share on other sites More sharing options...
fraz Posted April 24, 2017 Author Share Posted April 24, 2017 Cool, thanks for that. Looks to be plenty wall thickness for the larger valves. Will you have to put new seat inserts in or are they large enough to fit the L28 valve sizes? Knock wise you will be fine at 10.5:1 with a mild cam on our 95/98 pump gas. The chambers on the 05L have a decent amount of squish so you won't have the issues that a 10.5:1 N42 would have. Good luck! Interested to see how you go, the 05L seems a good starting point for a nice head to me. Would say I will have to get new valve seats. Can't remember the measurements. You're in chch? I'm down there a couple of times a year, I can post you a cylinder of pieces if your interested. Somebody told me you had a flow bench too? Quote Link to comment Share on other sites More sharing options...
WhitleyTune Posted April 25, 2017 Share Posted April 25, 2017 Just did a quick measure from the photos and looks like the seat diameter is around 42mm so yeah needs new seats. Heaps of meat in there though so should be a good thing. Yeah I am in Christchurch. I don't have a flowbench myself but have access to one. Would like to see a couple pieces! No stress though, only if you can be bothered sending them. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 29, 2017 Share Posted April 29, 2017 My understanding from the Japanese I'd talked to is the O5L has the same coolant cores as the P90, but with smaller cores for the intake and exhaust runners, and combustion chambers. The Bare O5L weighed more than a comparably stripped P90 I have so that may be the case given what appears to be thicker than usual casting in the runner. I can't bear to cut up the P90, but I think someone has in the past, that would confirm if the old tale is true or not. It was said they take the same porting as the P90 or N42 so maybe the water jacket was a standard part of the casting, with chambers and runners changed accordingly. Had to be something interchangeable in the cores you would think... Quote Link to comment Share on other sites More sharing options...
fraz Posted April 29, 2017 Author Share Posted April 29, 2017 Yes and no I think. Not changing the water jacket would reduce design and tooling cost, but would also increase aluminum cost. But they were being built at a time when designers only concentrated on making things function better. It wasn't until a few years later that the bean counters started putting the emphasis on costing less and less. So your probably right Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted May 3, 2017 Share Posted May 3, 2017 I also have an O5L head that I plan to use for my son's build so thanks for posting the pics. If you can provide some wall measurements for the intake & exhaust ports that would be great. I was the one who posted P90 cross section pics and the link is below. http://www.eng.famu.fsu.edu/~jthagard/3liter/pics/P90/ Quote Link to comment Share on other sites More sharing options...
fraz Posted September 12, 2017 Author Share Posted September 12, 2017 Here is a l28 gasket on the head. 35mm holes in the gasket. 29mm in the head. I test ported a piece of the head i cut and there appears to be enough meat in it. It was 5mm on one side and 1mm on the other. Ill get some more photos this week. Quote Link to comment Share on other sites More sharing options...
wenzlern Posted September 15, 2017 Share Posted September 15, 2017 Thank you! This is gold for me . I have a 05L that I wan't to use for a hot L24. But since they are quite rare around here I have no second head to cut and study. best, Nils Quote Link to comment Share on other sites More sharing options...
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