steveosupremeo Posted April 16, 2008 Share Posted April 16, 2008 well i searched but didn't find anything on this really.... I'm needing some new valve guides for my P90...Black Dragon offers a standard guide which i'm guessing is cast iron or something similar and a premium guide out of manganese-bronze. Does anyone know what the stock guides are made of? The stock ones seemed to last a good long time but I dunno if one or the other is ideal for a turbo motor?? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted April 16, 2008 Administrators Share Posted April 16, 2008 well i searched but didn't find anything on this really.... I'm needing some new valve guides for my P90...Black Dragon offers a standard guide which i'm guessing is cast iron or something similar and a premium guide out of manganese-bronze. Does anyone know what the stock guides are made of? The stock ones seemed to last a good long time but I dunno if one or the other is ideal for a turbo motor?? 1) How do you know for sure that you need valve guides and not new valves as well? 2) The Machine shop performing your cylinder head machine work, (the place that will be performing your grinding/cutting of the valve seats, facing valves, deck surfacing, jet wash cleaning, R&R guides, R&R of seats if need be, Heli-coil repair of stripped threaded holes, etc), WILL have valve guides in stock or at least access to them so I’d start there. If they do not or can not get them, then you are not dealing with an automotive machine shop. 3) Manganese Bronze guides are typical of high end race heads, that tend to get rebuilt very often, and most, (not necessarily all brands), of Manganese Bronze guides tend to wear the valve stems at a quicker rate than the cast iron guides. ALL L-series heads came with Iron guides from the factory, N/A and Turbo! If your engine is not a 600+ HP drag motor that will get torn down every 10-50 passes down the strip, then the cast iron guides will serve you well. Quote Link to comment Share on other sites More sharing options...
Dayz Posted April 16, 2008 Share Posted April 16, 2008 Thanks Paul, (Braap) I quite enjoy reading your post on engine work! You should do more. Dayz Quote Link to comment Share on other sites More sharing options...
steveosupremeo Posted April 16, 2008 Author Share Posted April 16, 2008 you are probably right in the fact that I may need new valves as well, i can just barely wiggle a few of the valves in the guides...maybe not really wiggle, but can feel a clearance from side to side. its using oil/smoking blue smoke and i found oil puddled on the back side of the intake valves that were closed upon removing the intake manifold. i figured it must be draining down even after shut down. i was using the ford viton seals at first and was hoping they were leaking really bad. I replaced those with the felpro datsun seals after about 350 miles of driving. It was actually a little better, but when replacing, thats when i found i could feel the clearance in the guides. if the wallet permits a guy on ebay sells the stainless SI valves for about $175 for the p90 and thats only about $50 more than stock ones from black dragon. Of course that is probably still overkill but it sounds cool to say you have stainless valves, lol. Quote Link to comment Share on other sites More sharing options...
NismoC32 Posted July 1, 2013 Share Posted July 1, 2013 (edited) Waking up an old thread, but I have a question about valves on a p90 head. I was wondering if you need to do change valve guides if you switch from stock to stainless SI valves. I'm thinking about friction problems due to heat expansion of different metals. Edited July 1, 2013 by NismoC32 Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 2, 2013 Share Posted July 2, 2013 Stock Nissan valves in the turbo cars were already stainless. I am not sure that ALL the L-series valves were, however I can't get them to rust. Quote Link to comment Share on other sites More sharing options...
rick240zed Posted April 29, 2014 Share Posted April 29, 2014 (edited) Are OEM valve guides for a P90 still available? Any links or partnumbers? Would you also want to use stock valve seals (in my case I am not building a big engine; just a P90 with between 9.0 and 10.0 CR and a mild cam with headers)? Edited April 29, 2014 by rick240zed Quote Link to comment Share on other sites More sharing options...
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