turbogrill Posted July 11, 2018 Share Posted July 11, 2018 Hi, The valve seats on the N47 exhaust ports sticks out and creates a pretty bad edge. I want to grind them down flush with the exhaust liner. Is it OK to grind the bottom of the seals down? Or will that weaken them? Quite a lot of material that needs to be removed. Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 13, 2018 Share Posted July 13, 2018 Bowl blending 101. One of the first things you do. Perfectly fine. Quote Link to comment Share on other sites More sharing options...
turbogrill Posted July 13, 2018 Author Share Posted July 13, 2018 1 hour ago, Chickenman said: Bowl blending 101. One of the first things you do. Perfectly fine. Awesome! Been doing it on the intake. Must be pretty big gains for little work, that ridge on the exhaust is pretty bad. ....would be cool to have a flow bench in my garage. Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 13, 2018 Share Posted July 13, 2018 (edited) Pay attention to the short side radius as well. Make sure it id not too sharp. Especially on the Intake side. The exhaust liners actually give a nice smooth radius into the port bowl. Edit: I'll send some pictures of my P79 " project " head that someone did some nice blending on. Big valves though. 45 mm Intake and 38 mm Exhaust!! Edited July 13, 2018 by Chickenman Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 20, 2018 Share Posted July 20, 2018 (edited) Here's the P79 head I just bought. Someone spent some considerable time on it. Pressure cabinet cleaned All new steel seats. All new bronze valve guides. New 38mm Manley SS Pro Flow exhaust valves. New 44 mm SS Intake valves . Intakes are wrong valves . Short style P79/P90 . We use N42/N47 style as they are longer. Gives you some more clearance for valve lift and as Camshaft is a re-grind, eliminates having extra thick Lash Pads. The exhausts are the longer style. Five are Manley, but one is a shorter valve and is not the same as the others. Not a big deal, as Manley still makes Valves to order. Going to order six Manley 45 mm Pro Flow Intake valves and one 38mm Pro Flow Exhaust Possibly Isky valve springs as well. They are new and sure as heck not stock. I'll put them on a spring tester and get the rate. Head will be a winter project. I'll finish off the Valve seats properly. Clean a couple of minor things up and do the #5 and #6 Cooling mod. Edited July 20, 2018 by Chickenman Quote Link to comment Share on other sites More sharing options...
turbogrill Posted July 20, 2018 Author Share Posted July 20, 2018 Nice! What do you do with your valve seats? Make sure the valve mating surface is clean? Or do you reshape them to match the cut valve angle? Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 20, 2018 Share Posted July 20, 2018 I haven't done anything to this head...Yet. This is how I received it from E-Bay. Best $150 bucks I've ever spent... well maybe this second Best. There was this girl... errr,.. never mind. Quote Link to comment Share on other sites More sharing options...
turbogrill Posted July 20, 2018 Author Share Posted July 20, 2018 10 minutes ago, Chickenman said: I haven't done anything to this head...Yet. This is how I received it from E-Bay. Best $150 bucks I've ever spent... well maybe this second Best. There was this girl... errr,.. never mind. Oh wow! Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 20, 2018 Share Posted July 20, 2018 I will be finishing off the seats with a 3 angle cut. Looks like PO just did a quick two angle. 30 degree top cut to get Valve seating in right spot. That wasn't done yet. Lap the 45 degree cut. 70 Degree cut is already there, but may need touch up. Need 45 mm Intake valves because the current 44 mm are too small for the seat diameter. May have to unshroud Intakes a bit. Exhaust valves are 38 mm currently. Pretty freakin' big. But good for a Nitrous or Turbo motor. Wasted on my NA motor. I may be able to cut them down to 37mm to gain some unshrouding. Some touch ups to some nicks in a couple of the chambers. Radius the sharp edges in the combustion chambers from the surface skim cut. Some other detail work. CC the heads. Trying to find Machine specifications for overall head height from face to VC rail. Measure 107.39mm in total height. But from casting numbers and amount of material left below Casting numbers it looks like the head is nearly Virgin. My N47 head on the other hand... has virtually no material below the casting numbers. Looks like its been shaved big time. But measures out at 108.17mm. Problem is. I don't know if N47 and P79 heads are the exact same dimensions fin overall height. They may not be. Some guesses from people. But I'm seraching for the Fcatory specs. On of Honowitz's books is suppossed to have them. Quote Link to comment Share on other sites More sharing options...
Chickenman Posted July 20, 2018 Share Posted July 20, 2018 This is how it came. out of the shipping box. Lack of Cam towers doesn't concern me. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.