Phil Posted February 22, 2015 Author Share Posted February 22, 2015 (edited) As above am about to get head work done at the min I was considering bigger valves but wasn't sure am going with the following specextended port polish 2mmupgraded valve stem sealsupgraded springs3angle valve seatsthe port polish will open the throats to 2mm mimic of 1.5mm oversized valvesmaybe this info will help someone who is doing this work>? and is this a list of what they are telling you they will do? id be keen for them to explain throats 2mm mimic 1.5 oversized valves? Just to make sure it wasnt a typo that they would open the seat up leaving you requiring a MIN of 1.5mm oversize valves! which would be a costly misinterpretation lol bigger straight fit valves are mad money. all sounds good then man. (zisco are good) Phil Edited February 22, 2015 by Phil Quote Link to post Share on other sites
AdamB Posted February 22, 2015 Share Posted February 22, 2015 (edited) I'm sorry but what a crock of shit. How on earth can a throat mimic a valve size? The throat can flow all the air I'm the atmosphere, but that doesn't mean the seat is going to flow that much. Classic case of a salesman trying to do an engineers job. Edited February 22, 2015 by AdamB Quote Link to post Share on other sites
maddox710 Posted February 23, 2015 Share Posted February 23, 2015 He must be selling a kidney to pay for this Quote Link to post Share on other sites
Calum122 Posted January 15, 2016 Share Posted January 15, 2016 Any updates to this thread. Is very interesting. Quote Link to post Share on other sites
AdamB Posted January 15, 2016 Share Posted January 15, 2016 Think Phil is still running stock valves, but I'm sure he'll chime in soon. Unfortunately valves are very often overlooked, even though its the first place to start when looking at getting air into and out of the engine... Quote Link to post Share on other sites
glanzagee Posted January 15, 2016 Share Posted January 15, 2016 putting bigger valves in theses head changes alot of thingsi learned the hard way and paid for it too be rectified ! heres what happens in the wrong hands ! (We have checked the valve spring pressures. At fitted length they are 55.6 to 58.4 lbs.Over the nose of the cam they are 124 to 126.5 lbs. which is very low, especially for a turbo charged application where the boost pressure is lessening the poundage on the inlet valves. You may risk valve blow by on high boost. Coil binding occurs at 0.80 inch. At the current fitted length you are 0.225 inch off coil bind at full cam lift. We would run as close as 0.060 inch on some engines if they require it. (1.5mm.) I would suggest that the spring poundages are increased by using a thicker spring seat. The current spring seats are very agricultural (Machined washers of some sort.) To use a thicker spring seat would invlove a purpose made seat to locate the bottom of the valve spring. This is currently located by a machined step in the head casting, outboard of the valve guide. Using a thicker plain spacer would lose this location of the valve spring. There is enough space however to machine a purpose designed spring seat.) this is just a very small part of putting bigger valves in rectified now and reving too 8250rpm (5e) next step back too back test on a flow bench. Quote Link to post Share on other sites
Calum122 Posted January 15, 2016 Share Posted January 15, 2016 Oh deary me! Don't tell me that are what those washers were for lmao! I did not refit those upon fitting the head! I was absolutely baffled as to what they were to be quite honest with you. Luckily I don't drive the car but duely noted! I am such a plonker lmao. Quote Link to post Share on other sites
glanzagee Posted January 15, 2016 Share Posted January 15, 2016 washer as in spring seat base whats been done too your head modification wise ? Quote Link to post Share on other sites
Calum122 Posted January 15, 2016 Share Posted January 15, 2016 Nah I was just doing a headgasket change lol. I'm no mechanic so obviously missed a few things lmao. I will sort it out Quote Link to post Share on other sites
Phil Posted January 23, 2016 Author Share Posted January 23, 2016 Just as an update I just replaced exhaust valves for new ones (stock)Low mileage stock springs268* cans 8.7mm lift ex and intakeSolid liftersEverything else standard.Revving to 7800ish Phil Quote Link to post Share on other sites
animal GT Posted March 4, 2016 Share Posted March 4, 2016 The thing I don't get now is. I've seen Dylan push out 550 or so bhp on a head that's not even ported never mind bigger valves. Grant it his graph doesn't look the best but I ask myself is it realy all worth the big costs? Ported head springs cams is all that's needed realy Quote Link to post Share on other sites
Phil Posted March 4, 2016 Author Share Posted March 4, 2016 The thing I don't get now is. I've seen Dylan push out 550 or so bhp on a head that's not even ported never mind bigger valves. Grant it his graph doesn't look the best but I ask myself is it realy all worth the big costs? Ported head springs cams is all that's needed realyI'm not sure Sean.Your likely the man to find out.I know that a big power turbo motor will make 450+ per litre That would be 585+ on a 4e I'd say to make that you would be looking every last bit from everywhere. And probably e85 or betterPhil Quote Link to post Share on other sites
AdamB Posted March 4, 2016 Share Posted March 4, 2016 It's not about making power, it's about making the car driveable and well mannered. Quote Link to post Share on other sites
Calum122 Posted March 5, 2016 Share Posted March 5, 2016 It's not about making power, it's about making the car driveable and well mannered. ^^^THIS^^^ There is a lot to be said for big peak power engines, but an engine that pulls solid throughout the rev range is a lot more difficult to do. A lot more work involved. Quote Link to post Share on other sites
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