need4speed Posted February 10, 2011 Share Posted February 10, 2011 If i use a cam that has 0.465" lift on the inlet AND exhaust sides, will i get away with not machining the valve guides? I seem to remember hearing that you could get away with not machining the guides unless the cam had 0.5" or more of lift? Phil Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted February 10, 2011 Share Posted February 10, 2011 It's not quite as simple as that you'd need to know what ratio rockers you are intending using. Quote Link to comment Share on other sites More sharing options...
Andrew Cleland Posted February 10, 2011 Share Posted February 10, 2011 I think you're probably into valve guide shortening territory there - Real Steel do a cam with .465" inlet & exhaust valve lift when used with 1.5:1 rockers (standard ratio) and they say it will need 100thou of the top of the valve guides or their shortened guides fitted. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 10, 2011 Share Posted February 10, 2011 Rockers are 1.6: 1 ratio, not 1.5! Maximum valve lift is 0.44", most cams are specified by the valve lift with stock rockers, so this is the figure you need to check. If you are AT ALL unsure, ring the supplier, I have found Paul @ V8 Tuner very helpful in the past. Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 11, 2011 Author Share Posted February 11, 2011 It now turns out that the heads may already have shortened guides! You see this engine isnt for my 110 - its already built and installed. Its for a capri. Speaking to my father (whos engine is going in the car) he cant remember if hes shortened the guides as the engine has been sitting so long ready to be transplanted. Is there any way i can tell if the guides have been shortened already without taking the heads back off again? Phil Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 11, 2011 Share Posted February 11, 2011 What era is the engine? Is it the later 10 bolt heads or earlier 14 bolt? It 10 bolt, once shortened, the step that the seal sits on is very close to the surface of the head, BBC had a really good picture of this in his build thread, but sadly the pics have gone This is what I believe the stock guide looks like: http://www.turner-en...es/bronzeg1.jpg So from that you may be able to judge yours against this picture. Earlier heads do not have the same step in the guide making it a bit more difficult to assess.... As you don't want to take the heads off again, I suppose you could measure compression before the guide top hits the spring retainer? I think I have a stock head around here to test against if you do it this way... Are the guides bulleted on the valve side? If so then they are probably shortened as well... I'd surprised if someone went to the bother of bulletting them and not grinding the top off them. Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 11, 2011 Author Share Posted February 11, 2011 They are the later 10-bolt injection heads. The guides have not been bulleted. I'll try and compare the pic with what the engine looks like. Im not 100% sure how id go about measuring it the other way you mentioned re the compression.. Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 11, 2011 Author Share Posted February 11, 2011 I suppose you could measure compression before the guide top hits the spring retainer? Yea on re-reading i know what you mean. If i have 0.5" or more travel before the cap hits the top of the guide i should be fine? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 11, 2011 Share Posted February 11, 2011 I would think so, yes I'd be looking for 0.550" to be sure! As they are the later heads, then you should be able to see the step quite easily Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 11, 2011 Author Share Posted February 11, 2011 Thanks for your help Bowie Phil Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 11, 2011 Share Posted February 11, 2011 Glad I could help Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 14, 2011 Author Share Posted February 14, 2011 Well. Had a look under the rocker covers today and the heads definately need to come off. Comparing what I saw with your pic, the guides will need shortened in order to fit the cam. Oh well. Quote Link to comment Share on other sites More sharing options...
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