LittleBlue88 Posted April 7, 2009 Share Posted April 7, 2009 Alot of the high-lift "performance" cams usually need checking for pre-load,due to the nature of a "high-lift" i.e taller lobes on the cam usually if fitted without checking will always keep the valves slightly open. The cure is to either put shims under the feet that hold up the rocker shafts or fit adjustable pushrods(not worth the hassle!) Quote Link to comment Share on other sites More sharing options...
LittleBlue88 Posted April 7, 2009 Share Posted April 7, 2009 Oooops,may have got my info mixed up! With hydraulic followers the valve open thing doesnt happen,but it does kill followers quicker if you dont deal with the pre-load Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 7, 2009 Share Posted April 7, 2009 .......can anybody explain preload to me please? (Cam kit specifys that preload must be set, haven't bought the cam yet so forgive me if instructions are provided.) When set the hydraulic lifter will be slightly compressed. As said the easiest is to shim under the rocker towers. you measure the preload with a piece of bent wire. You fashion it to the correct thickness for the preload figure and use like a feeler between the top of the lifter inner section and the underside of the circlip. Great way to while away an afternoon. Steve Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted April 8, 2009 Share Posted April 8, 2009 Yes Little blue is correct………… if the preloads are too harsh then you stand a chance of holding a valve slightly open. It is not unusual to see honing marks even after 100K ........ however, have the bores checked for ovality as they will always wear on the thrust side of the piston .......... if ovality is 3 or more thou then rebore........... If you use a stump puller, then you will need to have the valve guides shortened to stop spring bind ……………. Regardless of mileage / condition……. You will need new rocker shafts, rockers and valve springs. Also you will be better off using Rhoads bleed down lifters …………..dont pre prime them when fitting (it can mislead the preload measurements). With your combination of head and cam I would suggest giving some thought to having the block decked ……… whilst there you could also check the piston / deck height (squish band) and have the pistons machined if necessary (often the RV8 is OK). You will need to strengthen the bottom end for longevity ………… I suggest ARP studs in both top and bottom ends (thats another £200 !) This build may be of interest ……preload starts at about post 47 http://forums.lr4x4.com/index.php?showtopic=14006&st=0 Quote Link to comment Share on other sites More sharing options...
stuck Posted April 8, 2009 Author Share Posted April 8, 2009 Cheers for that Info BBC! Could anybody explain what having a block decked entails as it's not something I've come across before. Many thanks, Mick. Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 9, 2009 Share Posted April 9, 2009 Is basically the same as having a head skimmed. The top of the block is skimmed to remove any wear/corrosion and to make sure it is not warped. Steve Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted April 9, 2009 Share Posted April 9, 2009 And a number of Engineering co's don't like / won't deck a V8 due to the set up / equipement, being a "V" design IF you do have this done DO CHECK that all the liners are level with the surface of the block before committing money on it if any of the liners apprear lower you may be spendiung money on a block that may need THLs, not a gauarntee by any means I have seen liners below the block deck surface that are ok, but only a few, most are the other way aroun - liner issues blowing its coolant out etc, remove head and ooo look a liner isn't flush - and oooo actually that the suspect bore too Just a thought Also re the stump puller, get the tech specs of it and look at the cam timings / power delivery. There are a huge ramge of cams now on the market and the stump puller is an old one, not that theres anything wronmg with that but it was launched for lower cc V8s than the 4.6 being long stroke the 4.6 can benifit from other cams on the market, the choice is many, have a look at what your trying to get and then pick a cam to best suit it sorry for the rapidly typed post - on my way out so hope it makes sense ...................... mige Quote Link to comment Share on other sites More sharing options...
stuck Posted April 13, 2009 Author Share Posted April 13, 2009 Cheers for that Nige. Right Gents, Any tips on removing gudgeon pins without wrecking anything? I suspect the answer is a press but I haven't got one of those to hand! I've tried using the vice and a socket, put as much pressure on the vice handle as I dared but gave up before I damaged the piston. Is a trip to machinefart on the cards? Mick. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted April 13, 2009 Share Posted April 13, 2009 Cheers for that Nige.Right Gents, Any tips on removing gudgeon pins without wrecking anything? I suspect the answer is a press but I haven't got one of those to hand! I've tried using the vice and a socket, put as much pressure on the vice handle as I dared but gave up before I damaged the piston. Is a trip to machinefart on the cards? Mick. Why ? If they don't need replacing then leave alone, if they do then its machine shop time Nige Quote Link to comment Share on other sites More sharing options...
stuck Posted April 13, 2009 Author Share Posted April 13, 2009 Why ?If they don't need replacing then leave alone, if they do then its machine shop time Nige Ah! Had assumed they were a "if you strip replace" item like the big ends. Thanks for that. Whilst we are on the subject of rebuilds anybody got any tips on removing silicon sealent from gasket surfaces? Cheers, Mick. Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 13, 2009 Share Posted April 13, 2009 I've always used a scraper made from a broken hacksaw blade. Grind off the teeth and grind a cutting edge square across the end. Steve Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 13, 2009 Share Posted April 13, 2009 I use one of these, or just a stanley blade: Quote Link to comment Share on other sites More sharing options...
stuck Posted April 15, 2009 Author Share Posted April 15, 2009 Thanks once again gents! Next question I'm afraid Putting my shopping list together from Real Steel but can't find any mention of composite head gaskets for the 4.6, are they the same as the ones for the 3.9? I know I could ring Real Steel tomorrow but I'm hoping to place an order 1st thing tomorrow. Many thanks, Mick. Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted April 15, 2009 Share Posted April 15, 2009 I can't see them either - I would have thought the 3.9 ones would have the extra row of bolt holes. Best to ask them, because I'd be surprised if they don't stock the correct ones. Quote Link to comment Share on other sites More sharing options...
stuck Posted April 16, 2009 Author Share Posted April 16, 2009 I can't see them either - I would have thought the 3.9 ones would have the extra row of bolt holes. Best to ask them, because I'd be surprised if they don't stock the correct ones. Good point Sir, I'd forgotten about the difference in bolts! Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 16, 2009 Share Posted April 16, 2009 I've got a pair hanging on the garage wall. They are marked LVB500030. Got sent them in error and supplier refused to pay the return postage. Downside is they are Britpart. Steve Quote Link to comment Share on other sites More sharing options...
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