The thing is, if the only part that has been changed is the head gasket (ie cam, pistons, valves, etc are all the 'same'), then the most likely cause of the problem is incorrect valve timing. The engine would be particularly 'sensitive' to valve timing if you were using, say, a 74 or 76 deg Wade cam with flat-top pistons.
> >You done everything correctly as those markers on the cam timing wheel and >the thrust plate just don't line up if it's out. OK, what's causing valves >to hit. The only thing that comes to mind is the head has had more than the >prescribed amount shaved off it as most 6 cyl engines aren't as tolerant of >this as the 4 cyl i.e. the cam dial in tolerance isn't as great. A 4 banger >usually wont hit the piston +-1 tooth but a 6 usually does, this is why you >must rotate a OHC engine by hand thru 720 degrees before hitting the >starter. Bent valves are usually pretty obvious, well all the ones that I've >done/seen were. The guides will usually split before a valve actually bends. >A fair indication that you have valve and/or guide damage is to remove the >collets and see if the valve travels freely through the guide. It will be >very sticky if the valve or the guide is damaged. Exhaust valves wont trap >air in the guide like an inlet valve does so I guess the H2o method is good. > > One last thought, has this engine got high top pistons ala Zed engine? I >just might be on the money if it has. Valves can stretch, not much and >retainers can distort also, but you'd have to be so unlucky for this to have >happened. > >I'm outa here for a couple of days, so over to Steve for further help. > >regards >Terry (Happy and SAFE Easter everyone) > >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED]]On Behalf Of David Andrews >Sent: Saturday, 30 March 2002 12:17 PM >To: [EMAIL PROTECTED] >Subject: Re: L24 troubles. Please help > > >Ahhh the joys. > >Steve, Yes #1 was at TDC with the lobes both pointing upwards (ie >compression) and the distributer was pointed to spark number 1 so i >assumed that this was where its sposed to be. > >Terry, I had a look through the cam sprocket and saw that the two marks >you described lined up perfectly with number 1 at TDC compression. I have >since pulled the head off and have found two very light scrapes from >exhaust valves on pistons 4 and 5 but none anywhere else. This fits with >the noise that I hear as it only seems to come from that area.. ie is not >uniform across all cylinders. >Now given that the two timing marks you mentioned DO align up correctly... >and that I am fairly confident the chain didn't slip a crank sprocket >tooth. What on earth would cause it to knock valves (only lightly i >hope/think) only on #4 and #5 ?!. Beats me. >Oh and while i'm hear is there anyway, short of paying someone money, to >be more confident that exhaust valves are not totally bent with the head >off?. Sit it upside down and pour some water in there? And come back in >the morning and see if its drained through?. I dunno. >Any help much appreciated, >Happy Easter and as Telstra have changed all their broadcast stations >names to: "Drive Safe". > >Dave > >>>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<< > >On 3/29/02, 7:09:57 PM, Steve Lamb <[EMAIL PROTECTED]> wrote >regarding Re: L24 troubles. Please help: > > >> >distributer were in the position to fire number 1. I assumed that this >> >was TDC on the compression stroke. I then white-outed marks to match the > >> This may have been your mistake. Did you check that #1 piston was at >> TDC on the compression stroke before removing the head ?? > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
