Leadership Team Mcalvert Posted April 11, 2002 Leadership Team Share Posted April 11, 2002 I am a getting conflicting advice re setting the tappets on my Xflow. I understand that this should be done with the engine cold, and that the clearances should be checked while pressing down on the valve stem to ensure that everything is seated properly. I have also been advised to roll the engine around by a few degrees to see if there are any points on the heel of the cam where the clearance gets tighter or looser. I was told that if it gets looser, then I should re-adjust the clearace at that point. However, I found a posting here which seems to suggest the opposite, that it should be adjusted to the tightest point. Any advice? Thanks - Michael. Link to comment Share on other sites More sharing options...
Graham Sewell Posted April 11, 2002 Share Posted April 11, 2002 Whether you check the clearances hot or cold depends on the engine (1600 hot, 1700 cold, a bit of a simplification but check the manual for details). I believe that rule-of-9 applies to x-flow engines and I would doubt that any pressure that can be applied by hand to the valve stems would have any effect. However, if you get significant changes in the clearance within a few degrees either way, then I would suggest that the cam is knackered. As an example, I tried the usual rule-of-9 and on-the-rock with my engine (1700 SS)and the differences were typically none or 1 thou - so I use the latter method as it is slightly easier. Cheers, Graham Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
STEVE GILBERT Posted April 11, 2002 Share Posted April 11, 2002 If its the bit on the bottom that I wrote then i have edited it to say loosest, which was what i meant...Doh!. I always used this method on my xflow and gained nice quiet tappets. Not sure about pressing on the valvegear, wont you compress the springs Link to comment Share on other sites More sharing options...
Leadership Team Mcalvert Posted April 11, 2002 Author Leadership Team Share Posted April 11, 2002 Aha - that explains it then... However, what exactly is the point of seeking out the loosest point? I want to get what is going on clear in my mind... Thanks. Michael. Link to comment Share on other sites More sharing options...
Robster Posted April 11, 2002 Share Posted April 11, 2002 Confusion seems to reign here! The idea of pressing down on the rockers does work..but you are pressing down on the pushrod end, so the valve spring won't be affected. Gently pressing down on the pushrod end takes all of the slack out of the camlobe/pushrod/rocker train. As the cam is not on the lobe, there is no tension on the rocker, so it does not automatically sit back on the pushrod. Set the tappets when the opposite valve is fully open..ie 1 open, check/adjust 8 etc. Link to comment Share on other sites More sharing options...
Phil Posted April 11, 2002 Share Posted April 11, 2002 Steve Gilbert gave me some sound advice on my tappets when I was having trouble so follow his advice and you can not go wrong, I can now do the job blindfolded after some practice and have learnt that sticking it in third and using the front wheel to move the car and adjust the valves makes things more accurate, the best thing I did was to get a decent set of feeler gauges with one blade for 22thou and one blade for 24thou as this gives you more of a feel for things than a cheap multi blade set which stick and bend and brake. Link to comment Share on other sites More sharing options...
Graham Perry Posted April 12, 2002 Share Posted April 12, 2002 Roger King where are you ? Link to comment Share on other sites More sharing options...
Graham Sewell Posted April 12, 2002 Share Posted April 12, 2002 It is even easier if you get the correct hex drive adapter for a socket set from snap-on. It cost the eart but I love that tool.... Also, my feeler guage set has a 22 and 24 but the 24 was actually 23.5 (according to my micrometer so ended up using a 14 and 10 (double checked for accuracy)! Low tech luddite - xflow and proud! Edited by - Graham Sewell on 12 Apr 2002 08:22:10 Link to comment Share on other sites More sharing options...
Roger King Posted April 12, 2002 Share Posted April 12, 2002 Roger King has been unable to get online for 24 hours thanks to his phone company. Yes, use rule of nine. There should not be tight and loose points if everything is correct, but in practice you will find small inaccuracies in the base circle and the cam will also bend a bit under the influence of adjacent valve springs. I am now going to commit heresy and tell you not to worry too much about the clearances!!!! Firstly, with the potential errors mentioned above it is impossible to be precise and secondly, if you examine a pushrod after it has been running you will often see polish marks up it's length where it has been bending during running. All this movement while the engine is running makes a nonsense of worrying about being correct to the nearest thou'. I don't mean that you don't care about the clearances, merely that it's not worth worrying about being a thou or two out. Note that OHC engines with tappet pistons are much more precise in this respect. Link to comment Share on other sites More sharing options...
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