I.Mupferit Posted June 19, 2001 Share Posted June 19, 2001 Roger, following an earlier thread regarding building up oil pressure on a newly built engine, what would you recommend is the best way to do this without risking a knackered cam etc. I had a problem getting oil pressure up on the X/Flow previously fitted in my 7, despite having primed the pump, filter and oilways etc. Cranking over on the starter without the plugs just wouldn't get the oil pumping and it was only after a battery recharge that I saw the pressure start to climb. The question is a bit academic from my point of view as I don't intend building any more engines but, nevertheless, I would be interested to hear your views on this. Also I normally like to fill the filter whenever I change the oil as I just can't stand the thought of no oil pressure even if only for a few seconds. Is this a good idea or am I being a tad paranoid? Brent Link to comment Share on other sites More sharing options...
Roger King Posted June 19, 2001 Share Posted June 19, 2001 My answer to this is very clear - it depends....... The camshaft in a Crossflow is a very highly stressed component and it is vital to bed it in properly in order to avoid losing a lobe very rapidly. In this case, I personally prefer to prime everything (no you're not being paranoid) and start the engine immediately. Obviously all bearings will have been copiously lubricated at assembly and oil pressure should appear in a couple of seconds. In my view this is the lesser of two evils - camshaft wear against bearing wear. Conventional wisdom dictates that you should remove the spark plugs and crank the engine until oil pressure shows before starting for the first time and many people will argue that this is the correct procedure. For my part, I know that I have seen more cam failures than bearing failures on new engines. Once the cam is bedded in, I would always use the second method if an engine has been standing around for a period of time. For most OHC engines of the 16V type, I would recommend the second method on a new engine because the cams are generally much less stressed (lighter valves, weaker springs, no rocker ratio to increase pressure on lobes, less mass in the valve gear, larger contact areas, etc) Link to comment Share on other sites More sharing options...
elie boone Posted June 19, 2001 Share Posted June 19, 2001 You can take the dizzy out and with a old butchered dizzy axle and a drill you can prime the system. Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted June 19, 2001 Share Posted June 19, 2001 Roger. What about the K16 engines with the hydraulic followers? Do they 'fill' quickly? Link to comment Share on other sites More sharing options...
Graham Perry Posted June 20, 2001 Share Posted June 20, 2001 As someone who has had a lobe rip of a 264 cam in a Steel cross-flow when started from new, even though all the mentioned precaustions were taken I concur with everything Roger says. The one thing we didn't do which some recommend , was start the engine on only the inner valve springs only and run it slowly for half an hour or so. After the rebuild we did this and all was fine. Link to comment Share on other sites More sharing options...
Michael Peterson Posted June 20, 2001 Share Posted June 20, 2001 Brent: Just because you are paranoid doesn't mean they aren't out to get you. wink.gif Another reason to go Zetec, and stop wasting all that quid on prozac. Cheers! Michael Link to comment Share on other sites More sharing options...
Roger King Posted June 20, 2001 Share Posted June 20, 2001 I'd be inclined to remove the plugs and crank to get oil pressure on a K-series. The followers are unlikely to pump up until full running pressure is achieved, but no real harm will be done by cranking first. Link to comment Share on other sites More sharing options...
Roger King Posted June 20, 2001 Share Posted June 20, 2001 Isn't the English language wonderful? When I said "remove the plugs and crank", I didn't mean you to take the crankshaft out, but rather to crank the engine until you get oil pressure. Link to comment Share on other sites More sharing options...
I.Mupferit Posted June 20, 2001 Author Share Posted June 20, 2001 To get round the cam problem, on the X/Flow only, could you not crank the engine over without plugs or pushrods. That way there is no load on the cams and as soon as the pushrods are replaced you can start the engine knowing you will have instant oil pressure. Mind you from what I remember of my old X/Flow there is no direct oil feed to the cam lobes anyway. Don't these rely on oil from the cylinder head draining back down the pushrod tubes or are they lubricated by oil thrown off the big ends? Elie, I'm not sure what you mean by this as the oil pump is driven off the skew gear on the camshaft and for your idea to work, the camshaft would also need to turn. Brent Link to comment Share on other sites More sharing options...
Mike Bees Posted June 20, 2001 Share Posted June 20, 2001 Bugger. It was hard enough getting the crank out through those 4 little holes, I was hoping the so-called Monsieur King could advise how to achieve re-insertion... Mike Link to comment Share on other sites More sharing options...
Old Septimus Posted June 20, 2001 Share Posted June 20, 2001 When I rebuilt the X-flow in my '68 SIII about 15 years ago, I had the reboring and balancing etc. done by Baldyne in Bromley who were quite well known for Ford engines. They gave me a tube of colloidal graphite for applying to all the bearing and rubbing surfaces, in particular the cam lobes and followers during the rebuild. They said that if the rebuild was spread over several days a lot of the oil applied to the surfaces would drain away before the engine was started. I started the engine without building up pressure and it's been fine ever since. The graphite was not an automotive product but was supplied for running in machine tools and the like. Link to comment Share on other sites More sharing options...
Simos Posted June 20, 2001 Share Posted June 20, 2001 Mike, To quote the Caterham build manual "Insertion is the reverse of removal" Link to comment Share on other sites More sharing options...
John Whyman Posted June 20, 2001 Share Posted June 20, 2001 Insertion ?? dead easy--------one large tube of KY Jelly from the Chemist. Slips in a treat then !!! (ahem!!) Happy Motoring. thumbsup.gif C7 WJW. Link to comment Share on other sites More sharing options...
elie boone Posted June 20, 2001 Share Posted June 20, 2001 Brent, I did this to a Pinto engine but did forget that the Kent has a different drive for the oil pump. blush.gif Link to comment Share on other sites More sharing options...
Roger King Posted June 20, 2001 Share Posted June 20, 2001 Best engines of all for priming the oil are those with dry sump pumps that also incorporate the pressure chamber. All you do is to slip the drive belt off and spin the pump with an electric drill or speedbrace. This is how we used to get initial pressure on the Vauxhall Chevette HS works rally engines. Sadly, the modern trend is to use the existing internal pump for pressure, so this often no longer applies. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now