V8david Posted October 11, 2008 Share Posted October 11, 2008 Hi all, as the title says really, 3.5 V8 efi, puff of white smoke on start up whether hot or cold. Accompanied by rich oily burning smell. Couple of revs and all is fine, runs sweet, no more white smoke, even under hard acceleration. Any suggestions much appreciated. Is there a small amount of oil leaking down into a cylinder while it's standing? Slack valve guide perhaps? Is there anything to look out for on spark plugs if I take them out one at a time for a look? or anything else I can look for? Cheers Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted October 11, 2008 Share Posted October 11, 2008 This is just a general comment, as I'm not 'trained' on petrol V8s. I associate white smoke with burning brake fluid, assuming it is smoke and not steam. Does yours have a vacuum operated brake servo, and if so, what is the fluid level like? Good Luck. Quote Link to comment Share on other sites More sharing options...
timmymac Posted October 11, 2008 Share Posted October 11, 2008 not to sure about v8,s but might be valve stem oil seals letting a bit off oil in while it sits and then burns off straight away when running . i had the same on an rs turbo an oil seals curred that Quote Link to comment Share on other sites More sharing options...
V8david Posted October 13, 2008 Author Share Posted October 13, 2008 Thanks for the thought David, interesting to think away from the engine/engine oil. Brake fluid level is good. Also thanks timmymac. I had the heads off recently and replaced the valve stem seals. So being pretty much sure it's neither of those, is the only thing left the valve guides? Like you said it's as if a small amount of oil is getting in and being burnt off on start up. The engine oil level does slowly but surely go down and there are no external leaks. Can I assume it's not piston rings from the symptoms? As I said the smoke/smell clears straight away and remains clear until I stop and start again. Any more ideas welcome... Quote Link to comment Share on other sites More sharing options...
timmymac Posted October 13, 2008 Share Posted October 13, 2008 i wouldnt have thought it would be piston rings you may be right on the path of valve guides, cant be sure Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 13, 2008 Share Posted October 13, 2008 Engine oil burning would be black/very dark blue in my experience. Are you losing any coolant? Piston rings worn gives smoke at any revs/continually. Stem seals will give a puff of smoke when you 'blip' the throttle. Les. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 13, 2008 Share Posted October 13, 2008 Coolant = white /grey Oil = blue Fuel = Black Coolant & oil = grey (and stinks) Sounds like you may have the beginnings of a head gasket problem …………..next time you stop when hot, carefully release the coolant system pressure and see if you get the same white smoke on start up ? It could be that when the engine is stopped the coolant pressure is forcing its way in to cylinder via the head gasket. You dont need much to give a good puff of white smoke. Quote Link to comment Share on other sites More sharing options...
V8david Posted October 14, 2008 Author Share Posted October 14, 2008 Thanks for the replies. I'll give the coolant thing a go. Definitely white smoke and smells funny. I'll check the coolant level as well next time I drive (prob thurs) and update. Quote Link to comment Share on other sites More sharing options...
SteveRK Posted October 14, 2008 Share Posted October 14, 2008 Couple of thoughts & probably way of track - not familiar with the 3.5 engine/gearbox set up but a) if it is an auto? does it B) have a vacuum connection from the gearbox to the inlet manifold? Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 17, 2008 Share Posted October 17, 2008 Old Rover P5b's could suck brake fluid into the engine which created huge amounts of white smoke, done think it's that on a Rangie, Gearbox Vacum hose was a problem on some Opel autos using a GM box again huge amounts of smoke. I reckon you are on the edge of a head gasket failure ! Check water consumption, could be worth pulling the spark plugs to check their colour, if one is different you'l have a clue on the head gasket. Also keep a close eye on engine oil colour if it's turning yellow / grey dont use the Rangie until the head gasket is changed, my old V8 split the expansion tank when pressure got too high. Quote Link to comment Share on other sites More sharing options...
V8david Posted October 17, 2008 Author Share Posted October 17, 2008 Thanks for all the replys. I'll give it a check over tomorrow. Water consumption is good. When I first got it it was losing water all the time. Since then new head gaskets, valley gasket, coolant pipes and radiator. If it is losing any it's hardly any now, one of the core plugs has a slight leak. But I guess it only needs to be a tiny amount to produce a tiny amount of smoke. I'll try BBC's pressure release theory and check the plugs, and update tomorrow hopefully. I'll also have a look for that vacuum connection Steve. Cheers for the thought. Is it worth getting a compression gauge and checking the cylinders? Also where can I get proper genuine head gaskets? Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 17, 2008 Share Posted October 17, 2008 As I remember there should be a one way valve in the servo pipe (is it fitted the right way around) Compression test might give a clue Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 17, 2008 Share Posted October 17, 2008 As I remember there should be a one way valve in the servo vacum pipe (is it fitted the right way around, not sure what the effect would be) I had a problem with brake fluid in the servo on one 3.5v8, the master was leaking very little but enough to gather over time. Compression test might give a clue but if you can get a leakdown test it should tell you more. Quote Link to comment Share on other sites More sharing options...
V8david Posted October 19, 2008 Author Share Posted October 19, 2008 Right, had a good fiddle today and here's what I found: Not losing any water, well, literally half a cup full over months, which I can safely put down to the leaking core plug. No contamination of water in oil/oil in water. Engine oil definitely going down slowly but surely. Goes from 'high' on the dipstick to about halfway between 'high' and 'low' every 400 miles or so. No external oil leaks. Also performed a compression test, results as follows, in PSI: Cylinder 1: 140 3: 135 5: 150 7: 165 2: 160 4: 140 6: 160 8: 160 No idea if this good or bad. Not even sure if it is white smoke now. Definite funny smell on start up and a bit smokey, and losing engine oil. Next step leakdown test then? Any more thoughts most welcome... David Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 20, 2008 Share Posted October 20, 2008 It's starting to look like worn valve stem seals, were they replaced, if I remember seals are only fitted to either inlet or exhaust but I cant remember which. If so the smoke will only be on start up or after idling for a while and will be grey to blue (ish) Quote Link to comment Share on other sites More sharing options...
V8david Posted October 20, 2008 Author Share Posted October 20, 2008 It's starting to look like worn valve stem seals, were they replaced, if I remember seals are only fitted to either inlet or exhaust but I cant remember which.If so the smoke will only be on start up or after idling for a while and will be grey to blue (ish) Cheers sheltie50. Yeah, the valve stem seals were replaced. On the intake valves. Which makes me think it's the valve guides? There's hardly any smoke so it's hard to determine the colour! It's more the start up smell. The oil seems to go down faster after a long journey if that helps. As it's a heads off job I think I may just live with it for a while!... Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 21, 2008 Share Posted October 21, 2008 You can replace the seals without removing the heads (secret Indian rope trick) but I suspect just replacing the seals is not going to fix the problem. Steve Quote Link to comment Share on other sites More sharing options...
V8david Posted October 21, 2008 Author Share Posted October 21, 2008 You can replace the seals without removing the heads (secret Indian rope trick) but I suspect just replacing the seals is not going to fix the problem.Steve cheers Steve. Yeah, I can imagine with a tricky fiddle the seals could be replaced. But I reckon it's the guides so i'll do it when I rebuild the engine again. Just top up the oil for now. Thanks for all the help everyone. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted October 22, 2008 Share Posted October 22, 2008 Sound like guides, however, changing them is an ar$e of a job. It will be best to fit the later style guides that use the hooded stem seals on both inlet and exhaust. Generally its the exhaust guides that wear more then the inlets........... also the valve stems tend to wear more then the guides, so you may (or may not) just get away with new valves. Unfortunately all the replacement guides are not finished to size and need to be reamed, which in itself is not a pleasant task as the guides are quite hard............ then you have the unenviable job of pressing out the old ones and pressing in the new guides ............ ideally you will need to make a toll to ensure the new guides are pressed in square. Even a lot of the machine shops do not like that work......................... I had my original guides bronze lined and the tops machined to take the later type stem seals ............ I also had the tops reduced by 100 thou to allow for the greater valve lift on my engine. Quote Link to comment Share on other sites More sharing options...
V8david Posted October 22, 2008 Author Share Posted October 22, 2008 Sound like guides, however, changing them is an ar$e of a job. It will be best to fit the later style guides that use the hooded stem seals on both inlet and exhaust. Generally its the exhaust guides that wear more then the inlets........... also the valve stems tend to wear more then the guides, so you may (or may not) just get away with new valves.Unfortunately all the replacement guides are not finished to size and need to be reamed, which in itself is not a pleasant task as the guides are quite hard............ then you have the unenviable job of pressing out the old ones and pressing in the new guides ............ ideally you will need to make a toll to ensure the new guides are pressed in square. Even a lot of the machine shops do not like that work......................... I had my original guides bronze lined and the tops machined to take the later type stem seals ............ I also had the tops reduced by 100 thou to allow for the greater valve lift on my engine. Thanks BBC, does sound like horrible job! I'd be interested in the later type guides/seals solution. Are the any detailed picture references to any of the work in your threads? I'll start by looking through your V8 rebuild thread and go from there. (that thread is awesome by the way!) Cheers mate David Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.