Yet another smoking cossie here Main cause seems to be when the engine is on the overrun for a good few seconds, ie off the throttle, then as soon as you go back onto the throttle it puffs smoke out the exhaust, sometimes for a good few seconds. This happens particularly when you are using engine breaking down a hill then go back on the throttle. Note that when booting it up through the gears it doesn't smoke at all. It also doesn't seem to smoke when I'm just pootling about in traffic, or when I start it in the mornings.

It's also worth noting that I'm using 5W/40 fully synthetic oil and its using about half a litre every 500 miles. It also had a full top and bottom end rebuild with new piston rings about 3000 miles ago.

So from reading other threads how do I determine if it is:

1. Valve stem seals
2. Turbo seals
3. Breather system or something else?

Opinions would be much appreciated!

 

i had same problem with mine changed to millers 10w60 never seen a puff of smoke since plus it uses less

 

hi, what turbo you using, what boost are you roughly running? and what breather system have u got?
despite what many people will say, cossies do smoke on over-run its normal.

1. However some simple checks for the turbo are to take off the boost pipes and checking for oil,and also check the throttle body by opening it and then puting your finger in there or looking to see if any oil is getting in.

2.The top end was rebuilt but at what mileage and were the valve guides changed or just the seals?

3.the oil seems a little too thin as back in the 80's cossies used 20/50. so as suggested try a different oil such as mobil 1 15/50 or millers or silkolene etc.

500 miles to half a litre is a little high but not uncommon for a cossie.

 

I had to do a double take to see if I had posted this
This is exactly the same as mine,I have just kind of lived with it tbh.I keep saying as I am going to take the head off and investergate but it gets used everyday so I just keep feading it oil.I use 10/50 fully synth.

 

There is no reason why an engine of this design needs to smoke, other than very very slightly.
The turbo's do NOT have seals, so will draw a certain amount in, but there are mods that can help here.
Yours is almost defo stem seals, OR shagged guides, much over 40,000 and they will be shagged, they were chronically bad, but were shit material to start with from cosworth.
I use COLSHIBO guides, each one hand machined to size but they will never need doing again.
There will be pressure present in the form of crankcase pressure, the oe breather was emissions friendly unfortunately not power friendly.
Basically on a turbo car you can't have enough breathing, any pressure that builds will allow/help oil get past the rings.
A 10W60 would be my advice to use, the other problem with these cars is the stupidly tiny sump capacity, they really should have had a air to oil cooler as std(a stat'd one), but modine was cheaper!!, the oil simply gets too thin when ragging it.
All you can do is make sure there is a decent breather and it is clear, there is a different breather set up available called evac sump, where it uses the exhaust system to suck the pressure out, been used for years not used here, but works perfect.
Now before anyone says the exhaust is under constant pressure, it isn't, between each power stroke going down the exhaust a vacuum, or rather low pressure area forms behind it, the yanks use these with anti backfire valves, so in the event of a backfire it doesn't blow the sump off!!
tabetha

 

hi there, i was reading the problems people are having with smoke,and iv got 2 say, im also one got 4wd sapp running stage 3 and its smoked since i got it.the only time it does it is when im going down a hill and put the foot down again at bottom.then jst goes away! also alittle after boost,almost like a breathing problem. i dnt know,all i know is that its starting 2 piss me right off!!! i rebuilt the engine last year due to a fueling problem turbo was done aswell by CR turbos because i thot it was that.i also built the head using genuine ford valve stem oil seals...PLEASE HELP!!!

 

1 of the tricks employed to cut down on oil consumption is to have step gaps seals fitted on the turbo.
tabetha

 

Thanks for the advice tabetha. However, what makes you think it is the valve stem seals and/or guides on my case rather than the turbo?

 

a good indication of valve stem seals OR valve guides is to overrun down a big hill and give it a boot at the bottom - if it puffs out lots then its almost more than like stem seals or guides

Matt

 

Can't be 100% sure, but this is what I would look at if mine were doing the same.
How much was the head recon ?, were the guides replaced ?, the cossie eats guides big time, seen them shagged totally with well under 40,000 miles, people also reface the valves and this makes the edges super thin, result can be a few burnt edges and burnt out exhaust valves down the line.
A lot think sticking new stem seals on a knackered guide will sort the oil problem, it will for all of ten minutes.
tabetha