Britishbest Posted July 23, 2016 Report Share Posted July 23, 2016 Hi Guys, My car is finally on the road after 10 months re-commissioning and I'm having a fabulous time with her. I have an oil leak on the rear main crankshaft oil seal which I'll have to live with for now, approx a pint per 200 miles. I am getting oil on my exhaust partly from the above leak but also quite a lot from my gearbox (non overdrive) There's quite a lot of oil around the rear mounting, presumably this is coming from the cover higher up? Is this common? I'm periodically getting a lot of white smoke behind the car and coming into the cabin. As I don't have time for the next 6 months to remove the box is there anything that can be done, I thought maybe an aluminium 'deflector plate' above the exhaust? Today I have degreased and jet washed the area and will take her for a drive now to see if its coming from a different place. I will also tighten any bolts I can get to. Thank you in advance Colt Quote Link to post Share on other sites
ChrisR-4A Posted July 23, 2016 Report Share Posted July 23, 2016 Hi Colt, is it a 4 or 4a. Either the engine is worn or the crankcase venting is not working. Check PCV valve on 4A and rocker cover vent on both. Do a trial run with PCV removed, Manifold blanked off and vent rocker cover with a plain pipe down past sump. My 4a has run like that for years, even before the engine was rebuilt it only lost a few spoonfuls of oil on a trip not pints. Quote Link to post Share on other sites
Britishbest Posted July 23, 2016 Author Report Share Posted July 23, 2016 Thanks Chris. Its a 4A. PCV was replaced for a new one a month ago because oil was coming out the dipstick. Its worse today, at speeds of 55 upwards I get a lot of smoke from the exhaust, oil from the engine and gearbox I think. I used a quarter on the dipstick in 30 miles Does the engine have to come out for a new rear crank seal? I'm pretty sure the drips on the drive are engine oil not gearbox oil. Quote Link to post Share on other sites
ChrisR-4A Posted July 23, 2016 Report Share Posted July 23, 2016 (edited) Hi Colt, the standard rear seal is a scroll seal, not really a seal at all, more like an oil thrower/ diverter. If there is pressure in the engine due to poor breathing or worn bores then it will be forced out past the rear seal. What colour are the plugs after a run? Have you done a compression check? Seek a second opinion, where are you, is there a local group nearby? Edited July 23, 2016 by potts4a Quote Link to post Share on other sites
stillp Posted July 23, 2016 Report Share Posted July 23, 2016 If smoke is blowing out of the exhaust then I'm afraid it's burning in the engine, which is likely to be expensive. Changing the rear crank seal for one of the more effective designs won't help that. Pete Quote Link to post Share on other sites
Britishbest Posted July 23, 2016 Author Report Share Posted July 23, 2016 Hi Guys, The smoke isn't from inside of the exhaust its oil on the outside of the exhaust. Theres a tapped hole in the bottom of the bellhousing and its dripping a lot from that and also the small cover at the back of the bellhousing. Compression a month ago when setting things up were - 1 - 91 2 - 97 3 - 89 4 - 98 I think these are quite low? Quote Link to post Share on other sites
MadMarx Posted July 23, 2016 Report Share Posted July 23, 2016 The pressure values should be around 180psi Quote Link to post Share on other sites
Geko Posted July 23, 2016 Report Share Posted July 23, 2016 ouch! no wonder you have oil splashing all over...compression goes inside the block. You're good for an overhaul I'm afraid. Quote Link to post Share on other sites
Peter Cobbold Posted July 23, 2016 Report Share Posted July 23, 2016 White smoke in the exhaust gas suggests to me antifreeze burning. Quote Link to post Share on other sites
Britishbest Posted July 24, 2016 Author Report Share Posted July 24, 2016 Thanks guys Will limp on for this summer with some cheaper thicker oil (any suggestions, currently Halfords classic 20/50) then have to rebuild next year, most likely 89mm bores. Quote Link to post Share on other sites
Graham Harris Posted July 24, 2016 Report Share Posted July 24, 2016 The gearbox oil on the rear mounting is probably from leaking selector shaft seals . Graham Quote Link to post Share on other sites
ChrisR-4A Posted July 24, 2016 Report Share Posted July 24, 2016 Re oil , buy cheapest 20/50 or 20/60 you can find and add can of STP, this will thicken it up nicely and help prevent leaking and blow by. Quote Link to post Share on other sites
Britishbest Posted July 24, 2016 Author Report Share Posted July 24, 2016 Graham I think you are correct on the selector shaft seals as it looked wet there. Difficult to replace? STP oil treatment is a good idea Chris thanks. Quote Link to post Share on other sites
peejay4A Posted July 24, 2016 Report Share Posted July 24, 2016 (edited) You'll be surprised how a good leak from the crankshaft finds itself all over the underside, including around the gearbox. If you have 90 grade oil in the box it will smell different to engine oil so get a smear from around the selectors and give it a sniff. It's legal! Edited July 24, 2016 by peejay4A Quote Link to post Share on other sites
Graham Harris Posted July 25, 2016 Report Share Posted July 25, 2016 Selector shaft seals are not difficult to replace but you will need to follow the instructions in the workshop manual. Be prepaired to snap off a couple of selector fork tapered set screws , i have managed to do it a few times. Graham Quote Link to post Share on other sites
Britishbest Posted July 25, 2016 Author Report Share Posted July 25, 2016 Will try to check if it smells like gear oil. Quote Link to post Share on other sites
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