Chris Bracey Posted August 25, 2019 Report Share Posted August 25, 2019 I think my main bearings are worn. There is a deep rumble on start up and engine seems harsh on revving. Engine does not burn oil . I intend to fit an oil pressure gauge to assess the oil pressure but will mains cause low oil pressure. Thank you . Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 26, 2019 Report Share Posted August 26, 2019 Yes , you can replace mains and big ends with engine in car Can be a fiddle to get the sump down but easy to swap new shells if the crank is in good state Worn shells onn1500 is quite common due its long stroke they have a limited life Pete Link to comment Share on other sites More sharing options...
johny Posted August 26, 2019 Report Share Posted August 26, 2019 I would minimise running of the engine now as theres a risk of metal to metal contact on the crank which means it would need a regrind whereas at the moment you should be able to get away with just replacement std bearings. Of course really the crank needs to be accurately measured for ovality because the new bearings wont last long if the crank isnt within spec. Also while the engine is open its worth checking the condition of the oil pump and crank thrust bearing..... Link to comment Share on other sites More sharing options...
Chris Bracey Posted August 26, 2019 Author Report Share Posted August 26, 2019 John. Can you change the thrust bearing from under the car? Link to comment Share on other sites More sharing options...
johny Posted August 26, 2019 Report Share Posted August 26, 2019 Yes although Ive only done a 6 from underneath I believe the 4 is very similar. Obviously you can check the play beforehand but even if its within spec its worth having a look at the thrusts as I found mine pitted for some unexplained reason. Your biggest problem working from underneath, apart from access, is keeping everything clean and this is essential..... Link to comment Share on other sites More sharing options...
KevinR Posted August 26, 2019 Report Share Posted August 26, 2019 Personally, I don’t think struggling from underneath is worth the effort. Borrow or hire a hoist and take the engine out - it’s much easier and cleaner. Link to comment Share on other sites More sharing options...
johny Posted August 26, 2019 Report Share Posted August 26, 2019 True, its a difficult call as I think underneath is quicker but certainly more hassle and easier to cock up, for example the front seal block needs a bit of care or it'll leak afterwards.... Link to comment Share on other sites More sharing options...
Dick Twitchen Posted August 26, 2019 Report Share Posted August 26, 2019 4 hours ago, KevinR said: Borrow or hire a hoist and take the engine out Chris, I have one you can borrow depending on where you are in Hampshire. PM me if you like. Dick Link to comment Share on other sites More sharing options...
Chris Bracey Posted August 26, 2019 Author Report Share Posted August 26, 2019 Dick. I am near alresford but wont be doing it for a while. Thank you. Is it easy to get at engine from side to avoid removing the bonnet. Strangle the oil pressure was 50 at 1200 rpm. Sounds ok on tickover but there is a deep rumble at start up and if you rev it its harsh . Link to comment Share on other sites More sharing options...
KevinR Posted August 26, 2019 Report Share Posted August 26, 2019 The bearing rumble on start up is very common - its a sign that the bearings are worn (but still probably have a lot of life left in them) You can reduce it significantly be making sure you use an oil filter with a good "anti-drain-back" valve, and then turning the engine over on the starter to build oil pressure before actually starting it - this can be achieved either by not using the choke until the oil pressure has built up, or by having a "kill switch" in the Low tension circuit to the coil to stop the car from starting until the extra switch is switched. As for the rumble whilst revving, it could easily be "pinking" rather than a bearing problem - easily cured by getting ignition timing adjusted correctly. Link to comment Share on other sites More sharing options...
johny Posted August 26, 2019 Report Share Posted August 26, 2019 It is worth investigating all possibilities but I must admit Ive never heard pinking when just reving an engine at standstill - its normally under load like a hill or hard acceleration that it presents itself and then I think its more of a tinkling sound than a rumble..... Link to comment Share on other sites More sharing options...
KevinR Posted August 26, 2019 Report Share Posted August 26, 2019 53 minutes ago, johny said: It is worth investigating all possibilities but I must admit Ive never heard pinking when just reving an engine at standstill - its normally under load like a hill or hard acceleration that it presents itself and then I think its more of a tinkling sound than a rumble..... In general I agree, but I've encountered a similar problem with a 1500 Spit engine with worn bearings, where the biggest problem was actually the centrifugal advance retard mechanism in the distributor actually being seized, so only the vacuum capsule was doing anything - it took a lot of searching to properly diagnose. Link to comment Share on other sites More sharing options...
Nick Jones Posted August 26, 2019 Report Share Posted August 26, 2019 3 hours ago, Chris Bracey said: strange the oil pressure was 50 at 1200 rpm At what temperature? Pressure readings are worthless if the oil isn't properly hot. That's at least 10 miles on a fast road. Nick Link to comment Share on other sites More sharing options...
Chris Bracey Posted August 27, 2019 Author Report Share Posted August 27, 2019 Hi temp was just below normal. Link to comment Share on other sites More sharing options...
Dick Twitchen Posted August 28, 2019 Report Share Posted August 28, 2019 On 26/08/2019 at 18:33, Chris Bracey said: Is it easy to get at engine from side to avoid removing the bonnet Chris, Yes it is feasible if you have the room (most garages long and thin!) but you have the added pain of removing the bellhousing bolts. If I was going to do this work on the engine I would remove the bonnet and pull the whole unit and do the clutch while at it. Dick Link to comment Share on other sites More sharing options...
Anglefire Posted September 22, 2019 Report Share Posted September 22, 2019 I took mine out from the side without bonnet removal because I did it on the drive! But I had another engine to put straight in again, so wasn't rebuilding the one already installed. Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 22, 2019 Report Share Posted September 22, 2019 get the windscreen protected with a load of carpet or ply should it swing , it saves a screen Pete Link to comment Share on other sites More sharing options...
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