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MG MGB GT V8 Factory Originals Technical - Piston removal - engine in car?

Hi all,
The Rover V8 3.5 engine in my MGB has started to rumble when cold and so I have decided to do a rebuild. Problem is I borrowed the engine hoist when I originally fitted the engine and now I have no way of getting the engine out without buying a engine hoist for a one off job.
Can the engine be stripped in the engine bay? Has anyone experience of doing this?
I know it is going to be a pain but i have the heads off and think a glaze bust will do the bores so would like to fit new rings and shells and refurb the heads.
Will i need to take the cross member off?
Can the mains be changed if the bearing housing are slackened and removed one by one and the shells inserted?
This is all assuming the crank journals are ok
Any help / ideas appreciated
Steve
Steve D

Steve,

Could you not hire an engine hoist?

What year engine or engine number, and what is the oil pressure at hot idle and 3000RPM?

Do you know the engines mileage.

It would be a very difficult job trying to do a rebuild in situ. If its done a lot of miles the crank may need a 10thou. regrind, the bores may be ok and you might get away with a hone and new rings.

Difficult to drop the crank whilst the gearbox is still attached as the mainshaft of the box locates into the flywheel.

If it's the original cam and lifters they will definitely need replacing, the oil pump gears will need checking for wear and scuffing of the base plate.

The other problem is that you will not be able to get the block thorughly internally cleaned of all the gunge that builds up over the years which could make any work done a waste of time, a couple of small metal particle in the oil can ruin an engine.

Budget 600-800 depending on what need replacing.

Also when the heads are apart carefully check the rocker gear for wear and be careful of replacement parts as a lot of them are not OEM. I would not buy these parts off e-bay theres a lot of poorly made Chinese copies which have very bad tolerances.

Yor in a good location for Rover V8 parts but be wary of RPI prices.

Paul at V8 Tuner is very good for parts and prices or Real Steel.

Kevin.



Kevin Jackson

Steve,

Must be one near you.

http://www.hss.com/g/67715/500kg-Engine-Crane-Folding.html

It would allow you to fully strip the engine and have it hot dipped and all the oilways rodded through to make sure you get it really clean which is important after honing as the grit can get everywhere.

Kevin
Kevin Jackson

Steve
You can do it in there if you really want to but honestly it is not worth the effort. You will be working upside down and getting dripped on. It is a lot easier in the long run to get it out on the bench. If you alredy have the heads off it's no biggy to get it out. Undo the bellhousing , mountings etc,as normal then invite an unsuspecting mate around and between you with a jack under the bellhousing you can lift it out without a crane. They aren't very heavy and it will surprize you how easy they come out and go back in by hand. Sometimes I think it is easier than with a crane
With it out on the bench you will be able to replace the rear seal and check the clutch as well and your rebuild will be a whle lot easier
If you don't have an engine stand a good idea is to remove the clutch from the flywheel and then stand the engine on it's end on the flywheel on the bench this allows you to spin the engine around on the crank making it easy to get at to hone each bank of bores and refit pistons etc
Also--Yes you can change the mains one at a time by winding them around the crank but as usual make sure you fit the bearings with the oil supply holes to the block and make sure the oil hole position in your new bearing matches up exactly with the one you remove
Hope this is of some help Willy
WilliamRevit

thanks for the replies.
I have already fitted new:-
rockers and shafts
camshaft and followers
uprated oil pump
timing gear
new rear seal
The main problem I have is that the engine now smokes after hot starts. it was ok until I fitted the uprated oil pump and new camshaft (fitted at the same time so don't which is to blame) I am now getting a massive amount of oil into the rockers and it is going down the valve stems and smoking as no stem seals on early engines. The oil pump is a real steel high volume pump

The rumble is not bad at all and only there when engine is very cold.
The smoke is my main reason for the rebuild really

Was thinking of fitted 4.0 heads as they have stem seals and using a composite gasket?

The engine is a 1987 3.5 efi running with no injection now as on offenhouser JWR manifold and edelbrock 500 carb jetted as with RPI jet kit. Plug colour looks good so I think mixture is close. Mileage I was told was about 65000

cheers
Steve
Steve D

I've had the mains and big end shells off with the engine in car, if I'd had the heads off at the same time I could have taken the pistons out. This was just to check the sizes for ordering new and journals for condition, and whilst I could have fiddled the upper shells off the big ends the mains would have been a lot more difficult if impossible with the crank still in position. Whilst under there I discovered the right bank of con-rods is facing the wrong way. It should be possible to turn those round with the engine in-situ, with new shells of course, but as the old ones are still just in tolerance (after 100k) and the journals in very good to perfect condition (after 200k without a regrind) I'm leaving them until the clutch needs doing (80+k and counting) then do everything together as it will be much easier.

I switched the car off from fully hot and left it for three days before removing the sump and didn't get any drips ... apart from the oil still on top of the windage tray which I discovered while removing it!

Interesting Willy talks about replacing the mains with the crank in-situ even with the engine out, I was imagining I'd have to remove it, with the impact that has on the front and rear seals.
Paul Hunt

Steve,

Just a thought, you haven't disconnected the positive crankcase vent system have you? as this can cause the engine to pump oil up into the rocker covers an will pressurize those areas pushing oil down the inlet guides.

If not check your PCV system is working properly.

Make sure the area behind the baffle in the valve cover is not gunged up and clean the flame trap and check the PCV valve is operating correctly.

System should have one cover with a filter vent and the other cover should have a flame trap to hose to PCV valve then hose to centre port of the carb.

My original 3.5 engine had the problem when I just had the two covers with hoses to a catch tank.

Earlier P6 engines have a different arrangement.

Kevin.
Kevin Jackson

Hi Steve, i wouldn't mind betting that your cam shafts are the wrong way round, i had exactly the same problem after i had fitted mine, the rocker covers virtually filled with oil, worth a look anyway. HTH.
Graham.
Graham young

Good call Graham -- I take it you mean rocker shafts around the wrong way- The excess oil has to be coming from somewhere and they are the only oil feed up there
Willy
Correct me if I'm wrong but i think they are to be fitted with the oil holes facing down ???????
The 4.4 litre engines we use here are different in that they don't use rocker shafts-- Each rocker is mounted on a pivot and oil is supplied up through a hollow pushrod from the camfollower -- sorry wandering off the subject a bit. bye
WilliamRevit

Kevin,
at present I have one rocker cover with a small hole in it and the other has a flame trap screw in canister and then straight into the air cleaner.
Are you saying there is a valve that should be fitted on this setup?

Graham,
interesting point about the rocker shafts as i didn't realise they were handed. What is the actual correct setup for the shafts and I will check mine



cheers
Steve
Steve D

Steve,
From memmory on one end of each rocker shaft there should be eather a 'notch' or (as on mine) a 'score' (deep scratch).

Looking at the engine from the front, the right hand shaft should have the 'mark' at the top and facing forward.

The left hand shaft should have the 'mark' at the top facing backwards, HTH.

Graham.
Graham young

Steve,

The cover with the little pipe sticking up should have a small filter otherwise you will be sucking in dirty air, the other cover as i mentioned should have the flame trap the the PCV valve then to the carb centre port, this works more efficiently than plumbing it to the air filter.

The oil holes in the rocker shafts should face down towards the cam. Later replacement shafts do not always have the notches, if incorrectly installed you will get little oil to to the rocker to valve stem area.

I don't think this would cause your excess oiling problem which is normally down to excess tolerance between rockers and shafts and excessive crankcase pressure.

You said you replaced the rocker gear recently where did you get them from, not Britparts were they?

Are the rockers quite a snug fit on the shafts or is there any play?

Kevin.
Kevin Jackson

Kevin,
Beg to differ on this one, if shafts incorrectly installed you will flood the rocker valve stem area.
Been there done that, seen the evidence.
Graham.
Graham young

Graham,

Like yourself can only speak from experience and on my first 3.5 engine build I fell foul of the error in the Rover engine build manual and fitted one of my shafts incorrectly, it made no difference to the amount of oil in the cover of that bank of cylinders.

Also I made an error above as of course it is the pushrod cup in the rocker that receives the oil supply, the valve stem is only lubricated by oil mist.

If everything is properly installed then you would normally only get excess oiling in extended high RPM use as when racing, and it is normal to restrict the oil supply by reducing the size of the oilways in the heads.

Kevin.
Kevin Jackson

Steve,

Thought a picture of the vent system as installed in my car might help.

Kevin

Kevin Jackson

Kevin,

thanks for the picture.
Where did you get the valve from?

I got the rockers from Autopost in London who are Land Rover specialists suppliers. There is a bit of play in the rockers to shaft and I have to say I didn't expect that much. The new assys did stop the rockers making a tapping sound though


Graham
I hope you are right with the shaft theory. I have definitely had this area apart so I may have got it back together wrong. I will check

thanks
Steve
Steve D

Steve,

Dave Vale at V8 conversions usually has them in stock
01689 858716 or V8 Tuner.

At least if you get the PCV system working properly it will remove one source of the problem and possibly cure it, if not the excess rocker to shaft clearance is the culprit.

Were the rockers and shafts boxed as Landrover parts or Britparts?

You did change rockers AND shafts I hope?

Kevin.
Kevin Jackson

Steve,

Another thought, are the rockers the original ALLOY type and not the steel ones which are available.

Thwe steel ones definite cause excess oiling and I've read that they need modifying prior to fitting.

Perhaps a picture of the valve gear would help us.

Kevin.

Kevin Jackson

Kevin,

the rockers are steel.
Steve D

Hi all,

I have the pistons out now and the bore has a little step on it which has totally disapeared with a little rub of emery cloth around the rim so i am going to re ring only as it measure ok.
What is the best way to glaze bust - is it ok if I use emery paper and rub so as to make hatching type marks or do i need to buy a glaze buster tool?

The engine was sold to me with 60000 miles on the clock which i did see (I suppose it could have been broken or clocked)
My question is the shells, especially the mains are through to the copper. please see picture sorry struggled to get it to focus. To me they seem far to worn for a 60000 mile engine?
The crank is perfect so I am fitting new shells

I am going to try and change the mains with the engine in. Idea is lower crank a few thou and remove one cap at a time and gently tap the shell round and out. Push new on in.

Also Paul's earlier post said his con rods were the wrong way round - I can't see that they are handed? look the same to me? do they vary year to year?

spend spend spend

cheers
Steve

Steve D

Hi all,

I have the pistons out now and the bore has a little step on it which has totally disapeared with a little rub of emery cloth around the rim so i am going to re ring only as it measure ok.
What is the best way to glaze bust - is it ok if I use emery paper and rub so as to make hatching type marks or do i need to buy a glaze buster tool?

The engine was sold to me with 60000 miles on the clock which i did see (I suppose it could have been broken or clocked)
My question is the shells, especially the mains are through to the copper. please see picture sorry struggled to get it to focus. To me they seem far to worn for a 60000 mile engine?
The crank is perfect so I am fitting new shells

I am going to try and change the mains with the engine in. Idea is lower crank a few thou and remove one cap at a time and gently tap the shell round and out. Push new on in.

Also Paul's earlier post said his con rods were the wrong way round - I can't see that they are handed? look the same to me? do they via year to year?

spend spend spend

cheers
Steve

Steve D

Steve,

You've just answered the problem, steel rockers,these are Federal Mogul rockers and not rover rockers.

The recent batch have proved to be a poor fit on the shafts and from memory have an additional oilway that requires welding up.

Everyone that has fitted them has had the same problem.

Who supplied them as they should have made you aware of the mods required, personally I would return them as not fit for intended use and replace with genuine rover parts.

Real steel, V8 Tuner or RPI should be able to supply genuine Rover parts.

There are dots on the rod sides and it's the machined flat side of the rods that should mate together on each journal.
Kevin Jackson

Also ribs on the end caps, go the same side as the dot or pip on the rod. It's the face of the big end housing that is machined down on the side with the pip and rib, the result is that the bearing shell is closer to that end than the other, see http://www.mgb-stuff.org.uk/v8bearings.htm
Paul Hunt

Paul

This is a great thread and thanks for your input and excellent photographs and guidance on piston/conrod assembly.
Ian Buckley

Steve
Just to add to Paul's last bit if you don't mind Paul

If you have a look at a conrod with a bigend bearing fitted to it you will notice that the bearing is offset over to one side-- The design of this is to move the bearing away from the radius ground on the end of the crankshaft journal-- Therefore when refitting your piston-rod assemblies they must be fitted up with the bearings closest to the centre of the journal and the gap towards the end of the journal.
i.e. For each pair of rods on each journal the bearings are close together and the gaps are at the outside ends for clearance on the radius at the ends of the journal-- same for the caps. Otherwise the bearings will pinch up on the ends of the journals.

Bit of a bummer about them steel rockers but it looks like your engine needed pulling apart anyway--Them main bearings are enough to give you that rumble you were chasing
You don't have to drop the crank at all to change the mains over as they do have clearance already- just do them one at a time--start them off by pushing on the end of the bearing with something like a steel ruler and then push the bearing against the crank with your finger or thumb and turn the crank with your other hand and around they'll go---reverse for refitting --but really make sure the oil holes in your new bearings are in the same place-exactly--as the old bearings.

Hello Ian nice to hear from you again--not long till the Natmeet in your fair city now. Cheers Willy
WilliamRevit

Oops - sorry Paul, I hadn't scrolled down through your pictures etc. Anyway, Steve I guess the message for you is yes the rods only fit one way---Willy(red face)
WilliamRevit

No offence taken, Willy :o)
Paul Hunt

hi all,

main shells now replaced and just started fitting rings to pistons.

Thanks to you all for the excellent information.

Hopefully soon back on the road and smoke and rattle free

cheers
Steve
Steve D

This thread was discussed between 01/11/2009 and 08/11/2009

MG MGB GT V8 Factory Originals Technical index

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