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MG MGB Technical - Removing the engine
| I intend to take the engine and gearbox out of my roadster and would welcome views of the best way of doing it. Is it easier to take them out as one lump or the engine first and then the gearbox. Any tips or hints on the procedure would be appreciated. |
| Trevor Harvey |
| Trevor- Pulling the engine out of the car is considered to be something of a Rite Of Passage for MGB owners, and need not be an exercise in fear. Get at least one friend to help out, as there are moments when it is not an easy job on your own. Although it may seem that the removal would be easier if the engine and transmission were separated while still in the car, the easiest way for the amateur mechanic to do it is to pull the engine and transmission out as one unit with the engine hoist located directly in front of the car. It is possible to pull the engine separately, but to do so incurs the risk of damaging the first motion shaft of the transmission. In addition, realigning the engine with the transmission still in place can be maddening for the unpracticed. First, disconnect the ground (earth) on the battery. If you may be facing rebuild of the engine, you will find that it is best to remove the retaining bolt of the crankshaft’s harmonic balancer (harmonic damper) pulley wheel prior to removing the engine from the car. In order to loosen the retaining bolt of the crankshaft’s harmonic balancer (harmonic damper) pulley wheel for removal, the most professional method is to use an impact wrench after bending back the securing tab of the lockwasher. This method has the advantage that you do not have to worry about blocking the flywheel (if engine is separated from transmission, or blocking the wheels with transmission in gear). Another, and much more commonly used method for loosening the crankshaft’s harmonic balancer (harmonic damper) pulley wheel retaining bolt, is to place a 1 5/16” wrench / breaker bar against the left chassis rail (as you are sitting in the car). Put some wood or something thick and soft against the left chassis rail in order to prevent it from being scratched. Your wife's pillow is good for this (she won't mind you borrowing it for such a worthy cause). Take care to disconnect the High Tension (HT) lead of the ignition coil so that the engine cannot start. Blip the starter briefly, and the retaining bolt will be jarred loose. When reinstalling, note that there is a flat on the middle round section of the harmonic balancer pulley that you must hammer the tab of the lock washer down onto. This holds the tab onto the harmonic balancer pulley wheel, and you can then tab up the bolt head as normal. Be aware that the retaining bolt of the crankshaft’s harmonic balancer (harmonic damper) pulley wheel in the end of the crankshaft is not standard Whitworth, but is of Whitworth form: Diameter 1 5/8"-16 TPI, 1 1/16 Full Thread. If it is found necessary to clean up the threads, the operation must be confined to cleaning up only. These threads are highly stressed and must always be up to full size. Thus, it is not correct to use an American SAE - UNF form tap or die in order to clean up these threads, though you might get by in the end of the crankshaft, but definitely not on the bolt. To my knowledge, this is the one and only British form threaded fastener on any of the B Series engines. Note that BSF is 5/8”-14, rather than 16 TPI. UNF is 5/8”-18. CEI starts with 20 TPI at ½" and larger. Remove the gear change lever (gear shift lever) surround, raise the gearlever boot, then unscrew the gear change lever (gear shift lever) retaining bolts and lift out the gear change lever (gear shift lever). Drain the oil from the oil sump , and then disconnect the oil cooler hoses (flexible pipes) from both the engine block and the oil filter stand, and then disconnect as the case may be, either the oil pressure gauge hose (flexible pipe) or the oil pressure senor wiring from the engine. Disconnect both the throttle and choke (fuel / air control) cables, and then disconnect the fuel lines from the carburetors. Remove the carburetors and intake manifold as a single unit, along with the exhaust manifold, fan, distributor, alternator, heater valve, hot water pipe, hot water hoses (flexible pipes) and oil filter stand in order to both lessen the total amount of weight to be moved about and to protect these components from being damaged. If your engine is equipped with antipollution equipment, it should also be removed prior to attempting to remove the engine from the car. This should be done not only in order to reduce both the weight and the bulk to be lifted and maneuvered, but to protect the antipollution equipment. Even if you have no intention of reinstalling it, you can always sell it on Ebay to an owner who lives in a location where emissions testing is a prerequisite for obtaining an inspection sticker! Drain the coolant from the radiator and, if you are fortunate enough to have a functioning petcock valve installed onto the side of your engine, drain the coolant jacket of the engine block as well. Next, disconnect the thermal transmitter for the coolant temperature gauge, and then disconnect the coolant hoses (flexible pipes) from the coolant pump and the coolant outlet elbow housing. Now, crawl under the car. Do not forget to disconnect the front mounting bracket for the exhaust system located on the bell housing of the transmission and to remove the grounding strap. Chrome Bumper models have the ground (earth) strap on one of the front rubber engine mounts where it connects the engine front plate to the chassis. The Rubber Bumper cars have their ground (earth) strap on the right transmission mount where it connects from the forward machine bolt that holds the transmission mount to the transmission and the transmission crossmember. While you are under the car, remove both the electric starter and its solenoid, disconnect the clutch slave cylinder hydraulic hose (flexible pipe) and the clevis pin of its pushrod, and then remove the clutch slave cylinder from the bellhousing, as well as the speedometer drive cable from the main transmission casing. Next, disconnect the driveshaft (propeller shaft), and then disconnect the electrical connections of the solenoid that is located on the Overdrive unit. Crawl out from under the car, and then loosen the 3/8”-18 UNC machine bolts of the front rubber engine mounts, and then remove the gearshift knob and the shift boot retainer plate. Be aware that ¼ x 28 (fine thread) x ½” PoziDriv countersunk round head machine screws are used to attach the transmission tunnel cover to the transmission tunnel, and they screw into welded-on nuts on the reverse side of the transmission tunnel, except for the front one which has a similar nut on a removable plate that covers the extended hole forward of the shift tower. They are unaccountably long and usually of two lengths, and stick down into the tunnel, where their lower ends rust. The length (and pointed ends on Original Equipment ones) is apparently so that you can get all the various layers aligned on assembly. The original screws are not Phillips head screws, although commonly mistaken for such. Be warned that if you use a Phillips head screwdriver, you will chew up the heads of these PoziDriv machine screws. If this mistake has already been made, replacements can be found at these firms: McMaster-Carr at: http://www.mcmaster.com/ , MSC at: http://www.mscdirect.com/ , or Metric Multistandard Components Corp at: http://www.metricmcc.com . Remind yourself of how much fun you are having, then crawl back under the car, and remove the machine bolts that secure the rear transmission mount to the underside of the car. Now, crawl back out from under the car and whistle a happy tune as you proceed to remove the 4 machine bolts that secure the oil cooler, and then remove the machine bolts that secure the radiator diaphragm to the body of the car. Remove both the radiator and the radiator diaphragm, along with the oil cooler as well as its hoses (flexible pipes) in order to both give more room in which to maneuver the engine / transmission package and to decrease the angle to which the engine / transmission package must be tilted, making its extraction from the engine compartment much easier. This will also avoid damage to the radiator. Raising the rear axle of the car up about 8 inches to 12 inches on jackstands will allow the tail end of the transmission to drop down lower and give you a better relative angle. Beg, borrow, or buy a load leveler mechanism so that you can alter the angle of the engine in order to allow maximum maneuverability as you lift it in cramped quarters and make the extraction much, much easier. You might feel that such a device is an unnecessary luxury, but it is worth every cent not to scratch up your paint or dent and / or crease the sheetmetal inside of the engine compartment. This is why professional shops always have a load leveler for removing engines! Removing the fan from the engine is a good idea if you are using a mobile engine hoist, as on some types of mobile engine hoist, the fan can catch on it and be damaged. Place the base of the mobile engine hoist as close as possible to the engine bay and do not extend the arm of the mobile engine hoist any further than is necessary. Use the rocker arm studs as lift points only if you are certain that they are Original Equipment items as some of the replacement studs nowadays are of dubious quality. Most failures will occur as a load is applied at an angle to an attachment point, so make those attachments strong, or, better yet, make them nonexistent by using a sling. Although some use a length of chain enclosed in a bicycle inner tube, I prefer to lift the engine with a strap of heavy nylon webbing. Not only is it strong and easy to undo knots from, but its greater surface area in contact with the engine block makes slippage less likely to occur and it is less likely to damage paint. Pass the strap between the engine and its backplate, cross it over above the rocker arm cover and loop it under the coolant pump, and then tie the ends off with a simple square knot above the engine. With the hook placed behind the knot, it will not slip backwards, plus the square knot is self-tightening and will not slip either. Always remember the cardinal rule to never, ever, put any part of your body anywhere below a suspended engine. |
| Stephen Strange |
| Hi Trevor, Following on from what Stephen said about loosening the harmonic balancer bolt, the method I use is to remove #1 spark plug, then slowly turn the engine by hand until #1 piston is about half way down on its compression stroke and insert about 2 metres of 3/8" clean rope into the cylinder through the plug hole. Then the rope will fill the combustion chamber and stop movement allowing the bolt to be loosened. NOTES 1/ that the rope should be clean so that you don't get grit in the cylinder, poly rope is good. 2/ that the cylinder's valves must be closed so that you don't risk bending them with the pressure of the rope, hence half way down after top dead centre, as the piston will return to top dead centre when you swing on your spanner. Also you may need a long extension on your spanner to breaker the bolt's grip. Good luck Herb |
| H J Adler |
| I pulled my first engine this past winter to replace the clutch in my GT. No directions, just disconnected everything that was connected, and marked the parts well for reassembly. pulled it by myself. no big deal really. glad i did it and saved the money of having someone do it for me! and yes, i pulled the engine and tranny together. if you dont need the tranny, you can pull just the engine. Don |
| don g |
| Sure am glad somebody finally told me what I'm doing wrong, after about 500 engine R&Rs. And having a thousand or so done right next to me. And never even seeing an engine tilter, until after all that. And never pulling the gearbox unless that was what I was working on. Good thing you were not a flat rate mechanic when the cars were new, you'd have starved, if you weren't fired straight off. FRM |
| FR Millmore |
| Couldn't agree more FRM but people on this board seem hell bent on removing the engines and transmissions in one go. As you say if you don't need to work on the gearbox then why remove it. It is straightforward to remove the engine on its own and easy to replace it as well. It is also straightforward to realign the engine and gearbox provided that the gap between the backplate and bellhousing are kept parallel and as for bending the first motion shaft, fat chance. I just use a rope around the engine in front of the engine backplate with the other end going round the crank pulley. Engine balances well, no need for a tilter. |
| Iain MacKintosh |
| If the car is otherwise running at the moment slacken the pulley nut with the car in 4th and the rear wheels on the ground and handbrake on. The 'indian rope trick' is only needed if you have the engine out before undoing the nut, and even then you can probably lock the flywheel more easily. It depends what you are going to use to lift the engine out, but if it is a typical collapsible rental hoist it simply won't go in far enough or take the weight of both engine and gearbox. The one I was given to use wouldn't even reach the centre of the engine from the front, I had to go in from the side and physically drag the whole caboodle sideways against the run of the hoist wheels. It's not an issue with a roof hoist, but you will need to raise the *back* of the car as well as tilting the engine and gearbox to get them out an in together, but I'd get them out separately even if working onthe gearbox if doing it at home. If you have a late model with the round engine mounts they can be a right pain, and probably need the rack to be removed. Lots of other ways and means at http://www.mgb-stuff.org.uk/wn_clutchframe.htm and click on 'clutch change', changing the actual clutch being a minimal part of the whole job! |
| P Hunt |
| Thanks for all your views. I would prefer to take engine and gearbox out separately mainly because of the weight as I will be using a block and tackle fitted to the wooden roof beams of my garage by attaching a steel pole to several of the beams and spreading the weight. They are quite strong as I have lifted engines on them before but not with the gearbox fitted. Trev |
| Trevor Harvey |
| Fletcher, Hear, hear, I guess you or I could remove, rebuild & refit an engine in the time it takes steve just to write that lot! |
| Chris at Octarine Services |
| Trevor If you can get hold of a copy of AN MG IS BORN this covers separate removal. I took both out together on my GT but then I needed to get both out. If I only needed the engine out, I would probably leave the gearbox where it was. |
| Jason Smith |
| I have done it both ways and prefer leaving the engine in. I was not in a hurry and took it slow and methodically. Having small hands helps too. |
| Dana Wilson |
| Dana, How did you do it leaving the engine in ??? |
| Iain MacKintosh |
| Fletcher and Chris, I hope your tongues ane firmly in your cheeks and you're just winding Steve up for fun! For some of the less experienced people on here, his detailed information is worth its weight in gold. So when is the first International MGB clutch change competition? This could be done on line with web cams so we could all enjoy watching. My money's on Chris at the moment, but I expect Steve's dented pride may make his spanners (or are those wrenches over there) fly. David. P.S. How do you all undo the nut on the alternator pulley? |
| D Balkwill |
| Yes it may be worth its weight in gold but I still emphasise that it is ludicrous to take both units out together if there is no work to be done on the gearbox. You have no chance in bending the first motion shaft as it is made from a very high quality piece of material and as for lining up the engine to the transmission well that is just not an issue. Besides if you do have them both out it becomes much easier to fit the gearbox first as fitting the crossmember to the gearbox on the bench is a breeze. The complete unit is also very heavy and long and needs careful handling whereas the engine whilst heavy is easly manipulared because of its compact size. |
| Iain MacKintosh |
| WOW...Happy Holidays to all...and to all a new year is comming. |
| rich osterhout |
| I assume that you want to undo the nut on the alternator pulley with the alternator off the car in which case wrap an old fan belt round the pulley and grip the pulley tightly by the belt by squeezing the belt in a vice. Then undo the nut. |
| Iain MacKintosh |
| Thanks, Iain, That might have worked, but by the time i read it, the whole thing had been stripped down, cleaned, new bearings and back together. The nut was on very tight. Took a good lean on the breaker bar with the rotor in the vice! I wasn't saying that the engine and box should come out together, I wouldn't dream of it. I meant that the detail in the descriptions would be reassuring for a first time engine puller. |
| D Balkwill |
| Well now: Some people seem to be poking fun at Steve for posting such detailed instructions. Such effort and attention to detail in the posting may seem silly to those of us who don't need the instructions in the first place, but to a novice it might be quite different. I am quite confident that Steve did not sit down and write all of that just for Trevor. I think he wrote it long ago, saved it, and pastes it in whenever the question arises. I think Steve's instructions are meant for the inexperienced novice, and they are appropriate for such a person. Obviously Trevor is an inexperienced novice, or he would never have asked the question in the first place. So, I think Steve did right to paste in the detailed instructions. Charley |
| C R Huff |
| Agreed, Charley |
| Michael Beswick |
| I'm with Charley! |
| Roger T |
| Your right Charley...Tony |
| Tony Shoviak |
| Yes, tongue in cheek, well at least lightheartedly! Like Fletcher, I never use a load leveller because it is possible to balance the engine without one and whether the engine is alone or with box it is manouverable enough. Photo below of the V8 + box going into my roadster - no lifting of rear of car or even need to remove the bonnet. Also Steve makes comments pertinent to US cars - UK cars are often different - there is no way to easily remove the carbs & manifold as a unit for instance. It is easier and quicker to remove filters, carbs ( the linkages fall free and you don't need to undo the cables), heatshield and finally manifold. I leave all cables & pipes attached and just swing the heatshield, manifold and choke linkage out of the way. Perhaps one day I will do a video of the steps to remove an engine - but these things take a long time to film & light sucessfully. Clutch change race - my record is 90 minutes from drive in to drive out, but I did have an assistant working under the car and all the nuts / bolts were new and free! More often it takes me 4 or 5 hours, including coffee breaks - this week I removed an MGB engine, rebuilt it using a freshly bored block and reground crank and refitted the engine in 12 hours start to finish. 
|
| Chris at Octarine Services |
| Charley- Yes, I did in fact write it long ago, and do post it whenever the question arises. Of course, there's always a few people who chime in with a few details that I haven't covered, so I then incorporate the new information into what is already written, then save it for the next time that the question arises. Yes, it is intended primarily for those who have never done it before, but also for those who have done it on other cars and underestimate what's involved. It's intended for the perfectionist-leaning home hobbyist who wants to do it in the best, safest, and surest way that it can be done as a mere part of a larger restoration project, not for a commercial mechanic for whom time is money! In fact, none of my methods would be approved of in such an environment where financial income, not quality, is king. As for those who feel that the first motion shaft of the transmission is essentially incapable of being damaged, I dare them to put their beliefs to the test by sliding their engine part-way onto the end of the shaft, and then releasing the hoist to simulate an accidental release!!! I haven't done it myself, but I've seen the results. U-g-l-y! Expensive, too. That's why I always recommend taking the engine and transmission out as a single unit. Besides, once the transmission is on the bench, what owner could resist the urge to get in there, too?! |
| Stephen Strange |
| Iain, I removed only the engine because I was replacing rear main seal. I had been involved in removing both engine and transmission before and found it to be more work than I wanted to go through again so I opted for the engine only and was glad I did. I was fully aware that getting the engine and transmission to line up properly when going back in can be a complete bear but God smiled on me that day and it went in first shot! |
| Dana Wilson |
| "it went in first shot" Same here, couldn't understand why so many complain it is difficult. However mentoring a pal remotely he had major problems getting the front of the engine down far enough before the first motion shaft started going into the clutch splines, the pulley was hitting the rack. But that was CB, mine was RB with the lower and further forward rack - not by much but maybe it makes all the difference. I simply lowered the engine down and back to get the shaft through the cover plate, made sure it was in the middle, checked the gap all round between bell-housing and engine back-plate and made sure it was equal, and the engine simply pushed back as easy as that. |
| P Hunt |
| Most problems in mating the engine to the gearbox stem from poor alignment of the clutch plate - the input shaft splines mesh with that before the end of the shaft goes in the spigot bearing and effectively restricts the movement so if it is out of line by even a few thou then the engagement is hindered. This is why I ONLY use an old input shaft to align the clutch and ensure it is an easy sliding fit. For CB cars the trick to getting the input shaft in the clutch release ring is to angle the engine so that it drops down onto the shaft before the pulley or sump foul - then, with the crane stationary, apply rearward hand pressure to the front of the engine and drop the engine gently - it will swing back and down in an arc and mate perfectly. Put the gearbox in gear and a socket on the crank bolt and rotate the engine while applying backward pressure and the splines will mate. Adjust the gearbox (on a trolley jack) and engine till the backplate is parallel with the bellhousing and the engine should slide back into place with a satisfying clunk. Pop in the top left and bottom right bolts (these have tight holes on the bolts to act as locators) and do up before removing the trolley jack from under the gearbox and lowering the engine onto its mounts. Oh and in my shop - reliability is King - not price - I DO NOT want customers coming back with complaints, so things are done right, first time, I just don't spend time I can ill afford - I have a queue of customers wanting work done! |
| Chris at Octarine Services |
| After several years owning a 73 MGB, I switched to a 75 TR6. I had replaced the engine and installed the Ford N-type 5-speed gearbox in the MGB with no difficulty - alone and in one piece. On the TR6, the guidelines for changing the clutch indicated removal of the gearbox up through the floor. This involved removal of seats, tranny cover etc and was not a nice job. The gearbox is quite heavy and one is not in a good position to lift it out from under the dash. Aligning the first motion shaft splines into the clutch was a challenge. I think my next car will be another MGB! Barry 
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| BJ Quartermaine |
| Yes Barry - I too have done that job - never again! |
| Chris at Octarine Services |
| Chris- I am confident that any customer who turns to you for service will get a concientiously done job. I did not mean to imply that you, or any other shop owner who regularly contributes to this BBS, would do otherwise in their own personal shop. On another note, how about detailing on your website the conversion of your personal car into a Rover V8? There are plenty of people who would be interested due to your practical approach to all things mechanical. Some of these conversions are less well done, and you could save a lot of people a lot of trouble in dealing with the details. |
| Stephen Strange |
| Steve, The details of V8 conversion are more than adequately covered in Roger Williams book "How to give your MGB V8 power" which rests on my bookshelf alongside Peter Burgesses "How to power tune MGB 4 cylinder engines" in the same SpeedPro series by Veloce publishing. I used Roger's book to guide me through the process but perhaps, if I ever get a moment, I will add a few wrinkles I use to make life easier - like the access hatch in the inner wing to be able to undo / do up the starter motor top bolt! |
| Chris at Octarine Services |
| "undo / do up the starter motor top bolt" Can't speak for conversions or cast manifold, but with tubulars on an RB factory car I found a series of 3/8" socket extensions and a UJ did the job easily. And I had some practice with an abortive attempt at fitting a geared starter. |
| P Hunt |
| Chris- It isn't really the installation of a Rover V8 into an MGB that makes the conversion difficult, since the solutions to the problems involved with that have been worked out for a long time now. It's the other details that drive people to despair. Its things like where to put the ECU, the oil filter so that it can be changed with minimal hassle, the fuel injection stuff, how to deal with potential overheating, etc, etc, that cry out for an experienced individual to add a few pages to their personal website on the best way to accomplish it. To my knowledge, nobody has tried, and we're all the poorer for that lack of how-to knowledge. |
| Stephen Strange |
| I would like to thank all who responded to my original question of the best way to remove engine and gearbox.I appreciated all suggestions. I have removed the engine and did it leaving the gearbox in the car, (that still is to come out) It was not to difficult a job and was done over two days but then I was in no hurry. To my surprise it is a gold seal engine and was only discovered when looking for the engine numbers on the crankcase. It was caked in thick crud and looked like a black painted engine but was in fact gold. I am having difficulties in removing the distributor drive so as the camshaft can be drawn out. I have screwed a bolt in the end but it is still not coming out, any suggestions? Also, is there any way of knowing what type of camshaft is in an engine. would there be numbers stamped on it that would give this info. Thanks, Trev |
| Trevor Harvey |
| You have taken the drive housing off the top of the dissy drive haven't you? It's part 62 in this drawing http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=191&SortOrder=30 |
| Mike Howlett |
| Should be a screw holding that housing in, probably hidden under all that crud. |
| P Hunt |
| No I had not taken the housing off, you are right Paul the screw holding the housing was not seen until I cleaned it a bit. Thanks for that. I know nothing of the history of the vehicle other than what has been done in the last 10 years. It has obviously had an engine change as it is a gold seal engine but how can I know if it is a standard camshaft or has a performance one fitted. Trev |
| Trevor Harvey |
| Sometimes a Piper or Kent cam will have the cam spec stamped on the end - BPP270 or 717 are examples. Std cams have no marking at all. |
| Chris at Octarine Services |
This thread was discussed between 08/12/2009 and 16/12/2009
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