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MG MGB Technical - Engine reinstall
| Anyone had problems with the crank pulley fouling the rack? The gearbox is jacked up as far as it will go, but the front of the engine won't go down far enough to get the gearbox shaft fully in. The gap between the top of the bell-housing the engine backplate is smaller than the gap at the bottom, i.e the front of the engine needs to go down, or the gearbox to go up, but neither will move any further. This is a chrome bumper, and a car where someone else removed the engine. I've done a late rubber bumper, where I had the rack out anyway to get at the engine mount nuts, so no problem with that. It's as if the rack needs to be pulled forward, or the back of the gearbox tilted down i.e. slacken the rear crossmember bolts, but none of the three sets of instructions I have say anything about either of those. |
| Paul Hunt |
| Paul, In the past many contributers have suggested that you raise the rear wheels off the ground by 6 inches. This will decrease the angle that you have to wrestle the engine/gearbox into the car. Hope this helps. RAY |
| RAY |
I don't understand the description of the problem?? But there should be no issue putting the engine in with the steering rack in place. Done it many times. Now the tranny crossmember has to go in the right way... But you couldn't get the tranny mount bolts lined up it it were in backwards and the engine mounts were bolted down. How bout a better description of the problem???? |
| G Hanks |
| Ray From what I understand, Paul is only refitting the engine. The gearbox is still in the car. I have only performed this operation on a rubber-bumper B - about 27 years ago - and don't remember having this problem. |
| Dave O'Neill 2 |
| Paul- You only want the front of the gearbox up, not the whole thing. Reposition the jack to the front of the box, so that the angle of the box is more favorable. I never hadf a problem doing this. FRM |
| FR Millmore |
| Paul, if it is a CB shell und the engine came out of a RB car, you need th change the front engine plate AND the large diam pulley for the early smaller version, otherwise you will have a problem as discribed. Ralph |
| Ralph |
| I'm helping someone remotely so can't see the situation for myself. It is a CB car, with the gearbox still in, only the engine removed. Only the front of the gearbox has been raised, with a jack right at the front, the rear is still attached to the cross-member. It is the same engine going back and the correct one for the year. I'm assuming the gearbox and crossmember haven't been moved forwards (using the other set of holes in the chassis rails for the crossmember) while the engine was out (this was bought by the present owner as an abandoned project (maybe the PO couldn't get the engine back in ...)), but may be wrong in this, this is something the owner is checking when he can next get some time on it. If the cross-member is fitted using the front holes then we will 'walk' it back to the rear ones and that should be OK. By 'walk' I mean remove one bolt from the one side and slacken the other, then remove both bolts from the other side, pull the gearbox back and insert one bolt. Then remove the bolt on the first side and pull that back. I'm not keen to completely undo both sides as the gearbox will only be balanced on a jack and pulling it back could tip it off. If it is already in the rear ones then we will try walking the crossmember back anyway, fastening it temporarily with just one bolt either side i.e. through the front-most holes in the cross-member to the rear-most holes in the chassis rails. That is if the prop-shaft will compress that much, if not then we will move just one side back which should still gain us an inch. That and slackening off the bolts until they have just 3 or 4 threads engaged should lower the rear and so tilt the first motion shaft up just that bit more. I hope by a combination of these things we will do it, otherwise we will have to pull the rack forwards. |
| Paul Hunt |
| It doesn't explain the problem, but removing the crank pully might solve the problem. Then it can be installed after the engine is in. Charley |
| C R Huff |
| I did this about 17 years ago on a '76 B. The PO had pulled the engine alone. I don't recall any problems going back in. It's the only time I've dealt with an engine pulled without the transmission. Charley, help me - I can't recall and I'm not near my B right now - but can you get the crank pulley back on past the rack when the engine is in situ? If you can, that's probably a solution. Otherwise, Paul, I'd be tempted to drop the transmission, bolt it properly to the engine and put it back in the car as a unit. FWIW, Allen |
| Allen Bachelder |
| I think it would be easier & quicker to remove the gearbox & then refit the engine & gearbox as one unit. Joining the bell housing to the engine in situ will be a real pain in the butt. Apart from the lack of space to get tools in there, the clutch splines have to be aligned also. When engines & gearboxes are joined in situ, It's usually the gearbox that is fitted up to the engine, not what you're attempting. Barrie E |
| Barrie Egerton |
| Paul, The engine has to go in at a more extreme angle initially to get the nose of the gearbox input shaft into the ring of the pressure plate - then the engine can move back and inch or two and the front pulley will drop past the rack and the engine can then be levelled square with the bellhousing. So the engine has to move in an arc rather than straight. |
| Chris at Octarine Services |
| Just another thought - has the engine got the correct smaller pulley fitted or is it the larger RB pulley? The rack on the RB cars is further forward. The alternative is just to undo the rack mounting bolts and pull it forward. |
| Chris at Octarine Services |
| Don't be tempted to remove the gearbox Paul as this will cause an awful lot of extra work. As Chris says if the gearbox is jacked up and hitting the inside of the tunnel the engine has to go in at a more extreme angle. Engage the first motion shaft by turning the crank front pulley nut and then by keeping the gap between the backplate and the bellhousing parallel all round the engine should just slip back and the spigot bearing engage. With a couple of bolts entered you should be able to drop rhe engine on to its mountings. By the way I always grind a 1/32" at 45 degree chamfer on the front edge of the first motion shaft to ease entry. |
| Iain MacKintosh |
| Barrie E <<When engines & gearboxes are joined in situ, It's usually the gearbox that is fitted up to the engine, not what you're attempting.>> Not where midgets are concerned, and not with MGBs either, normally. With Midgets it is just as Chris describes. The engine is at a much steeper angle initially, then it is levelled off after clearing the front crossmember. Having raced Sprites and Midgets for about 15 years, engine removal and refitting without the gearbox was a common occurence. As I said before, I haven't refitted a B engine for a very long time, so I forget exactly how it went. My C/B B is due for an engine change in the near future, so I will have more idea after that, but not much help for the current problem. |
| Dave O'Neill 2 |
| Paul, FWIW, when my clutch went and the engine and box came out together, we subsequently discovered the gearbox crossmember had been installed back to front, though mounted in the (correct for my car) rearmost and second from front bolt holes on each rail side. I wonder, is it possible something like that would cause cramping at the pully if it were the case in this car? Regards Roger |
| Roger T |
| Allen, When I first got my 68 GT (with a GK engine) the cam timing was way off. I pulled the front pully and timing cover and reset the cam timing. So, from that I know that the crank pully can be removed with the engine in the car. I might have removed the radiator, but I'm not sure anymore. Charley |
| C R Huff |
| Thanks all. I'll find out the pulley diameter, what should it be (73/74 18V)? As far as I know this is the engine that came out of the car. Is there enough room behind the rack to refit the pulley to the engine when the engine is in? I imagined not, as the engine was only going to go back another inch and a bit anyway, and I thought the pulley was longer than that and is already sitting over the rack. Adding the problems of removing the pulley on a pulled engine, I would rather pull the rack forward if moving the gearbox cross-member back a bit doesn't solve it. As I say the shaft seem to be going in as far as it can, the end of the splines on the shaft may well be just starting to engage with the splines on the friction plate, but that is as far as it will go because we can't get the front of the gearbox up any more or the front of the engine down anymore to get the gearbox shaft and crankshaft in line. |
| Paul Hunt |
| From what you say it would seem that either the gearbox crossmember is reversed or it is bolted into the wrong holes on the chassis rails. I cannot remember a problem getting the front of the engine low enough to be able to align the clutch splines so it seems that the whole assembly is too far forward and that can only be because of the afore mentioned reasons. |
| Iain MacKintosh |
| When I installed the Moss supercharger pulley on the crankshaft I had to drop the rack. There is not enough room for it to come off in situ. RAY |
| RAY |
| The crossmember is where it should be i.e. in the rear-most holes, and the pulley is correct at 5 1/8". What are the points to look out for to tell if the crossmember is reversed? |
| Paul Hunt |
| Paul It can be a tight fit depending on where the jack is under the gearbox. It needs to be right up near the front edge of the bellhousing to get the angle upwards as much as possible and then it should go in ok. Having said that I usually leave the balancer off . it makes it a whole lot easier and easy to fit after the engine is in. Hope this helps Willy |
| WilliamRevit |
| I think I have found the answer myself as far as the *orientation* of the crossmember goes, and this is that the side with the cut-out on the top edge faces forwards and the straight side faces backwards. But in a couple of threads elsewhere that discussed the same thing opinion was that it didn't make any difference anyway. |
| Paul Hunt |
| Paul, Yes, that orientation is the clear impression gained from the diagrams in my Moss parts book (p21-22). However it is exactly that orientation which we found to be incorrect on 2 chrome bumper cars here - my 69 and a friends 72, both local production roadsters but from factory kit bodies. In both our cases fitted with the V forward the crossmember boltholes lined up mid-spaced to the chassis rail captive nut holes. When each crossmember was reversed (ie the 'flat' side with the round hole forward) the bolt holes lined up perfectly rail and chassis. We went with that orientation and neither car has developed any problems. Of course the engine mountings were correctly installed first. When my engine went back in I replaced the ageing engine mounts. Those in the car were holding perfectly well in the vertical axis but were straining forward ie the rubber was stretching as if the engine was being 'worked' toward the front of the car. That of course was with the crossmember installed with the V forward. As to whether it makes much difference which orientation is adopted, I note the 'towers' taking the rubber pads don't rise from dead-centre in the crossmember width. There is a wider spacing to the face edge in one side than the other. I don't remember if that is offset by the shape/positioning of the mounting rubber pads or not. If not, it would suggest that there is a difference in positioning to the chassis rail depending on the orientation chosen. Also, on the Moss diagrams. I note there were two different engine stay bars employed - one early and a different one from 74 to end of production. I also note that the GT up to 67 used a different system mounting the gearbox to the crossmember and that the GT did not employ the engine stay bar. The early stay bar mounted through the round hole, the later one mounted to a structure outside the V face - in effect a different crossmember shape for all cars from 74. Additionally, the crossmember to gearbox mounting rubber fitted to the crossmember with a single bolt up to 67, but with two from 67 to production end. Whether that altered the alignment of fitting components I don't know. Comparing the differences over time, and wondering whether these Moss diagrams originated from the factory (eg they are not in my factory service handbook) raises a string of questions for me which will probably never now, after so many years) find answers. In any event I hope this may have helped a little. If not to solve the problem, at least to rule out some possible contributing factors. Merry Christmas - I've done mine and lunch but at 5pm here your probably yet to wake to begin yours. I hope it is a good one for you and all your family. Regards Roger |
| Roger T |
There were 3 Xmembers used.All had the cutout at the front.I doubt it made any difference if it was reversed unless the steady bar was fitted. Barrie E
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| B Egerton |
| The restraint bar was only fitted to UK cars from the start of rubber bumpers (a few months earlier for North American) so isn't an issue in this case. From Roger's comments it *would* seem to make a difference, especially with the gearbox in but not the engine, and from what I can see *would* seem to push the gearbox forwards by perhaps an inch. However I've since checked my V8 and that has the notch facing forwards, as per the Workshop Manual and Parts Catalogue. I *know* that lines up as it didn't originally, and was attached using one pair of holes one side and the other on the other! It was only when the sump started leaking from having been rubbing on the front cross-member that I realised the engine mounting plates were on the wrong sides which brought the engine forward about an inch. With that corrected the crossmember lined up correctly with the rear set of holes both sides. |
| Paul Hunt |
| Paul If the gearbox is still in the car the gearlever has to line up with the rubber boot on the console. it is a simple matter of lining up the lever and fitting up the cross member in the correct position to suit Willy |
| WilliamRevit |
| The position of the gear lever relative to the hole in the tunnel and hence the boot is determined by where the crossmember is bolted to the chassis rails, and that *has* to be determined by which holes the crossmember lines up with one the gearbox is attached to the engine and the engine is attached to the front mounts. This is the only possible way to do it. Setting the gearbox position by where the gear lever happens to be in relation to the boot is putting the cart before the horse. For one thing precisely because the boot is rubber it will move to wherever the gear lever ends up, within reason, and certainly with standard components. |
| Paul Hunt |
| Can't see why this has been such a huge issue. Drain and Drop the box, remove the mount, bolt box to the engine in the workshop, jack the back of the car up, slide the complete unit in, locate the front mountings, then jack box up and replace mounting. Everything is easier that way!! |
| Allan |
| Was the clutch replaced in this engine? I've done this about a half a dozen times or so on CB cars from the late 60s and early 70s. The crank pulley will not clear the rack and drop down for proper alignment unless the transmission shaft is partly inserted in the clutch disc. If you did anything to the clutch (replaced the disc or whatever) and did not use an alignment tool while bolting it and the pressure plate back in place, the length of the transmission shaft prior to passing into the disc splines will keep the engine forward so that the pulley cannot clear the rack. It's been many years since I last pulled and reinstalled an engine, but remember having this exact problem once due to misalignment. No amount of "oomph" will force it together if the alignment is not correct. Clutch alignment tools are cheap from Moss and others. You might have other issues causing your problem, but if the gap between the bell housing and engine backplate is about an inch and a half (guessing from mental images long ago), it's likely your transmission shaft isn't going into the disc. |
| Rick Penland |
| There is no way you would get an engine and gearbox back in with the sort of hired hoists we seem to have available in the UK, I only just got an engine back into a rubber bumper and that was with the hoist at the side of the engine, wouldn't get anywhere near from the front. Yes, if you read the above the engine did take a curved trajectory down onto the gearbox shaft until the two sets of splines touched, which stops the engine going back any more until the front is lowered enough to get the crankshaft and shaft into alignment so the splines can slide together. But that couldn't happen as the pulley was now resting on the rack, and the gearbox was right at the top of the tunnel, the pulley was the correct size, and the gearbox was in the correct position. Hence the impasse. But we have eventually got it in by slackening the crossmember bolts which dropped the back of the gearbox to give the shaft a bit more upward tilt. That got them closer, and an almighty shove on the front of the engine got them together. Bolted together, and with the front mounts bolted to the chassis brcakets, confirms that the crossmember has been in the correct place all along, so why the difficulty (compared to others experiences, it seems) remains a mystery. And will remain so, unless anyone else fancies taking it out and putting it back in again just to see ... However I've just had a horrible thought. This was bought as an abandoned project and the engine already removed. The release bearing is new or nearly so, and I'm now wondering if it *is* new maybe the clutch was replaced by the PO and the friction plate put on the wrong way round ... |
| Paul Hunt |
| Paul, you will get quicker with practise! |
| David Witham |
| It may well be the splines aren't lining up, so the engine isn't engauging as far as it could. Put the car in gear, and try again. When you get to the trouble point try to rotate the engine back and forth which ought to get the shaft to line up and it will slide on properly. I only had an issue the first time I tried it, because I'd left it out of gear so the shaft moved with the engine and wouldn't line up. |
| Jason |
This thread was discussed between 19/12/2008 and 05/01/2009
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