So I got my driveshaft in the car today. It seems dangerously close to that cone shaped thingy at the rear of the body near the diff. I only have about 1/8th clearance between the front edge of the cone and the driveshaft. Seems like a good bump and the two could kiss. Any reason this cant be cut out as long as the parking brake mounts remain?. I dont see what purpose it serves.
Two functions. 1) Structure. 2) Hold up driveshaft should u joint fail etc. so you don't go pole vaulting!
You wouldn't be the first here to replace that brace with a deeper-section substitute. In fact, MG went from a shallow brace on chrome-bumper MGBs to a deeper brace on rubber-bumper MGBs.
Example: Terry Schulte's GT
(http://www.britishv8.org/MG/TerrySchulte/TerrySchulte-JK.jpg)
Before you do that though, you might want to double check pinion angle. Wedge shaped shims installed between leafsprings and axle are often used to adjust the pinion angle one way or the other. If you can make the angles work out, those wedges might buy you a little clearance.
Thanks for the info. I didnt realize it was a structural component. I am surpirsed since my car is an RB car but ther have been many surprises in this build. Ill definitely look at the pinion angle.
OK, it looks like I can remove abut 1/3rd off the front of that cone and then I will have plenty of clearance. Its just the very front where I have an issue. If the picture above with the tube welded in is strong enough then I should be fine as I will have a lot more of the cone left than the amount of steel that tube represents.
Keith, are you looking at that clearance with the car on the ground or in the air?
Remember that the drive shaft will rise into the tunnel when the car is on it's wheels.
Cheers
Fred
Fred, I actually had a jack under the diff so it was at its highest point in the car. That's what made me nervous. ON the ground the diff actually rubs the front of the cone and I cant get the tranny any higher. Whats also weird is that this car has lowering blocks on it so the diff is 1 inch higher in the car than stock. If I left off the blocks it wouldn't have fit at all.
Keith,
I'm inclined to suspect some fundamental installation issue with the axle - a lot of us have done axle and driveline installations without having to touch that structural piece. Have a good look at how things are put together and check driveline angles between bump and rebound before you commit to removing any sheetmetal.
OK, Ill check but it would have to be significant. I have the motor as low as it will go in the front and the trans as high as it can go in the back. Not exactly sure what to look for?
With the car sitting on the ground (it has a 2.5 inch rake front to back) the diff looks pretty level with the ground.
Also, how much clearance is acceptable. I would think at least 1/2 inch at the front of the cone? I have about 1/8th.
For curiosity's sake, I just measured my driveshaft clearance to that structural component at 2-1/4" at the rear and 1-1/4" at the front
This axle happens to be a Ford 8.8 with a pinion up angle of about 3 degrees, but most axle installations will be similar.
Crappy photo attached.......
drivelineclearance.jpg
How about posting some photos of your axle instal. - maybe some of us can point to a potential problem area.
Holy cow, Ive got nothing like that for clearance. Ill get some photos up.
OK, tough to get pics of this but maybe this will help. Seems like plenty of room in the back of the cone but only 3/8 inch up front.
(http://i1118.photobucket.com/albums/k618/Brownwood1/20140719_103917.jpg) (http://s1118.photobucket.com/user/Brownwood1/media/20140719_103917.jpg.html)
(http://i1118.photobucket.com/albums/k618/Brownwood1/20140719_104039.jpg) (http://s1118.photobucket.com/user/Brownwood1/media/20140719_104039.jpg.html)
(http://i1118.photobucket.com/albums/k618/Brownwood1/20140719_104640.jpg) (http://s1118.photobucket.com/user/Brownwood1/media/20140719_104640.jpg.html)
(http://i1118.photobucket.com/albums/k618/Brownwood1/20140719_104649.jpg) (http://s1118.photobucket.com/user/Brownwood1/media/20140719_104649.jpg.html)
(http://i1118.photobucket.com/albums/k618/Brownwood1/20140719_104709.jpg) (http://s1118.photobucket.com/user/Brownwood1/media/20140719_104709.jpg.html)
Keith. appears the ford engine /tranny is mated to the OEM MGB R/E. Your engine/Tranny is probably not sitting at correct angle for the MGB R/E. Originally I used the MGB R/E and it lived awhile. After installed the Ford 8.8 dif, the u-joints in the adapter shaft were shot. The angles were off badly and caused the failure. When we added the 8.8, we welded the brackets on the R/E housing to attain the correct pinion angle. no problems after 40+k miles. my 2 cents worth.
As Kelly mentions, you need to check the basic engine/xsmn power angle......it's possible that the xsmn mount needs to be raised.
OK, I got the rear trans raised to get 2 degrees angle at the engine. Pretty sure the bellhousing is right against the trans tunnel though.
I now have about 3/4 inch at the front of the cone and 2 1/4 at the rear. Still seems a little tight.
I honestly wish I had gone another way with this, like a V6. I got sucked in with the fact that there was a kit and that this car had a factory V8 option in Britain. I had no idea the entire car had to be reingineered! I'm sure it will be awesome when completed though !
Keith, don't throw in the towel just yet! Let's see what you've got:
Your engine mounts are presumably fixed, so raising the xsmn mount is the only variable to allow increased propshaft clearance - try to get as much height as makes you feel comfortable without bellhousing interference. (make sure it is the bellhousing and not the top of the T5 xsmn that is hitting - reason I mention is that it is routine to provide xsmn clearance for most swaps by providing 3/8" clearance at the dash panel/tunnel interface by using a BFH)
Now you should test the degree of driveline interference in the axle rebound condition (assuming that the MG original rebound straps are mounted) - support the body under the sills and slowly lower the RA to check.
Let's see how much, if any , interference exists, now.....
Don't worry about matching the power angle to the RA angle just yet
quote: "I honestly wish I had gone another way with this..."
Think about how much progress you've made since January when you first registered and started asking questions. People spend years getting as far. You'll get this clearance issue resolved soon enough. From my perspective, it looks like you're doing great.
Hey Curtis you are right! It was kind of a let down because I thought the car might go mobile by next weekend, not driving ready but mobile! This is a much bigger project than I expected. Probably had a wee bit too much confidence since I have done numerous engine swaps before. Anyway, it is coming along, just got a little frustrated. This project has pushed my skills and that's not a bad thing. Might just need to take a break for a few days as Ive been working several hours a day and all weekend since the 4th.
Graham, you are right, I am getting some contact with the tranny just in front of the radio and heater control mount. It looks like a beast to get in there and cut a hole from inside the car but that looks like the next thing I need to attempt.
I originally said to myself that if I was going to do one car, it had to be a V8! Need to remember that. Endeavoring to persevere :)
Quote.....cut a hole from inside the car but that looks like the next thing I need to attempt.
Hammering a flat at the offending location is more desirable than cutting sheetmetal.
Well, a SBF is not the easiest, but it's not that bad. Plus, it is more rewarding than most swaps. You are almost there, so hang tough as Telsa would say!
http://www.youtube.com/watch?v=bdrjlFqi1AkR)
OK, after some rest, I think I'm beginning to understand this. I read that the ideal engine angle is 3 degrees down. The best I can get is 4 or 5 degrees before stuff starts hitting stuff. So that tells me I need 5 degrees up on the pinion to get the driveshaft to 0 degrees.
Is that correct? Also, I am leveling the car using a jack for my degree measurements. the car actually sits lower in the front than back. Should I be measuring angles with the car level or with the car as it will ride?
Starting to have geeky fun with this now. :)
Using the side chrome strip as reference of zero degrees, the engine needs to be 3 degrees down at the back from this zero line (disregard any chassis rake). Once you have the engine/xsmn down at 3 degrees, the RA pinion needs to be pointing up by 3 degrees.
Edit: There is nothing magical about 3 degrees,.....it happens to be average for our conversions - if yours ends up at 2 or 4 or ?, you just need to match the pnion angle. The driveshaft angle is essentially immaterial at this point.
Here's a neat Harbor Freight digital angle finder that has a zero reference capability...had mine for years!
HFanglefinder.png
Thanks Graham! That's exactly what I have been doing, using the body line to get the car level. I think 4 degrees is doable without the tranny running into the trans tunnel. I am having to fabricate a trans mount as all of the Ford ones are so tall that they push the transmission up against the tunnel. I will get that sorted 1st then get the pinion angle sorted before I worry about clearance for the driveshaft cone. One step at a time....
Keith,
Have you tried the suggestion of taking a BFH to the underside of the trans tunnel? Everyone has either done that or cut out a section like Simon Austin demonstrates in his build. The BFH took me all of 20 min without the trans in place. Without doing this I think you will have clearance issue in the tunnel and at the rear loop.
Mike, I tried but I cant get in there without pulling the motor out again. I am all by myself on this project and it took me a day to get the motor in there. Plus it seemed somewhat dangerous to do it once so I don't want to push my luck. I see that as a very last resort.
I did look at what Simon did. That might be my best bet since I can do that without pulling the motor. Less work to cut and weld and less dicey for me working alone.
Hey Kieth,
the attitude of the car doesn't make any difference to the driveshaft alignment.
What is critical is the relationship of the trans output to the diffy pinion.
Ideally both angles should match. Meaning that if you draw a line straight through the trans and another straight through the pinion.
Those lines would be perfectly parallel in both planes. Reality often precludes that ideal alignment though so a degree or so difference won't cause any big issues.
Another important angle is the drive shaft angle. Measured from the trans to the pinion you don't want a perfectly straight line. The U joints need some angle to them. Otherwise they will wear quickly and cause all sorts of harmonics.
A vertical slope when the diffy is at ride height is most common, but a horizontal offset is acceptable as well.
Hope thats helpful.
Cheers
Fred
Yes that helps. I was going for a perfectly straight driveshaft but I see the idea is to have the angles match, trans down diff up at the same angle but have them on a slightly different plane so the driveshaft isn't perfectly straight between the two.
Keith, a perfectly straight drive shaft means the needle bearings won't rotate in the cups and you're probably looking at early u-joint failure.
Paul