and the Sykes tool......
Well mine is a cheap 30$ tool and works great, maybe not 100 times but thinking if it works 2 maybe 3 times it is definitely worth it. Mine is 5.5, 6 and 8mm tools and I used the 5,5 I think.
Hi, I had the same problem with the outer bearings on my 328, could not get them out with engine in place. So I decided to pull the engine out (had other issues to fix, like a leaking head gasket). Once apart the inner bearings were good but the shafts were worn. Instead of buying new shafts, I decided to repair the existing ones(because this was the only wear, gears and outer shafts were ok) machining the shafts and pressing on a steel sleeve, so it would fit tight in the bearing. Inner bearings on the 328 are normal bearings, no extra radial play, outside bearings are specific, with extra radial play. Hope this helps, I've never played with a 308 engine, but must be quite similar.
Hi, which portion of the shaft did you repair with a steel sleeve? Would be difficult on the gears show above for the outer bearing seat, since thread diameter and outer bearing ID are identical. Best from Germany Martin
Afternoon Martin, the inner portion, 10mm OD. I requested that the sleeve had an inner lip greater than 10mm so there would be no possibility of slipping off. Below is a picture of the bearings that came out of the engine, the small bearing is the inner, the big one is the outer and the box is from the new bearing from Superformance. Image Unavailable, Please Login
Martin, the outer bearing is not only held in place by the friction of the shaft, when you install the pulley and tighten the nut, it's almost impossible that the shaft will slip. Now on the inside( the small bearing) there is little friction holding the shaft to the bearing race. You need a tight fit here, plus I added a drop of bolt lock, just in case.
This is exactly, what makes me wonder about post #12. How that wear could arise. Best from Germany Martin
I had an outer bearing noise, so I tried to replace it with the engine in the car. Outer shafts and threads were intact. This is why I suggest that If you remove the outer bearing and you notice a lot of side play, something is not right. The inner bearing is a common bearing... no play, and the inner shaft(12mm, before I said 10mm, my mistake) fits tight. Greetings from Spain
No play doesn's exist. Otherwise the bearing would seize while in use There's 'standard play' (C2, commonly no lettering), extra play (C3 lettering), extra extra play (C4 lettering), decreased standard play (C1 lettering). Best from Germany Martin
Very true Martin, I’ll reword my comment... standard play, no lettering. But getting down to the point, I still think that replacing a bad bearing on the outside without checking the one on the inside is a poor job. The noise may dissappear for now but won’t take long before it’s back. IMO the shaft inside is prone to wear out, because there is no way to hold it tightly in the bearing race. This type of arrengment is used on cranks in 2 cycle engines, replacing the crank because it has spun in the bearing is quite frequent. Oh, just as a comment, I own a VW T3... can’t say anything wrong about it, above and beyond expectations, good piece of machinery
Hinecker, Unless something catastrophic happens or the oil is badly contaminated, I think the inner bearings would outlast most things on the engine. They have a fresh supply of oil and relatively low forces on them. The outer bearings are a known weakness and were too small (hence the shift to larger bearings in the later cars.)
Derek, when did they shift to larger bearings? Mine on my late carb car were still perfectly ok at 100.000kms. The whole f***ing job was just due to one of the seals behind the outer bearing badly leaking. The bearing in front was perfect. Probably because it got permanent fresh oil lubrication Best from Germany Martin
Morning Derek, IMO it's not an oil issue, when it was taken apart, both inner shafts had spun in the baring race.The bearings were fine and rolled smooth, the only bearing that failed was an outer bearing "noisy". As said before, the outer shaft takes a good grip on the bearing, the inner shaft doesn't. Best from Spain John
John, design or manufacturing flaw regarding tolerances? If looking at the design, the inner race should permanently maintain its press fit. Though, if the manufacturer fabricated at the lowest tolerance limit, it might have happened, that the inner race of the inner bearing got loose over time and heat cycles. Seen on waterpumps a few times. Loose inner races, which should be a press fit as well. Undamaged shaft portion at the lowest tolerance limit. Design of a loose fit of the outer race in an aluminium housing plus a loose fit on the shaft would be an exotic design. Thanks! Best from Germany Martin
Hello Martin, Yes, I have seen that happen on several devices, water pumps, electric motors, etc. And I do agree, one thing is the design and another thing are flaws on final tolerances given by the machinist. And of course, aluminum casings are much softer than steel so the "slip", usually occurs on the softest metal. Now comes the point, (Let's focus on the inner bearings only, ok), the bearings are fitted on the block using a punch(tight fit), so far so good. Afterwards the shafts are fitted into the bearings, ok? If the shafts fit too tight, you may damage the bearings when tapping them in, if too loose you end up with play. Afternoon Martin, Yah, would be an exotic design! My best guess is that it was not a tight fit from the beginning. Now it is, we’ll see how long it lasts. Working on engines, you eventually see what works and what doesn’t. IMO, instead of using ball bearings, since lubrication is garanteed, they should have gone to brass bushings and the problem could have been solved. You find this simple arrengment in camshafts, injector pumps, secondary shafts...etc. Lasts forever. Just like the belts, having the small sprockerts on the cams, saves a lot of width on the heads, but puts a lot of tension on the belts, best option maybe could have been chains. Oh well! It is what it is. Best from Spin John
Of course never apply installation force across the rollers. O.k., I thought the outer races are a loose fit inside the block. And that you install the bearings first onto the shaft. Like mentioned earlier in this thread I did not perform the job myself and did not see my engine while it was dismantled. After things warmed up in use I'm pretty sure, that the bearing's outer races are a loose fit due to heat expansion of the alu. Best from Germany Martin
No, the outer races fit very tight on the block, that is why you can’t fit them on the shaft first. I checked the manual first, and it explains how it goes back together, not many options, what I did on my own criteria was placed the block in th sun (45 degrees Celsius) and freeze the shafts, so tapping on the shafts was minimal. Also added a drop of nut lock. I do all the work on the car myself, that’s the advantage of being a mechanic Was tempted of getting rid of the bearings and installing bushings, but buyers in Spain don’t want mods or upgrades...I’ll stick to stock in case of resale. By the way, machining the shafts and making the sleeves was 15€. Best from Spain John
Hi John, now you leave me kind of helpless. Being a mechanical engineer designing also bearings situations on heavy machinery, I find these fits you describe unusual for the load situation we have here. At least not according with the literature. In my case, machining and making the sleeves would be zero Euros. I have a lathe and get scrap material for free from a small metalworking shop in the neighbourhood Best from Germany Martin
I just went through this and sorry I’m too lazy to look it up to confirm but I believe the Superformance site lists the S/N’s for the two different sized bearings.
So just to be sure, the outer bearing is a sealed bearing and should receive NO lubrication from the engine right?
Only the very early cars had unsealed front bearings (up to engine 03044 according to Ricambi.) They pushed the bearing closer to the pulley to reduce the forces on it in about '78 I think.
Morning Martin, Lucky you have lathe, that's fun! I find the bearing fit normal. I'm not an engineer, but I have installed dozens of bearings over the years. Experience has shown me that this type of arrangement is not the best for the given situation. As said before, in a well lubricated environment, why use a bearing??? Look at rods, wristpins, crankshaft, camshafts..., any problems? none...It's. That belt tension is nothing compared to what a wristpin bushing has to deal with. It's a proven fact. Best from Spain John.
Morning Kcab,, I checked the reference on the bearings, 308 QV and 328 use the same outer bearing, OD44mm, according to Superformance. Regards, John.
When did they switch to the larger outer bearings? With the 2Vi-cars? Or QV? I just looked into my srap box, what came out of my carb engine (late bearing design). 6203-2RS/C4 40mm OD. John, this is, how I would design that application. Press fit on the shaft. Loose fit in the block. Just in case, the bearing would seize and turn inside the housing, a separate sleeve in the block for the outer race, which could be replaced. Also made from alu for identical heat expansion. But o.k., this is, what I made recently on a bearing application with ODs in the 400mm region Best from Germany Martin
Hello Martin, Your design makes it easy to fix (and cheap) in case something fails, good idea. I'll buy that. Now, starting from scratch(and knowing what you know), in a well lubricated environment such as inside the crank case and considering(remember that you are in the design process) that you can re route oil passages to or through the shaft. What would you design? (don't have the chance to have an engineer working along with me every day, so might as well take advantage of the situation) John.