Replacing 308/328 Timing(Cam Belt) Drive Bearings

On the way to the FChat New England BBQ last weekend, my car started making an awful noise- like there were metal balls in the cylinders. I was only a couple of miles from fellow f-Chatter Verell, so I limped to his house.

After sulking around, trying to have fun at the BBQ (which I did achieve) and trying not to think about what that noise could be- Verell and I put the car on the lift. We removed the right rear wheel, wheel well, and fired her up. It was quickly obvious what was wrong. The gear at the bottom of the rear timing belt was jumping around in tandem with the awful noise. The car was running fine- just a bunch of racket. First photo points to this offending gear.
Behind that gear, are two bearings we are going to replace- along with many others.

So, Verell graciously volunteered his garage, tools, time, and knowledge and offered to help me do this huge job. Either we were fixing it there, or it was going on a flatbed! So- we decided to do it ourselves.

I live about 2.5 hours from Verell's place and my wife needed to come pick me up. I ended up catching a ride with another FChat guy (spider348- thanks again John) who got me about an hour closer so the wife didn't have to drive so far.

So- Sunday began:

First, we organized our plan, which involved a parts list.

Then, the real work began:

1. Remove heat shield above exhaust pipe

2. Remove front cover under steering rack and drain coolant- In the photo you can see what it looks like under this cover. I removed the small hose to the left and was not prepared for the Niagara falls of coolant that was released into my chest. Instead of just plugging the hose back in, I tried to grab the drain bucket I had at my feet. Anyway- we ended up having to dump a lot of water on the floor, and shop vac it up to clean up the mess. Sorry Verell!

3. Remove air cleaner housing and rubber band a shop towel over the open fuel distrib. Remove fiberglass air intake also. It's attached to the air filter housing. Mine came out through the top still connected to each other buy the rubber accordion hose. Your car may be different.

4. Remove rear timing belt cover- the three front bolts are simple, but the small nuts across the back of the cover are a pain. You need to get some off from the wheel well, and the top ones from above- hence the removal of the air cleaner housing. I also moved my warm-up regulator for better access to the top of the timing belt covers- this may not be necessary.

5. Now that the coolant is drained, you can move the coolant pipe (the big silver one going right up the middle) from the thermostat housing and swing it out of the way. You do not neeed to remove it from the car. If you are replacing the old coolant hose- go ahead and remove it. It will twist to the left so you can get to the front timing belt cover.

6. Loosen the adjuster for the alternator, and remove alt. belt.

7. I removed my alternator to clean/ rebuild. It is not necessary. You can search for this procedure if you are so inclined.

8. Loosen adjuster for AC compressor. The compressor must be moved out of the way and it's brackets must be removed so you can remove the front timing belt cover. Disconnect electrical connections. Be careful with the shims between to top bracket and the compressor. This is also well documented in other posts. When finished, the compressor is out of the way, buy dangling from it's hoses. It kind of leans on the back of the fuel tank. See photo. We had to split apart a fuel connection that ran between the two feeds for the AC. Also, the pressure lines it hangs off of are attached to the body by a small bracket that needs to be loosened but not removed. It's hard to get you hand in that area, so I wanted to just loosen it instead of having to line the bolt and nut up later.

9. Remove front timing belt cover. Again, the small rear bolts/nuts (7 or 8 of them) are a little tough.

10. Drain the engine oil and remove the crank case sump cover. It's a little tricky, because you must remove the oil dipstick tube, and the oil temp sender. These procedures are also documented elsewhere. We are going to replace the shift shaft seals "while we are here". More on that later.

That's it for right now, after a day of work. We are taking our time, and accomplishing many "while you are there, you might as well" tasks.

So far, we are planning on: rebuilding water pump, replacing all timing bearings and seals, removing cams and resealing everything including distributors, and cams, replacing shift shaft seals, main crankshaft seal, rebuilding alternator (covered in oil from a cam seal leak), replace timing belts (only six months old, but oily from the bearing giving way) tensioner bearings, general cleaning, etc.

I think I have bought all the parts we will need from T. Rutland and it's up to about $1100.

I will continue this post after this weekend to update on the progress.

A huge THANK YOU must go out to Verell for all his help with this very complicated procedure. There is no way I would even think of trying this alone. So- thanks Verell!! I hope someday I can try to repay the favor, or at least part of it!!
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

It's a fiddly job (I know), but you sure broke down in the right place!

Verell's the man

best of luck and have fun.

 

Thanks. You are correct- I could not have picked a better place for this to happen. We will be using your posts, R. Garven's posts, and Verell's posts and notes, and others to help us along. Verell is a very patient teacher- I'm in good hands.

John

 

Knew I'd be loneley/bored after the BBQ & prayed to Enzo for an interesting project & someone to work w/me on it(Heheh...).

Hadn't figured on timing drive bearings & a major service w/wp rebuild tho (LOL).

 

Sorry to hear about the problems but great photos and information for those of us about to embark on our first belt service.

 

Jwise,

Am sure Verell will do his usual super duper top notch job. Perhaps your car KNEW it was headed in the right direction and said to itself "Ok, it is now safe to let go."

 

ONE FORWARD, THREE BACK!
This project has indeed become challenging. One of the oil pickup tube studs has resisted all attempts at breaking it loose: Even double nutting with Loctite Red threadlock after a thorough degreesing didn't hold.

Also, the sump-cover-timing cover studs have proven extremely recalcitrant. Double-nutting is normally sufficient. With these, you can double nut until the threads are stripped! My cam action stud puller that normally pulls studs with the threads intact stripped the threads!

These studs just don't want to break loose, even after being heated red-hot & cooled a couple of times! Managed to get 2 out intact after resorting to a small pipe wrench! Another one broke off up at the surface of the timing cover flange. A third snapped off after MIG welding a nut onto the end(3rd time it was red hot!).

The last one is still pretty intact because we threw in the towel at that point.

In 35 years of working on cars of all flavors, I've never encountered studs as recalcitrant as these. Even ones stuck with Loctite thread lock yielded to 'hot wrenching'..

We're now pulling the engine so we can separate the sump/transmission case from the main block. This is the only way we can drill out the broken studs with reasonable confidence we'll get them out cleanly.

I've got a stand mounted radial arm drill press. We can turn the block upside down and swing the drilling head into position. With a cobalt drill bit, reasonable care, & a lot of luck, we should be able to take the stud out w/o tearing up the threads. At worst we'll have to drill oversize, & insert heli-coils.

That's it for this weekend. It looks like we should have the engine out next weekend.

 

Darn!
Sorry to hear of all the troubles. I was watching this thread all week to spot a follow up post, as I too was battling an oil leak and a bearing growl. I thought I'd "ride along" on this repair and learn from Verell's wisdom. Fortunately for me, I had my 308 on the lift today and the leak is a cam seal (rear bank / exhaust cam) and the growl is a water pump heading south. Both relative easy fixes.
Has anyone else had any difficulties with lower timing gear bearings and seals?
I'm going to be right there in the vacinity with T-belts removed, so I might still consider doing lower timing gear bearings and seals and a front crank seal if they are a common problem. Verell, whatdaya think buddy?? By the way it's an 84 QV with 32,000 miles. Anything else I should be addressing while I'm in there fighting the good fight against all that is greasy and evil? Also, how difficult is it to re-bearing a 308 water pump? It has a little bearing growl but is not leaking yet.

Thanks in advance for any input and good luck with those stubborn studs,

John

 

For stud removal, you might try heating the block locally and chilling the stud prior to trying to twist it out. I don't think it's a good idea to heat the studs red hot. That much heat probably negates any heat treating of the steel making it softer and weaker. Also heating the stud, without heating the aluminum, will tend to cause more of an interference fit. Conversely, heating the block and chilling the stud will relax the fit. I would think you could heat the block locally with a torch, at least to the boiling point of water and probably a little hotter, which you can test with a drop or two of water. An ice cube or dry ice held against the base of the stud, after heating the block, might be sufficient to chill the stud. The idea is to expand the aluminum and shrink the stud to hopefully break it free.

The numbers look like this:

Typical cast aluminum has coefficient of thermal expansion of about 12 E-6 in/in/F. Steel is about 8 E-6 in/in/F.

Assume: od of stud and id of hole = 0.25 inches. The aluminum will be heated to 270 F. The stud will be chilled (assume ice) to 35 F. The start temperature is 70 F.

The hole in the aluminum will expand

0.25*(12 E-6)*(270-70) = 0.0006 inches.


The stud will shrink (with ice)

0.25*(8 E-6)*(32-70) = -0.00008 inches. (not much help here)

The stud will shrink (with dry ice; -110 F a atmospheric pressure could probably get the stud to -40 F, don't want to get the stud too cold as it will get brittle)

0.25*(8 E-6)*(-40-70) = -0.0002 inches. (that's helpful)

So the total clearance gained by heating the block to 270 F and chilling the stud to -40 F is:

0.0006 + 0.0002 = 0.00062 inches. Not a lot but maybe enough to allow the stud to be broken free. Clearly, heating the block is the more important thing to do. But, heating the block will also heat the stud some also. So chilling the stud will help.

Hope this helps.

 

I know what you are saying about the theoretical thermal expansion coefficients etc. but I think in reality Verell's approach is probably the most realistic way to get this stud out. The large mass of aluminum will disipate the heat so efficiently that you probably won't get much of a local heat rise, plus it heats the stud by conduction. To get a local heat rise I think you would need such a large heat source that you risk causing big problems with the aluminum. By heating the stud the benefits are not expanding the stud because of course that just makes it tighter. It is the elongation along the length of the stud which does the job, it causes the products of corrosion at the interface to be separated by the high forces produced by the thermal expansion. When it cools it should help break free the corrosion bond. This is why when you have a seized nut and bolt, the heat should be applied to the bolt head and not the nut because the elongation of the bolt unseats the nut from the surface and brakes free the corrosion bond. It is also much easier to focus high heat onto the end of the stud. Just a shame it didn't work in this case. !!

 

Another snowball job!

I'm sure at the end of it you'll be glad it's all done....

BUT there is a simple/clever/affordable tool (Sykes Pickevant, UK) that can replace the cam drive OUTER bearings without the need for ANY stripping of sumps/covers etc. It just take an extra 2 or 3 hours on top of a belt change. I even do them on a "same day service" when the situation demands it.

Now, if the INNER bearing is shot, then it's not going to help, but even a new inner bearing is small enough to allow shaft float in the absence of the outer bearing, so unless the drive gear was completetly hanging out I'd bet the inner was/is ok......you could have been on your way in about 10 hours!!

The bearings fail for one or more of 3 main reasons...
1 drive gear nut loose
2 Belts overtightened previously
3 rust

when you fit the new bearings try to use SKF "C3" grade. Genuine Ferrari ones were when new, but most bearing shops only supply the std SKF grade. Std ones will be ok for several years, but C3's are better if you can get them.

The QV series engines had an upgrade to a larger drive bearing system from a certain number (mentioned in parts book).

 

Well, as already posted, the lump is coming out.

First thing Saturday was to pull the oil pick-up tube. Not to bad, just a little scraping of the aluminum with the flange of the tube (see highlighted photo of the three small studs which shows the scrapings on the side wall of the sump). Now that the tube is out, we will grind of a little of the flange so this won't happen again.

Next, we went to pulling the three studs. Two came out without much worry, but the third held tight. It's very cramped in the sump, so we tried many tools (open-end wrenches, ground thin sockets, different extensions, u-joints, etc.) but the last stud would not budge. Finally, we cleaned it well, and put some red loc-tite and two nuts on it and let it set overnight.

We moved onto the front case studs- see photo. A few came off like they should, but a couple were seemingly joined to the case. After double-nutting, we tried the stud-puller. It seemed to just strip the threads. Next, came the small pipe wrench- it worked on a couple of them, but would not fit on all of them. We decided that the final attempt was to re-thread a stud and see if welding on a nut would do the trick. No luck!! The first weld just split, and the second attemp sheared off the stud. Tools were being tossed all over the garage- it was time to back away and regroup. Aside from all that, it was pouring rain the entire time. No joy in Muddville.

After spending Saturday fighting every stud, and breaking two of them, we decided to call it a day and see if Sunday brings new found confidence.

Sunday arrived cool and sunny- perfect. Unfortunately, the removal of the loc-tite studs did not work. So, as I figured might happen- we decided to pull the engine and go from there. Once that decision was made- there were lots of tasks to do. So, me thinks a new thread will begin about a "308 QV Engine Removal"
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

Bill, theoreticly you're right about the coefficients of expansion. However, my experience matches peajays. The sump casting is ~1/2" thick, with even thicker bosses for the studs. Tremendous thermal conductivity. Unless you have access to either liquid nitrogen or possibly dry ice, you just can't chill the stud fast enough to create the necessary temp. differential between it & the Al sump casting.

Even the radial expansion will sometimes help by expanding the hole & crushing any corrosion products.

BTW, this car is exceptionally free of any signs of corrosion. Spent all of it's life in Dallas,Tx. Most of the gold irridited fittings are still bright gold. There's been no sign of rust or white Al oxide deposits on any of the studs we removed. It's more like they torqued very tightly into the housing.

We did consider just replacing the outer bearing & seal.
If the inner bearing had just been noisey with minimal off-center rotation, then that approach would have been reasonable.

However, The outer bearing wasn't just noisey, the drive pulley was moving off-center by more than the depth of the notches in the ring nuts(which make a good gauge). That means the shaft was seriously tilting the inner bearing's inner race off-axis.

My experience with an outer bearing failure with similar off-axis shaft motion was that the inner bearing had definite rough spots, & the outer bearing had totally destroyed itself & broken a couple of the balls.

Hence the decision to replace both outer & inner bearings.

The Sykes tool (pic below) is similar to the one described in this post:

http://www.ferrarichat.com/discus/messages/256120/7992.html

I've made tools like this in the past by grinding the heads of a pair of socket head cap screws into balls with two flat sides.

Ham308 made a functionally equivalent tool & posted a photo in this thread:
http://www.ferrarichat.com/forum/showthread.php?t=14913&page=2&pp=20&highlight=drive+bearing
Image Unavailable, Please Login

 

I agree, it's totally impossible to accuratley assess the condition of the inner brg. But when building an engine you can try the amount of slack the inner will allow and it really is quite a lot...much more than the nut notch guide!

I've now done probably 6 or 7 308's with major outer bearing failure, I've explained the pro's and con's and every owner has opted for the outer to be replaced only and see how it goes.

Not one has needed the inner done subsequently, and on several of these cars, I've now done the next belt changes, and no problems seem on the horizon.

I know it's a case of doing a thorough job etc....but now that you're pulling the engine you may as well change the main bearings, and big ends, oh and the valves and guides are a bit tired, and the rings have lost their tension and the bores are a bit glazed and the clutch is worn, the flywheel needs a skim and has loads of heat cracks, the plenum chamber would look great with new paint.....and on and on and on!!!!

If it were me, I'd have done the outers, enjoyed the summer with the car on the road and decided what to do long term in the winter!

 

Well, we'll find out the inner bearing's condition when we get things apart.

We'll also learn for ourselves & try to document how much off-axis excursion a new inner bearing will allow. We know we initially made the more conservative call.

Like the monday morning quarterbacks at the office, If we'd known that pulling the engine was a certainty, we might have made the initial call differently. However, we're clearly committed to a course of action at this point. So we'll just have a lot of fun doing the project. So far we're getting a lot of experience (which is what you get when things don't work out as planned).

LOL - Point taken... It's always easy to add on 'while you're in there'..

Well, no, JWise had his valves adjusted, along with compression & leakdown tested when his belts were replaced last winter.

 

This got me to thinking. Being an engineer, I went to the SKF web site to see how much axial missalignment they specify for these bearings.

The inner bearing is SKF #6201 is a single row deep groove ball bearing.

Here's what SKF states about axial misalignment:

"Misalignment

Single row deep groove ball bearings have only limited ability to accommodate misalignment. The permissible angular misalignment between inner and outer rings, which will not produce inadmissibly high additional stresses in the bearing, depends on

– the radial internal clearance of the bearing in operation,
– the bearing size,
– the internal design and
– the forces and moments acting on the bearing.

Because of the complex relationship between these factors, no generally applicable specific values can be given. Depending on the various influences of the factors, the permissible angular misalignment lies between 2 and 10 minutes of arc. Any misalignment will result in increased bearing noise and reduced bearing service life.
"

Taking the more liberal 10' value, and doing some rough calculations:

The timing drive shaft is about 4" long according to my (admittedly ageing )memory.

The max safe off-axis deviation is thus approx:

4" x Sin(10') = 4" x 0.0029 = 0.036"

I measured the ring nut notches. They are ~0.1" deep, and the shaft was vibrating noticably more than the depth of the notches.

So we observed the shaft exceeding the most generous spec for off-axis deviation by at least 3x, and probably more like 4x!

The car was driven after the bearing noise became very noticeable for over a mile at slow (20mph) speed to get to my place, and additionally for a few more minuites to maneuver it into the garage & onto the lift, and also while we were disgnosing it. Say a total of 10 minuites. Most likely the failure began many minuites before that, so there's a reasonable chance that the inner bearing was being operated significantly beyond it's maximum missalignment specs for something between 20 minuites to possibly an hour or more (JWise lives about 2.5 hours drive from my house).

None of this is conclusive, but this is the engineering equivalent of doing 150 or 200 in a 50mph zone for an extended amount of time. That isn't breaking the speed limit, it's blowing it away!

 

Verell,

Admire your attitude, wish I were around to help.
best
chris

 

Yeah, no worries. Enjoy your project...shame to miss all those track days/evening summer drives and days with girl/wife/family etc though. Never mind, there's always next year!

Didn't need the $5000 +? anyway. Would have probably spent it on fuel and tyres for the damned thing!

 

Ferrarifixer,
That last post was pure emotion, & didn't supply any further technical understanding.

You seem to be reacting as if I"m challenging your experience, or you personally. I'm not intenting to do so.

I've been trying to tell it like we thought it thru & be as technically objective as possible.

By the time we started posting, we were past the point of backing out as we had broken off studs. At that point, we couldn't have taken your advice of just changing the outer bearings.

I'm not doubting your empirical evidence of 6 long lasting outer bearing replacements, just trying to relate it to other technical information such as the mfg's engineering specs on the bearings. The mfg's specs were definitely sighificantly exceeded in this case.

When two sets of facts don't seem to match up, there's something that isn't properly understood somewhere.

Was the inner bearing actually damaged by it's specs being exceeded- no way to tell yet. Also possibly no way to be certain after we get everything apart unless there's obvious damage such as a chipped or rough race. Maybe the mfg's specs are ultra conservative, or aren't being interpreted correctly.

Now are you going to help us learn, or are you going to continue to try to make us feell bad because we didn't decide the way you would have, and aren't necessairily taking everything you've posted as being the last word on the subject?

You obviously have a lot of valuable experience as a professional technician, and I'm sure we would benefit from it.

 

Verell, (and jwise),

sorry to see it went a bit pear-shaped.

I've just got back from a week's touring in Ireland (beautiful country, but boy can it rain) and when I left, you were all set to fix it with the engine in the car. I see you got the dificult bit off, the oil pick-up tube, and it's a real shame to be beaten only by a couple of studs. You sure tried every trick in the book though.

What the hell, an engine in-out job must be fun as well

How's it going ??, keep us informed


best of luck
Richard

 

Huh !, don't bother to answer this, I just scrolled on down and found your new thread, "taking out a 308 engine" !

I'll be following with interest... keep 'em coming

 

We'll resume this thread shortly, with info on how we removed the recalcitrant studs. I just have to finish customizing my radial arm drill press so it will reach the studs while the engine's on a stand.

 

Well- we finally drilled out the studs and are prepared to split the transaxle from the block. ONE stud still remains from the oil pick-up tube in the sump.

The engine is fairly clean, at TDC 1-4 (we used a piston stop and degree wheel because the flywheel is sitting in a box right now- I can't believe how many marks there are on the engine to verify cam timing), and ready to remove the belts, cam covers (we are fixing a leaky cam seal) and start re-assembly.

The photos below show the engine up-side down getting a stud drilled out, the wheel gap these cars have when there is no engine-wow, and a post cleaning shot.

More later-
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

I have the same car and I would like to do a belt change myself. Lots of great info on this and other procedures. I'm a bit overwhelmed by the chance of serious setbacks as I'm not qualified for the worst case. Again thanks for posting the project.

Philip

 

3 fwd, 1 back...
Just a quick progress report. Saturday we separated the tranny/dif/sump from the engine. Took more than a little judicious prying as the sump-engine alignment pins, especially the one by the differential were really tight!

The timing cover came right off. As expected, the rear bank outer cam drive bearing had disentigrated. We had balls all over the place as soon as we pulled the drive gear off. The inner race was left on the drive shaft & really didn't want to come off. From the baked on grease we could tell that the bearing had really heated up! The seal was also partially melted!

The front bank outer bearing was very loose (spun freely, no feeling of lubricant resistance). Also I think I felt some very very slight roughnes. We both agreed that it was well on the way to failure.

RECOMMENDATION:
If your outer cam drive bearings have never been replaced, it'd be good pro-active maintenance to change them out at the next belt change. Otherwise you're risking catastrophic failure like this one. In fact, I'll go so far as to recommend changing the outer bearings every 30K miles or 10 years, whichever comes first. The inner bearings are running in crankcase oil, and are much less likely to fail as long as the outer bearings are replaced periodicly. I'd guess that the inner bearings are good for 100K miles or more as they're operating under much lighter load than the outer bearings & are constantly receiving fresh filtered oil.

When we removed the belt tensioners, one of them disentigrated also, bearings all over the floor again! My guess is that that tensioner was well on the way to failure!

REMOVED STUDS & HELICOILED HOLES:
Using an 6" angle plate & C-clamps I mounted the timing cover upside down on my drill press's X-Y table. Used a 3/16" ball nose carbide end mill to bore the broken studs out some more. Eventually the each stud loosened up & I was able to turn the shell of the stud out with a pair of needle nose pliars. A few minuites later the holes were drilled, tapped & helicoiled.

Meanwhile John pulled his cam covers & the Al ring cam seal housings. One of the front bank o-rings was pinched, which was probably the main oil leak. However, the cam seals were clearly worn & one even had rough spots on the dust lip & the seal lip felt slightly rough. The seal housings were given a good cleaning, all debris, etc. was scraped out of the o-ring grooves. The seal mounting surfaces were primed with Loctite type N primer, & the seal mounting area was given a thin coat of loctite 515 before the seals were pressed in. O-ring grooves received a few drops of oil & the o-rings were installed.

The timing cover cleaned up nicely with some citrus solvent followed by NAPA aluminium brightner. Looked like new!

All went well until we figured we had just enough time to
pull the inner bearings (2 minuites w/ a blind bearing puller), rebuild the timing cover, and maybe put the engine back together.

1 BACK:
Then we remembered the stuck inner race so John started working on it. Shortly thereafter we discovered we'd received the larger timing drive bearings & seals that the newer QVs & 328s use. At that point we were stuck until we got the right bearings & seals. Cleaned up & called it a day.

(John, BTW, I got that inner race off this afternoon. You'd pried it enough so that my 3-legged puller could grab it & pull it the rest of the way off.)

THERE's LIGHT AT THE END OF THE TUNNEL:
Goals for next weekend are:

Saturday - reinstall the timing cover, mate the sump/tranny/diff housing to the engine, install the cam belts.

Sunday - Transfer the engine back to the hoist, reinstall the spacer, flywheel, alternator, front manifold, etc. & drop the engine back into the car.