308 belts

i did it myself and it was pretty easy. pop rear passenger wheel off, pull out the fender liner, and the side of the engine is exposed. from there one of the belt covers is staring right at you and its just a matter of removing some bolts and screws. some were a little tight and hard to get to, but nothing complicated involved. it was all pretty obvious and straight forward.

 

Ross is correct. The rear bank timing belt cover is easy to get to and comes off easily. It's the front cover that is the problem. For that one, you need to move the AC compressor as well as the radiator pipe that runs down that side, the alternator belt and the AC bracket, which is a bit more of a PITA. But none of it is complicated, just a little time consuming. Then you can examine the belts and the tensioners. Just be careful not to loosen the belt tensioners without having the cams locked in place and the timing belts marked to the cams and lower drive. Otherwise, the instant you loosen the tensioner, the cams are going to move on you, you won't be able to realign them with the belt, and then things get really, really interesting.

Best advice -- if you don't know what you are doing, don't do it. Pay the guy who did your PPI to take a look at the belts. Or better yet, if you were going to be doing the belts this year anyway, just take it in and have them done. If you want to learn how to do it, find someone who knows how, offer lots of cold beer, and get them to help you.

 

The hard part is the belt for the front bank. The A/C compressor is in the way. If your A/C is working you don't want to open up that system. If you A/C not working it is pretty easy. I once removed the gas tank and then put the compressor where the gas tank was. If you want to worry about the belts then you should also worry about the tensioner bearings. If all you are doing is belts and tensioners then once you have the covers off to look at the belts you may as well replace the belts and bearings because there isn't much additional effort required at that point.

 

????? You can see the back of the rear bank belts just looking in, the front one should be same condition as they are always replaced in sets.......


You can even reach in and fell the tension on it.....

But you are right to change them in 3 - 5 year intervals regardless of mileage, IMO......

 

This question comes up very often, too often really. And, I feel, too many non mechanics try to give their "opinion", and it just simply confuses the issue beyond all reason. But there are some real facts that everyone, no matter where they want to stand on the issue should keep in mind.

Fact #1. The 308 and the TR use a a very early type of belt, a trapezoidal tooth design that dates back to the early 1960's. They were never designed to last as long, or to be as strong as the more modern curvilinear design that came along in the mid 1970's that Honda and Toyota used. The main benefit is that they track more accurately, but they are only half as strong as a comparable size curvilinear belt.

Fact #2. Ferrari (and Fiat/Lancia as well) recommended a replacement interval of 3 years or 60K Km. Beginning in the late 1970's the US EPA began requiring ALL cars sold in the USA to carry a 5 year 50K mile emissions warrantee, superceding all manufactures recommended service intervals.

Fact #3. The timing belt was considered part of the emissions system as it controls valve timing. Whether the belt could withstand being in service that long was beside the point. Why Ferrari waited until the mid 80's to change is unknown.

Fact #4. With the USA recieving cars with timing belt change intervals to 5 years or 50K miles, owners worldwide damanded the same coverage.

Fact #5. Once the emissions warrantee disappeared, Ferrari issued a service bulletin that ALL belt driven cars should be serviced on a 3 year 30K mile cycle.

Fact #6. We cannot see inside the belt visually, and this is primarily where the belt is going to fail.

Fact #7. If the timing belt breaks or strips teeth in any Ferrari, it WILL damage the engine. It WILL cost an extreme amount of money. Figure on average; $10K plus for a 308; $20K plus for a 348; $25K plus for a 355; and you really dont wanna know how much for a TR. I have heard costs to nearly $50K if its bad enough.

 

I just did mine two months ago, the belt and bearing that was in my car was 7 years old and it looks really good,
the bearing feels tight, but since I had to change my coolant, have my alternator rebuilt, and convert my
AC to 134A then I might as well change the T-belt and bearing too, it's about that time anyway. I just had to make
my own locking tool for the cam pulley temporarily until I can have my friend make one out of aluminum.

Pics shows the home made tools and shows the new belts and bearing installed.
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

I think Paul's post is one of the best summaries I have ever seen. However, regarding #6 a consultant once remarked to me that the belt almost never fails. It is usually a related, neglected component that causes an unfortunate situation that takes the belt with it.

Seamus

 

Forgive a stupid question, Mike, but in the middle picture, that tensioner is actually bad, right? Or is it distorted off center for some other reason?

 

It's the old bearing but not bad, and yes, it's off center because the tension is contracted and locked so I can remove the belt.
Them the bearing came after.

 

You can look at the belts and tell if they are bad. Fraying, chunks missing, teeth missing.
But you cannot look at a belt and tell if it is good. If the cords inside are broken the belt is bad, but looking at it won't tell you that. There's nothing wrong with looking, but if everything looks good it will be inconclusive at best. That's one of the reasons for paranoia here. You can't know.

 

I do agree with most of the above. My '84 qv owners manual gives a 90.000 km interval for belt replacement.
however doing the job moreoften provide the oppertunity to inspect all relevant parts more often. I support the suggestion that a true beltbreakage hardly ever will occure and i do think it's true that mostly one other part of the chain will fail.

So if you replace the belts make sure you do the inspection also!! Make use of the situation, not just getting the belts replaced and that's it, but inspect all parts involved when you're at it!

See for example the attached picture. This tensioner (of a 8V mondial) shows a dramatic crack. Breakage of it would certainly have let to trouble of the distribution and when you take it all apart after that happens, who is going to tell you what started it all..... The belt will be the most obvious to blame.

In this case the planned beltreplacement made this serious crack visible, maybe just in time...


So use your head, considder the huge cost involved if any malfunctioning happens and the relative small coast for replacement. Replace at an interval you feel comfortable to but don't let anyone tel you that "these cars are extremely sensitive for distributionbelt breakage and you MUST replace them every 10.000 mls" that's just a lot of B.....T!

(all of the above is my own personal feeling and experience but not to be used or seen as professional advise )
Image Unavailable, Please Login

 

What causes the crack?
Maybe an over torque of the lock nut?

 

it's not my car, i don't know.

but the point is to look ahead the belt and check all relevant parts while your at it.
This was just used as example

 

+1!! Thought I'd drop in from the F355 section. When I owned my 308 GTBi/308 GTB QV/328 GTB I would also always replace the spring in the tensioning unit as well as the belts and tensioner bearing. BTW, use Hill Engineering bearings and be extremely watchful for counterfeit bearings, as the market is currently being flooded with them. Before replacing I would apply Redline assembly lube to the spring to prevent binding. I'm rather amazed that this is not more widely done, as SOP. At the time, I spoke to other 3X8 owners who had as much as 50K miles on cars and as old as 1976 MY, and NONE of them had ever replaced these tensioning springs. Just my two-cents.

P.S. Be glad you can perform a major without dropping your engines!!!

 

I have been working on the cars for over thirty years and have never replaced those springs. They dont wear out.

 

Brian, I won't pretend to have anywhere near you level of experience, however here is my point. The tensioner springs are exposed to mechanical stress, heat-cold cycles, etc. The springs are required for the bearings to maintain a constant pressure on the belts. I am not an ME, but I would bet that a 25-30 year old spring would not have the same ability as a new spring to: supply the factory-specified degree of tension, possess the same degree of fracture resistance due to heat/cold-cycle embrittlement, etc... In reality, what I am trying to say is the springs cost about $7.00 each, IMO that's cheap insurance to bring the most critical area (the timing belt scheme) back into original factory specs. Just my opinion, but WTF do I know.

 

The springs do not maintain tension on the belts. The tensioner is locked in place by a bolt. That is what maintains tension. The spring is only used to perform the initial tensioning and is stronger than needed. Once tension is set the spring is just a hitchiker. Also if you allow the spring to tension the belt unrestrained while turning the motor over by hand it will in fact tighten the belt tighter than it should be. That spring is capable of making the belt tighter than a guitar string. No need to replace them.

550 tensioner is the same design. I was doing one the other day and using an ultrasonic tension gauge to measure it. I allowed the spring to tension the belt alone and measured it. It was at about 220 or 230 hertz. The spec on 550 is 125.

 

Thank you, Brian. Point taken. BTW, I know that the system is subsequently locked by the bolt. I used to do all my belts. If I was unclear in my post I apologize. I have a tendency to be too anal sometimes and maybe replace things that don't need to be.

Questions: In the scenario you described, the over-tightening (220-230 Hz) occurs only if the engine is turned over by hand at, e.g., the harmonic balancer, correct? If so, do you recommend not turning the engine over by hand at all when installing the belts when under tension? Also what is the tension of the belt (in Hz) when initially installed, tensioned, then locked?

 

i agree. i just hop in the trunk and lean over the engine and look in with a good bright flashlight if i need to see in there for any reason. no need to take all that stuff off to look.

 

the back of my cover is closed by the straight plate.

i notices this on one earlier post as well. My 328 does not have this backplating and i looked at google pictures but most of the 3x8 seems not to have it.

Can anyone tell me why some cars have a closed distribution and with others it's open.

 

Yes.

No. I am just saying that doing it that way even with old springs installed can result in a very tight belt. On the 308/328 series of car I usually tension them that way initially but back the adjustment off a little because it really does over tighten them if you rotate the motor over and over and lock the pulley down at the point it is the tightest.

To the best of my knowledge no spec was ever developed for 308/328 belts using ultrasonic testers. I just go by feel.

The quality of the belts is better than it ever has been so I feel pretty comfortable running them pretty tight in my own car but I am very aware of unusual noises in the event I develop a bearing noise in either lower drive bearings or tensioner bearings. I work the motor hard and it gets used at track events. In a spin belts have been known to slip when you suddenly spin the motor backward so I feel better with pretty tight belts.

In customer cars I cannot count on them noticing the early stages of bearing noises so the belts are installed at a more conventional tension.

 

In the 4v days in an effort to better protect the belts from debris the factory started installing thse shields. Many shops and mechanics complained because it made service jobs harder and it was no longer possible to get a really good look at the belts. The second reason was not that good of a reason but it did give many a sense of security being able to look at them. The factory responded to the complaints and left the shields off for a while but in a very short period of time many complained because the other camp thought the factory idea was a good one and on went the shields. Some of this was US only so I do not know what happened in other countries. All I can say is all US 328 and almost all 308QV should have them.

Many were taken off at service time and never reinstalled because so many mechanics thought they were a PIA.