| Author | Message | ||
| Robert W. Garven Jr. (Robertgarven)
Junior Member Username: Robertgarven Post Number: 64 Registered: 2-2002 |
Verell and all, I actually have all original steel pulleys. I am not sure swapping them would be possible for me now. I am not sure wether you guys no how hard it is to get to this on a gt4. I think it has better engine access than a regular 308, but every stud has to be removed to take off the smog pumps, water pump, cam covers etc. I think the later cars all had bolts. I am getting faster now that I have done this several times but still it takes me 3 full days just to carefully remove both cam belt covers, ac, smog stuff, alternator etc. I am a expert at the double nut thing now....... I really try to take my time examine everything and replace all the nuts, washers etc... I am averaging 1 stripped stud hole each time, replacing it with a time-sert. Rob | ||
| Verell Boaen (Verell)
Junior Member Username: Verell Post Number: 232 Registered: 5-2001 |
Robert, Based on the details you supply, my bet is you've got the plastic cam pulleys & one/both of them have an inner or outer edge that is changing diameter at as the pulley warms up & returns the belt to it's normal position. I'll bet the belt stays in position if you immediately restart the engine a couple of minuites after shutting it down. ie: while everything is warm. If you want to test this hypothesis: 1)Quick Test:Try pre-heating the pulleys with a hot air gun with the engine off. Then, see if the belt stays in the 'normal' position when you start the engine. 2)A definitive test you won't like: Swap cam pulleys between the front & rear banks. I concurr w/Ed, it's benign so just live with it, why it's doing it is academic at this point. I haven't checked further into the oil drip. Maybe some evening this week. Guess I'm wishing it'll go away... I'll probably end up degreasing everything, put some UV dye in the oil & watch what develops with a black light. Or, maybe I'll just make a little funnel from heavy duty aluminum foil & attach it to the dipstick tube with a hose clamp. That should route the oil as a film down the dipstick tube & keep it out of the alternator. Then do the UV light thing after the car's off the road for the winter. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1650 Registered: 2-2001 |
I doubt that it will give you a problem. If the belt was supposed to stay in the middle all the time then why would there be guides? One of the problems is that the belt is not wide enough to fill the width of the pulleys and any movement is noticeable. It is the same with the puppeys I developed also. My pulleys are the same width as factory and the belts are too and there is some walking on mine but the difference is that I have guides all around plus the round tooth belt made of a superior compound. | ||
| Robert W. Garven Jr. (Robertgarven)
Junior Member Username: Robertgarven Post Number: 62 Registered: 2-2002 |
Edward, Verell et al, Thanks for the advice. The pulley actually stays in the right position until it is started again, then it must move the 3/8" over near the inside edge, untill it get spinning or warms up. I looked seriouly at the tensioner assembly and it looked fine. Remember before I took the belt off everything worked except the failed drive bearing. I am wondering could one of the camshaft be slightly not straight causing this? The only thing I did not do (sorry Steve M.) is switch the tensioner assemblies. The labor on my car to do this made my shy away from that, that is why I replaced the tensioner bearing thinking that would help, plus i thought wrongly that the discovery of the not straight drive gear was the culprit. I guess I will replace the whole assembly next. Verell, I was thinking about your oil leak, after removing all the front bank stuff 3 times this year I noticed that a little oil (which I think is normal might be leaking from your AC compressor shaft or just by mounting and unomunting. I found several drip near the alt. and it was from this. Edward, since the belt is in the same position 98% of the time do you think that the wear of it moving would be enough for me to be concerned? Rob | ||
| Verell Boaen (Verell)
Junior Member Username: Verell Post Number: 222 Registered: 5-2001 |
Ed, Note that when running Rob's belt moves into the 'normal' outside position & stays there. Given this, It seems reasonable to leave well enough alone. IMHO it's academic what position the belt ends up in when the engine isn't running. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1637 Registered: 2-2001 |
Having studied and replaced timing belts since 1966, I believe the reason for the belt walking is the idler bearing bracket not being exactly square with the plane of the belt and I believe that it could be shimmed to run more in line. On most cars the belt fits exactly within the guides and since there is no tolerance to walk around you would not notice the movement. A Honda does not even use guides on the Camshaft but simply inner and outer guides on the crankshaft and with Hondas precise machineing I have never seen a Honda belt deviate on the cam pulley more than a MM or two. The Mazda 929 has a hydraulic tensioner that the pivot will wear out at around 250,000 miles and cause the timing belt to wear on the edges due to misalignment and the Isusu Trooper/ Honda Passport has a hydraulic tensioner that will leak the oil out and loose tension on the belt and cause a knocking sound that sounds like a connecting rod. Isusu is the only car manufacturer other than Ferrari that I have delt with that made a car that the engines had to be removed to replace a timing belt and they discontinued them as sales plummeted as soon as the public found out about the high repair costs on a supposedly inexpensive car. | ||
| Verell Boaen (Verell)
Junior Member Username: Verell Post Number: 221 Registered: 5-2001 |
Rob, Glad to see you've surfaced. I'd begun to wonder if you'd done something rash in despair. IMHO you're doing the right thing. Just drive it keep an eye on things. I suspect you're right, something is changing dimensionally as the engine warms up. What's really puzzling is how the belt ends up back in the 'abnormal' position when the engine is shut down. I'd expect it to take a position under rotation & stay there when the engine is stopped. (A Charlie Brown character had a sequence of phrases in response to such questions. I'd love to have them for future use. Anyone remember them?) I know what you mean all too well. It's really frustrating when you work your butt off to do something absolutely right & Murphy strikes w/something incomprehensable... I just discovered a drop of oil hanging from the underside of the mounting boss for the forward cam dust cover stud. Also the motor mount under it is damp w/oil. I'm absodamlutely positive I did everything right when I put everything together this time(sigh). I've put about 400 miles or so on the car since everything went back together. I noticed some oil dampness on the motor mount after about 200 miles, but there was no sign higher up on the engine/heads. I assumed it was either from oil trapped in the void inside the mount's mounting flange, or else one of the mount mounting studs was leaking... It's still a very tiny leak compared to what I had previously. If it weren't likely to get into the alternator, I'd ignore it on almost any other car. I'll take a better look at it tomorrow. Either one of the cam seals is leaking, or else something on the valve cover is. I don't see how it could be the valve cover tho, unless it's working its way out thru one of the cover studs. Since I'm not inclined to take the car off of the road until this fall, I'm going to figure out how to rig something up under the boss to catch the drip & direct it's draineage thru a tube down till it's safely past the alternator. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1633 Registered: 2-2001 |
No, due to the low demand and cost there was not enough interest to justify the effort. I do not know exactly what the difference is between the two and four valve engine pulleys and there is a chance the 2 valve pulleys would work. If I had a drive and cam pulley I could take some measurements and see. It takes sales of ten sets of pulleys to cover the cost to develop and produce the pulleys. I made eleven sets and sold ten. | ||
| DAVE SHEARS (Daveshears)
New member Username: Daveshears Post Number: 29 Registered: 3-2001 |
Edward did you ever make one for the 84 QV. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1624 Registered: 2-2001 |
I designed and have them made and sell them. I have one set left and they fit 2 valve injected 308s. Contact me personally if interested. | ||
| Bill Steele (Glassman)
Junior Member Username: Glassman Post Number: 58 Registered: 4-2002 |
Edward, Those pulley's are the cats pajamas. How and where, did you get them made? | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1622 Registered: 2-2001 |
Here is what I am talking about.   | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1621 Registered: 2-2001 |
This is exactly why when I designed the new timing belt system for my car that I added the additional outer guides to all pulleys. The Ferrari engine is not the most accurately finished product I have seen and since I already had witnessed the same behaviour that you witnessed I decided that the added security of additional guides was a safe insurance policy. It seems that Ferrari scrimped on the most critical area of their engines and why I saw fit to address the issues with a revised system. I now have a belt system that I trust for at least 100,000 miles. | ||
| Robert W. Garven Jr. (Robertgarven)
Junior Member Username: Robertgarven Post Number: 59 Registered: 2-2002 |
Robs Timing Gear Saga Finale? Well friends and fellow listers. I have not posted recently as I have been in the garage working on the Ferrari and am not sure what I have accomplished, if anything. If you remember I had a rear outer timing gear drive bearing fail. I replaced all the bearings (inner and outer) and thought I had done a great job. While adjusting the carbs I noticed that the rear belt was riding near the edge of engine side of the pulleys. Thinking I had made some error, I disassembled the whole thing again and found nothing amiss, except the rear timing gear was 7/1000� off (as checked on a lathe with a dial caliper) so I replaced it. I then re-assembled everything again with new bearings, belts and tensioner bearings. I was very confused to find that upon starting the rear belt was in the original (what I considered not normal) inside position! As I watched it slowly moved over to what I assume is correct position and stayed there. I was even more perplexed to find out that in the last 3 times I have driven the car, on immediate start up the belt starts at the inside position and moves to the outside position after the car gets warmed up and seems to stay there with no walking about. The inside belt seems to just ride in the outer position constantly. I have no idea if anything is wrong or the belt is moving in relation to heat expansion etc.? I have sat for hours and tried to diagnose what could be causing this. I have used 3 new belts and check all the components of the tensioner assemblies. The car starts quickly and runs great. I have become intimately familiar with every part of the system and cannot imagine what could be wrong (if anything). I imagine most mechanics replace the belts, give the car to their customer and no one looks at them until next repair. On the later cars with the inside cover plates I imagine once replaced you cannot even tell where the belts are riding. However they leave a rubber mark on the gold tensioner and a burnished area on the pulleys where they mark where they have been riding over time. My car had the marks originally about 3/8� from the engine side on the tensioner bearing and the belt seem to ride near the outside of the drive pulley bearing and pretty much near the outer edge (almost but not rubbing) of the rear exhaust pulley. I examine my engine every time I drive so I am not so much concerned about the belt breaking or fraying as much as what is causing this seemingly strange behavior. After 6 months of this I am just going to drive it and see what happens.. Unless any of you have any other ideas. I really love this car but I have lost allot of sleep on what I see as some kind of Sherlock Holmes mystery or maybe my own neurosis? I also had to cancel my Monterey vacation as the cost of all the parts was about what I had planned for the trip. Any comments would be appreciated. Rob |