Does anyone know what year the 3x8 moved to a two belt design for the water pump/alt. thanks. Shashi
on 2Vs 1 belt was used for wp and alt, also on early QVs in 1983 change happened in 1984 for all QVs . Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
My Feb '84, #50431 has the 2 belt design. Not sure when the change was made, but that's a reference point.
My March '83 QV Euro is like the middle diagram - two belts, one for AC and the second for the alt and wp.
My October 83 QV US is a single belt for water pump and alternator. Is there a kit to convert it to the two belt solution?
Why would you want to? Mr Scott of the Star Ship, 1701, USS Enterprise: "The more complicated the plumbing, the easier it is to stop up the drain."
I am assuming it will be more reliable. I lost the belt when the alternator seized and it started overheating.
I have an early 85 with the 3 belts, I understand the reasoning for at least the 3 belts is the belts have a much lower mass and don't fly off as easily at high RPM's
Thanks for all the info. Midway thru my first belt change today. I also have an 83 Euro with the single belt.
Change to the extra belt was in late 84. Also uses a smaller WP pulley so the WP turns faster to help cooling.
Do you have a reference that states that this was one of the included goals (or measurements of the driven and driving WP pulley sizes for each system)? The driven WP pulley is definitely smaller for the 3-belt system, but, from reviewing photos and figures, it seems to me that they also reduced the size of the driving WP pulley on the 3-belt system so the ratio is about the same for either system (although many of the figures are fudged and not to scale -- for example, the size of the driving pulley for the alternator in that "308-4V late" figure is shown as being much smaller than the harmonic damper when in fact it is about the same size as the harmonic damper as shown in the photo of an actual 3-belt system below.) Here's a photo of a 2-belt system: Image Unavailable, Please Login And here's the 3-belt system: Image Unavailable, Please Login Note the much larger alternator driving pulley in the 3-belt system (but the alternator driven pulley looks larger too). As usual , what I'd like are some actual measurements of these pulley ODs so that we can know more (we can subtract off a few mm to guesstimate the pitch diamters from the ODs). So if you can measure and post any of: 2-belt system WP driven pulley OD = ? 2-belt system WP driving pulley OD = ? 2-belt system alternator driven pulley OD = ? 2-belt system alternator driving pulley OD = ? 3-belt system WP driven pulley OD = ? 3-belt system WP driving pulley OD = ? 3-belt system alternator driven pulley OD = ? 3-belt system alternator driving pulley OD = ? Please do so -- so that we can calculate/know these ratios.
That, among other things. Ferrari had problems with these one belt cars slinging them off. Enough did it that they issued a service bulletin in Dec 1983 to address this unusual problem. It consisted of a kit that changed it to 2 belts. My 308 was a problem car. I threw 3 belts over a span of about 7 years. Through a heroic search by Brian at Rutlands back in 04 we sourced a kit and I converted mine. It has never happened again. Problem solved. Personally I think this one belt thing is part of the problem with premature failing water pumps but that is just my opinion and one I will happen to be keeping. I think people tend to put way too much tension on them with a single belt.
Do you have a copy of this SB to post? +1 -- The 2-belt (single belt for WP + alt) system was well-designed for the carb 308 (very light weight and simple -- just enough to do the job). When they added the much higher electrical loads of the CIS models, it didn't work so well.
I do. Give me a little while and I'll get it up here. I found a whole three ring binder of SB that I actually forgot I had last week as well. Anything else you need? I may have it.
They aren't always givers of a lot of technical information (nor confessors of their sins ) in these SBs -- so please post the pulley OD measurements of any parts that you have (if the SB is lacking in this regard).
Without looking at it I can almost assure you it gives no technical info. From memory, it only recommends a solution for any car that tends to have this particular problem in the form of a kit number. I'll dig it up when I head over there in a little while ( I keep my car, books and tools at a different house)
The only reference I have is my factory trained Ferrari mechanic who asked if I had any over heating problem once when I bought the car in. I asked why and he commented about the change over kit. When he checked the car and saw it was an 85 he just said that my car already had the new setup. perhaps his comment was also in reference to the change in WP pulley size and he did not check the crank pulley. All I know is I never threw a belt and never had over heating problem in 28 seasons of driving. Everything is original, including cooling hoses.
That's interesting because the kit had nothing to do with treating the overheating problems. It was just to deal with the shearing off of belts here and there by some cars. BTW, I swapped to two belts with the factory kit 8 years ago and never saw a change at all with the temps. Not even a little bit. The 85 two belt models had cooling issues as well, more or less, depending on the climate and driving habits. It wasn't until the 328 that the problem was finally sunsetted in the 3X8 series.
I'm not sure the one belt belt setup went too far into 1984 - my February '84 car has the two belt arrangement. I know your knowledge of 308s far exceeds mine though and there a couple of alternatives: 1. I could be wrong about the belt setup. I'm going to try and double check this tomorrow. 2. Maybe mine was also converted - is there any way to tell a conversion from factory two belt setup? Edit - just saw your post with the service bulletin which clearly states that the two belt design started later than my car. Guess its one of the above after all.
Yes, thanks -- but, as you predicted, it said nothing Please post your pulley sizes (new and old if you've still got them) sometime when convenient.
OKAY here's what I got from the parts on hand a couple motors in current build. 2-belt system WP pulley OD = 85mm 7mm pitch 2-belt system WP crank pulley OD = 110mm 7mm pitch 2-belt system alternator pulley OD = 59mm 7mm pitch 2-belt system alternator crank pulley OD = 110mm 7mm pitch 3-belt system WP pulley OD = 102mm 7mm pitch 3-belt system WP crank pulley OD = 90mm 7mm pitch 3-belt system alternator pulley OD = 59mm 7mm pitch 3-belt system (alt or AC not sure) crank pulley OD = 130mm 10mm pitch, This is from a euro QV damper. the other two pulley grooves are 90mm OD. On the Alternator though there are 3 different pullies that I'm aware of, 117938 QV 1985/84 don't have on hand ? 118803 single -- 59mm OD 7mm belt 123708 dual belt -- 59mm OD 7mm belt and then there are the variants between the AC compressors, euro & US.
