MotoReva MT-112 Frequency Belt Tension Tool

Andy- Looks like a really good deal. Closest I have seen is the Gates 507C Sonic Tension Meter, and that is usually $600+. Most of the tensiometers have all kinds of fancy functions you do not really need when the workshop manual gives you a straight frequency value, so this one looks like it is really worthwhile.

FBB- You watching?

http://www.royalsupply.com/store/pc/GPT-507C-SONIC-TENSION-METER-1029p16539.htm

Taz
Terry Phillips

 

Andy- Those Staegers were not notably accurate, either. The frequency measuring tools are way more aprecise and repeatable.

Welcome to the Ferrari world. Sounds like you will be a valuable addition. We can use all the pro wrenches on the site we can get.

Taz
Terry Phillips

 

Andy- The earlier cars had their belt tension measurement specced by Staeger (deflection force) instead of frequency, but you might be able to beat the frequency number out of one of our pros if you promised not to publish it. For the 550, though, you can just use the 575M numbers, which are the same as the 612 numbers. The 575M workshop manual numbers were developed with the old belts and not the new belts introduced before any US spec cars were delivered. The 612 has an updated 575M engine. The 575M WSM also has frequency specs for the auxiliary belts powering the waterpump and accessories.

Taz
Terry Phillips

 

Terry, I just bought the Motoriva tool and will be doing my belts this summer on my 456.Just for comparison I have a NAPA precision cam tension gague,an old Kricket, a JTC micrometer tension gague,A Kent-Moore tension guage, Some of these are available on ebay cheaply. I sold my Steager when I sold my 944Turbo,and I dont miss it because it was over rated and difficult to use. I will publish compaisons this summer to see if the cheaper guages work as well.In some previous post the ultasonic frequency was noted for our V12s. Do you remember where it was or what it is. My belts that came with the car are almost new-the car had almost 0 miles since the change because they couldnt make it run( the problem was the main cable ,alternator to starter wore thru the insulation going around a frame member- not visible unless you explored the intergety of the insulation by pulling the cable away from the frame.This caued the battery to run down afer 20 minutes and a trip home on a flatbed), so I am only changing because of the years since the change not the milage. Will do bearings and brackets at the same time. Will be interesting to see what frequencies I get from the belts on the car, as its running perfectly, at the same time check the belt tensions with the cheaper meters to see which is most accurate and reproducable.

 

Andrew- That would be great. Here are the numbers from the 575M and 612 workshop manuals. I have not asked any of the pros which ones are actually correct for the new belts. When you do your belt change, you can change to the late 550/575M belt tensioner bracket (Ricambi sells the bracket and tensioner bearing/pulley as a set) and you should be good, in my opinion, for the same five years between belt changes as the 575M/612.

The bottom attachment is from the 612 WSM, which has the same belts as the 575M and is the same belt now used on the 456/M and 550. Seems to indicate the value should be 167-180 hz vs 126 hz. Will have to work on that one.

Taz
Terry Phillips
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funny TAZ. It says for timing belts sum of the 2 branchs in the 300hz range. Why don't they just day 150hz or so? freaking ferrari!


And I would go with the WSM on the 575 tension. There could be some minor geometry change that will change the required tension.

 

FBB- No changes in geometry between the 575M and 612. They use the same camshafts, belts, tensioner bodies, tensioner brackets, tensioner pulleys, timing and driven gears, etc. Exacty the same.

The big difference is the 575M WSM was written in 2001 before the change was made to the 5 year belts (187744), early in 575M production. The 612 WSM was obviously written after the new belts were introduced. Bradan just had a 575M with a belt that had jumped a tooth, and that makes me suspicious we are using the wrong tension on the 456/M, 550, and 575M. All those cars are being retrofitted with the new belts, which are the only ones now available.

Taz
Terry Phillips

 

Not so strange. The tension on the two sides could be different until the engine has been turned over a few times.

 

I guess I'm not that smart. In practice you would test each side so 350hz for two belts means shoot for 160hz per belt. What does it mean to you?

 

Taz,

What was the original 575 Hz tension?

 

FBB- See post 9, but 126 Hz.

http://www.ferrarichat.com/forum/showpost.php?p=140545982&postcount=9

Taz
Terry Phillips

 

Andy- I actually think it should be more like the 612 and 165-180 Hz, but not positive yet.

Taz
Terry Phillips

 

It says the sum of the branches on the individual bank. My interpretation is that you measure the two long sections for a single belt and sum them up. Then repeat on the other bank.

I didn't interpret it as sum of the two banks. That didn't make any sense to me because you could pull one to 320 and the other to 0 and you are good. That can't be right so it must be something else.

Then again, maybe I am very confused.

 

John- I think you are correct on using both lengths on one bank. The shorter length should have a considerably higher frequency, and that would match pretty well with the 575M Hz spec.

Taz
Terry Phillips

 

Very interesting, this is getting closer and closer to a "DIY"/

I have one question, Ive done a number of belt changes on the 944Turbo (with two two harmonic balancers), which was like dealing with an engine with 3 cams and all the sprockets had marks on them that made it easy to align, the question is: Do the 456 engine not have mark/reference marks on the cam sprockets (or camgears) and crankshaft to be able to time it properly?

Why are there some comments regarding worries on "timing" the cams during a belt change?

Thank you.

 

The marks on Ferraris cams and pulleys are assembly marks to prevent bending a valve during assembly. Search cambelt and belt change for two or three thousand hits on the subject. Dean Halter's thread on doing a major on his car is a good starting point.

Taz
Terry Phillips

 

Yes, I read through his post, but found no reference to the timing marks.

 

Has anybody used this for tension-ing something other than a Ducati?

Thanks!

 

I used it to set the tension on the "accessory" belt on my 360 Challenge race car.
Jes

 

Have a search in this subforum using "Motoreva". Moorfan and Dersark_Painclinic have both posted about using this tool to check &/or set the tension on their 550's