[snowrx]

I've not seen a mention of a better timing belt option for those older car owners that have not found a $et of round tooth HTD pullies. At the risk of starting another boisterous belt discussion I offer the following.

Noting that some of the older parts cross refs mention early Nissan's used a 133 tooth trapazoidal belt, I looked into the models that used that belt and noted the 300ZX was one. Quick search for "300ZX racing timing belt" and I found that Gates offered one-
"-Constructed of HNBR elastomeric composites Up to 3x the lifetime of standard grade or OE belts
-Superior construction provides up to three times the heat resistance
-Gripping teeth reinforced with aramid and nylon rubber minimize wear
-As much as 300% stronger than the standard aftermarket belt"

These belts are slightly narrower than the Lotus specific ones, but the better materials should more than offset the width difference. Tooth engagement seems good, and I've run a Goodyear Gatorback "Nissan" belt before with no problems on the 910.

The Part number is T104RB, online prices are all over the place, I think I paid $65 USD.

As far as setting the tension or service life you're on yer own, I'm not going there....

 

[sleekgt]

How many miles you have on that belt? The picture looks like when it was just installed.

My 88 used the first Gates blue belt for 40K miles; it was very black around 20K miles. Not sure what risk a skinny belt presents, but if it's working, that's all that matters in the short term.

RE: tension - my mechanic used a good old fashioned twist/deflection method (including the 15K mile retensioning). No Burroughs gauge, no harmonic device (initially they did, but the readings were all over the map). They did a fixed deflection and 40K miles later, I was still fine. He pulled the cam carriers off to fix the usual leaks - no excessive wear due to the tensioning. Same mechanic did the 2nd Gates blue belt - lasted 10K miles until the unfortunate totaling of the car in an accident.

So I got an aggregate of 50K miles under my Gate blue belt(s) with regular tensioning. Your mileage may vary.

 

[carbuff]

How many miles you have on that belt? The picture looks like when it was just installed.

I'm pretty sure it's installed but not run yet. @snowrx 's car isn't yet finished.

BTW the pictures show the part number pretty good!



IIRC, the Nissan belts are 1 mm less wide than Lotus OEM belts. (Gates has a Nissan black belt that others with newer round pulleys have used with success.)

PS, I wonder if @Artie was present to paint the lettering on the cam-wheels (as he did on his V8's Garrett turbos)? LOL


Kudos to snowrx for acting as the guinea pig.

 

[Jcslocum]

Lightiningmotorsports.com has that belt for $54 in stock. I ordered 1 as I will need a new one and the new I have is already 2 years old....

 

[snowrx]

Like carbuff said, Zero miles on that belt as I just got it. I put maybe a thousand on the last Goodyear Nissan-spec belt.

Cams are painted in case I ever have to do a belt with the engine actually in the car! And stamped with numbers because I have another set of pullies I don't want to mix up with these after the paint goes away.

 

[MRDANGERUS]

Picture in this information page shows belt with round teeth!

More Information for GATES T104RB

What is right?

 

[snowrx]

carbuff "I'm pretty sure it's installed but not run yet. @snowrx 's car isn't yet finished."

Well, it was finished in mid-April but after the shakedown run I was overcome with a sudden desire to throw in a new imported :UK: crank and light-weight rods.....

I dropped the lump into the engine bay today, tomorrow the multitudes of hoses, pipes and wires get their due attention from the creeper. I'm starting to get better at it, pulled it in 7 hours this time!


MR DANGEROUS- Most of the adds I saw for the belt used a stock photo of a round belt. RockAuto had a description on their site that included the tooth profile and count. As you can see in the photos, it's trapezoidal.

 

[snowrx]

Test results- I ran the car for a few miles (finally!), and idled it up to 90 C, then tested the belt with the Kricket. I got a reading of 80 as it sat without loading with the crank pulley, and the belt is whining just a bit. This from a room temperature reading of just over 50 with a new belt.

 

[Jcslocum]

Will you reduce the tension a bit to lose the whine from the belt???

 

[carbuff]

@snowrx, are you running the spring loaded tensioner or the eccentric tensioner?




Much of the controversy regards tensioning the Gates Racing Belts has to do with their difficulty to set tension, and the propensity to whine.

Some have noticed that reducing tension to eliminate whine results in belt flutter (visible on the top).

Acoustic Readings with the Gates belts are difficult to repeat.



My blue belt is quiet at start up, but whines very slightly but noticeably when the engine is warmed up. I figure that is definitely in the ballpark for the round-tooth belt and eccentric tensioner!

 

[tilt100]

Carbuff,

I'm curious if you have tried to recify your whine issue?

I have the same issue and would describe it almost the same as yourself. At start the engine sounds great (love that first few minutes of no whine) then when the coolant temp is around 40 to 50 the whine starts to get noticable and by normal operating temp its more noticable. I've also noticed that if I drive for at least 15 mins or so even if the coolant temp is the same the whine is louder again, guessing everything has had a chance to expand and there's more tension?

I live in Phoenix and during the winter I generally drive with the windows down and listen to the exhaust sound which is a lot more pleasant. However now its damn hot here and that's not as practical, lol. Honestly I'm just extremely irritated by the whine, completely spoils my enjoyment of the car and would love to get rid of it (the whine not the car, lol). I bought the car with the blue belt already on. I did have a Lotus mechanic look at it a while back but he was working on other jobs at the same time and I don't think he really took the time needed. He's now moved away so I'm trying to find someone to look at it although that's a challenge in itself.

I've read a lot of threads on this as its a topic that seems to come up frequently, and although there seems to be multiple opinions on appropriate tensions, I have seen a number of folk claim to have the blue belt and no whine so was wondering if you had tried to correct this yourself or is there's no hope. Seriously I'd go to the regular belt if it got rid of the whine.

Would be interested in hearing from anyone else on this also.

Thx

Jerry

 

[snowrx]

I'm running the original spring loaded tensioner. The spring piston bottoms out at about 55 on the Kricket gauge, so I started at just over 50 (cold @ TDC with tension on the crank pulley) so that the tensioner had some travel left. I assume the blue belt has less give to accommodate the block expansion, so I'm seeing higher tension when hot.

The belt returns to Kricket 50ish with a cold engine.

I might play with a bit less when the belt has run in a bit, but the whine is barely perceptible with the hatch open, so not an issue for me. Unless 80 hot is an issue I'll probably leave it alone.

Being a data set of one with this particular belt at the moment, the acoustic methods have little value to me. I assume the trapezoidal belt will have a different acoustic signature than the round tooth. If there's a set method and App, I could get some numbers for the group later if there's an interest.

 

[carbuff]

My blue belt didn't whine until I R&Rd my belt to rebuild my engine. At first it was BAD, but I soon retensioned it with the result I mentioned. It's hardly noticeable now except to me.

I would definitely re tension yours if it bothers you.

There is a video of a fluttering, quiet blue belt around somewhere. Perhaps @Lotus4s can provide a link.

 

[snowrx]

A couple tanks of gas gone and so far so good. No noise and tension holding steady.
I'd give a mileage, but the speedo has decided not to talk to the transmission any more. Seems as if the speedo cable has shrunk and won't engage both the adapter and speedo at the same time.

 

[carbuff]

Seems as if the speedo cable has shrunk and won't engage both the adapter and speedo at the same time.

The only way I've ever been able to connect BOTH ends is to fully seat the binnacle end first, THEN line up the square peg and hole in the transmission. :x

 

[Esprit2]

A different topic thread from Jan 2018 refers readers to this earlier thread. Reading here, I can't help but notice a lack of information about appropriate tension for Gates Racing's Blue belts, either HTD (JAE Special/ no Gates p/n) or Trapezoidal (Gates p/n T104RB). If you use the new Gates BLUE belts, either HTD (no p/n, JAE special) or Trapezoidal (T104RB), then all the old black belt Burroughs and Krikit KR-1 tension values you may have used in the past NO LONGER APPLY. There is no factory support for the Blue belts, not from Lotus or Gates; so strictly from grassroots user experience, the appropriate tensions seem to be:

Burroughs = Krikit KR-1 --- Gates Racing Blue, HTD & Trapezoidal
. . . . 83-85 = 34-35

One advantage of the Gates Racing blue belts is that they're very stable with regards to tension. Continue to check tension regularly as specified in the Service Interval Chart, but you'll rarely have to re-tension a blue belt while it's in service. As experience is gained with the blue belts, we may very well learn that they simply do not stretch significantly, and that the above NEW tension spec will also apply when re-tensioning used blue belts. That's what my own limited experience indicates.

The belt tension is least when the engine is cold, and increases significantly as the engine warms to full operating temperature. A belt that whines when the engine is hot is too tight. Never re-tension the timing belt while the engine is hot, since there are no established HOT tension values. That puts a little pressure on you to get it right the first time, since re-tensioning will have to wait while the engine cools down over-night.

The blue trapezoidal belt (Gates T104RB) is about twice the cost of the old-school black belt, but the extra cost is a worthwhile investment... money well spent. Most internet sellers have them priced sub-$70 ($65-69); but I've seen a few in the $50s, and one at $116 ! Pay attention to what you'e doing, and don't spend too much.

Regards,
Tim Engel

 

[sleekgt]

In the spirit of updating the thread - I did notice I didn't mention details of the 'twist method' I had on my late 88 Esprit with the Gates Blue belt from JAE.

1. New belt installed at 30K miles in Oct 2011
2. Tension initially measured with ultrasonic tester, but not consistent
3. Tension ultimately set with 'twist method' - 45 degree twist on middle of belt right side of engine
4. At 48K miles (18K on belt), tension was still the same 45 degree twist
5. At 70K miles (40K on belt; about 40 months - exceeded factory 36K/36 months by 10%) - new replacement belt - same mechanic, same tensioning
6. Valves clearances adjusted and tappets replaced at same time; inspection for excessive wear showed none on 70K mile engine (40K miles belt). This verified that 45 degree twist was not too tight).

Sadly, the car was totalled 10K miles/ 10 months later.


Under the 'do you feel lucky' department: There is the less expensive Gates Blue belt Tim mentions above T104RB that is for a Nissan 300ZX.

http://www.lotustalk.com/forums/f164/blue-trapezoidal-timing-belt-371954/#post5002618

 

[Esprit2]

2. Tension initially measured with ultrasonic tester, but not consistent

Eddie,
2. Tell me about the ultrasonic tester. I'm not aware of such a tester, but I'm always interested in new methods. If you're referring to the frequency method, then what frequency was used for the blue belt. Again, I'm not aware of there being a frequency established for the blue HTD belt, but I'd sure like to hear about it when one is.

Note: Other sources say Gates Blue belt is 1"/25.4mm wide - it is actually a touch smaller - see pic below where a 40K mile belt shows 0.94"/23.9mm width. You can see the JAE logo burnished by dirt on the belt.

Both Gates Racing Blue belts' widths are Spec'd at 1.0"/ 25.4mm, and everything manufactured has a tolerance on it.

In your photo of the belt being measured by a dial caliper, note that the belt is all the way up in the throat of the jaws, next to the body of the caliper. Most calipers's jaws (all that I've seen) are relieved up there... ie, cut back. Measuring there would give an incorrect, smaller reading. To get an accurate measurement, hold the belt down on that part of the jaws that make contact with one another when closed. There you will probably get a slightly larger width measurement.

Under the 'do you feel lucky' department: There is the less expensive Gates Blue belt Tim mentions above T104RB that is for a Nissan 300ZX. It's reportedly 1mm narrower than the Esprit factory belt (24.4mm?) so it's similar to the Esprit Gates Blue belt 23.9mm.

The T104RB is the trapezoidal tooth version of Gates Racing's blue belt. The JAE exclusive blue belt is the HTD round-tooth variety. Both blue belts' widths are Spec'd at 1.0" (25.4mm).

The Lotus-branded belts are 26.4mm (1.04") wide. The nearest industry standard size is 25.4mm (1.0").
That slightly narrower standard width accounts for the 1mm difference mentioned earlier. The common cross-ref belts, the T104 and T249 (not really an HTD), are the narrower standard width.

Note that the Nissan 3.0 liter V6 went through an evolution of timing belt configurations... something like 4 or 5. So if you're going to search RockAuto.com for a Nissan belt that fits your Lotus, it's critical that you know which model year Nissans used Lotus-compatible belts. Not all did. Especially for the HTD belt. Nissan used at least three different round-tooth belts, only one of which was the HTD belt.

Regards,
Tim Engel

 

[sleekgt]

Eddie,
2. Tell me about the ultrasonic tester. I'm not aware of such a tester, but I'm always interested in new methods. If you're referring to the frequency method, then what frequency was used for the blue belt. [snip]

In your photo of the belt being measured by a dial caliper, note that the belt is all the way up in the throat of the jaws, next to the body of the caliper. Most calipers's jaws (all that I've seen) are relieved up there... ie, cut back. [snip]
Regards,
Tim Engel

Ah, Tim! Can never sneak anything past you. Yes you are correct - I used my caliper incorrectly and failed to see the relief cut in the jaws. I can't find the belt right now, but the difference is about 1.5mm and would be 1"/25.4mm.

RE: ultrasonic - sorry - getting careless. I remember one of the mechanics called it an 'ultrasonic' device - it was a tan-colored electronic device that supposedly a Gates (or at least Gates-provided) product. But at the time, I didn't ask about frequency - I just knew they were going to tension it that way vs. the mechanical device. That was 2011 before the belt apps for smartphones that are common now.

The same mechanic in 2011 will be doing my 87 Gates blue belt starting next Friday. If his memory is still intact, I'll ask him more details about that 2011 belt change.

 

[snowrx]

My T104RB is still working fine, though I have not been able to put many miles on it between head gaskets.