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Cal H
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Yeah, a little twisted...
;-)
You're just fortunate that it happened to the other guy, before the sale.

Later,
Tim
I feel sort feel bad for Noyes as the belt broke due to no fault of him, he seems like he is a real good guy. He came by my place the other day and as he promised he dropped off a bunch of spare parts and an extra exhaust manifold from a low mileage S4 to replace the cracked one off the SE.

I tried to buy the S4 engine and tranny but he says it is a spare setup for his S4. Until the other day he never mentioned that he had a spare Esprit to go with the spare engine LOL. Did you know he had an white S4 in auto storage? He asked where I getting parts and machine work as he was quoted something real expensive. I told him about Aaron's if he doesn't mind driving to the middle of the corn fields. So I think I will try to assist him in getting his S4 running cause he seems like an honorable good guy rather than the hit and run thanks for the money type of guy. So if you see a white S4 in our neighborhood this year its his.

Now it is making more sense. He dumped the SE to spend time with the easier to get running S4 and the reason he did not drop the S4 engine or the head into SE is because it was his spare set up for the S4. Only reason he gave me the exhaust manifold is because I asked "hey this one is cracked can I have that one on the engine? Who would have thought he would have said "okay you can have it".
 

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I've also been seeing a lot of 9XX tappets with the top wear surface breaking up (spalling... see attached photo). Chunks missing. It looks like an old concrete garage floor with areas of smooth surface material missing.

I don't know if that's a function of reduced ZDDP levels in modern oils, or if the tappets just have a limited life expectancy; but I'm now pretty quick to recommend buying replacement sets instead of replacing just the cracked ones... despite the cost. I'm getting a little paranoid about old tappets.
Snip
Regards,
Tim Engel
Tim,
Any data on the miles on the tappet failures? Would be interesting to know and correlate that with oil used, clearances etc as a tight valve would in effect hinder the rotation process.
Colin
 

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(Snip)... I contacted Gates and they do not recommend any belt as a replacement for the B912E6697F or A912E6697F in spite of the fact that they are an OEM supplier.
I've just proven that I have no life. On the Gates website, there's a search page that lists all the T___ part numbers. Click on one and a second page comes up giving basic specs for the belt, like number of teeth, pitch, rubber used, and tooth profile used. I just leafed through the entire darned list, and there is no generic Gates belt listed that matches the Lotus B-prefix belt with 133 teeth, Curvilinear tooth (HTD1), and either HSN (B-prefix) or HNBR (newer/ modern). We know they make such an animal for Lotus, but it's not on their published list for public sale.

If there's a generic version of the Lotus B-prefix belt on the streets (HSN, Curvilinear HTD1), we won't be getting it from a Gates distributor.

The Gates T188 fits, but it's old-school HCR rubber. The JAE/ Gates blue belt also fits properly, but it's the improved HNBR rubber, limited production, and hence more expensive. There is no 'Gates' HSN clone of the Lotus B-prefix belt on the street.

Now, other brands...? That's a possibility, but I don't have any part numbers. Anybody... ? All the street cross-ref HSN HTD belts are for other rubber companies' versions of the Gates T249. And like the Gates, they're all Modified Curvilinear (HTD2), and not a good fit on the Lotus sprockets.

Gates ....... T249,
Dayco ....... 95249,
Goodyear ... 40249

People use the 249, but I suggest using the correct Lotus branded belt, or the JAE/ Gates blue belt. They fit.

The Nipparts J1121030 belt was referred to me, but I've not confirmed it.

The Nissan VG30E SOHC 3.0 liter V6 engine as used in the Maxima, Pathfinder, D21 pickup truck, 200SX, 300ZX, and Infinity QX4. The Nissan V40 engine was a modified version of the VG30E used in the Nissan Quest/ Mercury Villager mini-van (Ford insisted upon a clearance engine). Both the VG30E and V40 used a 133 tooth timing belt... some of which also fit on Lotus 9XX engines.

However, like the Lotus engines, the Nissan went through an evolution of timing belts, starting with a trapezoidal tooth belt used up through 1985. That belt will fit earlier Lotus engines with the trapezoidal belt.

After 1985, the Nissan belt progressed through several different round-tooth versions. Exactly which round tooth Nissan belt matches the Lotus Curvilinear HTD1 isn't crystal clear to me.

Here are the Nissan round-tooth belts:

*Pre–July 1993 = SHALLOW Groove.
*Jul 93-Aug 94 = DEEP Groove.
*Aug 94 Onward = HTD

That last belt, the HTD, could be of interest to Lotus owners. But I'm not certain if it's the Curvilinear HTD1 we want, or the Modified Curvilinear HTD2 that would be just another T249 clone. Both the tooth profile and the rubber used need to be confirmed.

Regards,
Tim Engel
 

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Tim,
Any data on the miles on the tappet failures? Would be interesting to know and correlate that with oil used, clearances etc as a tight valve would in effect hinder the rotation process.
Colin
No, not really. When I first noticed cracked tappets showing up, I didn't realize I was looking at the start of what might be a trend, so I didn't really keep records on them all.

The X180R would have been at 21-22,000 miles. Not high mileage at all, but it's first owner rode it pretty hard. That's the one with 12 of 16 cracked, so we changed them all.

Then there was an '88 with a lot of cracked tappets (half?), and the one that split in two in my hand. That was around 59,000 not-very-hard miles.

There's an '89 SE that had more than half the tappets cracked or questionable enough to replace. I don't have a record of the mileage, but I think the owner has... I'll ask.

Other than that, I doubt that I'll be able to dredge up much in the way of mileage history.

Regards,
Tim Engel
 

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[snip] When I first noticed cracked tappets showing up, I didn't realize I was looking at the start of what might be a trend, so I didn't really keep records on them all.[snip]
Then there was an '88 with a lot of cracked tappets (half?), and the one that split in two in my hand. That was around 59,000 not-very-hard miles.
[snip]
Regards,
Tim Engel
I know many have thanked you in the past, but I again want to thank you for this incredible information. Your experience, attention to detail, and wealth of knowledge is appreciated. :bow:

Ironically, my 88 is also at 59K miles, still sitting in the shop waiting for the mechanic to fix the circlip issue that you, Travis, and others have observed as a trend (parts waiting from Netherlands and mechanic has been under the weather, so a bit of delay).

It pains to learn of this tappet issue; along with the circlip, fuel tank rusting, distributor pick up wire breakage, etc - while I certainly don't relish it, having the knowledge to plan for them is priceless.

The tappets will be on the checklist when the timing belt, cam towers come off around Sept 2014. Not familiar with the Esprit head, but assume that has to come off to replace the tappets.

My 100K mile goal was planned rather simply; stash a bunch of cash, find a good mechanic and drive the wheels off. But the stash has been taking a hit lately; maybe I'll have to sell the Quaife :(

Hey guys, just a joke rotfl

I tell ya, I knew the Esprit would be an adventure - a journey like no other. :popcorn:
 

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Head does not have to come off to get the buckets out - they will drop out of the bottom of the cam towers just fine.
 

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(Snip)... It pains to learn of this tappet issue; along with the circlip, fuel tank rusting, distributor pick up wire breakage, etc - while I certainly don't relish it, having the knowledge to plan for them is priceless.

The tappets will be on the checklist when the timing belt, cam towers come off around Sept 2014. Not familiar with the Esprit head, but assume that has to come off to replace the tappets. (Snip)...
Welcome to the world of old cars. They all have their flavors... this is the Esprit's. It could be worse... the body could rust. We have a list, we know about it, and we have solutions.

Removing the tappets is an easy task while shimming the valves, and shimming the valves is routine maintenance, not a problem. Loosen the timing belt and slide it off the cam pulleys. Remove 8 bolts and 2 nuts securing the cam carrier to the head, lift and roll the carrier inverted as it slides up off the two studs. Finger-slip the tappets out the bottom of the carrier and place them in order. Clean them with Brakleen and mark them with a Sharpie so you can put them back exactly where you found them. Repeat for the other carrier.

Dye check or magnaflux them for cracks. At a minimum, wipe them with Brakleen or gasoline. The thin fluid will seep into a crack you wouldn't otherwise see, highlighting it with a wet line. No crack of any length is acceptable.

Regards,
Tim Engel
 

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Welcome to the world of old cars. They all have their flavors... this is the Esprit's. It could be worse... the body could rust. We have a list, we know about it, and we have solutions.[snip]

Dye check or magnaflux them for cracks. At a minimum, wipe them with Brakleen or gasoline. The thin fluid will seep into a crack you wouldn't otherwise see, highlighting it with a wet line. No crack of any length is acceptable.

Regards,
Tim Engel
Given your info that longevity is somewhere between 22K (hard X180R use) and 59K (easy use), I'll probably just get a whole new set. My mileage will be about 66K at that point, so good time to replace to get me to the next valve adjust at 102K (estimated late 2017). I should reach my 100K mile (on my watch) by 2020. Sounds far away, but that's the plan.:coolnana:
 

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Cal H
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About dozen owners so far reporting in on cracks other than those that Tim mentions. It is not a mileage issue but if you bounce the needle off the redline a lot it should really be looked often all other when it says check and adjust valves. For most cars very small cracks (harder to see) with wear marks on 2 or more tappets in the 40-50K range . Larger cracks and obvious pitting 50-60K range that look a lot like Travis's pictures. 2 car including mine that the tappet failure is fairly certain led to T belt failure. One reported unusual ticking sound from the engine at idle before engine failure at complete stop. One thought he heard ticking sound but unsure. There are probably more failures of suspicious nature but because of uncertain circumstances I will call them T belt failure of unknown causes. Roy reported one unlucky owner had three T belts breaking on his car so I would suspect that 1 or more t belt failures might have been caused by the tappets as one would think just one belt breaking would cause an owner to really pay attention to the condition of the belt. A lot of people are on the change the T belt band wagon which is good. But it looks like this is an issue one should check on as it is unclear how many t belt failures are masked by cracked tappets. I'm sure many just see the damaged belt and conclude damm I broke the belt and now I need top 1/2 rebuild and that is as far as the investigation goes. The former owner of my car was pretty dumb founded when the cam got stuck and shredded the belt. He was no novice with Esprit's as he has owned a G car, 88, 91, and his present S4. When I told this story to Tim during the car purchase process he related the tappet failure of the X180R and others. That is when we really started look for others with tappet failure. Travis was one of the first to respond when we put out the call.

Most cars were driven like a typical Esprit, Occasional robust driving in the upper RPM range (Short duration play). Yearly light track days with many just parade, with a few driving infrequent HPDE days. Nothing like the the use the X180R had
 

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There's an '89 SE that had more than half the tappets cracked or questionable enough to replace. I don't have a record of the mileage, but I think the owner has... I'll ask.
The SE had about 60,000 miles when the engine was pulled. The owner generally drives in a spirited manner, and the engine had a couple of track days on it.

Regards,
Tim Engel
 

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Roy reported one unlucky owner had three T belts breaking on his car so I would suspect that 1 or more t belt failures might have been caused by the tappets as one would think just one belt breaking would cause an owner to really pay attention to the condition of the belt.
I'm curious about what was going on there. Three belts on one engine is too much to be either coincidental or bad luck.
I'm sure many just see the damaged belt and conclude damm I broke the belt and now I need top 1/2 rebuild and that is as far as the investigation goes.
If a broken tappet takes out the belt, there will be tappet debris inside the engine that will have to be dealt with before the engine will run again. Someone will know. If the owner just takes the car to a shop and writes big checks, he may not know the bottom line cause, but 'somebody' certainly knows. Broken tappets leave ugly finger prints.

Regards,
Tim Engel
 

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Cal H
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I'm curious about what was going on there. Three belts on one engine is too much to be either coincidental or bad luck.If a broken tappet takes out the belt, there will be tappet debris inside the engine that will have to be dealt with before the engine will run again. Someone will know. If the owner just takes the car to a shop and writes big checks, he may not know the bottom line cause, but 'somebody' certainly knows. Broken tappets leave ugly finger prints.

Regards,
Tim Engel
When Roy told me that story about 3 t-belts it raised my eyebrow a bit and made me wonder about it too. I'm just speculating but one t-belt could have been plain old belt failure, Had the head fixed but just put back together with old followers then another failure or two. Just don't know but 3 belts breaking that is strange. That would certainly suck the life out of his Lotus experience that he would never recover from.

Yes there are a lot of people that take their cars to a shop and it appears their main concern is how much is it going to cost to fix it. I agree that someone knows details how a failure occurred. But how many mechanics share fault analysis with the average customer. I'm sure mechanics would share info but do customers really want to know or ask for details? Not many. Most mechanics just generalize a repair, and say this is broken or bad, we need to replace/rebuild this, and this is how much it is going to cost. The the customer goes okay fix it and that is the end of that. All the reports of tappet inspection and cracks were from people that work on their own cars.

Well you saw the damage on my head and cam carrier from the broken tappet and the stuck cam. My cam is chipped too. The tappet debris was not terrible although the head was cleaned up a bit by the time we took a look at it. The follower was in 3 pieces so it was not like it exploded into a million pieces. We sort of have inquiring minds and while we consider it just plain normal behavior to delve into fault analysis there is a just small group on this forum that participate in such conversations. Have you ever looked around at peoples faces when they listen into a LOON conversation at an event? Does not matter if we are talking about mechanics or driving technique. They are like WTH these are not run of the mill car people. Their facial expressions can be funny. Even LOON's that are not as highly skilled is far superior than the average car person and a lot has to do with how the members share info, mentor others and the experience gained during tech sessions.
 

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Cal H
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I thought their eyes were just glazed over with boredom. :)

Tim
That is because you lose most them in 1st several of sentences LOL.
I've had people come up to me like one of the Ferrari guys that mentioned they wish there were more members that were active in car repairs like us. I think the Testarossa guy talks car. So I asked him what do you guys talk about? best car wax? He laughed and said no they don't even talk about that as most don't even detail their own cars. rotfl
 

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Im very curious of the belts.
My Dad owned a Machine Shop. I was in charge of repairing machines unless time/cost was an obvious constraint.
In all the ten years I worked for him - no belt ever broke on any lathe or milling machine.
Yes, they do stretch but not much. The belts are under stress and high torque every day for hours on end. They are exposed to heat, oil, coolant and of course gobs of torque.
Worst enviornment for rubber. I have seen cracked belts but not all through.
The timing belt is exposed to nothing like this. And the torque on the belt is nothing like the v belts.
Of course there is more meat on the v belts, but proportionally there has to be more stress to a timing belt giving up than just turning cams.
 

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Belt driven lathes and mills don't change speed anywhere near as much as an engine. They also don't see temperature changes from below zero to several hundred degrees. The stresses on those belts is nothing like in an engine bay. Also there is ozone generated by the alternator, which oxidize rubber.
 

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Im very curious of the belts.
My Dad owned a Machine Shop. I was in charge of repairing machines unless time/cost was an obvious constraint.
In all the ten years I worked for him - no belt ever broke on any lathe or milling machine.
Yes, they do stretch but not much. The belts are under stress and high torque every day for hours on end. They are exposed to heat, oil, coolant and of course gobs of torque.
Worst enviornment for rubber. I have seen cracked belts but not all through.
The timing belt is exposed to nothing like this. And the torque on the belt is nothing like the v belts.
Of course there is more meat on the v belts, but proportionally there has to be more stress to a timing belt giving up than just turning cams.
And as proof, in those 10 years you worked there not a single automobile timing belts broke and the engine imploded.
 

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I've just proven that I have no life. On the Gates website, there's a search page that lists all the T___ part numbers. Click on one and a second page comes up giving basic specs for the belt, like number of teeth, pitch, rubber used, and tooth profile used. I just leafed through the entire darned list, and there is no generic Gates belt listed that matches the Lotus B-prefix belt with 133 teeth, Curvilinear tooth (HTD1), and either HSN (B-prefix) or HNBR (newer/ modern). We know they make such an animal for Lotus, but it's not on their published list for public sale.

If there's a generic version of the Lotus B-prefix belt on the streets (HSN, Curvilinear HTD1), we won't be getting it from a Gates distributor.

The Gates T188 fits, but it's old-school HCR rubber. The JAE/ Gates blue belt also fits properly, but it's the improved HNBR rubber, limited production, and hence more expensive. There is no 'Gates' HSN clone of the Lotus B-prefix belt on the street.

Now, other brands...? That's a possibility, but I don't have any part numbers. Anybody... ? All the street cross-ref HSN HTD belts are for other rubber companies' versions of the Gates T249. And like the Gates, they're all Modified Curvilinear (HTD2), and not a good fit on the Lotus sprockets.

Gates ....... T249,
Dayco ....... 95249,
Goodyear ... 40249

People use the 249, but I suggest using the correct Lotus branded belt, or the JAE/ Gates blue belt. They fit.

The Nipparts J1121030 belt was referred to me, but I've not confirmed it.

The Nissan VG30E SOHC 3.0 liter V6 engine as used in the Maxima, Pathfinder, D21 pickup truck, 200SX, 300ZX, and Infinity QX4. The Nissan V40 engine was a modified version of the VG30E used in the Nissan Quest/ Mercury Villager mini-van (Ford insisted upon a clearance engine). Both the VG30E and V40 used a 133 tooth timing belt... some of which also fit on Lotus 9XX engines.

However, like the Lotus engines, the Nissan went through an evolution of timing belts, starting with a trapezoidal tooth belt used up through 1985. That belt will fit earlier Lotus engines with the trapezoidal belt.

After 1985, the Nissan belt progressed through several different round-tooth versions. Exactly which round tooth Nissan belt matches the Lotus Curvilinear HTD1 isn't crystal clear to me.

Here are the Nissan round-tooth belts:

*Pre–July 1993 = SHALLOW Groove.
*Jul 93-Aug 94 = DEEP Groove.
*Aug 94 Onward = HTD

Regards,
Tim Engel
Just to ad more fun to the equation, have you looked at motorcycle final drive belts. I know the BMW 800 used a belt drive, though I don't know the specifics of it. My Buell uses a 128T aramid fiber reinforced belt. It's very strong, but wrong tooth count. I do believe one of the Buell belts is the correct 133 tooth, and if not, I'm sure some Harley belts or other makes would be.
 
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