Maintenance & Restoration

cwopaul · 11-27-2007, 07:44 PM

We plan on purchasing a 17' Casita in the near future and need some help selecting a TV. We are using a maximum towing weight of 4,000 lbs and a maximum tongue weight of 400 lbs. We own a 07 Highlander (4cyl) and feel that it is not up to the job of towing this trailer. We have looked at a new Tundra (4.7L) and 4 Runner (V6) and have no question about the Tundra being a capable TV, but would like to hear from anybody regarding the 4 Runner. While looking for a TV two additional questions came up. 1) Has anyone had any experience, good or bad, with Toyota engines that use a timing belt instead of a timing
chain? In general, the 4.7L V8 and some V6 engines have belts.

2) Does a vehicle with unibody construction and front wheel drive have the strength and traction for use as a TV? Thanks in advance for the help.

Rick B · 11-28-2007, 09:19 AM

Quote:

We plan on purchasing a 17' Casita in the near future and need some help selecting a TV. We are using a maximum towing weight of 4,000 lbs and a maximum tongue weight of 400 lbs. We own a 07 Highlander (4cyl) and feel that it is not up to the job of towing this trailer. We have looked at a new Tundra (4.7L) and 4 Runner (V6) and have no question about the Tundra being a capable TV, but would like to hear from anybody regarding the 4 Runner. While looking for a TV two additional questions came up. 1) Has anyone had any experience, good or bad, with Toyota engines that use a timing belt instead of a timing
chain? In general, the 4.7L V8 and some V6 engines have belts.

2) Does a vehicle with unibody construction and front wheel drive have the strength and traction for use as a TV? Thanks in advance for the help.

++++++++++++++++++++++

I have had two 4Runners, both the 4.7 litre V8 models. They are great for towing, as the V8 comes with a transmission and engine oil cooler standard. I used to tow my 17' Bigfoot with the 4Runner and have on occasion, towed my heavier, 26 foot stick built. With a WD hitch, the V8 4Runner can tow up to 7,000 lbs. My current 05' Limited also has rear air suspension, so it is great for dealing with the tongue weight of the trailer, and easy to connect/disconnect, as the rear of the vehicle can be manually raised/lowered.

Rick

Brian B-P · 11-28-2007, 04:55 PM

Quote:

...We are using a maximum towing weight of 4,000 lbs and a maximum tongue weight of 400 lbs. We own a 07 Highlander (4cyl) and feel that it is not up to the job of towing this trailer.

The Highlander is rated by Toyota to tow 3500 lb at most (that's the V6, the 4-cylinder may be lower, I don't know). Therefore, 4,000 lb is too much.

Brian B-P · 11-28-2007, 04:57 PM

Quote:

Has anyone had any experience, good or bad, with Toyota engines that use a timing belt instead of a timing chain? In general, the 4.7L V8 and some V6 engines have belts.

The fashion in camshaft drives has changed with time. For a number of years, the most reliable and quiet design was a belt, and my Sienna has a timing belt in its V6. The current standard at Toyota is to use timing chains, since they have become quieter, and because the roughly 100,000 km life of a belt had become a limiting factor: the first required service other than fluids and filters was to change the timing belt, so to keep pushing that first-major-service frontier further out chains are back (including in the current Sienna).

Either design is fine if you follow the recommended service intervals. My old Tercel never had a timing belt problem; I just changed it every 100,000 km or so as recommended. I think the details of the installation are more important than the belt versus the chain: the Toyotas and Hondas which I have owned fully enclose the timing belt, which then stays clean and free of oil, while some other makers leave the belt partially exposed and vulnerable.

I wouldn't let this factor affect my choice of engine, but the other advantages of the newer designs (generally better power and perhaps efficiency) might tilt me towards the newer generations, which would then likely have a timing chain.

The 4.7 L Tundra V-8 is the 2UZ-FE, while the 5.7 L is the 3UR-FE. While only one litre apart in displacement, these are different families (UZ versus UR), and the latter is essentially the replacement for the former. I believe that the UR uses a timing chain, but even if the UZ uses a belt, that's not likely the most important difference.

Brian B-P · 11-28-2007, 05:08 PM

Quote:

Does a vehicle with unibody construction and front wheel drive have the strength and traction for use as a TV?

This is two questions, regarding strength and traction.

Unibody construction is not in itself a concern for towing [b]strength. Either unibody or body-on-frame construction can be used to make a structure which is very suitable for towing, and either can be used to make something which can't take the strain. The intent and detailed execution of the design of the specific vehicle is the important part. For instance, typical unibody minivans and SUVs have structures which incorporate suitable hitch mounting points, and are suitably strong for towing their rated loads, while some passenger cars are not intended for this use, and may not be able to handle it. Since most body-on-frame vehicles now made are trucks, it seems like the separate frame ensures good towing strength, but it's largely the fact that they are trucks (intended to haul and tow) that makes them suitable.

Often - perhaps normally - a front-wheel-drive vehicle loaded with a trailer still has carries more load (weight) on the front tires than the rear, while many rear-wheel-drive vehicles also tow with more load on the front, so in one sense the front-drive has a [b]traction advantage. Reality is that under acceleration some load transfers to the rear axle, hurting front-drive traction but helping rear-drive traction. If the trailer is very heavy relative to the tow vehicle, then rear-drive may have an important advantage: the specific combination should be considered.

In practice, I find that I am more likely to slip the front tires due to traction loss on loose gravel to snow while towing our 3000 lb trailer with my front-drive minivan than while not towing, but much of that is simply the result of more load to haul without a proportionate increase in traction, which is a problem for any tow rig. A friend of mine bought a four-ton 30-foot travel trailer and had it delivered to his campground lot; the delivery driver - using a full-size rear-drive truck - had difficulty moving it on the grass due to inadequate drive traction. Five tons of vehicle and less than two tons of that on the drive wheels has limited effectiveness, whether those are front wheels or rear wheels.

I believe that all Toyota SUVs and almost all Toyota pickup trucks sold in Canada are four-wheel-drive, although the trucks tend to be part-time systems that are useless until switched on under limited conditions. That makes the front-versus-rear discussion irrelevant for many people who are considering only SUVs and trucks.

Pete Dumbleton · 11-29-2007, 07:52 PM

Brian's given you a lot of good info, so I'll just add my two cents worth on timing belts and chains. The belt on my Ranger's 4.0L engine is out in the open, which means it gets dirtier than if it were enclosed, but it's also right out there where I can see it. Having changed that belt and also having changed the timing chain on a Dodge Slant6 (less than 100K miles and it was stretched enough to affect ignition timing), the belt is a lot less trouble (had to remove radiator, etc. on Dodge to do the work; had to remove nothing except the belt on the Ranger).

That said, however, the real difference and probably the real reason belts got a bad name, is the INSIDE of the engine. If the valves are of the "interference" type and the belt or chain fails when the engine is running, parts collide, are damaged and some rebuild is needed $$$. If the engine is "non-interference", parts don't collide but the engine must have the valve train synchronized to the crankshaft when the new belt is installed.

cwopaul · 11-30-2007, 03:49 AM

Quote:

Brian's given you a lot of good info, so I'll just add my two cents worth on timing belts and chains. The belt on my Ranger's 4.0L engine is out in the open, which means it gets dirtier than if it were enclosed, but it's also right out there where I can see it. Having changed that belt and also having changed the timing chain on a Dodge Slant6 (less than 100K miles and it was stretched enough to affect ignition timing), the belt is a lot less trouble (had to remove radiator, etc. on Dodge to do the work; had to remove nothing except the belt on the Ranger).

That said, however, the real difference and probably the real reason belts got a bad name, is the INSIDE of the engine. If the valves are of the "interference" type and the belt or chain fails when the engine is running, parts collide, are damaged and some rebuild is needed $$$. If the engine is "non-interference", parts don't collide but the engine must have the valve train synchronized to the crankshaft when the new belt is installed.

Yes Pete ,Brian's information has been very helpful for me and I want to thank him for responding. I have also heard stories about the engine damage that can occur if a belt fails. I assume this is the result of pistons and valves making contact in an "interference" type design. Do you happen to know which design toyota uses?

Roger H · 11-30-2007, 05:24 AM

cwopaul,

I've had Toyota trucks and Landcruisers since 1982 and all of the versions of the 4cyl and 6cyl engines they've produced since then. I've never heard of the timing belt or chain failing in a Toyota engine that is serviced at the recommended intervals. The 3.4L V6 I have in my current '02 Tundra is a non-interference engine, and there is no replacement interval recommended for the timing belt; there are only inspection intervals.

Roger

Brian B-P · 11-30-2007, 03:44 PM

Quote:

I have also heard stories about the engine damage that can occur if a belt fails. I assume this is the result of pistons and valves making contact in an "interference" type design. Do you happen to know which design toyota uses?

Yes, that's the interference problem. I suspect that there are Toyotas in both categories: if the valves are highly angled from the cylinder axis, or the valves open a large distance, or the combustion chambers are small (meaning a high-compression design) then interference is more likely - which is so many details that it is difficult to guess. I know my Hondas have been interference engines, and my old Toyota Tercel was not, but I don't know about modern Toyotas which we might use for towing (such as the 3MZ-FE 3.3L V6 in my Sienna, or any of the Tundra engines). I'm just not concerned enough about the risk (given the appropriate maintenance as Roger mentioned) to be aware of the specific consequences for my engine.

John Perry · 11-30-2007, 04:18 PM

I have had many Toyota vehicles in my lifetime and never had a problem. My oldest grandson still has a 1976 Toyota PU that I gave him and it now has 460,000 miles on it. I had a 1991 Toyota PU that I sold to my next door neighbors father who lives in Southern Mexico. It now has almost 500,000 miles on it. Neither of these vehilces has had anything other than routine maintenance done on them.
I bought a new Tacoma 27 months ago and it now has 52000 miles on it. It is the only Toyota that I have ever had a problem with. About 3 weeks after I bought it the A/C started making a funny noise.
I went back to the dealership, they apologised for the incomvenience, gave me a loaner car and replaced the entire A/C system. It has been trouble free ever since.
Buy a Toyota, you will not be disappointed and you will save money in the long run.

John

Bill MacDermod · 11-30-2007, 06:44 PM

If you buy a Toyota you had better like the color bcause you will have it a looong time

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