Driversound

So what would cause a 22R to blow a head gasket?

Overheating?
Broken chain guides/timing problem?

Is this a common problem for the 22R?

I'd just like to know before I start looking for a project truck. Thanks.

Pumpkinyota

Well, the normal stuff that causes a vehicle to blow a head gasket, usually overheating. This is not a common issue for this motor if it has been maintained at all, however, timing chain cover issues are often mis-diagnosed as head gaskets on these due to water getting in the oil. The only real weak spot in these motors was the timing chain and timing chain guides. The chain stretches, flaps, destroys the TC guides, and then eats a hole in the side of the TC cover just below where the water pump attaches. This can cause the introduction of water to oil, but usually not oil to water. For those that don't know this motor, this often times is confused with a head or head gasket issue due to the water in the oil.

I hope this is helpful!

Pumpkinyota

Well, lol, I have to in part, respectfully disagree with your disagreement.

First, it's true that any block/head combo that is put together of differing materials with differing thermal expansion coefficients, not to mention the electrolysis issue, is going to be "MORE" likely to fail than one that is engineered identically but using the same materials. That being said, the sheer bulletproofness of the 22-R and 22-RE motors under extreme conditions has been documented time and time again.

Here's one example of such, specifically referring to Hi-Lux pickups, quoted from wikipedia:

"The Hilux has gained a reputation for exceptional sturdiness and reliability, even during sustained heavy use and/or abuse, and is often referred to as "The Indestructible Car". This was further reinforced on the BBC motoring show Top Gear, when a 1988 Hilux with 190,000 miles (308,000 km) on the odometer was subjected to extraordinary abuse (in series 3, episodes 5 and 6). This consisted of driving it down a flight of steps, scraping buildings, crashing headlong into a tree, being washed out to sea and completely submerged, driving it through a garden shed, dropping a caravan onto it, hitting it with a wrecking ball, setting the cabin and bed area on fire,[7] and, finally, placing it on top of a 240-foot (73 m) block of flats that was subsequently destroyed by a controlled demolition.[8] Although it was now suffering from severe structural damage, the truck was still running after being repaired without spare parts and only with typical tools and equipment that would be found in a car's toolbox, such as screwdrivers, motor oil, and a wrench,[9] however WD40 was used to get the engine going after it had been recovered from the sea. The Hilux currently resides as one of the background decorations in the Top Gear studio."

The 22-R and RE motors are NOT known for head gasket problems any more than any other 70's - 80's steel block, aluminum head 4 bangers. That being said, yes, head gaskets can and do, in fact, fail.

Second, why is it that the drivers side timing guide fails? Chain stretch. If these chains did not stretch appreciably, or the tensioners did not fail, there wouldn't be enough slack in the chain to allow it to contact the guide all that much, and certainly not enough to allow the chain to travel the next 1/2" to contact the TC cover. If chains didn't stretch, we would never replace them. You are correct that the guide failure is what makes coming into contact with the TC cover possible (as I stated above), but it doesn't just "fail", it requires chain slap to do so.

It may be very unlikely that YOU as an intelligent, capable person can be confused by this issue, however I have seen armchair mechanics (and even some more qualified mechanics) make this mistake frequently. I have re-built, or assisted in rebuilds on at least 3 separate 22-R projects where we got the vehicle dirt cheap, as the owner thought it was a blown HG.

Most of your facts are true, but the context is little off...

Driversound

Wow, thank you for the wealth of information. I am somewhat familiar with alloy head and iron block problems (3VZ) but I have not heard too many failed 22R's due to just blown head gaskets. The chain was usually the problem. I have seen many ads for Toyota pickups stating that it has a blown head gasket and the mileage coincides with not replacing the chain/guides. Usually about 100-150K miles. I guess the only real way to know if to take off the timing chain cover. Either way, if I find one cheap enough I'm just going for a rebuild along with a new clutch. Thanks guys!

Pumpkinyota

There is an easy check for blown head gaskets. Just pull all the spark plugs and look for one or two that are REALLY sparkly clean due to the steam cleaning they got when the HG blew =)

Unfortunately, 100-150k is probably about when an HG would begin thinking about blowing too...

Rebuild and clutch always equals win in my book

Driversound

Great! Thanks for the tip. I want one for a daily driver so looks don't count too much but dependability does.

I already have an 09 Tacoma 4x4 but I like projects!

Pumpkinyota

Well, sorry, I don't mean to continue the flame war, but just a few points....

First off, I never said, or implied, from my first very post, that you were "wrong". In fact, I quite agree with the bulk of the facts that you present, just not how you state them with relation to the main topic under discussion, whether or not head gasket failure specifically is "common" on a 22-R or RE motor. Please bear with me while I address these.

I do agree that just about anybody with common sense, experience, and a degree of mechanical aptitude can tell the difference between a blown HG and a timing chain cover failure. However, I'm sure anyone will agree, these are not qualities that many people possess. If you don't know much about engines, and your redneck uncle Jimmy is helping you troubleshoot your problem, oftentimes said redneck uncle will know a little bit about american V-8s and virtually nothing about import 4-cylinders. The distinction may not be important to you, however, many people cannot conceive of the thought of a water pump on the front of a TC cover. As a result, some "car people" who think that they are diagnosticians see water in the oil and immediately suspect a head gasket.

Actually, I never stated that I have only "assisted" in three rebuilds in my life. What I said was "I have re-built, or assisted in rebuilds on at least 3 separate 22-R projects where we got the vehicle dirt cheap, as the owner thought it was a blown HG." What is meant by that is that I have purchased one of my toyota trucks from an owner who mis-diagnosed a TC cover issue as a blown HG, and within a few months helped two friends make and repair similar purchases. In my area, a running first gen 4x4 typically sells for 2500-4000$. All of these trucks were bought from dumb rednecks who were sure that there was head gasket failure, and priced the trucks accordingly ($500 or less). I am actually unsure how many Toyota 4bangers I have built, rebuilt, tuned, tweaked, or repaired, but I have been doing it for 14 years now. I think the total is probably pretty high.

If you like, I can send you the chain I pulled out of my 22-R last week. There was enough slack in the chain that when it was installed in the motor, I could pull the chain from the drivers side and touch it to the chain on the passenger side. Lying on the ground pulled tight next to the brand new chain, it was .5+ inches longer than the new chain, which means that the chain had stretched by over an inch in total. I think that this just might be enough stretch to cause timing chain system failure.

This is true, however it is also common for coolant to be introduced to the crankcase, and thoroughly mixed with the oil, causing your oil to have a nice "mocha" color and consistency. Unless you know how to properly diagnose an engine, this can be easily confused with many other failures that cause coolant/oil mix, such as cylinder sleeve cracks, head cracks, TC cover failure, HG failure, etc.

That is wonderful. I have not questioned your diagnostic ability, or your qualifications even once, please refrain from doing the same with mine. I too have a long and rich toyota-filled past.

The fact is, what Driversound asked about was whether these motors are known for blowing head gaskets (like a land rover, or range rover, for example). My response was that no, they are not. If you disagree, you are more than welcome to, my experience has been different. I also stated that some people make poor diagnoses. They do. I have seen it repeatedly. People also do drugs, light firecrackers in their hands, have to go to the hospital to have things removed from their rectums, etc. People are often not intelligent. You know how to diagnose a blown HG. I know how to diagnose a blown HG. If he didn't before, Driversound now knows how to diagnose a blown HG. Do we need to say any more on this?

Pumpkinyota

Me too =)

I will probably give my 'Coma to my wife when I finish the frame-up on my '79, and use the '79 as my daily driver. What is cool about re-building one is that you know how to fix just about everything whe you are done =)

Pumpkinyota

No prob, the internet is full of BS, sometimes you gotta call someone out and see if they actually know what the hell they are talking about


Define common? It is definitely one of the top three causes of catastrophic failure in an R motor, but catastrophic failure of an even occasionally maintained R motor is about as common as a volcanic eruption in Kansas. Well, ok, that is a slight exaggeration, but still...

From what I have seen, it seems the following are the three most common "catastrophic" failures (by which I mean failures that prevent the motor from running). The percentages of these, with no scientific backing whatsoever other than my own personal feelings, seem to be:

60% - Timing chain system failure (tc guides being the majority of these)
25% - Head Gasket failure
15% - Blown rings.


Ok, so regarding Chain Stretch:

I don't have measurements on the old chain yet, I will take those later today. The chain in question seems to be a strange fluke, it stretched over a 50,000 mile period, which is most definitely NOT normal. But, here is some general information:

The 22-R circa 1981-1984 was unique to the 22 series of R motors in that the timing chain, sprockets and guides were more like those of the 20-R, double row with metal TC guides. As a result, guide failure is not very common on an early 22-R. What is more common (and just happened to me, which is why I replaced the chain) is that when the chain gets slack to the point where the tensioner can't keep up any more (or the tensioner fails), the cam sprocket jumps a couple of links, advancing cam timing by several degrees. If you are driving the vehicle when this happens (and since it commonly happens when the engine is under load, you usually are), it feels like the world is ending. My truck made a number of loud choking noises while I was going uphill at 55 miles per hour and 3000 RPM in third, and shook the whole vehicle while it shuddered horribly to a halt. Upon removal of the valve and TC covers, the chain was slack to the point where I could touch it together in the middle, with the tensioner fully deployed at max tension. As a result of the skipped links, the cam was advanced 15-20 degrees, I have no idea why my valves are still intact.

On the 22-RE motors, from '85 on, the TC was a single row chain, with plastic guides. Any slack in the chain was immediately transmitted to the drivers (slack) side TC guide. Also, being a single row chain instead of a double row, the TC was weaker, and more susceptible to stretch or breakage. Between the increased amount of stretch, and the new, crappy plastic guides, that made the TC cover, water pump issue arguably the weakest link in a motor known previously for its indestructibility.

Chain stretch, specifically, is a well known occurrence. Just ask any motorcycle rider, and their chains are built much heavier than any timing chain. The biggest culprit for causing a chain to lengthen, or "stretch", is not actual stretching or lengthening of the links (I'm guessing you know this already due to the fact that you put "stretch" in quotation marks earlier ). Instead, it is caused by wear at the pins and bushings where the individual links connect. Here is a picture of what this looks like on a bicycle chain:




Since I don't have the actual chain in front of me at this time to measure, or a brand new one to compare measurements with, let's look at a completely hypothetical timing chain. Lets assume a timing chain that is 64 links in length, where every link is .5 inches from the center of the pin to the center of the next pin. Such a chain, in a straight line, would be just a hair over 32 inches long (in circumference, through the center of the pins), or about 18 inches doubled.

In such a case, if every link "stretched" by 1/64th of an inch (or 0.015625), the entire chain would gain an inch in length. If every link "stretched" by 1/32nd of an inch (or 0.03125), the entire chain would gain two inches in length. Realistically, if you get out a pair of calipers and look at the distance involved, it would not seem unrealistic to see up to 5/64ths per link of "stretch" (or pin and bushing wear), which would manifest as a whopping 5 inches of gain!

The tensioner is probably capable (again without measuring) of removing 2-2.5 inches of slack from the chain at full extension. This could leave as much as 2.5 inches of slack in our hypothetical chain.

In a 22-RE motor, most TC guide failure seems to occur at around 100-150k. I can't imagine 5 inches of slack at this point, but it certainly wouldn't need that much. Even 1/4 inch past what the tensioner can handle, plus the wear damage that is already occurring due to normal use would be enough to make the guide fail. I think 1/4 to 1/2 of un-tensioned slack in the chain should be enough to let the chain run to the water-pump edge of the TC cover, but I don't know for sure.

Thoughts?

GenXr

Wow,....

pumpkin' I respectfully request you re-watch the TOP GEAR episode you quoted. You will find that the featured (and abused) Hilux was equipped with toyota's 4cyl diesel engine and not the gasoline powered 22R series engine.

With that said, I wouldn't call a TV episode containing unscientific abuse of a vehicle as evidence "well documented" of the 22R series engine's longevity. A sample size of 1 is anecdotal at best and is not empirical or typical of the production vehicle.

Although 1000's of posts on numerous forums describing and complaining about blown head gaskets does not by itself qualify as empirical evidence of the HG weakness, (unless a formal study were undertaken to document the number of occurrences)...They are statistically prevalent enough to warrant more than casual correlation supporting the case for chronic HG failure.

Based on my own observations studying and reading about HG failures of 22R motors on the internet (anecdotal), and my own experience with two failures (same vehicle) I am led to believe the HG's on 22r engines are prone to failure regardless of vehicle maintenance habits.

I'm of the opinion there are two kinds of 22R engine owners, those that have had an HG failure and those that will. It's just a matter of time.

That said, there are just as many 22r engines with 200K - 300K miles on them as there are that have experienced blown HGs.

Pumpkinyota

As it happens, I watched it last night and was logging on to post a retraction on the top gear bit. That being said, that piece of "evidence" was not meant to be empirical or scientific, but a rough example of the kind of abuse that these motors can take. Next time, I will find an example that refers to the right motor =/.



The simple fact is, the head gasket is a weak spot on ANY motor, especially those with a head and a block that are made of dissimilar metals. From my personal experience, as well as the reading (anecdotal) that I have done, my OPINION is and will remain that this is not a motor that is "known" for HG failure. As you state, many of these vehicles make 2-300k on a head gasket, that is just impressive. How many Chevy or Ford vehicles (and I say this as a guy who LIKES Chevys) can make a similar claim? I have two close family friends with 2wd Toy pickups that have each gone over a half a million miles, and they have both had head gaskets done (as part of a general re-build, NOT because of failure) at 300k.

You are more than welcome to your opinion, and it seems to be a well reasoned one, I just don't share it.