All You CHT Gauge Drivers Report Here

[Jivermo]

Here, hear!

[airkooledchris]

From 73 onward the buses were just asked to perform cleaner than they were ever designed to run at. End result = Hotter running engines.

From 73 onward the engines also got bigger. how many guys running 1.7's are complaining about dropping exhaust valves, in comparison to the 2.0's? how many of these hot running engines are original VW builds, Vs rebuilds of unknown quality in both parts and execution?

These questions were precisely why I was so happy that Colin hooked up a DD CHT gauge to the BobD when he did, so we could get some real data on what these engines were doing when new (and what was possible when properly tuning a properly built engine.)

It should also be noted that, for the sake of tuning your engine to make your CHT's happy, we generally don't care around here what the smog rules are. If I can run 1 engine build for 75K miles slightly rich, im ok with that, if the alternative is running it slightly lean and having to rebuild it after 45K miles.

I haven't yet been able to properly test Colins last suggestion of retarding the timing, but will soon. Id like to get on the highway long enough for the temps to get back up to their high numbers and *then* make my adjustment to the timing. This way I can pull right back onto the highway and see if the numbers change for the better, and what, if any, side effects there are.

[72Hardtop]

There were plenty of 1.7L buses that dropped seats. My bus was one of them when my grandfather owned it. I was with him when it occurred back ~75 or 76. There is a big misconception that the 1.7's were less likely to and that is false. I've got (2) very close friends who were VW dealer mechanics (Woolverton VW Ontario, Ca.) who later went independent who've stated they saw plenty of early T-4 with dropped seats (mostly buses).

The T-4 cooling system is very capable of handling up to approximately 2.3L or so. The 2.0's and dropped seats had a lot to do with those damn head gaskets being used in them which was later dealt with under the tech bulletin that was issued out. But in the end a lot of it had to due with owners also neglecting their valve adjustment check intervals and routine maintenance. Most just figured they'd run like any other vehicle on the road.

Roll forward 40 years and we still have some people doing the same hurtful things to these poor vehicles. But with the right head builder dropped seats are a thing of the past so long as the vehicle owners keep up with routine maintenance.

[Amskeptic]

A) There were plenty of 1.7L buses that dropped seats. My bus was one of them when my grandfather owned it. I was with him when it occurred back ~75 or 76.
There is a big misconception that the 1.7's were less likely to and that is false.
I've got (2) very close friends who were VW dealer mechanics (Woolverton VW Ontario, Ca.) who later went independent who've stated they saw plenty of early T-4 with dropped seats (mostly buses).

B) The T-4 cooling system is very capable of handling up to approximately 2.3L or so.

C) The 2.0's and dropped seats had a lot to do with those damn head gaskets being used in them which was later dealt with under the tech bulletin that was issued out.

A whole bunch of us were alive at the time these cars were new. No doubt, there were many engine failures. Look at all we did not know at the time, look at all we had to do to keep these engines within the emissions standards.

Now, let's do some logic.

A) grandpa's engine failed,
B) two friends remember that they saw early Type 4 engines drop valve seats.

Therefore: Your conclusion is that early Type 4s were intrinsically sensitive to failure.

BUT

C) my 1.7 heads gave me 515,000 miles
D) hundreds if not thousands of people have kept abreast of my summertime Death Valley floggings
E) I have always used head sealing rings

Therefore: my conclusion is that a stock Type 4 dual carb bus engine is more than capable of staying glued together.

What is the readership to conclude?

Well, they are free to collect information and arrive at their own conclusions.

FAILURE has causes. But what does NON-failure have to say?

All I have ever done is follow the damn directions. I have spoken with dealership mechanics and many others, and I still think that if people would follow the directions, these engines do fine.

My only resume "brag" is that I am still waiting for an engine failure in one of my VWs.

Now, for the readership, I must reiterate that the head sealing rings do not "cause" failure.
That's just blaming the canary in the coal mine.

Volkswagen published a technical service bulletin with three wholly interdependent tasks. Some people pick up and run with erroneous conclusions.

PROBLEM:
piston scuffing on the 94mm pistons

SOLUTION:
a) increase cylinder/piston clearance
b) notch connecting rods
c) delete sealing rings

ANALYSIS
a) all efforts here were to give the 94mm pistons room to expand - VW said to heck with people complaining about the "big" engines cold piston slap

b) oil escaping from the connecting rod journals now sprays the undersides of the pistons to help keep them from expanding ahead of the cylinder barrels under hot load

c) this allows *quicker* heat transfer from the cylinder heads to the barrels to help the barrels expand before the pistons scuff.
Colin

[72Hardtop]

How many road side tear downs does that 515,000 include? I'd bet we could dig a few up...on the flip-side the average customer/owner would have just kept driving until

[Bleyseng]

I would add that the oil squirter notch also was to spray oil on the cylinder walls to help with the scuffing problem.

My 2 cents is that the 1.7/1.8 ran cooler and didn't really have the valve seat dropping syndrome that happened with the 2.0L's. I think also that the 76-78 exhaust system made these engines run hotter and leaner than the dual carb engines. Is it just because of the 94mm pistons? I don't think so as the 73 914's didn't suffer this but the 74-76 2.0L 914's with their leaner AFR's and bad exhaust did.

I also would add that most people did not follow the maintenance schedules after the warranty period expired. VW's had those damn every 3,000 or 5,000 services which was a pain in the ass so people just ignored them or at least just changed the oil. Ignoring the valve adjustments was common as I worked on lots of friends cars back then doing the basic services. They drove those cars until a problem arose usually too tight of valves and the poor running that resulted. Then I would get a call to look at a car and help them out as they had little money for the dealership repairs. I have to add the the FI cars also had leaning out problems due to all those hoses that cracked as they got older.

[Amskeptic]

How many roadside tear downs does that 515,000 include? I'd bet we could dig a few up...on the flip-side the average customer/owner would have just kept driving until

Road Warrior
I did preemptive engine refreshes about every 100,000 miles, stuck in new guides and exhaust valves, bearings, and piston/cylinder sets . From 360,000 miles onward, machinists warned me about cracks developing in the exhaust ports.

It never stranded me in 30 years of ownership and never required a roadside teardown. The one 24-hour "unexpected layover" was Winnie TX 2002, when a gallery plug blew out. I lay that at the feet of the machinist in Glendale CA "Martik's Metric Motors", who sold me a "matched" set of connecting rods that were 23 grams out. Car got me home to New York, but unhappily.

The heads were killed by an error from Carl McQuillen's Racing Engine Machining (I was so hopeful that he cared) who decided to ignore my recommendation to chill the guides when he pressed them in. Duh, one came loose and allowed oil to rapidly build up carbon between the piston and head, crushing the crown of the piston (sounded like a bad valve adjustment). My Ebay replacement heads cost 200.00 and gave me another 73,000 miles before the car got killed in Colorado by a head-on with an idiot.

Squareback
The only issue I have ever had that can be laid at the feet of the factory was an incorrectly hardened seat in the factory original head that fooled me into thinking that I had seat recession. It did not strand me, because I caught the tightening valve in plenty of time to select when I wanted to deal with it.

BobD - no issues never

Chloe
Many many many many many many machine shop errors, build errors requiring just one emergency teardown to replace the heads ruined by wrong size exhaust valves (!) $80.00 used heads have done flawless 30,000 miles since.

I love these cars, I love these engines, but I will not second-guess the factory engineers except for one modification . . . Porsche valve adjusters.
Colin

[Amskeptic]

I would add that the oil squirter notch also was to spray oil on the cylinder walls to help with the scuffing problem.

No.
I am on a tear here to STOP idle armchair speculation in this thread.
Since when did any HORIZONTAL engine have ANY PROBLEM with "insufficient lubrication" of the cylinder walls????? The notching was to use the oil as a heat transfer medium!

My 2 cents is that the 1.7/1.8 ran cooler and didn't really have the valve seat dropping syndrome that happened with the 2.0L's.

My 2 cents is that people don't remember the diabolical air-injection system that lit the exhaust gases on fire in the exhaust ports on the '73-'74 carbureted buses. The only reason that the 1.7 heads were stronger is because they had more metal! More metal in the smaller combustion chambers.

I think also that the 76-78 exhaust system made these engines run hotter and leaner than the dual carb engines. Is it just because of the 94mm pistons? I don't think so as the 73 914's didn't suffer this but the 74-76 2.0L 914's with their leaner AFR's and bad exhaust did.

The '73 914/6 replacement was, IIRC, a D-Jet.
The 914/4 followed the bus through the initial 1.7/ '74-'75 1.8/ '76 2.0 progression
The bus was the first indication to the factory that aluminum's expansion rate goes up quadratically inside of a cast iron cylinder.

The exhaust system as a cause of heat? The exhaust system is a downstream afterthought that reacts to what is going on the combustion chambers. In 1975, the U.S. put the screws to CO/HC/NOX emissions and that is what increased the heat load. Because the '73-'74 buses were exhaust catalyzing in the ports (ouch!) they tested those poor heads horribly. I remember well the frying hot air-injection pipes and failed back-pressure valve in my poor Road Warrior. The fuel injected buses were a step back towards civility, but that new driveability was occurring with some lean hot combustion, no doubt. At least with the later CA fuel-injected buses, the catalytic converter was doing the catalyzing heat at the rear of the car.

I also would add that most people did not follow the maintenance schedules after the warranty period expired. VW's had those damn every 3,000 or 5,000 services which was a pain in the ass so people just ignored them or at least just changed the oil. Ignoring the valve adjustments was common as I worked on lots of friends cars back then doing the basic services. They drove those cars until a problem arose usually too tight of valves and the poor running that resulted. Then I would get a call to look at a car and help them out as they had little money for the dealership repairs. I have to add the the FI cars also had leaning out problems due to all those hoses that cracked as they got older.

Who was bitching about the 3,0000 mile oil changes/6,000 mile tune-ups? It was the then norm. People ignore things they don't want to think about today too. Slobs have been a part of human history.
In my universe, people overran the recommended service intervals, yes, but they did not tell the dealer to skip services.

We did have a great deal of ignorance in the service stalls. Dealer mechanics were being rushed into all of this new-fangled emissions technology, hating every step, and just trying to get the damn car to pass and out to the next car. There was NO discussion of timing at the torque peak . . .

So the question was, did these engines fail due to errors or due to their intrinsic weaknesses?
I got my answer . . .

[Bleyseng]

To answer your question:
I think it was human error or laziness. Seattle in the 70's was slowly recovering from the economic crash of 1969 when Boeing laid off 50,000 workers. So yes, after the warranty period expired people I knew quit going to Dealers and looked to save money on servicing. I did a lot of "friends" cars on weekends to save them money plus put some in my pocket too. I don't know how it was in the rest of the country then but times were tough here until the 80's. I quit doing this in the early 80's as I was too busy running a construction company and just concentrated on keeping my own cars and trucks serviced.
If you recall, the 2.0l engine came out first in the 914 in 1973 to replace the poor selling 914/6 2.0L. VW adopted it as you still see the part numbers "039" on the 2.0L parts which were the codes for the 914 2.0L parts. All the other 914 engine were either bus or 411 engines.
Yes, the 1.7 heads had more material under the valve seats. There used to be cut away pics of the 4 basic 1.7, 1.8, 2.0L and 2.0L heads showing the amount of material there.

[72Hardtop]

To answer your question:
I think it was human error or laziness. Seattle in the 70's was slowly recovering from the economic crash of 1969 when Boeing laid off 50,000 workers. So yes, after the warranty period expired people I knew quit going to Dealers and looked to save money on servicing. I did a lot of "friends" cars on weekends to save them money plus put some in my pocket too. I don't know how it was in the rest of the country then but times were tough here until the 80's. I quit doing this in the early 80's as I was too busy running a construction company and just concentrated on keeping my own cars and trucks serviced.
If you recall, the 2.0l engine came out first in the 914 in 1973 to replace the poor selling 914/6 2.0L. VW adopted it as you still see the part numbers "039" on the 2.0L parts which were the codes for the 914 2.0L parts. All the other 914 engine were either bus or 411 engines.
Yes, the 1.7 heads had more material under the valve seats. There used to be cut away pics of the 4 basic 1.7, 1.8, 2.0L and 2.0L heads showing the amount of material there.

The cut away pic (Len Hoffman showed) also showed the differences between a new OE VW 2.0 head and the new Spanish AMC 2.0 head. Len Hoffman stated I recall that when choosing one or the other I'd choose the AMC due to it having more surface area in two critical areas. He also stated that when choosing either a 30+ year old VW head or an AMC head the AMC head wins hands down no debate.

One other thing to note was when one would drop off their bus at the dealer there generally was never time to allow the engine to cool to stone cold prior to valve lash check. Over time one can see what the long term effect would be.

[Amskeptic]

One other thing to note was when one would drop off their bus at the dealer there generally was never time to allow the engine to cool to stone cold prior to valve lash check. Over time one can see what the long term effect would be.

We were told to bring it in the night before on the 6,000 mile services.

Are you familiar with the physics of what happens when the engine is started cold and brought into the workshop bay? It is a different thing than an engine already operationally warmed and cooling down, then started and brought into the bay.

VW recommended that the Type 1 engines (hitherto at .004") increase their clearances by 50%.
The Type 4 engines were designed around .006" but even so, the dinky screws/nuts on the 1700s were not up to it, the larger 1800 screws/nuts were introduced with the .008(!) clearances that came with the sodium cooled exhaust valves of the 1974 air-injection dual carbureted hell. Then, down in Mexico, VW increased the valve adjusting screw sizes yet again, even with hydraulics across the range..

[72Hardtop]

Was that dealer specific? According to the friends I know who were dealer mechanics...no. The vehicles were parked aside until cool then dealt with. No different than an independent shop as well.

[Amskeptic]

Was that dealer specific? According to the friends I know who were dealer mechanics...no. The vehicles were parked aside until cool then dealt with. No different than an independent shop as well.

It was dealer-specific.
Dealers were giving Volkswagen hell for this cold valve adjustment requirement, so they relaxed the "standards" to "if the oil is less than 122*F".

Here's what happens with a *cold* engine started in the lot and driven into the bay.
At three minutes from stone-cold, the aluminum between the combustion chamber ceiling and the rocker supports expands first. This serves to move the rockers away from the valves, yielding a false loose reading. Dealer mechanic who used to set the valves to .004", would end up killing the engine.

An engine that has already driven to the dealer with warm crankcase, heads, valves, pushrods, contracts differently than a stone cold engine expands! Here, the cast iron barrels with piston heatsinks are expanded more than the pushrods, and you can end up with a false tight that clatters til the next adjustment.

The "solution" from 1971 on was pretty much let the damn things hammer. But the precision of the initial .004" adjustments was easier on the engine's longevity. Now of course, everything has gone to hell in a handbasket and the hardness of valves and screws is anyone's guess . . .
Colin

[Bleyseng]

Was that dealer specific? According to the friends I know who were dealer mechanics...no. The vehicles were parked aside until cool then dealt with. No different than an independent shop as well.

It was dealer-specific.
Dealers were giving Volkswagen hell for this cold valve adjustment requirement, so they relaxed the "standards" to "if the oil is less than 122*F".

Here's what happens with a *cold* engine started in the lot and driven into the bay.
At three minutes from stone-cold, the aluminum between the combustion chamber ceiling and the rocker supports expands first. This serves to move the rockers away from the valves, yielding a false loose reading. Dealer mechanic who used to set the valves to .004", would end up killing the engine.

An engine that has already driven to the dealer with warm crankcase, heads, valves, pushrods, contracts differently than a stone cold engine expands! Here, the cast iron barrels with piston heatsinks are expanded more than the pushrods, and you can end up with a false tight that clatters til the next adjustment.

The "solution" from 1971 on was pretty much let the damn things hammer. But the precision of the initial .004" adjustments was easier on the engine's longevity. Now of course, everything has gone to hell in a handbasket and the hardness of valves and screws is anyone's guess . . .
Colin

That's why the Porsche swivel foot adjusters are the "cats meow" and a worthy upgrade to any* type 4 engine.

* (01/25/14 SlowLane edit: any solid lifter only Type 4 engine)

[Amskeptic]

The "solution" from 1971 on was pretty much let the damn things hammer.

That's why the Porsche swivel foot adjusters are the "cats meow" and a worthy upgrade to any* type 4 engine.

* (01/25/14 SlowLane edit: any solid lifter only Type 4 engine)

Yes, but we please need Porsche swivelfoots with the new big screw diameters so we don't have to poach all the 1700s . . .
Colin