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Bleyseng
Samba Member
Joined: July 03, 2005
Posts: 4752
Location: Seattle
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 Posted: Mon Jan 15, 2018 9:10 am Post subject: Re: On rebuilding stock heads |
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| Wildthings wrote: |
| I got 250K miles out of a set of used 1800 heads that had no work done to them but to have the guides replaced when I first bought them and have known others who have gotten 250K out of Vanagon AC heads and one that got 350K out of factory heads on a late Bay. Keeping an engine well tuned and the cooling system operating in factory condition will alleviate a whole lot of head problems. |
This is just not what most bay owners have experienced. Late Bay's with a 2.0L had valve seats dropping out by the thousands. 120K with stock 2.0L heads is very good and the heads should be tossed as its better to get new castings with quality guides, seats, valves, springs etc.
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50338
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| Posted: Mon Jan 15, 2018 10:18 am Post subject: Re: On rebuilding stock heads |
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| Bleyseng wrote: |
| Wildthings wrote: |
| I got 250K miles out of a set of used 1800 heads that had no work done to them but to have the guides replaced when I first bought them and have known others who have gotten 250K out of Vanagon AC heads and one that got 350K out of factory heads on a late Bay. Keeping an engine well tuned and the cooling system operating in factory condition will alleviate a whole lot of head problems. |
This is just not what most bay owners have experienced. Late Bay's with a 2.0L had valve seats dropping out by the thousands. 120K with stock 2.0L heads is very good and the heads should be tossed as its better to get new castings with quality guides, seats, valves, springs etc. |
Unfortunately most owners didn't keep their engines tuned all that well and still don't. Nor do they maintain their cooling systems all that well. Forty years back it would have been very hard to go through a parking lot and find a VW that had a good engine surround gasket and most rigs would have been spitting and sputtering as they ran down the road and leaving their mark wherever they parked. After college, had I not started dating a girl that owned a typical badly neglected bug and gone through the steps to actually make it run right and been very happy with the results, I don't think I would have ever gotten into VW's.
About once ever five hundred miles, especially when traveling, when I go to check the oil I pop the tranny into neutral, turn the ignition on, walk back to the engine compartment, pull the coil lead and put it near a ground, rotate the crank passed the timing mark to verify the timing is dead nuts on and then check the oil. This way I know with very little effort on my part that the engine is still in time. I will let people who believe that one must use a timing light to check and set their timing continue with their once in a blue moon tuneup schedule and the resulting once every few year head work schedule.
Two other things have made VW ownership easier for me. On my first VW the recommended oil for three season use was 30wt, a recommendation I followed as I never saw any reason to run anything heavier, so I was getting a cooler running engine than many, and also since my first Type 4 engine was from a 412 I ran the stock 412 timing setting of 27° BTDC giving me a bit cooler heads. I vary off those numbers a bit today, but not by much. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21513
Location: Oklahoma City
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| Posted: Mon Jan 15, 2018 12:44 pm Post subject: Re: On rebuilding stock heads |
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| Quote: |
Wildthings wrote:
I got 250K miles out of a set of used 1800 heads that had no work done to them but to have the guides replaced when I first bought them and have known others who have gotten 250K out of Vanagon AC heads and one that got 350K out of factory heads on a late Bay. Keeping an engine well tuned and the cooling system operating in factory condition will alleviate a whole lot of head problems. |
| Quote: |
Bleyseng wrote:
This is just not what most bay owners have experienced. Late Bay's with a 2.0L had valve seats dropping out by the thousands. 120K with stock 2.0L heads is very good and the heads should be tossed as its better to get new castings with quality guides, seats, valves, springs etc. |
I agree. In General...the vast majority of Bay owners rarely see the North side of 150k before head related issues.
Even a well cared for 411/412 engine usually needs the minimum new guides at about 125K. With new guides you regrind the existing valves if they are in good condition to get concentric seat sealing. Usually by that time at least one exhaust stud needs an insert...but otherwise good to go.
After that....I have run heads well cared for, lightly loaded...basically touched up heads like that to 175-200k. In that range with a 411/412...the largest risk is actually snapping off an exhaust valve head.
And.....
| Quote: |
Unfortunately most owners didn't keep their engines tuned all that well and still don't. Nor do they maintain their cooling systems all that well. Forty years back it would have been very hard to go through a parking lot and find a VW that had a good engine surround gasket and most rigs would have been spitting and sputtering as they ran down the road and leaving their mark wherever they parked. After college, had I not started dating a girl that owned a typical badly neglected bug and gone through the steps to actually make it run right and been very happy with the results, I don't think I would have ever gotten into VW's.
About once ever five hundred miles, especially when traveling, when I go to check the oil I pop the tranny into neutral, turn the ignition on, walk back to the engine compartment, pull the coil lead and put it near a ground, rotate the crank passed the timing mark to verify the timing is dead nuts on and then check the oil. This way I know with very little effort on my part that the engine is still in time. I will let people who believe that one must use a timing light to check and set their timing continue with their once in a blue moon tuneup schedule and the resulting once every few year head work schedule.
Two other things have made VW ownership easier for me. On my first VW the recommended oil for three season use was 30wt, a recommendation I followed as I never saw any reason to run anything heavier, so I was getting a cooler running engine than many, and also since my first Type 4 engine was from a 412 I ran the stock 412 timing setting of 27° BTDC giving me a bit cooler heads. I vary off those numbers a bit today, but not by much. |
This is very well said. The vast majority of bus owners did not and so many new to VW owners still do not...take the very best care they can of their engines.
While it is entirely true...that the type 4 head is "capable"....with the best care and strategic light refurbishment....of running 200K+ miles......
.....because what you noted above is also entirely true....decades of abuse and reuse....make original head castings an unknown and very risky.... risk. I just cannot in good conscience recommend that anyone should just "run em"...until they die....unless you have owned a bus and engine since it was new and know exactly how you treated it...and even then....its a risk.
Its not 1985 anymore...with zillions of good cases and moderately used parts laying around.
The problem with running them until they crap out....which seems like a money saving thing at first thought.....does not really save money depending on the mode of failure.
There is more than one mode of failure...ranging from heads just causing engine running so badly that you finally have to retire or rebuild them at high miles. Even that does destruction. Everything runs hot and lots of contamination on the oil.
One cannot just assume that they will run until a seat drops...and you can limp home and get new heads. Its just as common that when a seat comes out at 3000+ rpm on the highway....it turns, jams a valve open, snaps the head, wastes the piston, rod, cylinder, main bearings and oil cooler.
If you are lucky with that method of death...the engine does not actually seize.
On the other hand even without a seat dropping out you can snap a valve head off...most common cause of death actually. More than half of those I have seen...causes engine seizure if it snaps at highway speed.
That almost always damages everything....one or more rods, the camshaft....and almost every HARD seizure at speed....when you carefully measure the main bearing bores leaves a "witness mark" deformity at the angle position where the crank locked up hard.
Usually this dos not destroy the case. This deformity spans maybe 1.5 clock positions.....but it makes the main bores just a little less accurate for new bearing fit....and just adds to the long term collective damage to the case...speeding you onward to the next align bore.
There are just not as many good cases and cranks left floating around in my opinion....to take the risks of running heads into the ground. Ray |
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