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My Musical Valve Train, by Westie Aircooled....
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purdman
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Joined: January 25, 2005
Posts: 40
Location: Portland, OR
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PostPosted: Mon Apr 04, 2005 8:33 am    Post subject: My Musical Valve Train, by Westie Aircooled.... Reply with quote

Need some advice.
I bought a 82 Vanagon in Jan. and have let it sit b/c I haven't insured it yet. It seems to me that it is way louder now, with alot of pinging, hammering, etc. I remember when I bought it and drove it home it sounded fine, but now with the occasional nieghborhood block cruise, it sounds loud. From what I've read you should let the lifters 'pump' up. How long should I do this for, and should I rev the motor or just let it idle?
Also I feel that I should adjust the valves anyways, since I have no idea when the PO did it. I am having trouble visualizing this 'screw' that you are suppose to turn .5 to 2 turns? I have the bentely, but I'm still confused. I need to know if I should replace the Valve cover gaskets everytime I pull the covers?
Would you guys also recomend doing a compression test before and after to see if my valve status has improved?
When you do a compression test should I pinch the fuel lines?
How can I tell if I need a valve job?
How much should a valve job cost, and how much should a engine rebuild cost?
Thanks for any responses, I want to reach enlightenment with my westy..
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Ericthenorse
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Joined: October 03, 2004
Posts: 782
Location: Los Osos CA.
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PostPosted: Mon Apr 04, 2005 8:44 am    Post subject: Reply with quote

Very Happy If you haven't driven it for a while, it might need to warm up fully to let the valves pump up... I would suggest adjusting them so you know when they were done.. find a friend with a bug.. he/she probably has a manual with a good picture.. you should also look at some of the topics on this forum. valves has been the hot topic for the last week or so.. if you have read the Bently manual, go ahead and pull off the valve covers, the adjusting screws and lock nuts will be obvious... Good luck, and if you have questions let us know... Twisted Evil
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'91 vanagon carrat-slammed,5 speed,4 wheel disks,17x8.5's
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Randy in Maine
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PostPosted: Mon Apr 04, 2005 8:55 am    Post subject: Reply with quote

I am going to fess up that I stole all of this from ratwells site over in the Baywindow FAQs. Pretty good write up IMNSHO.


1.6 Hydraulic Lifters:
In 1978 VW introduced Hydraulic lifters to the Type IV (GE) engine. Because they were only used for 2 years they attract the usually disdain and confusion that the Type IV engine, fuel injection, etc that other late model features have to endure. Bob Hoover thinks they are a good idea and like the rest of the Type IV improvements that's good enough for me coupled with the fact they've never caused any damage and seem to keep the valve adjusting screws from wearing out as quickly as they do with solid lifters.

The advantages are clear:

Quieter valve train
Lower maintenance
An ability to adjust for thermal expansion of the engine
Built in shock absorber, eases stress on valve train
How they work is easy to understand: instead of setting the valve gap to 0.006", the adjusting screw makes contact with the valve stem and you turn the screw 2 full turns and you're finished. No feeler gauges are required! The engine pumps the lifter full of oil and as the clearance of engine parts change due to engine heating (the valves stretch) the lifter adjusts automatically. Besides fewer valve adjustments it means less wear on the valve train because the engine is adjusted at all temperatures not just when the engine is warm.

Many manufactures use hydraulic lifters in their engines and VW went to this system to deal with the ever difficult engine maintenance access imposed by the sedan body styles. Hydraulic lifters were a solution to this problem: self-adjusting which implies that no valve adjustments are necessary to eliminate the need to remove the valve covers.

The fact is that engines with hydraulic lifters require adjustment just like other engines do. The difference is that they are self-adjusting AFTER they have been set properly. If that is not the case, you will either a) break a lifter in it's bore b) pound a valve seat c) burn a valve that's left open. If you really care about bus engine maintenance, perform a leak down test to verify your valves are correctly adjusted. It's the only way to be 100% sure.

It is prudent is to adjust the valves upon purchase of a new vehicle if you are told the engine has hydraulic lifters. In fact you may have a 78-79 bus with solid lifters or even a 72-77 bus with hydraulics because engine replacement is common with these old vehicles. Assuming you have hydraulics when you have solids will cause you a lot of grief down the road that would have been avoided by a brief post-purchase inspection.

Regarding adjustment: some folks think the adjustment should be 1/2 or 1 1/2 turns. The truth of the matter is that the lifter will pump up to the correct oil level no matter what you set it to but the initial setting is important: two turns of the 10mm valve adjusting screw with 1mm threads will preload the lifter ~1.5mm (remember the rocker ratio). This is about half the distance that the piston inside the lifter can travel. If you use too little preload you are stressing the lock ring that holds the lifter together and it may break while the engine is running. If you use too much preload, then when the lifter pumps up the valve will not seat properly and compression and performance will suffer.

The advantage of solid lifters over hydraulics is that they are 100% predictable which is why folks prefer them, especially engine builders. This implies hydraulics require an inspection now and again even though they might not require an adjustment.

Opinions are divided on hydraulics but it comes down to this: you either have them or you don't. When they work as advertized it's a lot less maintenace work for you. When they give you trouble, it's a lot more trouble than any solid lifter will give you. It's for this reason that the engine builders prefer solid lifters on stock 72-79 Type 4 engines: hydraulics compound warranty issues. Weighing the pros and cons it makes the most sense to simply stick with what you have.

Car owners don't like change, especially VW owners and I've read a lot of excuses wrt hydraulics but the only one that holds water is that regular solid lifter adjustment helps you to notice a dropping valve seat or stretching valve because you are examining the lifters more and you get to measure a shrinking gap. Type 4 heads fail for one reason: folks think they are ok and drive them hard when they are not ok. No matter what kind of lifters you have, you should remove the valve covers periodically to inspect the heads.

Hydraulic owners aren't totally in the dark wrt dropping valve seats: you can measure the distance of the spring retainer to the head using a depth measuring tool. Even better would be to perform a leak down test because you'll be able to tell if any of the valves aren't seating properly and you won't need to remove the valve covers.

The real argument against using hydraulics is that the 1978 implementation is not perfect and when you let the engine sit the lifters bleed down. This is because when they are full of oil and rotate in their bores, the oiling hole in the barrel will eventually let oil out and air in under the pressure of one of the push rods. If you start the engine every day you should never hear the ticking sound of an air bound lifer. If you let it sit for a week them you might hear it for 10 seconds. If you let the engine sit for 4 years, as I did once, you might hear the ticking lifters sound for 30 minutes. The solution to this problem is simple: drive your bus regularly and don't let it sit. Unfortunately for those of us buying used buses we have to contend with noisy lifters and all of their issues due to PO abuse.

How long should you wait before deciding the lifters won't pump up on their own? I'd say 35 minutes. After that you'll have to remove the lifters from their bores with a magnet and bleed any "soft" ones on the bench. Some folks think adding ATF or Rislove or Marvel Mystery Oil helps to pump up stuck lifers. Some folks use a thicker oil to raise the pressure in the galleries. Either way, bench bleeding is not required to maintain the lifters. It's a one time fix to correct a history of abuse.

A lot of VW advice is dispensed by folks who are just repeating what they've heard. If you feel you must take their advice and remove them from your engine because you've been told it will blow up, then be prepared to remove the cam and replace the push rods as well because the ramp of the cam, push rod length and valve geometry are different between a solid and hydraulic engine. More important is the fact that hydraulic cases don't have the 2nd oil control valve like all other dual relief cases have and you'll be trying to out engineer VW by your modifications.


1.1 Compression Testing:
You've bought a compression tester but it doesn't contain any instructions. Here's what to do:

if you have hydraulic lifters, run the engine the night before for 30 minutes to make sure they are pumped up.
adjust valves if it's near adjustment time
break torque on the plugs with a cold engine so you aren't removing them when the threads in the head are softer from the heat. Just keep them snug.
run the engine for 5 minutes to warm it up
remove all four spark plugs
key off to disable coil and injectors
unplug double relay (left plug is mandatory)
There is now no fuel spray or spark. If you are using the ignition key to power the starter you'll need to pull the 12v wire from the ignition coil.

hook up your remote starter (very useful for this procedure; disconnect battery, hook up, reconnect).
thread in your compression gauge
open the throttle wide open for maximum breathing
run starter for 10 pulses of the needle (events)
repeat and average your readings
put a drop of oil on the threads of the plugs when you put them back in and torque them down when the engine is cold. Bentley says 22 ft. lbs which also jives with the value specified on the spark plug box (my NGK B6ES say 18 ft. lbs for aluminum head so I use that value).
To interpret results see section 1.5 When to rebuild.

Removing the coil wire doesn't do much because the spark plugs are already out unless you have to rely on the key to run the starter. In that case also remove the white wire to disable the injectors.

The bigger problem is that the starter, via double relay, is going to run the fuel pump so it has to be disabled by pulling the plugs on the firewall.

The remote starter I like is the one from Sears (#21018 from Sunpro/Actron) with the light on the top that tells you the power is on. It was recently brought to my attention that it's no longer at Sears but I did find KAL3221 at the Kal-Equip website which is exactly the same version.


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