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DrDarby
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Joined: May 12, 2004
Posts: 6534
Location: Northern Illinois
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 Posted: Thu Aug 06, 2015 9:22 am Post subject: 1979 Westy 2.0 fresh engine lifter going solid? |
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I'm about at wits end with this bus. Some background: I've just celebrated my 39th year working on air cooled VWs. I'm VW factory trained and ASE certified. The bus is a bone stock 79 Westy 2.0 Hydraulic, stock fuel injected with a DPD air conditioner that Ive upgraded with a rotary compressor, hoses etc. It has been very well maintained by both owners and it sees active use with occasional long distance trips.
The numbers matching engine made 139,000 miles and while it ran OK it was tired, compression was about 95-100 on all 4, cam was starting to show signs of going flat.
The block was line bored .020 cylinder holes trued and was reassembled with a new stock hydraulic cam and lifters, valve guides, exhaust valves, seats checked and heads step cut to eliminate the copper ring. Cylinders cleaned up like new as did the pistons and were reassembled with NOS VW rings. Valves set to 0 clearance +1 turn.
After the initial install and proper start up and checking, we broke in the cam during which time we heard an occasional intake backfire that went away after about 5 minutes. The the lifters mostly pumped up and we then changed the oil and hit the road. It ran great although an occasional lifter would clatter then go away.
It left here and hit the road making it to central Illinois (from Northeast Illinois) where they stopped to refuel. Restart had some clatter but went mostly away then 5 miles down the road 60 became 50 then 40 and the engine started making all kinds of noise.
Towed it back and we could not get it to start, thinking bad gas we drained the tank and flushed the lines. It then started but was backfiring into the #1 cyl intake and other lifters clattering like crazy. Reset the lifters to Boston Bob specs (.006 drive, reset, drive etc). We drove it for two weeks, kept resetting but the #1 intake valve would eventually stay open causing backfire in the intake, burning the paint off of #1 runner.
Many resets later we relented and pulled the engine.
We split the case, rechecked everything, cleaned up the lifter bores, rechecked deck height etc. we installed another brand new set of lifters, this time Genuine VW parts and blueprinted the oil pump.
Got it back together and had some other issues to fix and finally had it all together and re-broke in the lifters etc. This time I hit the road, ran great, plenty of power etc. lifter clatter at each start up even warm but put about 300 miles on it and it ran great.
Customer picked up the van and two days later, power loss, backfire from #1 intake and hard starting again.
We reset the valves to Boston Bob specs .006 to give it the benefit of doubt and it was fine for about two hours of running at high idle and all the lifters pumped up and were nice and quiet.
About 10 minutes into my 20 minute drive home it began bucking slightly, lacking power on hills and then began backfiring into #1 intake again. it was 1am so I limped it home with #1 plug wire off and injector unplugged.
We have reset the valves I cant count how many times, replaced the lifters, verified oil pressure is within spec, checked valve seats (heads are now on opposite sides) and continue to have the #1 intake lifter pump up too much and hold the valve open. As a related note, on first original start up the #3 intake valve was doing this but hasn't done it since initial break in was done.
I just ordered a set of hydraulic lifters converted to solid and am going to try them.
Anybody have any ideas??
Thanks for reading this novel !
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Midwest Autosavers, Inc. Woodstock, IL |
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SGKent 
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Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Thu Aug 06, 2015 9:40 am Post subject: |
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| burning the paint off of #1 runner. |
Sounds like weak valve springs or loose seats. The valve springs control how the lifter bleeds down during service. Weak springs could allow both over pumping on a lifter, and valve sticking in a guide. Clatter implies loose valve train or sticking valve, and not tight valve train as in over-pumped.
Another possibility is that valve guides were not properly reamed and that they are a little tight, grabbing the valves occasionally. If instead the guides were over-reamed then the valve could wobble and not seal up properly.
Since you did not put new valve seats in, you might consider staking the old ones in case they are coming loose with heat. It is not an approved solution or long term fix but it may answer the question what is happening. I have seen it in a shop before many times where valve seats in aluminum heads seem quite tight at room temp, but even running a head in a power parts washer gets it hot enough that seats will fall out in your hand.
I would also look closely at who did the heads. If they are not a shop accustomed to precision 2L T4 head machining, and the heads were done on a mechanic's work bench, then that is likely to be part of the issue. A refresh and hand lap could be pulled off on a head with 10,000 miles but not on one with 140,000 miles. I won't go into this too deeply but having worked both as an automotive machinist in a high end shop building everything up to Indy and FI engines, and having worked as a mechanic both in my younger days, no shop mechanic can duplicate the precision of a quality machine shop that is familiar with a particular type engine part.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin
Last edited by SGKent on Thu Aug 06, 2015 12:13 pm; edited 5 times in total |
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Tcash
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Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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| Posted: Thu Aug 06, 2015 11:11 am Post subject: |
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Off the net.
Pump up can be caused by weak valve springs, sticking valves, sticking lifters, high oil pressure, radical cam grind or over revving the engine.
Reset the lifters and do a Vacuum Test. This will rule out valve train problems.
Make sure you are pulling enough vacuum for that cam. Low numbers would indicate you got the wrong cam.
Measure the springs installed heights.
Pull the spring off #1 and test it. It may be weak. You can do this without pulling the head.
You don't mention changing the pushrods.
Hyd had steel pushrods. I don't know if Aluminium would expand enough to cause pump up?
Or putting spacers on the rocker shafts.
This keeps the rockers from walking.
Good Luck
Tcash |
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Randy in Maine
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Joined: August 03, 2003
Posts: 34890
Location: The Beach
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Wildthings
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Joined: March 13, 2005
Posts: 50337
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| Posted: Thu Aug 06, 2015 5:38 pm Post subject: |
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| I agree with others on the valve springs. Don't know if you reused your old ones or bought new ones, but hydraulic lifters require a stronger spring than solid lifters. Were the springs shimmed to give the correct load at your installed height? I wonder if stale gas is part of your problem? Gasohol ages poorly and after a few months of sitting in the tank will cause buildups on the valves stems causing them to stick in the guides. Could also be that the guides are too tight to start with. |
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