valve slipping

[skimhead]

Hi, last summer I did a 1000 mile highway roadtrip and had to adjust Cyl #3 exhaust valve 4 times (to increase gap). I did notice the engine miss about 4 times also. CHT never rose above 425F. Other valves held their clearances. I'm planning a trip 8 times that long this winter and expect that adjusting valves every 250 miles will be problematic, if not fatal. I've had issues with valve seats sinking/dropping before but very rarely since driving with a CHT. The motor was rebuilt (top/bottom) about 4000 miles ago or less.

Thx, Andrew

[telford dorr]

Model year? Engine type?
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'71 panel, now with FI
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[skimhead]

1979 panel hightop Bay
2 liter FI

[my59]

Recessed valve seat or valve stretching.....but why are you increasing gap? 79 FI would be hydro lifters if it was stock, and your adjustment would be 1.5 to 2 turns after contact of adjustment tip.
What was done during rebuild?
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my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget.

[Wildthings]

If you are having to adjust your valve lash that often with solid lifters then the head needs to come off and be properly rebuilt or replaced with a new one.

If you have hydraulic lifters, four adjustments of 0.006" each would add up to .024" total or about 1/4 turn of the screw. Photographing the head would be a good way to keep track of the position of the screws.

[skimhead]

I'm using solid lifters

[williamM]

X2 on head rework- How many miles on the engine since overhaul and who's heads are on there now-- WAY better than dropping a valve- [img]

[/img]
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[SGKent]

(1) how old are the heads? Or were the heads rebuilt or replaced with new, and who did the work?

(2) how much did you have to adjust them?

(3) was the engine cold each time you did the adjustment?
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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

[skimhead]

not sure of age of heads, were rebuilt approx 4k miles ago by The Bug Shop in Delta BC Canada. Each adjustment was from no gap to .008" with engine cold

[SGKent]

the heads need to be replaced. Buy new ones from Len Hoffman. https://newsite.hamheads.com/2017/01/16/vw-2-0-transporter-cylinderheads/

It is possible a valve is stretching or a seat was not put in right, but you have a long voyage ahead so I would not trust the heads you have on it now. These bus engines were kinda built with disposable heads. They really run hot because of how they are used. Original heads for a 1979 bus are almost 40 years old with most of their life severe service due to the temps they run at. What you are seeing is not uncommon.
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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

[aeromech]

People use the term “rebuilt engine” loosely. One guys rebuild isn’t equal to another guys rebuild. T4 heads seem to be the biggest failure point on these engines. That’s why it’s very important to include the highest quality possible and I’ve seen a pair of these heads cost $700 to rebuild. That’s was roughly 8 years ago.
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[skimhead]

Hi, I just purchased a new 1800cc AMC head from CIP. The studs were not installed but included in a separate bag. I need to know the torque specs for the different studs ie rocker-arm, intake, exhaust studs.

Thx, Andrew

[Wildthings]

[timvw7476]

[skimhead]

manuals do not contain info on stud installation torque just nut torques

[tommu]

You'll need to search around for previous discussions, like this one:

https://www.thesamba.com/vw/forum/viewtopic.php?t=553943

I think you're looking more for an idea of stud installation technique than specific torque values. Of course once the stud are in then nut torque is critical.
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[skimhead]

any tips on stud installation appreciated thx

[Joey]

I've always just jammed two nuts together on the stud, screw the stud in and lightly tighten it. Maybe 5 ft-lbs.
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Joey

‘60 Kombi - '74 Bus - '79 Panel - '65 Beetle

[Wildthings]

[skimhead]

thank you all for your information