Valves clearances keep reducing

[advinnie]

Hi I have a new ish 1600 engine in my bug done no more than 1000 miles. Anyway around 900 miles I had a bad head so pulled the engine and fitted new heads. I set the valve clearances to 0.006” done 50 miles max and recheck clearances and they had gone below 0.003” reset the again done another 50 miles and a few of the clearances had once again reduced. Cylinder two exhaust valve had gone to 0.003” cylinders 1 & 3 are fine still at 0.006” cylinder four inlet is good but exhaust clearance on that cylinder had also reduced to 0.003”
Any ideas on what’s going on?
Does it take time for the valves to settle in?
I did grind the valves into the seats when I first got the new heads

[Tom K.]

I believe this is the normal settling in period when you install new heads or push rods. If you are just removing and reinstalling existing stuff, then you can avoid the problem by organizing everything so that each push rod goes back in its existing spot with the same valve. But when replacing stuff, the various parts have to get to know each other, and adjusting valves frequently is the way to deal with it. But twice or maybe three times should be enough. If it continues, then you might want to remove your rocker arms and inspect those adjuster bolts for unusual wear.
_________________
'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[advinnie]

Ok I will keep an eye on it and see if they settle down, thanks for the reply 😁

[andk5591]

Super important - did you do the correct cam break in and use the correct break in oil?
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[advinnie]

Yes I did and drained it changed the oil filter and continued to use straight 30 mineral

[andk5591]

I don't know the oil composition where you live, but here the zinc and phosphorus levels in most motor oils are too low for a flat tappet cam engine. As mentioned, you can continue to monitor the valve settings, but I recently replaced an engine for a customer that was requiring valve adjustments every couple hundred miles....He improperly broke in the engine and his cam was going flat...
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[HippyTom]

My two bugs have 1600 Single ports. One has 25,000 miles on it and the other about 10,000 miles. When I adjust my valves they've always tightened up a bit. And when I adjust them I tend to adjust them just a hair loose. But this is over the course of several thousand miles. Valve stems stretch slightly over time, which could explain slight tightening. A little loose won't hurt anything. A tight valve will inhibit rotation and isn't good. Just my experience with valves.

[advinnie]

Well all valves now set to 0.006” let’s see want happens over the next few months.
Cheers of your help and advice all

[andk5591]

Personal valve adjustment experience - Fresh engine - May need some adjustment after a couple hundred miles. Then I like to check around 1000...maybe need .001 or .002" tweak. Then I check every oil change....Usually small adjustment required every other oil change (around 6000 miles or so).

Keep a log of how many miles, how much of an adjustment on each valve. You want to watch for trends. I do the same thing - If any one valve requires excessive adjustment, I document it and see if there is a continuing trend and plan accordingly.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[advinnie]

Good idea I will do that 😁