81 Engine Issues

[KenO]

Hi Gang-
I have recently discovered engine oil in my coolant reservoir on my original 81 1.6 diesel rabbit pickup.  So...

Before diving in and pulling the head, I have some questions.

I believe this is a 11mm head bolt engine and where / what should I looking at to determine if there are critical ailments that would open a new can of worms?  Basically, where are the common weak spots when I am in there?  Or is it worth replacing the head gasket and hope for the best?  There are  about 180k miles on the pesky rabbit and having a difficult time with keeping it in time.  Discovered last fall the woodruff key was missing between the crank and timing pulley and pulley and crank slots were ovaled out from a loose bolt.  Purchased a new crank gear and hand made a new key that feels tight but if I go in deep on this engine - I will address the issue.  The body is rust free and it runs decent but I am not made of extra money and curious of your thoughts of what I am getting myself into. 

I am skilled with v8 fords and what we have on the farm but I haven't done any deep engine surgery on one of these vws.  Think I am about to start an adventure...

Thanks,
ko in NW Wy

[sgnimj96]

   If the head gets the ok, and it's going back on, I'd be looking for these
https://www.ebay.com/itm/VW-Head-Stud-Kit-12pt-1-8-2-0L/383231202901?hash=item593a5c1655:g:b34AAOSw1RBeAP4O
   and since I'm cheap and have other cars to drive,  I browse here first for parts I could use
https://www.rockauto.com/RSS/vehiclefeeds.php?carcode=1367737&m=wc&l=en&html=true

Many have suggested,  you DON'T want to sink a lot of money into those old engines
autohaus,  fcpeuro,  eEuroparts, and others are all pretty competitive
Doing a valve adjustment,  if you get that far,  can be ridiculous finding those shims
   here's where I ended up
https://www.fcpeuro.com/Volkswagen-parts/Valve-Adjuster-Shim/

[fatmobile]

Probably just a head gasket.
 Is it seeping oil at the front of the head,
by cylinder 3?
That's where all the pressure is between the head and block.
 That's where the pressure is high enough to push into the cooling system.

With the 11mm headbolt block,
 which I assume you have since it's an '81.
 The bolts are too short and put too much pressure in a small area in the block.
 That can cause the block to crack or threads to strip out
when you install them.
 That's why studs were suggested.
 I like buying them used over on the vortex,..
 since 11mm studs fit the gasser engines too.

[ORCoaster]

I would be for pulling the head to see the condition and size of cracks between the valves.  Anything greater than the width of a dime is not acceptable. 

You can also measure the amount the pistons come up over the block with the head off.  Nothing saying that the gasket your replacing was properly matched to the amount of protrusion you actually have.  You may be giving up power, economy and easy starts. 

I would opt for the ARP studs, I just did that a bit ago on my turbo'd PU. 

But all in all it just sounds like you blew a gasket.  Not hard to fix and not terribly expensive either. 

[KenO]

Wow!  Thanks for the replies, what a wealth of knowledge you are sharing with me.   

It sounds like I need to pull the head and investigate what the cross - contaminating 'issue' is and go from there.

Yes, there is grease or plenty of built up old oil below cylinder #3, I hope a new HG will fix this problem. 

With the head off, it will provide an opportunity to check the accuracy of the TDC mark.  I am experiencing an issue with the IP timing and cannot twist the IP beyond 90 mm which I was told to advance it to 95 - 99 for best efficiency at our elevation.  But this is something I hope to resolve while the engine is open. 

While I am in this deep, will check the head for integrity issues and if that passes - a valve job.
 

Sorry for the continual questions but curious minds cover lots of topics, here are few more inquiries...

Being I do not have a valve grinder, but have a seat grinder - will pick up new valves to install - does it matter where or what kind or make of valves to purchase? 

And should I or can I convert the solid lifters to hydraulic? 

Lastly, on the new HG - reviewing chapter 5, page 24 in the Bentley shop manual, it talks about thickness.  Can I determine which HG to purchase with the head on?  If not, should I wait until it is apart and order the exact replacement or should I just order the middle or 1.50 mm head gasket?  And, what gasket brand should I get or stay away from?  Was looking at Rock Auto and other sites provide too many choices for my inexperience...

Thanks again and sorry for the late response - had shoulder surgery and back on the computer again with 2 hands...

I appreciate all of you, 
Ken

[ORCoaster]

With the head off you can do all that you mention and then raise the pistons and measure the protrusion of each one.  That will tell you what thickness of gasket to purchase.  You don't want to just buy the middle one because it may not be the one for the job.  With shipping so fast these days it will be there before you need it possibly. 

Not sure if it much matters what valves you buy.  I can't recommend one over the other.  Maybe those that do more rebuilding than I can chime in on that score.

I am also not sure you can convert a mechanical head to a hydraulic just by inserting the right lifters.  Have never heard that method.  I think the hydro heads use different bolts and maybe an oil passage.  Or coolant, Again deferring to others more familiar with that.

I think you will be fine ordering from Rock Auto.  I have only had one part that was of poor quality from them and sent it back.  An electrical one. 

[fatmobile]

I'd keep it mechanical.
 I've heard others talk about chipped cams on hydraulic heads.
 Saw it happen on one of mine.

You'll want to spray the new head gasket with something.
 Hylomar or copper.

[KenO]

To-Spray or Not-To-Spray opens an interesting discussion...   

I don't have any experience rebuilding a VW but when it comes to a new head gasket - to spray depends upon the material of the HG, metals being mated together, and internal pressures / fluids being contained.

I will purchase a new HG and order the proper thickness after the head is off.   

Something I often do, depending upon water / oil passage galleries is open up the HG 'holes' to match the engine and head passages, as long as it does not cut or cross a sealing 'bump'.  Of course, this only works on non-metal gaskets.  There are obvious reasons when to open these passages and I can tell you which older ford v8 need them but would be only a guess on these tiny vws.  Curious if this is a practice is accepted or frowned upon or if there are brands of HG that need enhancing or spraying...

Thanks for the advise...

Ken

[libbydiesel]

Do NOT enlarge the holes in the head gasket!!

They are specifically sized in order to regulate the flow evenly around the hot areas of the head.  Enlarging the holes will only create localized hot spots which is very bad! 

I used to install head gaskets dry and would get the occasional weeping leak at the drain holes and more often at the high pressure oil channel (between #3 and #4).  A while back I began using hylomar spray and it has cured those issues entirely without any perceived downside.  I have also disassembled several engines with the original head gasket and despite the Bentley manual recommending dry installation, the factory used a sealant very similar (or the same) as hylomar when originally assembling these engines.  When using the spray I do a very light spray on all four surfaces.  The coating is light enough that it just changes the sheen of the surfaces but not enough that it shows the blue hylomar color. 

[ORCoaster]

I always coat the head, the block and the two gasket sides.  I have used both Hylomar and a copper spray.  It cures the symptoms of getting the gasket tight in those questionable areas where you may end up with a future failure because of a thousandth of an inch difference. 

We are talking about cylinder pressure that is more than double in a diesel compared to a V-8 Ford gasser.
Just taking the precautionary principle into consideration.  Spray also can help hold that gasket in place when you are getting the head in place.  If you didn't remove the exhaust manifold, some don't, you will have your hands full getting it down and in place.  You might get it down but in place really counts.

To do that some use their old headbolts as guide pins.  They whack a couple of them off at the base of the head and cut a slot across the shank for a screwdriver.  Then before they set the head they finger tighten one in each opposing corner and use them to slide the head into place.  Then remove the bolts with the screwdriver when it comes time to insert the actual bolt.

You may already have that as a set practice but I thought I would mention it as you said you didn't know VW engines very well.

Hope it goes swimmingly.  Just don't breathe the diesel. 

[fatmobile]

 I think the hylomar helps the gasket stick to the block and stay in place
better than the copper spray.
Got to agree, pay close attention to where the gasket is supposed to sit.
 How much it hangs over or lines up with each edge.
The pins don't line it up perfect.

 Also will mention there are sometimes extra holes drilled near the "corners" of the cylinders.
 Like they did with the 1.9s.
To release steam pockets.

[libbydiesel]

...some use their old headbolts as guide pins.  They whack a couple of them off at the base of the head and cut a slot across the shank for a screwdriver.  Then before they set the head they finger tighten one in each opposing corner and use them to slide the head into place.  Then remove the bolts with the screwdriver when it comes time to insert the actual bolt...

Yup, I do that.  It works a treat. 

[KenO]

Great information.   

I plan to pull the head this weekend and see what can of worms I find.  You may get some more noise from me but this grasshopper thinks he is ready to get his hands dirty.

Have a parts and supply list growing - now I think I will look into upgrading the stock air filter to something external.  If you have any more advise, I am all ears.

I really appreciate everyone's input. 

Thanks again, Ken   

[ORCoaster]

now I think I will look into upgrading the stock air filter to something external.

Suddenly I have a vison of a big cube on the roof or hood about the size of a mini fridge with adjustable flaps on it and 4 different filter components inside.

My day was way to stressful I think. 

[KenO]

Sorry I have let this discussion go for so long.  Had a personal folly and been recovering for the last year. 

Last weekend, pulled off the head and this is what I discovered:

The head gasket was definitely bad, lots of coolant leakage between cylinders and head bolts, the block appears fine.
The block deck is pitted and several of the bolts were a little rusty but look fine.  Chased all the threads with a tap and are in good shape.
Surprisingly, there isn't any real ring ridge or carbon build up in the cylinders at 180k miles (still has original clutch).
Somewhere in the past, the timing must have been off significantly enough to leave considerable witness marks from the valves in the tops of the pistons.  Wonder if that stretched the bolts and caused other issues?
The cracks between the valves are thin as a pencil line and look fine, the valves look reasonable.
When I do the fluid leak test on the valves, most do not hold solvent for more than 15 seconds.

So, some choices to make...
First off, I like this vehicle and would like to keep it rolling down the road if not too cost prohibitive.
I realize this is a 11mm engine and I doubt I can find a 12mm replacement near NW Wyo? 
The local machine shop will need 3 to 4 weeks plus and if everything is reworked/replaced, cost $400 plus. 
Should I gamble and have the head rebuilt, dive into it and do an ole fashioned lap job or purchase a replacement head? 
       The only 11mm heads I can find are at PP and new at that for $750, what other options are available?
       Or is there a better machine shop to send the head to? 

Looking to purchase head studs - thinking of APR 204-4701.

Have a mahle head gasket (3 lobe or notches, what came off) and a complete engine gasket set.

This is my dilemma and I have the green light to invest $1,000.  The body is great, no rust, just aged.

Suggestions?