

| Subject: | Re: When & why replace heads? A Friday Dennis Discussion. |
| From: | John Rodgers |
| Date: | Fri, 7 Apr 2023 22:45:01 -0500 |
Dennis and all. The many reasons, Dennis, you listed is why I FINALLY opted for the Subaru engine. I put a completely rebuilt 2005 2.5 L engine in my '91 CARAT. I got desparately tired of the troubles the 2.1 L wasserboxer was causing and the continuing cost of repairs. I am so very glad I did. For the most part trouble free operation, plenty of power, and better gas mileage. BUT I am keenly aware of the fact these engines can give trouble also. They are not perfect, but I find them better than the old WBX. The big plus is that this is a modern design, modern metallurgy, modern electronics, and parts are plentiful. I am enjoying the heck out of mine. On Fri, Apr 7, 2023 at 6:33 PM Dennis Haynes <d23haynes57@hotmail.com> wrote: > For many engines the cylinder heads and the sealing of the heads to the > block tend to be the first thing to require service. The Vanagon adds an > additional "dimension" to the opportunity for failure due to the method of > sealing at the top of cylinders and then the outer gasket sealing the water > jacket. > > As for removing the heads for repair or replacing them that is part of a > diagnostic and inspection process. The only reason that the heads would > really need to be replaced is if they are damaged or cracked. Fortunately > Waterboxer heads are available and relatively cheap. For most engines heads > get repaired including welding and machine work and there used to be > machine shops in many parts stores that provided those services. At current > labor rates even a simple valve seat grind and valve replacement will > quickly exceed the cost of anew head, especially if the guides also need to > be done. > > So lets look at the most common problems with the Waterboxer heads. > Probably the most common is leaking at the outer water jacket gasket. Next > is failure of the seal between the heads and the top of the cylinder(s). > > For the outer water jacket gasket leaking or failing, this is always due > to the gasket and/or the sealant failing. The failure could be just a > failure of the sealant causing a minor drip or the gasket actually spitting > and allowing for a near instant dump of coolant. Failures can also happen > quickly after a replacement due to inconstant dimensions of the gasket, the > case, head, and yes the cylinder barrels or the base of the bores that the > cylinder barrels sit on. I have had this gasket fail and embarrass me on a > number of occasions. > > For the sudden failure splitting over time, this is usually the result of > the gasket seal having a slow leak. Which will then cause the head to > corrode under the gasket. This corrosion will grow and eventually penetrate > the gasket forcing it to split on the flat surface. Sudden coolant loss. > This event is a trauma to the engine and can cause a lot of damage quickly. > Warped and cracked heads along with tweaking the head studs. If the outer > gasket is the only concern, if the head can be pulled without disturbing > the cylinders it is common to pull the head(s), clean the surfaces, also > clean the groove sand replace the o-rings on top of the cylinders, new > gaskets, with proper installation and torquing the heads may be all the is > needed to set things right. > > For the top of cylinder to head seals the usual symptom is in-ability to > keep the cooling system free of air and coolant being pushed out when > engine is heated and underload. Sometimes this is illusive only happening > after some extended driving period. This failure is almost always due to > the studs losing tension which can happen for a number of reasons. Also, if > the cylinders are not perectly square and level as a set, you won’t get a > good seal up there. This can be caused by miss matched or out of spec > cylinders or a worn, damaged, warped engine case. If the cylinders are > parallel but just a different height different thickness gaskets may be > used at the top of the barrels to compensate. You will need to make or have > made custom gaskets from copper sheet. > > One needs to consider that as part of removing the heads things can > quickly go wrong or be found that will move the job to engine replacement. > You need to be prepared for this possibility for both the time and money. > Keep in mind that for as much this engine can accept some repairs like may > automotive engines it is designed as a throw away. Going back to even the > beetle days these alloy based engines supplied as dealer supplied factory > rebuilds almost always had a brand new case. Rebuilt heads and most > internals, but always a new case. Many problems will come back to a bad > case. > > Dennis > > > > -----Original Message----- > From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Dan N > Sent: Friday, April 7, 2023 6:11 PM > To: vanagon@GERRY.VANAGON.COM > Subject: Re: When & why replace heads? > > *"My question is what are the main reasons for replacing heads and how do > you know when you've reached that point?"* > > Compression test and leak down test? - The rings and cylinder walls may > still be good but the valves and valve seats are worn... > > On Fri, Apr 7, 2023 at 3:01 PM David McNeely <davmcneely40@gmail.com> > wrote: > > > Very ignorant here, but my feeling is leaking heads mean it's time to > > do the job. Do you want the engine to blow up when moving at high > > speed (or any time for that matter)? > > > > On Fri, Apr 7, 2023 at 6:45 AM Spencer Allen <soxndubs1951@gmail.com> > > wrote: > > > > > I had my 85 stock westy inspected and some brake work done and the > > mechanic > > > says I should replace the leaking heads. I may have jumped the gun > > > and ordered the GW super duper ($$$) reworked AMC heads. The thing > > > is my OE heads have been leaking for the last 20 years and 60K I've > > > owned it. The major leaking occurs during the winters while it's > > > stored in my garage so when spring comes I have to top up the fill > > > tank with about a qt of coolant. Summer it does drip but nothing > > > major. Engine runs fine with no white exhaust smoke. My question is > > > what are the main reasons for > > replacing > > > heads and how do you know when you've reached that point? > > > Spencer > > > > > >
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