

| Subject: | Re: Engine Replacement Options |
| From: | David Kao |
| Date: | Tue, 12 Aug 2008 11:46:54 -0700 |
This is indeed an option. But the rule of you get what you pay does apply in this case I believe. A worn engine will never be the same with rebuilt parts, especially for critical parts like cylinder heads. I do wonder how well in general rebuilt heads perform. I am kind of reluctant to have my used AMC heads rebuilt. Either just use them as they are or forget about them and buy new. I always have fear getting near to a machine shop. David --- Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote: > Valve guides are replaceable. A beast of a job but doable. > The real problem of worn valve guides is worn intakes can cuase oil to get > sucked in and worn exhausts will allow exhaust into the crankcase. Fuel > injected cars tend to wear the intakes. The intake vlaves can get a stem > seal (washer) to keep the oil away from the guide. Same part as used on the > air cooled. > > Dennis > > > >From: David Kao <dtkao0205@YAHOO.COM> > >Reply-To: David Kao <dtkao0205@YAHOO.COM> > >To: vanagon@GERRY.VANAGON.COM > >Subject: Re: Engine Replacement Options > >Date: Mon, 11 Aug 2008 22:30:33 -0700 > > > >Yes, you are right that valve guides must be checked to be within > >the wear limit to be reusable. Bentley says to insert a new valve > >(not the old valve) into the valve guide. The end of the valve stem > >must be flush with the end of the valve guide then wiggle the valve. > >The wear limit in this case is 1.2 mm movement. I did not measure > >the wear on my OEM heads before I installed them on my 83.5. But > >I remember that I could barely wiggle it at all. I felt there was no > >possibility they had reached 1.2 mm. So I skipped the check with a > >dial measuring tool. The Valve guide wear on my AMC spare heads > >are more significant. But they are still much smaller than 1.2 mm. > >The heads are still fairly usable I believe. > > > >I am confident that my 83.5 Engine has a solid short block. But > >of course only time will tell. Currently it idles very nicely. It > >accelerates the way it is supposed to. The cooling system appears to be > >completely normal during my two recent trips to Yosemite. I am sure > >there are lots of miles to go still for this Westy. So I will not face > >a decision between rebuild or conversion any time soon. > > > >I hope to reach 200k miles before I will need another rebuild. > > > >David > > > > > > > > > > > > > >--- Mike <mbucchino@CHARTER.NET> wrote: > > > > > You need to measure the valve stem to guide 'wiggle' against the book > > > standard, to know if it's at or beyond the wear limit. The valve has to > >be > > > a certain distance off the seat; per the book. I don't remember these > > > measurements of the top of my head, but you can't judge without > >measuring. > > > And you're right, they need to be dry for an accurate measurement, the > > > lubricant will take up some of the play. > > > A engine with a new, strong top end has been known to be last straw > >for a > > > marginal bottom end. You may learn this old lesson first hand > >soon......... > > > > > > ----- Original Message ----- > > > From: "David Kao" <dtkao0205@YAHOO.COM> > > > To: <vanagon@GERRY.VANAGON.COM> > > > Sent: Monday, August 11, 2008 9:03 PM > > > Subject: Re: Engine Replacement Options > > > > > > > > > >I absolutely agree with you that I took a risk in not doing anything, > > > > not even checking, the short block. The reason was the 83.5 Westy had > > > > only 110K original miles. Most 1.9 WBX engine wore out from the heads > > > > first. Very few had short block problems. I bought the Westy when it > > > > was less than 60k mile young. I knew the history of it pretty well. > > > > I don't think I took too much a risk in assuming that the short block > > > > was OK. > > > > > > > > I have a pair of used AMC heads. It passed my alcohol leak test too. > > > > But when I checked the valve guides they were not as tight as that on > > > > my 83.5 heads. My 83.5 heads were VW OEM and were put on by a VW > >dealer > > > > only about 20k miles ago. I lapped the valves and checked the guides > > > > before doing the leak test. The guides were amazingly tight still. > > > > So I knew I had an excellent pair of heads to begin with. That's why > > > > I only replaced the cylinder/piston liners. The valve guides of my > > > > used AMC heads are definitely not as tight. If there is oil in the > >guide > > > > you won't feel a play when wiggle it back and forth. But if it is free > > > > of oil (clean and dry) then I can feel a play when wiggling it. > > > > > > > > I think the heads are still quite usable. But then it may be a > >question > > > > how long it will last and how well it will work. Nothing beats a new > >pair > > > > of OEM heads at $1000. If the budget permits that's the way to go. > > > > > > > > David > > > > > > > > > > > > --- Mike <mbucchino@charter.net> wrote: > > > > > > > >> The seating of all the valves is not the only thing that must be > > > >> checked, > > > >> when choosing to rebuild a head. You haven't said that you've > >removed > > > >> the > > > >> springs to check the valve-stem-to-guide clearances/ wear and > >cleaning of > > > >> carbon deposits. > > > >> > > > >> > I used alcohol for the leak test. I poured it to the opposite side > >of > > > >> > the > > > >> > valves and check for sign of leak on the valve stems. Mine had no > >leak > > > >> > for > > > >> > 3 minutes and possibly longer than that. > > > >> > > > >> > > > >> Removing the rods to replace the rod bearings and take the > >opportunity > > > >> to > > > >> inspect and measure the crank's rod journals. This may uncover > >damage > > > >> that'll point to a total overhaul; 'not checking' at this point in > >the > > > >> disassembly is a mistake. One that may bite you in the ass sooner > >than > > > >> later. It's not a huge step to go all the way at this point. > > > >> > > > >> > Rebuilding a short block is something I have not tried. > > > >> > > > > >> > David > > > >> > > > >> > > > >
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