Problem diagnosed? '78 Westy return from 4,000 mile trip.

Find/Fix/Report Back

Moderators: Sluggo, Amskeptic

Post Reply
Jivermo
IAC Addict!
Status: Offline

Problem diagnosed? '78 Westy return from 4,000 mile trip.

Post by Jivermo » Wed Aug 21, 2013 8:36 am

I did a quick compression check on my engine this morning, and may have found the source of my problems. If you followed my earlier post about the Westy missing under load during the last stages of my trip viewtopic.php?f=3&t=11576 you know the details pretty well. I had to do the test by myself, so I was running from the front to the back to check the gauge. I'm going to do it again, with my son, and squirt oil in the cylinders to see if the rings are involved. #1 came in at about 130, #2 at 70, #3 at 90, #4 at 90. When Colin and I adjusted the valves, when he was here in April, #2 looked a little suspect on the exhaust adjustment. If Colin decides to come by here next week, I guess we'll have an interesting time of it, between this engine and his popping out of 4th deal. Stay tuned!

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Problem diagnosed? '78 Westy return from 4,000 mile trip

Post by Amskeptic » Wed Aug 21, 2013 12:33 pm

Jivermo wrote:I did a quick compression check on my engine this morning, and may have found the source of my problems. If you followed my earlier post about the Westy missing under load during the last stages of my trip viewtopic.php?f=3&t=11576 you know the details pretty well. I had to do the test by myself, so I was running from the front to the back to check the gauge. I'm going to do it again, with my son, and squirt oil in the cylinders to see if the rings are involved. #1 came in at about 130, #2 at 70, #3 at 90, #4 at 90. When Colin and I adjusted the valves, when he was here in April, #2 looked a little suspect on the exhaust adjustment. If Colin decides to come by here next week, I guess we'll have an interesting time of it, between this engine and his popping out of 4th deal. Stay tuned!
This does not say too much . . . yet.

Type 4 engines are allowed to run at 76 psi so long as all cylinders are within 20% of each other. Three of your four are acting as a team. You have a one a BIG shot thinks its all the schizzle.

Now, you could be thinking, "I have one good cylinder and three weak ones."
But, you could be thinking, "I have three so-so cylinders and one carbon-loaded mess on #1 from a leaking valve guide that allowed oil to carbonize in the combustion chamber, raising the compression pressure on that one cylinder."

In reality, keep your diagnostic eyes open. If compression shoots up more than 30 psi, yes, rings on the low cylinders, see if it shoots up on #1 too, what the heck. You might need to pull heads to decarbonize and freshen up clean things, and you can do pistons and cylinders lickety-split at the same time.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

Jivermo
IAC Addict!
Status: Offline

Re: Problem diagnosed? '78 Westy return from 4,000 mile trip

Post by Jivermo » Mon Aug 26, 2013 4:43 am

Once again, it has taken me quite awhile to figure this interesting mystery out. The upside is that I keep learning about my bus. Turns out that my old Sun compression tester had a leak, so my cylinder tests were skewed. I bought a new tester, and all of my cylinders are in excellent shape-so that problem was ruled out. As Colin has said, be as happy when you are able to eliminate a suspect, as when you actually pinpoint the problem. I was. Saturday morning, I woke up determined to figure this thing out. I got my timing light out and managed to check the timing. It seemed very close to being right on the numbers. Aopisa had reminded me of Colin's Dictum #7: "Grounds, Grounds, Grounds!" I had gone over every ground in the bus that could be related, starting at the battery and transmission ground strap. All good contacts there. So, back to the vacuum front. By all indications, based on posts here and my Bentley, I had a vacuum problem. But I had LOOKED at all my connections, pulled the S boot and inspected that, and really eyeballed the entire hose system. Now, I decided, I was going to pull all of the hoses off, check them all for leaks, and replace any questionable sections. When I went to check the Intake elbow to aux. air regulator hose that drops down into the a dark recess, I found no resistance as I tugged on it. The metal tube had gradually slid down, and off the hose. A visual inspection looked perfectly fine...the hose appeared to be attached. I pushed it back onto the tune, clamped it, and started the engine. It purred. End of my suffering. So, yet another dictum: "Vacuum, vacuum, vacuum!" The good part is that I now have the experience under my belt to recognize the symptoms of a leak, and know that just a cursory visual inspection is not good enough to rule out this kind of problem.

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Problem diagnosed? '78 Westy return from 4,000 mile trip

Post by Amskeptic » Mon Aug 26, 2013 7:21 am

Jivermo wrote: yet another dictum: "Vacuum, vacuum, vacuum!" The good part is that I now have the experience under my belt to recognize the symptoms of a leak, and know that just :cyclopsani: a cursory visual inspection is not good enough :cyclopsani: to rule out this kind of problem.
Tell it, Brother Ian!
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
ruckman101
Lord God King Bwana
Location: Up next to a volcano.
Contact:
Status: Offline

Re: Problem diagnosed? '78 Westy return from 4,000 mile trip

Post by ruckman101 » Mon Aug 26, 2013 9:59 am

I love happy endings.


neal
The slipper has no teeth.

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Problem diagnosed? '78 Westy return from 4,000 mile trip

Post by Amskeptic » Mon Aug 26, 2013 2:11 pm

ruckman101 wrote:I love happy beginnings.

neal
Colin

Me too.
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

Post Reply