1983 Vanagon Resurrection Part 1: Top End Rebuild

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asiab3
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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by asiab3 » Sat Mar 19, 2016 3:40 pm

Latest post of the previous page:

I'm not sure about the EGR, but backfires mixed with low power just screams "mixed plug wire order."

Intake backfires typically occur when combustion occurs with the intake valve open, or the exhaust valve doesn't let the charge out before allowing the next cycle to start.

1-4-3-2?
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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sat Mar 19, 2016 4:02 pm

SlowLane wrote:
energyturtle wrote:It seems to be coming from the EGR block off? I blocked it off with the original gasket and a piece of a coke can.
Did you sandwich the Coke can piece between the EGR valve body and the gasket? If so, the valve bobbin may have poked a hole in the thin aluminum. The bobbin sticks out from the mounting plane of the valve body.

If you just used a piece of Coke can for a blocking plate, well, that probably isn't going to work for very long, if at all.
I'm confused. The EGR body that is hooked to the throttle is still intact and functioning. I blocked it off at the top where the EGR tube attaches that comes from the metal filter on the exhaust manifold?

Scottie

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sat Mar 19, 2016 4:10 pm

asiab3 wrote:I'm not sure about the EGR, but backfires mixed with low power just screams "mixed plug wire order."

Intake backfires typically occur when combustion occurs with the intake valve open, or the exhaust valve doesn't let the charge out before allowing the next cycle to start.

1-4-3-2?
Robbie
Robbie, I totally agree. The firing order is correct based on where the rotor is pointing at TDC for #1 on the compression stroke. Spinning the road wheel to turn the crankshaft worked great by the way. My points were heavily worn. I'm replacing them tomorrow, putting on new plug wires, and go through another valve adjustment. Patience is not my strong point. I'm going to regroup and hit it the A M. Thanks again. I remember your first post on this forum. You have turned into a great resource. Super intelligent guy you are sir:)

Scottie

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by Amskeptic » Sat Mar 19, 2016 5:14 pm

SlowLane wrote:
As I understand it, the exhaust contact width controls the rate of heat transfer from the exhaust valve to the valve seat (and thus the head itself). Too wide a contact causes the valve to run colder than designed, and I guess also causes higher head temperatures?
Contact width has nothing to do with causing higher temperatures. The temperatures are created by combustion and the heat is going to leave however it can. The contact width is dealing with two parameters:
unit pressure
heat transfer

We would love a generous contact width to shed heat, but once the unit pressure drops (surface area divided by spring pressure) below rock crusher psi, then carbon gets stuck in the sealing area and pits the hell out of the valve contact stripe. I go for slightly wide on the exhaust, modern gasolines are cleaner, so why not take a little drop in unit pressure in the name of heat removal?
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by Amskeptic » Sat Mar 19, 2016 5:17 pm

energyturtle wrote:
SlowLane wrote:
energyturtle wrote:It seems to be coming from the EGR block off? I blocked it off with the original gasket and a piece of a coke can.
Did you sandwich the Coke can piece between the EGR valve body and the gasket? If so, the valve bobbin may have poked a hole in the thin aluminum. The bobbin sticks out from the mounting plane of the valve body.

If you just used a piece of Coke can for a blocking plate, well, that probably isn't going to work for very long, if at all.
I'm confused. The EGR body that is hooked to the throttle is still intact and functioning. I blocked it off at the top where the EGR tube attaches that comes from the metal filter on the exhaust manifold?

Scottie
Not significant to this inquiry. Backfires, of course find the weak spot in the exhaust system, but the source of the backfiring is the problem.
ColinCokeCanEquippedSince1978
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sat Mar 19, 2016 5:39 pm

Backfiring out the intake, and look for the weakness in exhaust? I sealed it up tight. If I stick a tater in the exhaust pipe the engine dies immediately. Yes, its called a TATER.
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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by SlowLane » Sat Mar 19, 2016 10:39 pm

energyturtle wrote: I'm confused. The EGR body that is hooked to the throttle is still intact and functioning. I blocked it off at the top where the EGR tube attaches that comes from the metal filter on the exhaust manifold?
Okay, got it. I thought you had put the blocking coke can piece between the EGR valve body and the intake plenum.

The location you have chosen, the intake to the EGR valve, will work, as long as the EGR valve itself isn't leaking. There is a rubber diaphrgm inside the valve which is prone to failure. If it is cracked or split then that's another potential source of vacuum leak.

If you don't require the EGR valve for emissions inspection, why not just remove it entirely and bolt on a proper blockoff plate? Parts that aren't there are parts that wont fail.
'81 Canadian Westfalia (2.0L, manual), now Californiated

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sun Mar 20, 2016 6:59 am

SlowLane wrote:
energyturtle wrote: I'm confused. The EGR body that is hooked to the throttle is still intact and functioning. I blocked it off at the top where the EGR tube attaches that comes from the metal filter on the exhaust manifold?
Okay, got it. I thought you had put the blocking coke can piece between the EGR valve body and the intake plenum.

The location you have chosen, the intake to the EGR valve, will work, as long as the EGR valve itself isn't leaking. There is a rubber diaphrgm inside the valve which is prone to failure. If it is cracked or split then that's another potential source of vacuum leak.

If you don't require the EGR valve for emissions inspection, why not just remove it entirely and bolt on a proper blockoff plate? Parts that aren't there are parts that wont fail.
That it what I was looking for. Makes total sense. I did not know the function of the EGR, nor was I aware of the diaphragm. I will remove it this morning, do some further tuning, and report back this afternoon. Thanks a bunch bus brother. The struggle is real:)

Scottie

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by SlowLane » Sun Mar 20, 2016 8:57 am

energyturtle wrote:
SlowLane wrote:The location you have chosen, the intake to the EGR valve, will work, as long as the EGR valve itself isn't leaking. There is a rubber diaphrgm inside the valve which is prone to failure. If it is cracked or split then that's another potential source of vacuum leak.

If you don't require the EGR valve for emissions inspection, why not just remove it entirely and bolt on a proper blockoff plate? Parts that aren't there are parts that wont fail.
That it what I was looking for. Makes total sense. I did not know the function of the EGR, nor was I aware of the diaphragm. I will remove it this morning, do some further tuning, and report back this afternoon. Thanks a bunch bus brother. The struggle is real:)
Indeed it is, and sometimes one wonders if it is all worth it, until you get behind the wheel and the van runs like it was intended to.

The block-off plate doesn't need to be anything special. Just as long as it is flat enough to form a seal against the gasket and thick enough to not bend when gently torqued down. Also, the mounting holes in the air plenum are open to the interior of the plenum, so you should give some thought to sealing the mounting bolt threads with some sort of sealant.

In fact, before I had to resurrect the EGR on my van for California emissions, I think I had blocked off the EGR hole in the plenum by threading it with a 1/8" NPT tap and screwing a brass NPT plug into it. was simpler than fashioning a plate.

Whichever way you go, don't discard the EGR parts. The EGR filter in particular is getting hard to find for Federal emissions Vanagons, and the supply of good EGR valve bodies is thinning out as well. Save the gaskets too. There should be one gasket with a tiny orifice that meters the amount of exhaust gas that actually gets injected into the engine. It should have been in the location where you put your coke-can fix. If you hang onto all the pieces, you can probably sell them for good coin to some poor sap who is trying to get his Federal emissions Vanagon to pass smog in CA.
'81 Canadian Westfalia (2.0L, manual), now Californiated

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sun Mar 20, 2016 1:02 pm

Block off worked great. I disconnected the entire assembly at the side of the plenem. Now it back fires through the tailpipe. Yay! Points are shot. I'm going through that and timing. More to come soon. Progress!
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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sun Mar 20, 2016 5:22 pm

https://m.youtube.com/watch?v=hFqAbkJByNY
Here is the finished product. Thanks to everyone for the help.
Scottie

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by energyturtle » Sun Mar 20, 2016 8:06 pm

Amskeptic wrote:
energyturtle wrote:
SlowLane wrote:
energyturtle wrote:It seems to be coming from the EGR block off? I blocked it off with the original gasket and a piece of a coke can.
Did you sandwich the Coke can piece between the EGR valve body and the gasket? If so, the valve bobbin may have poked a hole in the thin aluminum. The bobbin sticks out from the mounting plane of the valve body.

If you just used a piece of Coke can for a blocking plate, well, that probably isn't going to work for very long, if at all.

I'm confused. The EGR body that is hooked to the throttle is still intact and functioning. I blocked it off at the top where the EGR tube attaches that comes from the metal filter on the exhaust manifold?

Scottie
Not significant to this inquiry. Backfires, of course find the weak spot in the exhaust system, but the source of the backfiring is the problem.
ColinCokeCanEquippedSince1978
Colin,I just read this again. and I missed it the first time. You meant the backfire will find the weakest point to escape, right? The source of the backfire was loose intake bellows, horrible points, and a busted EGR diaphragm. Solution: new points, fresh valve adjustment under fully pumped up lifters, hose clamps on the bellows, cork and coke can for EGR delete, set the dwell, and adjusted the AFM. Thanks again to everyone that chimed in on this thread. It was greatly appreciated!
Scottie
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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by weswsimpson » Sun Oct 23, 2016 7:12 am

I had the back fire through the intake issue and it was bad hydraulic lifters and thus poorly timed valves. I used an inspection camera through the spark plug holes and that really shows you if your valves/lifters are working as they should.

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by Amskeptic » Sun Oct 23, 2016 4:18 pm

weswsimpson wrote:I had the back fire through the intake issue and it was bad hydraulic lifters and thus poorly timed valves. I used an inspection camera through the spark plug holes and that really shows you if your valves/lifters are working as they should.
Define "poorly timed valves".

Valves are timed solely by the camshaft gear-to-crankshaft gear index marks.
Colin ?
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by weswsimpson » Thu Oct 11, 2018 9:24 pm

I had stuck or compressed lifters that wouldn't "pump-up" which resulted in valves that wouldn't fully open using the traditional method of adjusting valves. I should have said poorly "adjusted."

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Re: 1983 Vanagon Resurrection Part 1: Top End Rebuild

Post by Amskeptic » Fri Oct 12, 2018 7:52 pm

weswsimpson wrote:
Thu Oct 11, 2018 9:24 pm
I had stuck or compressed lifters that wouldn't "pump-up" which resulted in valves that wouldn't fully open using the traditional method of adjusting valves. I should have said poorly "adjusted."

I waited nine days shy of two years to read of this most-important clarification . . . :cyclopsani:
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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