| Author |
Message |
williamM
Samba Member
Joined: August 07, 2008
Posts: 4333
Location: southwest Arizona
|
 Posted: Sun Jun 23, 2013 8:06 am Post subject: |
 |
|
| williamM wrote: |
| BusBerd wrote: |
I actually had some time tonight so I went at it.
I took the fan pulley off (which required taking off a lot of other stuff.) and determined that the fan was indeed indexed correctly. My bus originally had AC (now gone) so there is a pulley behind the fan. I tried installing the fan without that pulley behind it, but the fan then binds to the fan housing and the fan will not turn. It need the unused AC pulley there as a spacer.
So I indexed the fan correctly again with the AC pulley behind it.
I also tried to find TDC a little more accurately and it does indeed put the indexing notch on the fan somewhere near 1 o'clock.
I don't understand. How can it be that far off. The cam or crank cannot jump out of sync unless you crack the case, right? I only went down to the pistons and cylinders. |
I would mark that spot on the pulley and use the degree band to set the timing at 28 degrees and call it fixed. The pulley can come off the fan - maybe it got put back on in the wrong place. |
Maybe
_________________
some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
|
| Back to top |
|
 |
twinfin
Samba Member
Joined: June 20, 2006
Posts: 62
Location: Santa Cruz, California
|
| Posted: Sun Jun 23, 2013 12:03 pm Post subject: |
|
|
Couple of thoughts???
1) Fan and Pulley mounting positions:
Look at photo above. Notice where the square notch in the center of fan (between 2 of the 3 mounting bolts) is in relation to the 0 degrees mark on the Pulley(11: oclock as was said earlier). This is the "correct" 1 of 4 possible mounting positions of the pulley on the fan as mentioned earlier.
2) Wrong notch scribed on pulley:
Correct me if wrong, but The Type 4 engine used in the VW 411/412 and Porsche 912E/914-4 are timed not by the pulley but through a hole at the top of the cooling box. The TDC mark on there fans are on the fan itself and corresponds with maybe the 1:o position you have.
Is it possible that you have a fan from one of these other engines and that the mark was scribed incorrectly on the pulley by another set of hands matching straight across from the 411 etc TDC fan mark???
3) Balancing a wrongly separated pulley and the fan:
Well sort of...
Though we know that this is a no no. It happened ...so the option's are:
A) Buy another fan assembly that was untouched (a gamble at that).
B) Send your fan/pulley, crankshaft, flywheel and clutch assembly off to be properly balanced as one spinning unit. That's how Jake does it.
C) Do what Ive personally ;o) seen "Clatter" do and use a Dial Indicator against the pulley while rotating the fan on the engine and nudging the almost tight pulley here and there for overall roundness then lock it down.
Let us know what the final outcome is for sure.
-Damon
_________________
________________________________
"It's knowledge to learn from your mistakes. But it's wisdom to learn from others!"
------------------------------------------
“He that goeth to bedde wyth Dogges, aryseth with fleas.”
"The Blue Submarine"
1977 Campmobile, Type 4 2.0 liter Federal, Non-Catalyst, Fuel Injected with Valvetrain from the type4store, 411 Heat Exchanger Preheaters, S&S Header, Supertrapp Silencer. ...and a lot of help from Clatter and TCash and friends! |
|
| Back to top |
|
|
Amskeptic
Samba Member
Joined: October 18, 2002
Posts: 8568
Location: All Across The Country
|
| Posted: Sun Jun 23, 2013 1:02 pm Post subject: |
|
|
| BusBerd wrote: |
I actually had some time tonight so I went at it.
I took the fan pulley off (which required taking off a lot of other stuff.) and determined that the fan was indeed indexed correctly. My bus originally had AC (now gone) so there is a pulley behind the fan. I tried installing the fan without that pulley behind it, but the fan then binds to the fan housing and the fan will not turn. It need the unused AC pulley there as a spacer.
So I indexed the fan correctly again with the AC pulley behind it.
I also tried to find TDC a little more accurately and it does indeed put the indexing notch on the fan somewhere near 1 o'clock.
I don't understand. How can it be that far off. The cam or crank cannot jump out of sync unless you crack the case, right? I only went down to the pistons and cylinders. |
You mentioned a tight spot as you rotated the engine, and I severely recommended that you not rotate the engine until you investigated.
There are a couple of causes of tight spots other than a split/reassemble the case error:
A) You rotated the engine with the flywheel off and the distributor drive gear in without a distributor pushing down on the drive gear. This will mangle the brass gear on the crankshaft and screw up your distributor indexing
B) You are in the middle of a camshaft gear failure. Chewed up cam gear teeth can give you a tight spot in the rotation and an inadvertent skip, but you would have evidence in the oil strainer and some pretty terrible noises.
I have seen a couple of instances of fans not indexed to the crankshaft correctly, where the little dowel has been crushed or mashed into the spacer. Then I see hack saw marks all over the pulley as people reinvented a TDC mark.
The hub merely needs to have a woodruff key correctly installed in the crankshaft and in the cut-out of the hub. You can inspect by removing the 13mm bolt with the special washer that holds the hub on.
For idiot proof fan/hub indexing, rotate the engine to put the little dowel on the hub at 10:30AM or whatever to allow the next fan-to-hub bolt to be at 12:00 sharp. The other bolt holes should be at around 8:00 and 4:00.
Now orient the fan before you insert it into the fan housing, dowel hole at 10:30 and a bolt hole at 12:00. Keep the fan loosely rotatable as you get all three bolts started and the hub and fan ought to index to each other successfully.
With a guaranteed fan-hub-crankshaft orientation, rotate engine until timing notch is lined up with the "0" on the scale, distributor-be-damned.
Now see which rocker arms have clearance, #1 or #3, don't even bother with #2 and #4.
If #1 has clearance, proceed. If not, rotate the engine 360* until #1 rockers have clearance.
(hydraulic lifters you don't get to check clearance, so instead make sure that #3 rockers are moving in opposite directions as you sweep before and after "0", then line up "0")
If you do not get:
A) #1 valve clearance with solid lifters
B) #3 overlap with hydraulics
at a known "0" with correctly assembled fan that has a factory notch on the inside pulley half, go to your weirdo 1:00 o'clock position and see if you do.
If so, engine choreography is botched.
Colin
_________________
www.itinerant-air-cooled.com |
|
| Back to top |
|
|
Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50338
|
|
| Back to top |
|
|
BusBerd
Samba Member
Joined: November 19, 2005
Posts: 834
Location: Minneapolis, MN
|
| Posted: Sun Jun 23, 2013 8:55 pm Post subject: |
|
|
| busdaddy wrote: |
| You've got a 1 in 4 chance it's right so line up the middle notch like Ratwell shows and put the ring on with the mark near the timing scale. |
Not sure what you mean "middle notch". I have not seen Ratwell's page on this.
| busdaddy wrote: |
Now.....how do you propose to align and balance the fan after reassembly? |
align and balance the fan? wha?
EDIT: I just saw your previous post. For some reason that did not show up before. I get your references now. THANKS!!
_________________
"The large print giveth and the small print taketh away."
1977 Westfalia Camper Bus 2.0L Fuel Injected Engine, Manual Transmission
Last edited by BusBerd on Sun Jun 23, 2013 9:31 pm; edited 1 time in total |
|
| Back to top |
|
|
BusBerd
Samba Member
Joined: November 19, 2005
Posts: 834
Location: Minneapolis, MN
|
| Posted: Sun Jun 23, 2013 9:16 pm Post subject: |
|
|
Well, well, well, I was right I was wrong.
It turned out to indeed be the fact that I put the outer pulley ring on the fan incorrectly (think I'll ever do that again?). Once I got everything back together I was able to set my timing to the timing scale.
and just for good measure, I took the starter off, took it apart, and cleaned the be-jesus out of it. Cleaning all the contacts inside. It was quite dirty where the brushes meet the thingy (coil?). It starts much quicker now.
So, to re-cap. After disassembling the fan months ago to sandblast it and clean it, I put the outer pulley ring back on incorrectly so that my timing marks were way off. Once I found TDC on #1, I took the fan off and disassembled it again so that I could put it back together correctly, indexing the TDC mark. (There are 4 screw points that are interchangeable).
Thanks guys!!!
Berd
Although it is beside the point now, here are some of the pics I took of the woodruff key and fan hub. It looked good to me. no gouging.
_________________
"The large print giveth and the small print taketh away."
1977 Westfalia Camper Bus 2.0L Fuel Injected Engine, Manual Transmission |
|
| Back to top |
|
|
BusBerd
Samba Member
Joined: November 19, 2005
Posts: 834
Location: Minneapolis, MN
|
| Posted: Sun Jun 23, 2013 9:49 pm Post subject: |
|
|
| Amskeptic wrote: |
You mentioned a tight spot as you rotated the engine, and I severely recommended that you not rotate the engine until you investigated.
There are a couple of causes of tight spots other than a split/reassemble the case error:
A) You rotated the engine with the flywheel off and the distributor drive gear in without a distributor pushing down on the drive gear. This will mangle the brass gear on the crankshaft and screw up your distributor indexing
B) You are in the middle of a camshaft gear failure. Chewed up cam gear teeth can give you a tight spot in the rotation and an inadvertent skip, but you would have evidence in the oil strainer and some pretty terrible noises.
I have seen a couple of instances of fans not indexed to the crankshaft correctly, where the little dowel has been crushed or mashed into the spacer. Then I see hack saw marks all over the pulley as people reinvented a TDC mark.
The hub merely needs to have a woodruff key correctly installed in the crankshaft and in the cut-out of the hub. You can inspect by removing the 13mm bolt with the special washer that holds the hub on.
For idiot proof fan/hub indexing, rotate the engine to put the little dowel on the hub at 10:30AM or whatever to allow the next fan-to-hub bolt to be at 12:00 sharp. The other bolt holes should be at around 8:00 and 4:00.
Now orient the fan before you insert it into the fan housing, dowel hole at 10:30 and a bolt hole at 12:00. Keep the fan loosely rotatable as you get all three bolts started and the hub and fan ought to index to each other successfully.
With a guaranteed fan-hub-crankshaft orientation, rotate engine until timing notch is lined up with the "0" on the scale, distributor-be-damned.
Now see which rocker arms have clearance, #1 or #3, don't even bother with #2 and #4.
If #1 has clearance, proceed. If not, rotate the engine 360* until #1 rockers have clearance.
(hydraulic lifters you don't get to check clearance, so instead make sure that #3 rockers are moving in opposite directions as you sweep before and after "0", then line up "0")
If you do not get:
A) #1 valve clearance with solid lifters
B) #3 overlap with hydraulics
at a known "0" with correctly assembled fan that has a factory notch on the inside pulley half, go to your weirdo 1:00 o'clock position and see if you do.
If so, engine choreography is botched.
Colin |
Thanks Colin! I just saw this now.
(I have hydraulic lifters).
Yes, I am worried about the slight tight spot in the rotation. It happens every other rotation. I only notice it when I am trying to turn the engine by hand. I have a feeling that it is one of the pistons that are rubbing against the side of one of the cylinders. When I brought my heads, pistons, and cylinders in to the machine shop, they said that one of the cylinders could not be reused because of the scoring along one side of it. So, I am wondering if one of the piston rods are slightly off. What would make the piston go in at a slight angle to score one side of one of the cylinders??
I could figure out exactly which cylinder it is, or narrow it down, because it happens at the same point in the engine's cycle each time.
It is not too severe. I mean, if the engine were out, I could still rotate it by hand in the tight spot, but with the engine in the bus the angle is too awkward for me to do that by hand so i use a wrench on the Alternator pulley.
_________________
"The large print giveth and the small print taketh away."
1977 Westfalia Camper Bus 2.0L Fuel Injected Engine, Manual Transmission |
|
| Back to top |
|
|
Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50338
|
| Posted: Sun Jun 23, 2013 10:10 pm Post subject: |
|
|
| BusBerd wrote: |
Yes, I am worried about the slight tight spot in the rotation. It happens every other rotation. |
If it happens every other rotation it would have to be cam or valve related. The piston goes up and down once with each rotation, while the cam does a full turn every two rotations.
You could remove your rockers and see if the problem goes away. If it doesn't go away then it has to be the cam itself. 
Maybe you are just seeing better compression on one cylinder than the others. This would be common with a brand new engine that wasn't broken in yet. |
|
| Back to top |
|
|
|
