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ashman40
Samba Member
Joined: February 16, 2007
Posts: 15987
Location: North Florida, USA
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 Posted: Mon Oct 26, 2020 11:07 pm Post subject: Re: H30/31 PICT with SVDA distributor |
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| ashman40 wrote: |
| hvactaylor wrote: |
| Can anybody tell me about the 3 degree retard on the #3 lobe that VW put in their distributor because the oil cooler sits in the fan housing and the #3 cylinder takes the brunt of that heat? Is that still a consideration on the single ports? I don't ever hear talk about that anymore. |
Is your SP engine still running the original oil cooler inside the fan housing? Upgrading the oil cooler to a doghouse was a common upgrade. |
To add to my comment, the need for the retarded #3 ignition timing was the oil cooler that blocked airflow to cylinder #3. When VW went to the doghouse oil cooler it allowed better airflow to #3. Since then, VW stopped retarding #3.
If your current fan shroud is the non-doghouse style, having a distributor with a retarded #3 is a benefit.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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hvactaylor
Samba Member
Joined: December 01, 2019
Posts: 10
Location: KS
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| Posted: Tue Oct 27, 2020 7:41 am Post subject: Re: H30/31 PICT with SVDA distributor |
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| My cooler is still in the fan shroud. |
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ashman40
Samba Member
Joined: February 16, 2007
Posts: 15987
Location: North Florida, USA
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| Posted: Tue Oct 27, 2020 2:13 pm Post subject: Re: H30/31 PICT with SVDA distributor |
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| hvactaylor wrote: |
Can anybody tell me about the 3 degree retard on the #3 lobe that VW put in their distributor because the oil cooler sits in the fan housing and the #3 cylinder takes the brunt of that heat? Is that still a consideration on the single ports? I don't ever hear talk about that anymore.
| ashman40 wrote: |
| Is your SP engine still running the original oil cooler inside the fan housing? Upgrading the oil cooler to a doghouse was a common upgrade. |
My cooler is still in the fan shroud. |
If you plan to fix up your SVA distributor and it has the retarded #3 cam lobe, it is very important to install the distributor correctly so it is #3 cylinder's ignition that gets retarded.
Steps to follow:
Manually rotate the crank pulley to get the engine into position so #1 cylinder is at the end of the compression stroke near TDC. Do this by rotating the crank CW while you watch the #1 intake valve open (start of intake stroke) and then close (start of compression stroke). Continue rotating another 180 crank deg until the TDC/timing mark on the crank pulley lines up with the case split. You are now at the end of the compression stroke for #1 cylinder (TDC).
Remove the distributor from the case and look down at the drive gear inside the case. The top should look like this:
Adjusting the gear by 1-tooth will rotate it by 30deg (there are 12-teeth on the gear). Due to production tolerances, your drive gear may be off by as much as +/-15deg from the above pic. Less than 15deg off is acceptable. But if it is more than 15deg off from the above pic you will need to adjust the gear until it closely matches the above pic.
(Proper drive gear orientation is not normally critical for most distributors that fire every 90deg of rotation, as long as you make sure #1 cylinder receives a spark at the correct time it doesn't matter where #1 plug wire is installed on the cap. But with a VW distributor that has the retarded #3 cam lobe you MUST ensure the correct cylinder is retarded. This means you must install the distributor & its drive gear as specified per the factory specs (above pic).)
When your drive gear is oriented correctly, install your distributor so the cog at the bottom snugly engages the offset slot in the top of the drive gear. It will only fit one way.
Note where the rotor is pointing. This is where the #1 spark plug wire needs to be installed on the distributor cap so it will deliver a spark to the #1 cylinder which is at the end of the compression stroke.
Rotate the distributor body so the #1 plug wire notch on the rim is below the rotor tip. This notch now represents your #1 plug wire position.
Static time your #1 cylinder to TDC (or whatever your distributor model should be timed to). Make sure the test lamp turns ON at the point where the timing mark lines up with the case spit while rotating the crank pulley in the CW direction.
Rotate the crank pulley 360deg until the TDC mark once more lines up with the case split. This is TDC for cylinder #3.
Check the static timing for cylinder #3. You should find that the test lamp only turns ON AFTER the TDC mark passes the case split... about 3deg after. This confirms your #3 cylinder is firing 3deg retarded from #1.
!! If you find that as you rotate the crank pulley CW the test lamp for #3 cylinder turns ON BEFORE the timing reaches the case split... you have done something wrong and the #1 and #3 positions around the distributor are reversed. It is #1 cylinder that is retarded, cylinders #2, #3 and #4 are firing more advanced than #1. Start over.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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