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Fri Sep 02, 2022 8:23 pm

Okay guys and gals.

VEHICLE: 1975 VW WESTY, MANUAL TRANS, 1800cc, FUEL INJECTED
Current dwell: 44 deg
Current timing: 4 deg BTDC set here or the recommended 5 deg ATDC. Doesn’t make a difference.

Name this sound, it is so random I don’t know what to think. Sometimes it is frequent and sometime it’s silenced. This is an engine noise and only presents itself under load. Bonus points for a fix. Your time is hugely appreciated. Thank you.

https://mavrikblakinc-my.sharepoint.com/:u:/g/pers...kcATidri4w

Fri Sep 02, 2022 9:35 pm

where is the noise loudest?

Carb or FI

Fri Sep 02, 2022 10:31 pm

Sounds like a game Robbie would play.

So my guess is lifters.

Fri Sep 02, 2022 10:43 pm

it's probably afterfire, due to your messed up timing.
You say the call out is 5 degrees After TDC? VW had some goofy emissions settings in the '74-'75 years, & it all works if the vacuum retard & advance cans are both working. Most times, the retard portion, the spigot pointing back at the distributor body, is long since blown out & you revert to the later 2.0L setting, meaning 7.5 degrees Before TDC, at idle, all hoses plugged. Checking that it gets to 28 degrees or so at 3,500 rpm, checking with a timing light on the VW scale of course. Then you hook up your advance hose, leave the retard off & plugged at the hose. Drive THAT. : )
Also, dwell, not really into it, when you set a new set of uncratered points, at .016", the dwell naturally falls in the vicinity of 48-50 degrees. We lube the rubbing block, drop a few droplets engine oil on the felt at the center of the distributor shaft (impeded oil vapor from getting up in there & wreaking havoc)
And we drive 12-14k with no further service. At least that's my way. YMMV.

Sat Sep 03, 2022 6:26 pm

timvw7476 wrote: it's probably afterfire, due to your messed up timing.
You say the call out is 5 degrees After TDC? VW had some goofy emissions settings in the '74-'75 years, & it all works if the vacuum retard & advance cans are both working. Most times, the retard portion, the spigot pointing back at the distributor body, is long since blown out & you revert to the later 2.0L setting, meaning 7.5 degrees Before TDC, at idle, all hoses plugged. Checking that it gets to 28 degrees or so at 3,500 rpm, checking with a timing light on the VW scale of course. Then you hook up your advance hose, leave the retard off & plugged at the hose. Drive THAT. : )
Also, dwell, not really into it, when you set a new set of uncratered points, at .016", the dwell naturally falls in the vicinity of 48-50 degrees. We lube the rubbing block, drop a few droplets engine oil on the felt at the center of the distributor shaft (impeded oil vapor from getting up in there & wreaking havoc)
And we drive 12-14k with no further service. At least that's my way. YMMV.

I’m going to try this and report back. Thank you!

Sat Sep 03, 2022 7:26 pm

Valves adjusted?
No tin screws dropped down the intake?
Intake system checked for vacuum leaks?
Fuel pressure check 28-38psi with no kinks in any hoses?

Put a vacuum gauge in place of the small decel valve hose. A needle tick along with he noise indicates a head/valve/cam issue. Most FLAPS rent them for free.

Robbie

Sun Sep 04, 2022 12:41 pm

Wishing you luck with it, I did neglect o mention WHY the 5 degrees After TDC timing gets tossed. It's the vacuum retard feature, that retard portion of the can is what pulls the points plate way back to that setting. So if you dare to set your idle timing there, with a known or unknown bad vacuum retard can, you've essentially set the entire timing curve back many degrees, never to arrive at the 28-30 degrees Before TDC these engines prefer to run at.

With a failed retard, the vacuum advance pull can only do so much, timing remains retarded, EVERYWHERE. The centrifugal advance weights can't correct it either. That's why a timing light is critical, to see/measure both idle spark event as well as full centrifugal spark event at higher engine speeds, then plugging the known good advance can up to the system to 'add' extra degrees as well.

Sun Sep 04, 2022 2:01 pm

Daddy are we there yet?

It is some kind of misfire. You need to listen closely with a piece of hose to find exactly where the sound is coming from to isolate the potential causes. when you tell us exactly where it is coming from we can tell you where to look next.

Sun Sep 04, 2022 2:21 pm

richparker wrote: Sounds like a game Robbie would play.

So my guess is lifters.

Thank you. Lifters are upgraded to the hydraulic version and set with 2 turns at TDC on each cylinder.

Sun Sep 04, 2022 2:23 pm

SGKent wrote: where is the noise loudest?

Carb or FI

Thank you. Centre of engine observed through hatch inspection cover. Fuel Injected.

Sun Sep 04, 2022 2:43 pm

8675-30-9 wrote: SGKent wrote: where is the noise loudest?

Carb or FI

Thank you. Centre of engine observed through hatch inspection cover. Fuel Injected.
Best Guess is you have either (1) an intake valve too tight. You are hearing it spit back into the plenum, or (2) possibly a loose intake valve seat but I do not hear a ticky tack sound that would indicate it.

Put a long screwdriver on top of the plenum and listen See if you hear it better. Also put the screwdriver or stethoscope next to the distributor and see if it is louder there. It should not be.

Mon Sep 05, 2022 4:29 pm

SGKent wrote: 8675-30-9 wrote: SGKent wrote: where is the noise loudest?

Carb or FI

Thank you. Centre of engine observed through hatch inspection cover. Fuel Injected.
Best Guess is you have either (1) an intake valve too tight. You are hearing it spit back into the plenum, or (2) possibly a loose intake valve seat but I do not hear a ticky tack sound that would indicate it.

Put a long screwdriver on top of the plenum and listen See if you hear it better. Also put the screwdriver or stethoscope next to the distributor and see if it is louder there. It should not be.

Thanks again. I'm on it. I am super attentive to detail when setting the hydraulic lifters. At TDC starting on cylinder 3 and for all cylinders, rotating 180 deg in the firing order, I back the rockers off completely, then tighten until there is no gap +/- 1/16 of a turn (a gentle tap on the pushrod side while holding the end to the valve to ensure no space between pushrod or valve, there is a very audible clacking when there is a gap present), then a full 2 turns (i have already completed this task with 1-1/2 turns and had the same results.)

As well, i had another NEW distributer I swapped yesterday with the same results. The original distributer with the one vacuum connection pointing back to the distributer is pooched on this port. The timing jumps around. The new one doesn't jump around, but only has the advance spigot ONLY, no reatrded one. Apparently these distributors are not found anymore in new or even good condition.

Maybe a leak-down test is needed here. Could this be a weak spring somewhere? The gas is only about a year old and I don't think these engines are that sensitive to octane levels, are they? Regardless, I am onto the next phase pinpointing sound here and will report back once again.

Mon Sep 05, 2022 5:21 pm

a vacuum advance only can will work just fine.
Around the Westcoast of the US, year old gas is a question mark, newer cars with solenoid-sealed fuel tanks may use it, but in older vehicles, the ethanol fuel collects water & ages quickly. Like unusable in a two-stroke engine in sixty days quickly. Four strokes have an easier time burning it but not by much.

Mon Sep 05, 2022 5:31 pm

there is a tiny spring inside the lifter, You have to be able to feel it still able to move to full extended before you take your two turns. I think you have that but if the sound is coming from the plenum it is either a misfire like a crossed plug wire or carbon track in the cap, or the valve is leaking. If a valve is leaking it is either adjustment or the seat. This assumes you have the timing set to approx factory for whatever distributor type that ended up in it.

[img]https://www.thesamba.com/vw/forum/album_page.php?pic_id=1778938[/img]

[img]https://www.thesamba.com/vw/forum/album_page.php?pic_id=1778939[/img]

Thu Oct 27, 2022 2:40 pm

SOLVED!!!! My apologies for the delay on this. This indeed was pinging. I had an aftermarket distributer installed in the engine there when this sound was made. I since tried another aftermarket new dizzy, with the same results. That is 2 distributors that gave me this problem. I assume it was because of a wrong curve on the distributors that differs from that of the dizzy's required for the fuel injected 1800??

I put the old distributor in there and WHAM it ran perfect through the gears. Problem is, that the timing jumps all over the place at idle and i can't get it perfect like i would like to!! SO. I am aware these dizzy are no longer available in any form so I am told. Anyone have any ideas on where to go from here for a new dizzy that can accommodate the FI curve requirements?? Please advise. You responses are appreciated.

I would like to thank you all for your attention and contribution to this thread thus far, so appreciative for this community!! :D 8)

Thu Oct 27, 2022 2:55 pm

https://www.thesamba.com/vw/forum/viewtopic.php?p=9425786
https://123ignitionusa.com/123ignitions/volkswagon/

Pricey ($$$), but well-made and either selectable or programmable curves. Available with simulated vacuum advance portion, too.

Thu Oct 27, 2022 4:15 pm

Bill at SparkWerks rebuilds them. That said, if the idle speed is close to 1000 RPM that will cause timing drifting, so will a timing light that is going out, or if the inductive pickup is directional, facing in the wrong direction.

Fri Oct 28, 2022 7:06 am

What is the part number on the side of your stock distributor?

205AB?

https://www.thesamba.com/vw/classifieds/detail.php?id=2179422

Even though this ad is old, looking at it might help you. This is from Bill Fowler

Sun Nov 13, 2022 11:28 pm

Thanks everyone. Bus is in storage now until April, so project on hold until the new year! Thanks to everyone who has helped out. Merry Christmas and Happy New Year in 2023. I will reach out then for sure. Take care.

Mon Nov 14, 2022 12:16 am

8675-30-9 wrote: Thanks everyone. Bus is in storage now until April, so project on hold until the new year!.

story time, so gather 'round

So many builders, rebuilders and shops like myself absolutely despise people like this.

Weather turns, car has a known issue and gets parked for months but when the roads are clear and it's 60* out all of a sudden they need (insert part/issue addressed) yesterday and get all pissed when they get told we are 6, 10 weeks backed up.

You would be wise to get on a list NOW because distributers, transmissions, engines aren't gonna be here tuseday from amazon. I mean seriously, I can't tell you how many times I have heard "well, the brakes were shit but the weather's nice so now I want to fix it"

My transmission guy goes thru this all the time. "trans was noisy in October but I want it fixed. What do you mean it won't be done until the end of august? It's May now!"

don't be that guy, and if you do want to be that guy, expect a long wait