Oil Pressure Blow-by?

[sludge20]

Hello gang.

Developed an interesting problem with my 58 frankenbug.

Successfully completed a full 12 volt conversion, rebuilt the entire brake system from scratch, and did a complete top end rebuild on the FO series engine this car has crammed in it.

I did replace the 28 PICT carb (interesting as it an original VW Solex, but does not indicate -1 or -2....).

I also installed a magnafire type points system.

Anyway, got everything timed and tuned (7.5 degrees BTDC, 800 RPM, 50 degrees dwell at 300RPM...etc....)

Within a week, I developed the infamous oil leaking out the rear seal only when running AND the car will not idle until it is well warmed up.

I have tuned, retuned, and adjusted. I even disabled the electric fuel and choke on the carb.

No mater what, I cannot get her to idle on her own unless I have a bit of pressure on the gas. Once warmed up, the exhaust backfire goes away too.

NOTE: I use Rob and Dave's directions for carb tuning, and both the Muir and Haynes books for timing.


Anyway, my theory is that I am developing excessive oil pressure once warmed up, and probably have an air leak somewhere on the intake that seals when the engine is warm.

The oil pressure issue shall be resolved shortly with a sand rail style breather box. I had brand new bail type covers and properly seated, brand new cork seals, but the passenger side one blew off while driving, my first indication of a pressure issue.


What is odd is that it does not mark its territory when parked.


Am I correct in my thinking, or am I missing something obvious?

[sjbartnik]

Do a compression test
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[glutamodo]

I think you are confusing oil pressure with crankcase pressure...
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Andy T.


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[sludge20]

Compression is 90 ish on each.


And correct, I misstyped which pressure I has discussing.

[Johnous]

vacuum leak?

[Eric&Barb]

Check that the valve cover seals have not drooped at the top making them into a kind of one way valve. Use stock valve covers with the top center dimple that VW came out with in the early 1970s to help prevent that from happening.

Having the breather tube from oil filler to air cleaner will help.

90 PSI is pretty low compression and hopefully the rings will seat in to improve that and reduce blow by.
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In Stereo, Where Available!

[sludge20]

[sludge20]

[Eric&Barb]

[sludge20]

I spent Friday troubleshooting and only found that the number three spark plug was slightly loose. I also went ahead and rerouted and installed the oil breather system. Was time for an oil change anyway, so I switched to a high mileage oil.The breather system now not only runs from the case covers, oil filler, and box, it outlets into the air cleaner. It also uses different routing of the hoses to prevent kinks.

Rectifying that plug issue helped a bit, but I still could not get the engine to run at idle.

I gave up due to the heat (had been averaging 100F with 90% humidity here all week) and restarted at zero dark thirty Saturday.

Found that the vacuum plug on the carb tube was bad. Created a solution for that as previously stated. Also double checked valve settings- they were all still right where they should be.

Also found a bit of corrosion on the distributor contacts. Stupid me, I put the old cap back on instead of the new one when I went pointless ignition.


The bug was now running much, much smoother, except it still would not idle.

Completely by accident I found the idle issue a few hours of profanity laden troubleshooting later. I had accidentally knocked the wire to the idle cut off solenoid when fiddling with the crab. I plugged it back in and still had the same problem.

Talk about embarrassing. I removed the solenoid, plugged the hole, and the bug has been running like a large primate after a forced reproductive action...

Never thought to even check it for over a week? Gah. Shame on me.

I also rechecked the compression a few times. Found out I was doing it wrong. Actual compression is is now around 125+/- except for three which is now averaging 110.

Wow. That breather completely solved my oil slinging issue in the engine compartment. After 25 miles of normal driving over the weekend I took it out on the nice and empty highway before work. I beat on it a bit, but was able to maintain 60mph without issue. Not a drop of oil anywhere afterwords.

Anyway, thanks to the folks here, and the other threads on this site. My bug has never better.

[Eric&Barb]

Great to hear you fixed it!! Yes, we all have those head banging moments... For some reason the easy fixes seem to be the easiest to skip or forget.

Thanks for updating this thread. Way too many threads out there where the OP just seems to fade away without posting the solution.
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In Stereo, Where Available!

[sludge20]

Well, perhaps I fixed it...

Ran GREAT up until this morning. Headed out to work, drove down to the corner store for a healthy breakfast of coffee and smokes. Wen to pull out of the lot and BANG sputter lug.....

Strangest thing. Managed to limp the car the two blocks back to my house.

Starting to wonder if there are some serious electrical issues.

Haven't really had time to troubleshoot yet due to work. Good think work is only six blocks from my house...

However, I did discover this: When sitting in may driveway on a slight incline, it starts right up and idles smoothly. As soon as I press the gas, it stumbles, backfires out the exhaust, and behaves as if it is starving for air.

Any thoughts before I go tearing into this project? I did check the fuel pump, filter, needle valve and float before I left. They were all in good working order.

Ill take a look at the timing when I get home this evening. I am hoping thats it, but my gut has me thinking that perhaps the doggone MagnaFire module went bad.

Sorry for the newbie type posts, I am about 15 years out of practice wrenching on VWs.

[Eric&Barb]

Look to see if the accelerator nozzle is partly or completely clogged.
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In Stereo, Where Available!

[Cusser]

I'd also confirm with a timing light that the distributor/spark is actually advancing.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Dauz]

pull the idle jet and blast some car cleaner through it

[Cusser]

[sludge20]

So, I got home from work and did some troubleshooting. Cleaning the carb was first on the list. Checked fuel lines and pump. Filter good. Checked the timing and it was spot on and advancing as it should.

Fired her up and drove away! Odd part is the carb wasn't dirty. Didn't find anything wrong. So I drove down to the pub for a quick pint. In the three blocks it takes to get there, suddenly the stereo shuts itself off and comes back on. Engine backfires...

Still running well, but there was a clue!

Sure enough, I finished my pint and MacBook, it won't run.

So I pull over and check my connections. Everything's good. Nothing grounding out. (Rang it through on a meter).

Started it back up, made it a block and kaput...

On e of my fellow bug owners happened to drive by so we started working on it in a parking lot I rolled into.

After proper discussion, we both agreed something was grounding out. So, one at a time we disconnected and reconnected wires from the circuit in question. Being it is an Frankenbug and years of previous owners created a Cthulu like mess of the wiring harness and painted over wires, etc. This was about all we could come up with.


Here is the mind blower: wasn't the radio, lights, or anything else logical.

Turned out the short to ground was in the wiper motor. Disconnected the wiper and she started right up.

That's a new one on me.


Thanks for all the advice!