TheSamba.com :: View topic - I think I overheated on the way home. Videos added!!

Sun Jul 06, 2014 7:09 pm

I was heading back home to Calgary from Kinbrook Island provincial park by Brooks today. Going there Friday was a breeze I was saying to my wife that the bus is running great. Coming home was another issue. Almost uphill all the way #1 highway until the Siksika Indian reserve turn off to the 901. Also with a headwind. At some points I couldn't get passed 70kph. My foot was to the floor most of the way and down shifting to 3rd and back to 4th. Also at one point The engine hesitated for a second like a miss. I pulled over and the oil light flickered at idle but went out when I reved the engine. You could smell the engine from inside. I limped it home about 100km Now it doesn't like to run and when it does it seems like it is running on three cylinders. I parked it for the night to cool off and I will check the compression after work tomorrow. Is there anything else I should check? I hear the valve seats are bad for pulling out on the type 4 engine. I drive a 1973 Campmobile. 1.7L solid lifter with a Weber progressive. Any tips would be appreciated. I recently purchased a VDO cht gauge but didn't put it in. I'm kicking myself now for not doing it. Thanks in advance!

Sun Jul 06, 2014 7:15 pm

Hi
Do the basics first. Pull, number and inspect the plugs, Valve adjust, Dwell, and timing.
Good Luck

Sun Jul 06, 2014 7:19 pm

Tcash wrote: Hi
Do the basics first. Pull, number and inspect the plugs, Valve adjust, Dwell, and timing.
Good Luck

Thanks Tcash. I will have a full report tomorrow night.

Sun Jul 06, 2014 9:20 pm

One nice advantage of the progressive is that most all of them are tuned to run on the rich side. :wink:

Mon Jul 07, 2014 7:41 pm

So I did a compression test and found 0psi in cylinder 1. Luckily I borrowed the shops borescope and found the exhaust valve was stuck open. After a valve adjustment I was back to 120 psi compression. Thanks for all your repair suggestions Tcash!

Here is the video. look at the valve at the top of the screen.

Mon Jul 07, 2014 9:25 pm

Nice video
exhaust valve was stuck open
If the valve was stuck open. You have a problem between the valve stem and valve guide. A vacuum gauge would show if a valve was sticking open.

If it was the valve adjustment was tight and hanging the valve open. You are ok.

Good Luck

Wed Jul 09, 2014 8:26 pm

Looks like I have more to contend with, I am getting a noise now. I talked to an old school Porsche tech today and he said he has seen this before and this noise is from a worn camshaft. I will be checking it out this weekend. probably measuring the lift on all the valves and doing some more borescoping.

Wed Jul 09, 2014 8:46 pm

Get a vacuum gauge. It is a great diagnostic tool.
Good Luck

Wed Jul 09, 2014 8:54 pm

Tcash wrote: Get a vacuum gauge. It is a great diagnostic tool.
Good Luck

I have one Tcash. Should I "T" it off the carb? Thanks for your time!

Wed Jul 09, 2014 10:15 pm

FreedomBuild wrote: Tcash wrote: Get a vacuum gauge. It is a great diagnostic tool.
Good Luck
I have one Tcash. Should I "T" it off the carb? Thanks for your time!
You need good manifold vacuum like the brake booster hose.

Wed Jul 09, 2014 10:43 pm

A progressive typically has one or more nipples that give manifold vacuum.

One or more ports will also have ported vacuum, meaning they will not have vacuum when the throttle is closed.

You want to use a nipple that give manifold vacuum and not ported vacuum.

Thu Jul 10, 2014 5:30 am

Thanks Wildthings. I think there is a port where manifold vacuum goes to the booster. I may t off there.

Thu Jul 10, 2014 7:59 pm

I had a chance to hook up the vacuum gauge to my bus tonight. I tee'd it up on the hose that goes from the manifold to the brake booster. I took a reading cold at high idle.

Then I took a reading with the bus at operating temp.

Then a reading while revving and dropping back to ide.

It all seems to point to late valve timing as per the diagnostic sheet I have for vacuum testing. I think I will double check my valve adjustments then check my ignition timing. I am thinking for ignition timing 35 deg advance @ 3500 rpm? Does that sound right? I have Pertronix mechanical advance distributor and flame thrower coil.

Thanks for the input!

Thu Jul 10, 2014 9:26 pm

Is that hoses on or hose off? For most setups you want 28-30° BTDC at 3500+ rpms, hoses off.

Thu Jul 10, 2014 9:55 pm

Wildthings wrote: Is that hoses on or hose off? For most setups you want 28-30° BTDC at 3500+ rpms, hoses off.

I have a mechanical advance distributor. Would it be the same?

Thu Jul 10, 2014 10:39 pm

FreedomBuild wrote: Wildthings wrote: Is that hoses on or hose off? For most setups you want 28-30° BTDC at 3500+ rpms, hoses off.

I have a mechanical advance distributor. Would it be the same?

Yes

Thu Jul 10, 2014 11:09 pm

Test your gauge on another vehicle. Your readings are low. You should see 16-20. Look at #5 in this video.
With your 120 compression readings you can rule that out.
Good Luck

http://www.thesamba.com/vw/forum/album_page.php?pic_id=1204766

http://www.thesamba.com/vw/forum/album_page.php?pic_id=838456

http://www.thesamba.com/vw/forum/album_page.php?pic_id=479390

Distributor Specs

Fri Jul 11, 2014 2:28 pm

Use a length of hose to search for exhaust leak/s near the cylinder head flanges...I'll bet you find 1 or more. The collars themselves can crack and leak (downstream from where they mate to head).

Fri Jul 11, 2014 5:04 pm

udidwht wrote: Use a length of hose to search for exhaust leak/s near the cylinder head flanges...I'll bet you find 1 or more. The collars themselves can crack and leak (downstream from where they mate to head).

Thanks! I will have to check that out.

Wildthings wrote: FreedomBuild wrote: Wildthings wrote: Is that hoses on or hose off? For most setups you want 28-30° BTDC at 3500+ rpms, hoses off.

I have a mechanical advance distributor. Would it be the same?

Yes

Thanks Wildthings.

Tcash wrote: Test your gauge on another vehicle. Your readings are low. You should see 16-20. Look at #5 in this video.
With your 120 compression readings you can rule that out.
Good Luck

Tcash I am approximately 1,048 m (3,438 ft) above sea level, that would cause lower vacuum readings too wouldn't it?

Fri Jul 11, 2014 5:28 pm

FreedomBuild wrote: udidwht wrote: Use a length of hose to search for exhaust leak/s near the cylinder head flanges...I'll bet you find 1 or more. The collars themselves can crack and leak (downstream from where they mate to head).

Thanks! I will have to check that out.

Wildthings wrote: FreedomBuild wrote: Wildthings wrote: Is that hoses on or hose off? For most setups you want 28-30° BTDC at 3500+ rpms, hoses off.

I have a mechanical advance distributor. Would it be the same?

Yes

Thanks Wildthings.

Tcash wrote: Test your gauge on another vehicle. Your readings are low. You should see 16-20. Look at #5 in this video.
With your 120 compression readings you can rule that out.
Good Luck

Tcash I am approximately 1,048 m (3,438 ft) above sea level, that would cause lower vacuum readings too wouldn't it?

Yes, higher elevation will yield lower vacuum and CR numbers.