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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Fri Nov 04, 2016 8:44 pm Post subject: 1300 problem diagnosis needed |
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1300 engine, dual port, new 30pict 1 carb, mechanical advance dist with built in electronic ignition.
Running poorly. Idle speed wanders 750-850 RPM. Sometimes stalls on deceleration. Seems to be low on power. Also an oil leak on right side which doesn't appear to be pushrod tubes.
Spark plugs in picture shows left bank-3,4- a beautiful reddish brown. Right bank, 1 is pure white and 2 is pure black. Like 1 is running way too hot and 2 perhaps too rich. The plug is just black, not filled with gunk like burning oil.
Compression 1-90, 2-90, 3-100, 4-105
Vacuum gage oscillates 14-16
Max advance set at 28 BTC. Max is reached about 2300 RPM
Can anyone give me a clue what the problem could be? |
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luvthemvws Samba Member
Joined: February 13, 2012 Posts: 117 Location: Middle of nowhere
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Posted: Sat Nov 05, 2016 12:45 pm Post subject: Re: 1300 problem diagnosis needed |
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I think the intake valve on #1 is stuck open. The #1 cylinder thus force-feeds #2 and makes it appear too rich. Also, pushing cylinder pressure up the intake valve stem and leading to leaks.
Pull the 1-2 valve cover and turn the engine with a wrench (ignition off). Watch carefully the movement of all rockers and valves on that side for equal movement.
Rock on. |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Sun Nov 06, 2016 2:05 pm Post subject: Re: 1300 problem diagnosis needed |
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Thank you very much. I think you nailed it except that the problem seems to be a crack under the valve rather than a sticking valve. There is a crack from the intake to the exhaust valves where they are closest together. There is also a crack running down the spark plug threads. Anyway, a replacement head is in order.
It looks like number 1 may have been leaking around the joint with the cylinder. At least, the top of the cylinder has wet oil on it which number 2 doesn't.
They both appear to have been leaking at the crankcase end. That would likely be the source of the baby marking her spot when parked. I read elsewhere (Muir update) that blue silicone sealant is the best thing to use at the crankcase end as opposed to the paper gasket. Is it reasonable to apply a bead of sealant without removing the piston from the cylinder completely?
On the other hand, it would be nice to get the cylinders out to get them clean. If so, is it better to remove the pistons from the cylinder or to slide them out enough to pull the wrist pins? There isn't much ridge at the top, so I assume there isn't much at the bottom. I don't think there are many hours on the rebuild.
And finally, any advice on finding a replacement head? There is a casting number in the top 113 101 375 A and 20. Is this sufficient for identifying a replacement head?
I really appreciate the help. I've never been this deep into a VW before. |
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tobiasax Samba Member
Joined: May 07, 2004 Posts: 202 Location: Sweden
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Posted: Sun Nov 06, 2016 11:51 pm Post subject: Re: 1300 problem diagnosis needed |
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These cracks are rather common. Many people have them on good running engines without knowing.
The cheap solution would be to re-tightsen the heads and see what happens. _________________ __________________________________________ |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Mon Nov 07, 2016 8:11 am Post subject: Re: 1300 problem diagnosis needed |
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But this isn't a "good running engine". Something is wrong. |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Sat Jun 03, 2017 3:40 pm Post subject: Re: 1300 problem diagnosis needed |
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Followup. I installed a new head. In the process found that the previous rebuilder had a copper sealing ring under cylinder 2 but none under 1 which left one cylinder higher than the other! I removed the ring and sealed the bottoms with Formagasket 3. I ran it a bit and started a tuneup. Valves adjusted, check compression. #1 120, #2 118. Plugs look same as before. #1 white, #2 black! I guess I eliminated a lot of possibilities. I swapped plugs left to right, on the unreasonable chance it was a spark plug problem.
It seems that for some reason cyl 1 is getting a lean mix and 2 is getting a rich one. Beats me how this is happening. An air leak could cause the lean, but wouldn't explain the rich.
Anybody have a clue where to look? Thanks,
storm |
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RolandD Samba Member
Joined: January 15, 2017 Posts: 247 Location: Menomonee Falls, Wis
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Posted: Sat Jun 03, 2017 8:14 pm Post subject: Re: 1300 problem diagnosis needed |
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What exhaust are you running?
Crazy Roland |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Sun Jun 04, 2017 4:47 pm Post subject: Re: 1300 problem diagnosis needed |
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Simple dual exhaust. The left bank-the good one- has started backfiring some on decelleration |
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RolandD Samba Member
Joined: January 15, 2017 Posts: 247 Location: Menomonee Falls, Wis
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Posted: Sun Jun 04, 2017 7:53 pm Post subject: Re: 1300 problem diagnosis needed |
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Like an old dune buggy? Not a 4 -into -1 and then a split into 2?
If like a dune buggy, what is the chance there is a restriction on the bad side?
Crazy Roland |
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vwjetboat Samba Member
Joined: May 11, 2017 Posts: 1732 Location: Florida
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Posted: Sun Jun 04, 2017 7:59 pm Post subject: Re: 1300 problem diagnosis needed |
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intake cracked between heat riser and intake part? only seen that once.. but there was a crack behind the intake between the tubes .. only found when off and had to look real hard.. |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Tue Oct 03, 2017 5:22 am Post subject: Re: 1300 problem diagnosis needed |
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The saga continues. 1300 engine, dual port, new 30pict 1 carb, through an adapter. I installed a new vacuum advanced distributor and my timing light shows it is working. Compression test- all 110-115. As a result of previous problems, the right head was replaced and it may not be exactly the same as the left one.
If I short out the plug for cyl 1 or 2 the idle speed drops drastically. Shorting out 3 or 4 has no effect! The plugs for 3 and 4 are each the beautiful tan I would look for in a good running engine. 1 and 2 are the black of a too rich mixture. The exhaust from the left bank is noticeably cooler than the right and has less volume.
Since this would possibly be the result of a vacuum leak, I sprayed starting fluid on the intake manifold which had no effect.
As expected, the engine runs poorly.
Anyone have a suggestion what should be checked next? |
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Slow 1200 Samba Member
Joined: July 02, 2004 Posts: 2106
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Posted: Wed Oct 04, 2017 4:25 am Post subject: Re: 1300 problem diagnosis needed |
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1-4-3-2? |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Wed Oct 04, 2017 10:49 am Post subject: Re: 1300 problem diagnosis needed |
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Slow 1200,
Thanks. As I thought over your answer I realized that interchanging leads to plugs 3 and 4 might cause all that I am seeing. I went with mixed emotions to check. If you are right, the fix is easy and I'm a dummy. If you are not right, I was not that stupid; but the car isn't fixed. So, I'm glad or sorry to report that it is wired correctly. I really want to thank you for making the effort. It was a great solution, just not correct this time. I also checked for tracking in the distributor cap and found none.
Still looking for ideas. |
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earthquake Samba Member
Joined: January 10, 2008 Posts: 3984 Location: SANDY VALLEY, NEVADA
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Posted: Wed Oct 04, 2017 1:27 pm Post subject: Re: 1300 problem diagnosis needed |
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How are the rubber boots between the intake and the end housings, they seem to crack on mine all the time. Must be the southern Nevada heat.
Casey _________________ 74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]
95 Chevy C3500 dually
98 Ford E150
Link to Kelly J. Nolte 3/20/53 - 11/6/08
https://time-zonelabs.blogspot.com/p/about-kelly.html
DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison] |
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Slow 1200 Samba Member
Joined: July 02, 2004 Posts: 2106
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Posted: Thu Oct 05, 2017 11:06 pm Post subject: Re: 1300 problem diagnosis needed |
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Stormc wrote: |
Slow 1200,
Thanks. As I thought over your answer I realized that interchanging leads to plugs 3 and 4 might cause all that I am seeing. I went with mixed emotions to check. If you are right, the fix is easy and I'm a dummy. If you are not right, I was not that stupid; but the car isn't fixed. So, I'm glad or sorry to report that it is wired correctly. I really want to thank you for making the effort. It was a great solution, just not correct this time. I also checked for tracking in the distributor cap and found none.
Still looking for ideas. |
too bad! hope you find the culprit |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Fri Oct 06, 2017 11:46 am Post subject: Re: 1300 problem diagnosis needed |
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earthquake wrote: |
How are the rubber boots between the intake and the end housings, they seem to crack on mine all the time. Must be the southern Nevada heat.
Casey |
I attempted to check that by spraying starting ether on them. I did pretty much the whole intake and detected no change. Someone else observed a crack in the intake and I wanted to check for that as well.
Why the best-looking plugs are in the cylinders that seem to be non-contributors is what is mystifying me. I can't even decide if it is fuel or electrical, but I'm leaning toward fuel. |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Oct 10, 2017 5:00 am Post subject: Re: 1300 problem diagnosis needed |
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If the center-section of the intake manifold is not properly inserted and lined up with the end-castings, it can trap fuel, would match your symptoms. Have seen it once or twice. |
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Stormc Samba Member
Joined: June 05, 2014 Posts: 21 Location: Elkins, NH
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Posted: Mon Nov 20, 2017 12:54 pm Post subject: Re: 1300 problem diagnosis needed |
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I want to provide closure, albeit unsatisfying. The synopsis so far. Spark plugs in R bank showed a problem. One white, one black. L bank were perfect tan. I removed the R head which was badly cracked. I bought a pair of heads, but only replaced the R one as the left seemed to be perfect. Engine running poorly, L plugs beautiful tan, R plugs black. Shorting out the plugs showed that the L bank was contributing nothing! Compression normal. No vacuum leaks detectable. Ran out of ideas.
Removed the L head and could find no problem with it or the manifold. Replaced the head and it is running well. Have not checked compression or cylinder balance or even checked the plugs, but the problem has been solved. Unfortunately, I still have no idea what the problem was.
Thanks to all the guys who attempted to help. I wish I had an answer to what was going on. |
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