Lots of Smoke and Low Compression Help

mykafone

I need a little help again on my 1835 buggy

Running good, then it started to produce lots of smoke and you can tell it is burning oil.

Pulled the plugs and the two forward(1 and 3) front spark plugs are really oily and lots of build up all over them.

Did a compression check. all 150# except #3 which is 120#. slowly turning the motor over you can audibly hear #3 "swwissssh" as the motor turns over.

pulled the end of the header off so I can see 4 separate exhausts and 95% of smoke seems to come from cylinder 1.

I pulled the head off of the side with low compression and there is no scratching of any sort on they cylinders so hopefully the rings are ok. there is a ton of build up on the head and the valves.

cylinder and valves for #3

Image may have been reduced in size. Click image to view fullscreen.

cylinder and valves for #4

I haven't pulled the head on the other side yet but I will tonight. Based on some phone advice from my bother in law I pulled the head and am planning on taking them to machine shop to have them checked out.

any thoughts? any advice? Why is the problem on the two front cylinders and not just one side? Thanks in advance

Bajaman65 · Posted: Thu Apr 16, 2015 5:36 pm Post subject:

What carb's are you running? Single or Dual? Those are thin wall 92's, did you over heat it? We need more info. Confused

TURBOEDVW · Samba Member Joined: July 13, 2004 Posts: 181

Are those 90.5s?? That would be a 1776? Look like AA pistons to me. I broke an AA ring land but it was from detonation and 15 psi boost.

mark tucker · Posted: Fri Apr 17, 2015 7:12 am Post subject:

head joints looked to be leeking some,not bad,probably when cold.pull cylinders&check pistons&rings for breakage & tension . pull appart heads check guides&vj,port if needed clean & reassemble after all is right.use stainless ex valves(or both in&out stainless valves)gap keepers.cut out step,set deck to 0 and use .040 copper head gadgets.tune properly,remove rag from fan and go have fun.

SBD · Posted: Fri Apr 17, 2015 8:39 am Post subject:

It's all because of those EVIL Type III COOL TINS! #Bad Talk

:2gunfire: Shhh

Unless this engine has a Type III cooling system. Then it was something else. Liar

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W1K1 · Posted: Fri Apr 17, 2015 11:37 am Post subject:

check the valve guides, thats where mine was. It was a big white smoke show. One guide fell out and was mushroomed up under the valve
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1965 squareback 1500E
1971 bay window westy- subi swap

vwracerdave · Posted: Fri Apr 17, 2015 3:18 pm Post subject:

mykafone · Posted: Fri Apr 17, 2015 7:38 pm Post subject:

It has dual Kadron carbs on it.

I'm new to the hobby, minus a vw bug when I was 14, and I felt like I had the carbs dialed in pretty well. I was always tinkering with them. My gut feeling is yes I probably ran it too lean, but I've driven the heck out of it and when this happened it was in a short trip to the gas station. Soooooo????

I was told it was an 1835 but by all means I would not be surprised if it's not. Honestly I don't even know how to tell. The piston seems to have 90.43 stamped on it.

modok · Posted: Fri Apr 17, 2015 8:40 pm Post subject:

Check the rings and check the guides.
You cannot SEE if a ring is sealing or not, but you can check the gap and side play. There is a lot of DUST on those jugs, too much of that kills the cast rings very fast unless it has good airfilters

Dr OnHolliday · Posted: Fri Apr 17, 2015 10:01 pm Post subject:

Your rings are toast, and the heads will need disassembled and cleaned up too
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1965 Type 1 sunroof Baja / about 70k miles on self-rebuilt '74 1600 and counting / SP heads and aftermarket valve keepers / non-doghouse shroud with external cooler and filter / 1.5 qt extended sump / Weber 32/36 DFAV progressive carb / 009 dist with Pertronix / 1.25 ratio rockers and ball adjusters / 1.5" stainless steel J-pipes and carbon steel baja exhaust

g3bill · Posted: Fri Apr 17, 2015 11:59 pm Post subject:

Please let us know what caused this damage when known. I'm looking at the AA Hypertec piston sets but with thick wall. Seeing as there made in China I dont know the quality, also wonder if the rings were made there also, if so I'd most likely install better rings anyway if rings are interchangeable from brand to brand? I thought thin walled P/C sets were ok with bugs or light weight VW's... I wonder about the discoloration of the one jug, like it over heated?
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Quokka42 · Posted: Sat Apr 18, 2015 12:05 am Post subject:

90.5 usually aren't thought of as "thin walled." The AAs come with nice cast iron rings that seal quickly, but yes you can replace them with others easily enough - they are a standard size. A broken ring or dropped guide are the most likely answers, but we'll have to wait and see.
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mykafone · Posted: Fri May 01, 2015 11:04 am Post subject:

Ok I took both heads down to the machine shop and had em checked out. All good.

I took the cylinders next and had em mic'd. they were .004 on the bottom and .005 on top.

I believe that is within spec according to the back of my parts magazine. It says side clearance is .004-.016 Does this sound correct??????????

So I guess im going to slap on new rings and give her a whirl.

How do I know what thickness of rings to choose from?

It looks like it has "total seal rings on it" since there is one on top and two on bottom. but im not sure.

Any more advice would be greatly appreciated to get me through this project.. Thanks

bugguy1967 · Posted: Fri May 01, 2015 11:01 pm Post subject:

How did the machine shop check them? If the chambers aren't blasted or had the carbon removed, they didn't check well enough. If you had adequate clearances, no signs of bad scuffing, and your heads were fine, there wouldn't have been a problem. I think a crack in the chamber is the issue. Was there any pooled up oil in any of the chambers?
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"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

mykafone · Posted: Mon May 04, 2015 11:12 am Post subject:

Im not sure how he checked em. He just told me they were all at "40"(i think thats what he said) and good to go.

There was oil pooled in the #1 cylinder when I pulled it.

Ive checked everything over for cracks and I didnt see any, but I will check again more thoughly tonight.

W1K1 · Posted: Mon May 04, 2015 11:32 am Post subject:

this you couldn't see from the outside of the heads, but it had all the same symtoms you describe. A ton of smoke & oil, and it fell out when I pulled the valve.

_________________
http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap

mykafone · Posted: Thu May 07, 2015 9:24 am Post subject:

I closely inspected the heads again and no visible cracks.

After closer inspection of the pistons and rings I noticed that the oil rings on the 2 cylinders that had the most carbon buildup were showing signs of wear. the inner ring is showing wear ont he little bumps in the rings. the cylinder that had the oil inside has the most wear on this ring. could this be the issue??

Boolean · Posted: Thu May 07, 2015 7:37 pm Post subject:

Sounds like they only checked if the valves leaked.
That is not your issue, and the heads needs to be taken apart.
I'm guessing the problem is in the heads.
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modok · Posted: Thu May 07, 2015 8:57 pm Post subject:


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