TheSamba.com :: View topic - 1600cc Oil Leak In Between Cylinder and Head- 1970 Bus- HELP!!

Sat Apr 16, 2016 5:19 pm

Hello,

I have a brand new 1600 engine, the only rebuilt parts are the block and heads. Everything else is new. I ran the engine for about 80 miles and I noticed I had a leak that appeared to be coming from the valve covers because it was all over my heater boxes. I replaced gaskets and valve covers, but the oil leak did not go away. I used german cork gaskets and SCAT valve covers. Even after making these changes, my bus continued to leak oil, thus after a good look, I noticed that the oil leak was coming from where the heads and cylinders mate. I have no clue how this is happening because the head studs were torqued to specs. Furthermore, the cylinders (AA) are new and the heads have been machined. I took out my engine to take a closer look, see photos to reference the problem I just described.

ANY HELP WOULD BE VERY VERY GREATLY APPRECIATED!!

Note: head studs were torqued to specs in a "star pattern"

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Sat Apr 16, 2016 5:29 pm

There are two things going on but I cannot tell you if the first one is due to not breaking in yet or whether it is because you have a problem with the rings.

1) When you look at the top of the piston you will see it is clean around the edge and bottom. This is where the oil has washed the carbon away. Typically this pattern means oil is washing past the rings. With 80 miles on it there is no way to tell if it is because the rings are not bedded in, or because you did not install the rings properly, or because it is overfull with oil. The breather must be clear too for the crankcase pressure to release itself, so if you did not do the breather right that could cause it.

2) the cylinder did not seat in the head. The oil washing past the rings is being pushed out between the head and the cylinder barrel.

I cannot tell you how to fix it. Typically when I build an engine I have every step done that must be done so that I do not have these kinds of problems. In your case you can have a bad cylinder that is perhaps not parallel, the case can be uneven or the head can be warped. Also if you did not follow the torqueing pattern and tension that can also cause it.

Sat Apr 16, 2016 5:59 pm

Thank you Steve.

In regards to the rings not being installed properly, that could very much be the problem. I had a VW guy here in Houston with 20 years of experience install the rings on the piston heads. I took out the AA rings and replaced them with American made rings, can't recall the name brand, but they're supposed to be McDaddy rings. However, I installed the cylinders myself, it was my first time doing it, so perhaps I did something wrong. I followed the bug me video step by step. I did quite a bit of research on ring alignment (the openings were placed in a manner where none were stacked on top of each other) all were positioned at somewhat opposite ends. If i remember correctly, I placed them at 4 o'clock, 8 o'clock and 12 o'clock.

The oil leak problem I'm having is not only on cylinder# 1, I also have the same problem on cylinder# 3. Does this mean anything? 2 cylinders don't have problems, but the other 2 on opposite ends do.

Thanks,

Luis

Sat Apr 16, 2016 6:19 pm

Deves rings perhaps?, I've had a few sets come up weak lately for other brand engines, engines that are a lot more challenging to get out and dismantle than a VW's :evil:

That head wasn't sealing fully, when you lapped the barrels did you notice if the top fin was making contact with the bottom of the head by any chance?
Did you measure the barrels for height and check thier squareness when on the case?

Sat Apr 16, 2016 6:51 pm

BusDaddy,

I still have the box for the rings I was talking about, the brand is Hastings, they were manufactured in Hastings, MI. Below are several pictures showing the spacing between my head and cylinders. Let me know your thoughts.

Sat Apr 16, 2016 6:55 pm

busdaddy wrote: Deves rings perhaps?

I will never use deves ring again....my first time using them = freight train. than God it was on my own engine....not a clients.

I agree with steve...you can clearly see where the cylinder didn't seat in that 1 hole.

also, people have a REAL bad habit of over oiling the rings/pistons during a build.

when I do them, everything is spotlessly clean and I wipe a thin (think fingerprints on a window kind of thin) oil in the cylinders only, then assemble.

busdaddy...Deves are made by those evil sweed's (pricks!)

Sat Apr 16, 2016 7:22 pm

Vaaaahhhttt?, ju guts sumtin againnnst da peoples from da low countrrriez?

You are lucky it was your own build, I didn't experience that luxury :cry:
And yes, they were wiped off before dropping them in the holes, no slobbery drool oil job here, bottom line is the oil rings were just too weak, grrrrr.... :wink:

Sat Apr 16, 2016 7:29 pm

busdaddy wrote: Vaaaahhhttt?, ju guts sumtin againnnst da peoples from da low countrrriez?

yea, I do....especially when it costs me time and money (truth be told, I have yet to fix it...I just feed it's habits.

to the o/p you need to check that the cyls are LEVEL when snugged down to the case, usually by using a bunch of washers/sockets to snug them to the case then a true flat edge to make sure they are level.

your heads may be cut at different depths as well. hastings rings are pretty good and I usually use them

Sat Apr 16, 2016 8:15 pm

I'm still a rookie, so this may be a dumb question.. Is it normal for oil to be on top of the piston heads?

I will have to admit that I did oil the crap out of my rings and pistons during assembly.

Forgot to mention, my bus ran outstanding, absolutely no problems at all. Oil pressure, compression, temperature, idle, and just overall performance was outstanding. The only problem here is the oil leak described. I know some VW people don't mind oil leaks, but I hate them. I actually get mild anxiety from seeing oil leaks, don't know why, but they put me in a bad mood.

Sat Apr 16, 2016 8:32 pm

Broken record here but since no one else brought this up.... How's your breather working?

I pulled an engine down once for these kind of leaks and after a full reseal found that the crankcase breather system was way too small. You over pressure the crankcase and the oil has to go somewhere. Can you show us pics of your engine when it was installed?

Sat Apr 16, 2016 8:39 pm

aeromech wrote: Broken record here but since no one else brought this up.... How's your breather working?

I pulled an engine down once for these kind of leaks and after a full reseal found that the crankcase breather system was way too small. You over pressure the crankcase and the oil has to go somewhere. Can you show us pics of your engine when it was installed? Steve brought it up as well. Since the rings are probably not fully seated yet, doesn't that increase crankcase pressure over what would be normal? Also, is it overfilled with oil?

Sat Apr 16, 2016 8:51 pm

How do I check if the heads are sitting properly on the cylinders? Do I check the depth of the heads to make sure both cylinders are mating and there is no gap where oil could leak through? What I don't understand is how did oil get in my cylinders (1 & 3) in the first place? rings can't be worn, valves and valve guides are new.

On a side note, I know worn valve guides could be the source of oil. According to the guy that rebuilt my heads, all valves and valve guides are new. How can I check to see if they are indeed new and not worn?

Sat Apr 16, 2016 9:08 pm

here are several pics of my engine installed

Sat Apr 16, 2016 11:11 pm

I've always oiled the rings liberally building an engine and never had trouble with rings seating - but then I was never shy about running the RPM up and down to seat the rings as well as flex them.

Who checked the end gap on the rings and the land clearance? We could have captured rings here if the clearance is too tight which is sometimes is because some of the rings made assume they are going in a piston and bore that has a little wear.

Sun Apr 17, 2016 4:06 am

lap the cylinder to the head with some valve grinding compound
WD-40 the rings for quick break in :wink: NOT motor oil :roll:

Sun Apr 17, 2016 5:28 am

How do rings cause an oil to leak at the head?

I bet the head is not depthed the same, or cylinders are not parallel after torqueing.

Sun Apr 17, 2016 7:46 am

:cry: when your oil control ring and compression rings let excessive oil into the cylinder- it causes a lean running condition and over heats that cylinder- the excess oil is not all burned and settles to the bottom of the cylinder- this causes a cool spot that distorts the head and allows the oil to escape under compression.

This engine would run great till the spark plug fowls as oil does not compress- raising the compression of that cylinder which along with the lean run condition is a wonderful- though short lived - power booster. :roll: :roll: :roll: maybe-

Sun Apr 17, 2016 8:12 am

BenPonKombi wrote: here are several pics of my engine installed

Sun Apr 17, 2016 11:45 am

the argument of what to put on rings to assemble is as old as the hills. Some folks in racing used to pour a handful of bonami into the carb to help seat the rings. I have bored blocks for all kinds of rings - from cast to steel to moly. From fleet engines to Cosworth Indy engines - Ferrari engines, to overbored big block drag boat and dragsters. That included some NASCAR engines. I have yet to see a set of rings fail to seat. Next time you watch a program where Ferrari or one of the other high-end engine makers is building a new factory block you will see them use liberal oil on the rings - not WD40, not dry but oil. No STP etc, just oil.

What is important - very important is that the ring end gap be proper for the type of engine, and that the ring land clearance be within spec. Those specs are in Bentley for the VW engine. All the Kolbenschmidt and Mahle piston and liner sets I have bought were good - although they needed to be cleaned with hot water and soap to get rid of the debris from boring. I have seen problem sets with replacements that don't fit right. If the ring land does not have enough clearance it will capture the rings. If the gap is too small they will butt against each other. If the gap is too big they will lose compression and oil.

Also make sure the rings are in the correct order and not upside down. Each manufacturer has their own design so one must read the instructions.

Sun Apr 17, 2016 12:48 pm

That set of Deves that bit me in the ass fit perfectly, the issue was they were a little too ummm.... limp if you know what I mean. That MoFo laid down a smoke screen like you see in old war movies when they are taking the beach.

Right now the oil doesn't bug me as much as the leaks at the head, the oil was just the canary in the coal mine that exposed it. Afterall it only had 80 miles on it so they may not have seated in yet.