1976 Riviera - Blow-by??

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 11:42 am

I purchased a 1976 Riviera last summer, which has been running reliably for the past year. When I bought it, there was quite a bit of gunk and old oil on the top of the engine, but I was not too concerned, as there was no evidence of an active leak on the ground (my first mistake...). I took it on several trips through the Cascades and Coast range over the past year where it did fine, but ran hotter than I expected (based on how my 1972 ran) on the long grades and lost oil pressure at temps ~ 240. Compression as of 3 months ago was 140-150 all around, and the engine was rebuilt around 20,000 miles ago. I have gradually noticed more and more oil on the ground and on the top of the engine - collecting in front of the fan, beneath the dipstick. Also, the breather hose seems wet.

Here is what I have done over the past month (by myself and a VW mechanic)):
- replaced rear seal
- replaced dipstick boot
- replaced filler pipe gasket
- replaced oil cooler (it was dented!)
- sealed push rod tubes
- sealed breather box top
- cleaned engine and painted (to better identify source of leaks)

Oil leak is now worse than ever - pooling in front of fan at base of dipstick. Dipstick tube is wet. Small amount of oil on top, near breather box. I am not able to feel much case pressure through the dipstick and breather, even at high rpms, but it sure seems like that is what is going on. Can I be experiencing that much blow-by with such good compression?

What should be my next step here? (Of course, you realize that your answers will determine whether I make it to Maupin...)

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 11:46 am

One more relevant piece of information...

I have noticed what I think is some rod noise at start-up, which goes away after it is warmed up. I also think that I may have heard it under load.

The picture is getting bleaker, isn't it?...

hambone · Post by **hambone** » Mon Jun 08, 2009 11:46 am

My gut says a seal leak or something of the sort. Try to isolate it. Maybe some of the replacement that was done wasn't done correctly or faulty parts.

Gypsie · Post by **Gypsie** » Mon Jun 08, 2009 1:44 pm

When you say "sealed' have you assured that the sealing was effective? May be one of the addressed items still leaking.

Have you checked the oil filter seal. Same General area and I have had at least one get a crimp. (Course with a '76 might not be a filter like my '80...)

When you replaced your oi cooler did you put both sets of washers on the outside under the nuts or did one set find it's way between the cooler and case? (another Gypsie fauxpas and maybe another unsimilar to '80 item)

When you say "rod noise", do you mean push rod or connecting rod? Lifter/pushrod noise I'm familiar with, but would like to know what to look for for Connecting Rod noise if that's what you mean.?

Hydro Lifters?

The fact that it is ending up on top makes me think it is likely not pushrod tubes but oil and the big wind in the area can push oil all over.

One last possibility I can think of it the distributor oring. Mine was leaking and making a mess in the same place you are describing.

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 3:03 pm

I replaced the rear seal and dipstick boot myself, and had the rest done by a local VW mechanic when that didn't solve the problem.

The push rods do not look like they are leaking to me. In fact, when I first picked up the bus from the shop after the seals were replaced, there was a large amount of oil coming from the left side. I found a zip tie sticking out of one of the push rod tubes! When I pulled it out, that leak stopped.

There is a small amount of oil between the heads and cylinders on both sides, but not enough to explain what I am seeing. I really think it is coming from the top, and my hunch is that it is coming up through the dipstick itself, since that is where it is all collecting.

I will check the distributor o-ring.

As far as "rod noise", I am far from an expert, so I don't really know what I am hearing. There is a knock at startup, which gets better as the engine warms, and then comes out again under load - like going up a steep grade.

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 3:04 pm

Solid lifters

hambone · Post by **hambone** » Mon Jun 08, 2009 3:08 pm

That ain't good...
could be piston slap, if an engine gets overheated perpetually, the piston skirts rub against the cylinders.
Or you could have a rod(s) starting to wear out, clearance between the bearings and the crank too great.
If it gets worse under load, then you could be looking at Rebuild City. Stop in have some jo you're in good company....don't mind the mess of discarded engine cases.
But maybe have a pro have a listen-see before you do anything drastic.
Although it does sound like you have an engine near the end of it's wear cycle.

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 3:18 pm

That is what I have been thinking - I was hoping that you all would point out something that I have overlooked. As I mentioned, it got hot plenty of times last year 240-260 going up long grades. I would always stop and let her cool down at that point, but I never had my 72 get that hot.

The thing that I don't get, is how my compression could be where it is. Anyways, other than trying to stop the oil from coming out (which won't be possible if it is really blow-by), my biggest question is when do I have to do the rebuild. I am going to do it myself, so it will take me some time... I am hoping to be able to limp through camping season, but dragging a wife and 2 kids around right now may not be the best idea. I am not sure if I am comfortable bring it out to Maupin with this all going on.

hambone · Post by **hambone** » Mon Jun 08, 2009 3:23 pm

Wear limit and implosion are a razor edge...you can drive it for years that way until BLAMMO.
I'd be fine alone in that sitch, but with a family and kids I'd probably not feel safe.
Compression is only 1 indicator of wear. An important one, but not the only thing that gets old and tired.
Maybe they only did a topend build; the same happened with my old engine - great compression but the thing vibrated itself 1/2 to death. New p&cs in a case way past it's service life.
So I wound up
viewtopic.php?t=5515
Now I nervously fret over a NEW engine. Can't win.

Gypsie · Post by **Gypsie** » Mon Jun 08, 2009 4:15 pm

hambone wrote:That ain't good...
could be piston slap, if an engine gets overheated perpetually, the piston skirts rub against the cylinders.
Or you could have a rod(s) starting to wear out, clearance between the bearings and the crank too great.
If it gets worse under load, then you could be looking at Rebuild City. Stop in have some jo you're in good company....don't mind the mess of discarded engine cases.
But maybe have a pro have a listen-see before you do anything drastic.
Although it does sound like you have an engine near the end of it's wear cycle.

All good stuff.

I have a few cases too...(harumph....)

This'll be interesting.

As much as taking yer chances with a AAA card in hand I think the 'fam' factor calls for an immediate answer before chances are taken.

Q for the group..
Is there any way to tell if yer pistons are too close to the head while everything is together? Don't think so but one hopes....

fancy pants · Post by **fancy pants** » Mon Jun 08, 2009 4:29 pm

Good advice on having a pro listen to it. I am going to take it in later this week (not to the same place that left the zip tie in the push rod tube...).

Are there some diagnostic tests that would be useful at this point? Leak-down test?

fancy pants · Post by **fancy pants** » Wed Jun 10, 2009 11:49 am

I tried to record the sound here. Not sure that I had the ideal recording equipment, but I think you get the idea.

Thoughts?

http://s245.photobucket.com/albums/gg46/jshepski/

Randy in Maine · Post by **Randy in Maine** » Wed Jun 10, 2009 12:28 pm

Can you make the noise go away by removing one plug wire at a time?

vdubyah73 · Post by **vdubyah73** » Wed Jun 10, 2009 1:28 pm

sounds like an exhaust leak. block tailpipe with a wet rag, try to stop exhaust from exiting the tail pipe. It may make a leak easier to pinpoint. Look for soot around all exhaust connections as well. Does noise diminish as engine warms up?

cooperm81 · Post by **cooperm81** » Wed Jun 10, 2009 2:51 pm

fancy pants wrote:I tried to record the sound here. Not sure that I had the ideal recording equipment, but I think you get the idea.

Thoughts?

http://s245.photobucket.com/albums/gg46/jshepski/

Sounds just like mine when the oil pressure idiot light comes on. Same exact sound.

Itinerant Air-Cooled

Itinerant Air-Cooled

1976 Riviera - Blow-by??

1976 Riviera - Blow-by??