Exhaust manifold problem re-post w/pic's

[wmmulvey]

1969 A-4 Late model w/RWC system in salt water.
Pic’s to follow at end of post

PART ONE
Good water flow out the exhaust

Using a IR temp gauge

1. Engine block side of the manifold at good temp all around the block.
2. Upper part of the manifold temp around 190
3. Lower part of the manifold smoking and temp over 300 in a very short time.

My opinion is that part of the water passage is clogged.

PART 2
Bought a used manifold and as per Moyer instructions, with some changes did:

1. Filled the input/output ports with Mauriac acid (lot of foaming) and let
stand overnight.

2. Flushed and neutralized

3. Plugged the input/output ports

4. Removed the drain plugs and the freeze plugs and filled with Mauriac
acid (lot of foaming) and let stand overnight.

5. Flushed and neutralized

6. Using a coat hanger probed all openings and flush and repeat several
times until no more garbage came out.

7. Replaced freeze plugs and fittings.

PART 3

Removed the original manifold and installed the used one with new gaskets.
Fired it up, good water flow out the exhaust, and had the same problem as in PART ONE.

PART 4

I intend to use the same procedure with the original manifold as in PART 2. After that Intend to get it professionally flushed.

How do I get this done and who would do this kind of thing?

I have heard of hot tanking but have no info on this or how it works.

Hope I was not to long winded but really had to explain the steps I followed.

ORIGINAL MANIFOLD



FLANGE SIDE BURNT



FLANGE SIDE TOP VIEW BURNT


INTAKE/EXHAUST SIDE BURNT BELOW PORTS



TIA FOR YOUR HELP.

Regards
Bill
Home Port NJ

[romantic comedy]

cant see the pictures

[wmmulvey]

Photos updated

[Loki9]

1969 A-4 Late model w/RWC system in salt water.
Pic’s to follow at end of post

PART ONE
Good water flow out the exhaust

Using a IR temp gauge

1. Engine block side of the manifold at good temp all around the block.
2. Upper part of the manifold temp around 190
3. Lower part of the manifold smoking and temp over 300 in a very short time.

My opinion is that part of the water passage is clogged.

This sounds normal to me. The water jacket in the manifold really only covers the top half or so of the manifold and I think it's just one straight passage. The lower part of the manifold is always hotter, particularly at the front corner (UHS). If you cleaned it out well and are getting good water flow through it, that's about all you can do.

From your photos it looks like maybe your gaskets were leaking a little. Did you ever observe any smoke?

[sastanley]

Bill,
This is not an official endorsement, however, some of us have changed the flow of the manifold by running the t-stat housing hose down to the bottom of the manifold and then run the forward manifold hose to the exhaust mixer..forcing water uphill thru the manifold rather than downhill...it is unofficially called the "Thatch modification", after user thatch that pioneered it..

What is the temp gauge reading on the engine?

[67c&ccorv]

1969 A-4 Late model w/RWC system in salt water.
Pic’s to follow at end of post



PART 2
Bought a used manifold and as per Moyer instructions, with some changes did:

1. Filled the input/output ports with Mauriac acid (lot of foaming) and let
stand overnight.

2. Flushed and neutralized

3. Plugged the input/output ports

4. Removed the drain plugs and the freeze plugs and filled with Mauriac
acid (lot of foaming) and let stand overnight.

5. Flushed and neutralized

6. Using a coat hanger probed all openings and flush and repeat several
times until no more garbage came out.

7. Replaced freeze plugs and fittings.

PART 3

Removed the original manifold and installed the used one with new gaskets.
Fired it up, good water flow out the exhaust, and had the same problem as in PART ONE.

PART 4

I intend to use the same procedure with the original manifold as in PART 2. After that Intend to get it professionally flushed.

How do I get this done and who would do this kind of thing?

I have heard of hot tanking but have no info on this or how it works.

Hope I was not to long winded but really had to explain the steps I followed.



TIA FOR YOUR HELP.

Regards
Bill
Home Port NJ

You let the part stand in muriatic acid overnight???

I'm surprised you even have a part left.

[dthibaul]

Hot tanking

Bill,

As far as getting the manifold "professionally" de-gunked, you may be talking about what used to be done at radiator shops to old car radiators and referred to as "boiling". I was replacing the hot/wet side this past year and decided to remove/acid flush the manifold and for extra measure went looking for a radiator shop. Not too many of them exist any more, and if they do, they don't boil units anymore (just replace the whole thing). I was traveling every week to Muncie IN and happened to find a radiator shop that still boils and had it done (interesting looks from TSA as it went through x ray). After all was said and done and re-installed, there was a breach between one of the hot chambers and wet chambers of the manifold causing water intrusion into the oil. This may have been caused by too agressive an approach with the acid, or the boiling- hard to tell. I just bought a new unit from MM and all is well now.

Don

[wmmulvey]

This sounds normal to me. The water jacket in the manifold really only covers the top half or so of the manifold and I think it's just one straight passage. The lower part of the manifold is always hotter, particularly at the front corner (UHS). If you cleaned it out well and are getting good water flow through it, that's about all you can do.

From your photos it looks like maybe your gaskets were leaking a little. Did you ever observe any smoke?

300+ degrees is not normal. According to the cooling diagram on Pg 26 of the A-4 manual, there are 2 water passages.

There was smoke from burning paint. No exhaust smoke.

[wmmulvey]

Bill,
This is not an official endorsement, however, some of us have changed the flow of the manifold by running the t-stat housing hose down to the bottom of the manifold and then run the forward manifold hose to the exhaust mixer..forcing water uphill thru the manifold rather than downhill...it is unofficially called the "Thatch modification", after user thatch that pioneered it..

What is the temp gauge reading on the engine?

I will try the "Thatch modification". Can't hurt.

I did not look at the temp gauge.

I used a IR hand held thermometer and measured the temp at all points of the block and head. All temps were in the normal range.

[hanleyclifford]

Have you considered the possibility that the block could be blocked in just one or two places, allowing water to get thru, but bypassing some areas?

[wmmulvey]

Have you considered the possibility that the block could be blocked in just one or two places, allowing water to get thru, but bypassing some areas?

I have a bypass valve setup.

I ran the RW directly through the thermo to the manifold inlet.

I switched, closed it and ran directly through the block.

I switched and ran it through both.

The results were still the same.

Again all............THANKS FOR YOUR HELP

[ILikeRust]

According to the cooling diagram on Pg 26 of the A-4 manual, there are 2 water passages.

I would not give too much significance to that diagram - it's just a pictorial/diagrammatic represention showing general water flow. I don't think it's mean to be a literal schematic.

It's not so much that there are distinct "passages" for the water - rather, the rectangular outside shape of the manifold, very much like the block itself, is a "jacket" that surrounds the intake and exhaust passages.

Picture your typical exhaust manifold:



Now of course, ours are a combined exhaust/intake manifold, but this is just for general purposes here.

Anyhow, now imagine you want to surround that manifold shape with water. So you put a box around it. The space in between the interior intake/exhaust "pipes" and the outer "box" (jacket) is where the water flows through.

The only thing I can't specifically recall is whether there is a jacket space on the side of the manifold that is up against the block. It might be the case that there is less of a jacket space on that side of the manifold.

The only thing I can think of - and mind you, this is a total SWAG - could you possibly have a little ignition timing issue? I'm totally theorizing here, but it seems to me that if your timing is a bit too advanced, you would get ignition before the exhaust valve is closed, causing part of the explosion to be blowing out the exhaust. Like I said, I'm just totally skylarking/theorizing here.

[Loki9]

You might find this thread interesting.

Among other things, there's a photo of a manifold cut in half showing the L-shaped water passage that runs along the top and side of the manifold. I believe that is the only water passage.

[hanleyclifford]

The engine block internally offers a number of paths for cooling water to take from the injection point to the thermostat housing even with the bypass closed. Just because you are getting good flow thru to the exhaust does not mean that your block is not plugged in some areas and simply offering preferential flow for the water.

[ILikeRust]

Well it certainly seems that water flows only along the "outside" surfaces of the manifold, so that the portion closest to the block does not have a water jacket and is instead a solid casting. So it would make sense that that side will be significantly hotter than the outside surfaces.