Pressure testing manifolds?
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URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=31350
Printed Date: November-28-2024 at 10:31am
Topic: Pressure testing manifolds?
Posted By: Dreaming
Subject: Pressure testing manifolds?
Date Posted: August-28-2013 at 2:01am
| I know that there is a thread on testing manifolds, but I am having trouble finding it. Would someone be so kind as to point me in the right direction? I picked up. A used set of manifolds for the 94 , and would like to bench test the before I install them. |
Replies:
Posted By: SNobsessed
Date Posted: August-28-2013 at 8:57am
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I think you could pump air pressure into the water jacket & dunk the whole thing into water. A stream of bubbles = bad. Testing hot condition would be much harder. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: DrCC
Date Posted: August-28-2013 at 1:33pm
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You have to block-off the riser. meaning, block the water passage between the manifold and riser with like a rubber gasket etc.... |
Posted By: Dreaming
Date Posted: August-28-2013 at 2:37pm
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OK, so I have the riser and manifolds apart, and off of the motor. there is a center section that I assumed is for exhaust gasses, and the outside (rectangular holes) that I assume are for water. correct? - If I use some aluminum tape, cover all the holes at the riser opening(making sure they do not leak between from side to center) - pressurize the elbow hole at the front of the manifold - then dunk the 4 exhaust ports in a bucket of water I should see no bubbles, correct? If this sounds OK, how much pressure should I put on the manifold? what is typical exhaust pressure, or better yet, what is the water pressure on the manifolds? sounds like I am checking to make sure the outer (water jacket) does not leak to the inner? (exhaust section) sorry for the newby question, liquid cooled exhaust is all new to me. |
Posted By: SNobsessed
Date Posted: August-28-2013 at 5:58pm
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I think it will take more than tape. Dr had a good idea, get some gasket material. I would use 15 PSI. Do you have a kiddie pool? I would dunk the whole thing as long as you are going this far. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 8122pbrainard
Date Posted: August-28-2013 at 7:04pm
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The tape isn't going to work. I agree with Chris that Al has the good solution. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Dreaming
Date Posted: August-28-2013 at 10:44pm
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Thanks Guys, I'll try that tonight. I do have a storage bin that can handle the whole manifold, and a radiator tester, so i'll give it a run. |
Posted By: KRoundy
Date Posted: August-31-2013 at 11:46am
Kris - you are having all the fun right now. Can I come over and play with your boat? While mine is at the upholstery shop I have nothing to do with all my time and my wife wants me to clean the gutters.  I think if you take some pictures of this entire process this could end up in the FAQ. ------------- Previous: 1993 Electric Blue/Charcoal Ski Nautique Current: 2016 Ski Nautique 200 Open Bow |
Posted By: Dreaming
Date Posted: August-31-2013 at 4:26pm
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Good point Kevin! So part of the fun was testing, part of the not so fun is that one of the manifolds was bad.... good thing I tested. I will take some pictures of the process, this is a question that comes up a lot
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Posted By: ArtCozier
Date Posted: August-31-2013 at 5:44pm
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I usually just leave the riser and manifold assembled, make sure the exhaust side is dry, then connect a water hose to the front hole. (without any leaks at the connection) Prop the manifold up in operating position (Outdoors!!) then turn the water on full blast. The more volume the better. Let it run for about 3-5 minutes, and look in the exhaust dumps for water. The water will of course flow out of the exhaust hose end. You can reach in there and block the hole with your fingers to create a bit of pressure if you want. Try to not spatter water back upward in the riser while doing this. Never missed a leak yet. And another advantage is that it tests the riser and the gasket too. Art ------------- "Art" |
Posted By: Dreaming
Date Posted: September-01-2013 at 12:51am
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Art, That sounds like a good way as well! Mine were disassembled already, so here is what I did, there may be a better way, but this way seemed to work. 1. Drill out a hole and install a "barb fitting" in a spare manifold drain plug ( if you have drain cocks, just use the drain fitting) I used put the barb fitting through the plug, and superglued it in place  2. Seal the water jacket openings between the manifold and the riser. I used aluminum tape and a sheet metal backer plate to keep the pressure from blowing the tape out. Gasket material or rubber would have worked better, but I did not have any on hand.   3. re-assemble the riser and manifold, be careful not to damage the tape/gasket. tighten all four bolts on the riser so that the gasket seals good and tight  4. remove the brass elbow fitting at the front of the manifold, and install the barbed fitting/manifold plug. Now, the water jacket should be sealed except for the opening in the barbed fitting.   5. I used a radiator tester (hand pump with gauge) to put air pressure in the manifold. I connected the hose of the tester to the barbed fitting on the manifold  6. pump up the water jacket to 15psi as suggested by SNobsessed above 7. submerge the manifold in water and watch for bubbles. if there are bubbles, determine where they are coming from. there should be no leaks from the manifold, however, if you made a poor seal under the riser, it will show up as a leak.  This one was a leaker... note the bubbles. Here is a shot of the problem area. the crack is about 4 inches long.  I hope that this helps someone else. This was about a 15 minute job once I understood what I was trying to do... thanks for the help from all those who posted above.  |
Posted By: 74Wind
Date Posted: September-01-2013 at 1:54am
JBWeld to the rescue.....   ------------- 1974 Southwind 18 1975 Century Mark II |
Posted By: SNobsessed
Date Posted: September-01-2013 at 2:53am
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Great write up! ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: ArtCozier
Date Posted: September-01-2013 at 11:01am
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Good procedure. The only downside is that it doesn't test the riser or the joint between the 2 parts, which can be a frequent source of leaks, especially in the older PCM manifolds and with the older black gaskets. Not so much with the newer, white gaskets. I have a piece of 1/2" steel plate drilled to match the bolt holes that I use for manifolds that don't have risers on them. I saw a riser once with an internal hole in it the size of a penny. A faulty casting that was fine for over 100 hours. One thing that you have to watch on the PCM manifolds is the thickness of the internal walls right at the gasket joint. Sometimes they will get thin right there at the gasket, resulting in a poor joint, because they usually don't line up perfectly with the corresponding part of the riser. A machine shop can mill off a few thousandths from the surface and you have a new start. If they have a really good flat surface sander for doing cylinder heads, sometimes they will use that and it's less expensive than milling. Check the riser side also for erosion of the edges of the wall. I like to use a VERY thin application of hardening-type Permatex sealer on both sides of the gasket. And don't forget to match the "tab" on the gasket to the riser when you re-assemble. Otherwise you can get an air bubble in the cooling water side. The blocked-off slot should be on the higher end. Many owners don't realize the importance of good manifolds to the life of an engine. Most engine suppliers won't even warranty a replacement engine unless you put brand-new manifolds and risers on it. Art ------------- "Art" |
Posted By: Dreaming
Date Posted: September-01-2013 at 7:37pm
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Art, I really appreciate your insight. I have always been a car guy, so while the mechanical side of these boats doesn't intimidate me, I can certainly use the experience that others have to guide me. I'll definitely check the assembled manifolds once I put the new riser gaskets on to be sure they are not leaking at the riser or at the gasket. Since I am isolating whether the block is cracked or not, I want to make sure that I have eliminated all the problem areas. I like permatex products, and will pick some up for the assembly process.
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Posted By: ArtCozier
Date Posted: September-02-2013 at 12:02pm
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Couple of items to take a look at before you dive into the cylinders: I have seen one instance of a core plug inside a valve cover leaking through the Allen drive socket. I think that was a 302; not too sure that the newer 351 heads have the same type plugs in there. Next would be a leaking intake manifold gasket where the water crossovers are. ------------- "Art" |