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Pressure Check 454 FWC Exhaust and Intake manifolds

F

fresh_creek

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Can anybody help me out with h

Can anybody help me out with how much pressure is required to check exhaust manifolds and the intake manifold for possible leaks? I have a water intrusion problem on one of my engines and am trying to figure out where it's coming from.

Thanks in advance........
 
"If you are talking about the

"If you are talking about the cooling passages within the manifolds, the rating on the cooling cap represents the operating pressure. My old stuff is rated around 7 PSI (FWC - mid 80s). Usual leaks show up well before that level is reached.

If you are testing just the cast iron components, they should easily handle 15 psi.

"
 
Thank you...... I am going to

Thank you...... I am going to individually test the cast iron/cooling passages for possible leakage. Getting water in the oil and can't figure out from where. Have had the heads worked and reworked due to this problem happening to me twice now without the boat even getting back in the water and just running it in the yard while doing other work! The machine shop swears that they did their job right and that they are not cracked.
Any thoughts on the intake manifold for checking it and the amount of pressure for pressure testing?
 
"I check mine with 15 psi. Loo

"I check mine with 15 psi. Look for pinhole leaks, not for a gusher--that's likely. A pinhole is all you need to cause major trouble.


Jeff"
 
"Thanks, will do. Has anyone e

"Thanks, will do. Has anyone ever put water in the manifold when pressure checking it to look for possible water seepage too beside just the gauge just going back to zero?"
 
"That's the best way; the

"That's the best way; the water won't compress like the air will and the pressure will build up quickly, too.

One of my old friends used to add a 'glowing dye' to the coolant passages when looking for troublesome leaks. I'd guess it is similar to what the 'septic inspectors' use when they test drain fields.

Giving the machinist the benefit of the situation, why did you take the heads to him in the first place?

Did you check the deck for distortion? Did you check the intake faces, too?

Finally, did they broach the heads? If so, how much was removed?"
 
"Thanks, I thought too of usin

"Thanks, I thought too of using dye if water was a good idea.
I took the heads to the machine shop because of a stuck valve/water in the oil. The heads were reworked and the boat ran fine for a 2 day trip (250 miles) back to the Bahamas. After being here with the boat docked 5 - 6 days, I went to start it and knew as soon as I did that I had a problem. I pulled the valve covers and found again a stuck valve. At that point, I pulled the boat, pulled the heads and took them back to the same machine shop. They again reworked the heads and I shipped them back to where I am and installed them. As I mentioned, the boat is still out of the water and after putting the engine back together I again have the same problem with only mabey 2 - 3 hourse of run time on it? A stuck valve again. I took the heads off and cleaned them/got the valve free but don't know wher the water is coming from.
What do you mean by check the deck for distortion and broach the heads?

Also, I want to thank you guys for your help.........

JP"
 
Broach heads = mill the gasket

Broach heads = mill the gasket faces into a true (or flat) condition.

Check the deck = measure across the head gasket surfaces of the block to ensure trueness.

How did you install the heads when you reassembled the engine?

Was the same valve stuck (before and after the trip to the machine shop)?
 
"I did not check/mill the gask

"I did not check/mill the gasket surface or check the surfaces. I installed the heads per normal procededures and torq specs. And yes, I beleive it was the sme valve stuck again......."
 
"hmmm, Water is not getting i

"hmmm, Water is not getting into the oil thru the exh manifolds, more likely the intake, and even more likely thru the oil cooler. Are you loosing coolant? IF so, the intake man. is suspect. If SW is getting in, I'd think oil cooler. I take it ur in Andros?
Are you using some RTV on the water passages on the intake when the reinstall is done? What size engine is this?"
 
"Yep, on Andros....... The eng

"Yep, on Andros....... The engine is a Gen IV 454 Crusader. I did use Permatex high heat silicone gasket maker around the intake water jackets (don't have the tube in front of me for exact name)and torque per the specs the heads and the intake. I was I think a little low on my FWC system when I started to take her apart. I was able to pressure check the intake and it does not appear to be leaking either. I am wondering if the intake was torque to spec last time it was put together and that possibly being the problem?

makomark, I used the same as mentioned above on the head bolts. I keep heaing that you don't need to use anything on the head bolts to loctite to just grease....."
 
"Andros; Is Chicharnie hotel

"Andros; Is Chicharnie hotel still there on the north side? It's been about 10 years for me.
On head bolts. I've used Permetex aviation sealer, I've used teflon laced thread sealer, I've used Permetex #3, all with good luck. Many of the head bolts penetrate into the water jacket in the block, and do need sealing.
I'm still not sure if your issue is coolant loss or seawater getting in. It is possible to use a radiator pressure tester on just the exh manifolds and HE by disconnecting and plugging the 1 1/4" hose going to the thermo housing. Do this test full of coolant, for a faster response. This test would be done after a failed entire engine pressure test."
 
"I don't think that "R

"I don't think that "RTV" like stuff works real good for the head bolts. I'm thinking along lines with Dave - fresh water/coolant or sea water???? The thread sealant is necessary on the head bolts. Not using it will permit coolant to leak via the threads.

I'd be inclined to think coolant more than salt water. Oil cooler may be source but only if you 'loose' a lot of oil. The oil will go out much easier than the sea water will come in.

Is the installation using standard gear or V-drive? Is the cylinder with the troublesome valve lower than the rest (#7 or #8 on a standard install)? How old are the exhaust manifolds/risers/elbows? (if 5-7 yr or more, you could have internal failure in the riser/elbow that could let the salt water in and cause hydrolock.)

I think you'll need to block off the 'feed hose', to the circulating pump, from the HX, to test the manifolds using the HX.....???"
 
"I think you'll need to bl

"I think you'll need to block off the 'feed hose', to the circulating pump, from the HX, to test the manifolds using the HX.....???

Ah, correct. My memory now comes back. I disconnected each exh man on front and back ends to take that particular manifold OUT of the test. Again, this is done with a failing entire engine test..."
 
"I used windshield washer flui

"I used windshield washer fluid to pressure test my exhauust system parts, with pure white paper towels in the openings to catch any leaks. The blue color stains the paper towels readily, so if there's a tiny leak you see it.

Jeff"
 
"I used Permetex "Ultra Bl

"I used Permetex "Ultra Black' high temp RTV Silicone gasket maker on the head bolts. It's #4 cylinder that had the valve stuck. The manifolds have not been changed, but the risers/elbows have been 1 year ago. It's a standard gear Borg Warner 1.5-1. I did block off the 1 1/4 hoses and tried to pressure check with 15 lbs. psi and had no leakage at the exhaust ports.
I am wondering if I had a possible issue with the intake manifold bolts because when I removed it a couple seemed to be a little loose. I'm at a point of putting it back together and running it to see what happens. Scratching my head on this one.........."
 
"Just so we have the pressure

"Just so we have the pressure test process done right: Reconnect all the hoses. FIll the HE with water/coolant. Purge air, using the bleed pipe plug on the thermo. housing. Pump up the HE using a radiator test pump WITH the pressure gauge. You can either use the style that replaces the pressure cap, OR use a style that pressurizes thru the overflow hose with the stock pressure cap; either will work. Pressurize to 7 psi or so. Come back in a few hours to recheck the pressure. If you are loosing pressure, then there is something leaking, somewhere. If this passes with a cold engine, recheck with a warm engine, let it sit overnite, pressurized. Report your findings."
 
"Also, I don't like the us

"Also, I don't like the use of RTV on the bolt threads. Its great stuff for several places on the engine, like the oil pan, the intake man. water passages, the rear seal area and the intake man. front and back edges. I fear that rtv on bolts will let curls of dried rtv into the oil system or water system. Neither heat, solvent or time will remove loose rtv from an engine."
 
"RTV on the head bolts also wo

"RTV on the head bolts also won't do real well in keeping the coolant in the water jacket. Once it leaks past the thread, into the oil it will flow.
Permatex #3 works ok as does perfectseal or the GM assembly compound. I've also heard, but never tried, Loctite's PST (Pipe Sealant w/ Teflon) works ok.

recommend you chase all the head bolt threads and the intake bolt threads before reassembly. Clean the head decks thoroughly (acetone is good) before installing marine head gaskets. install heads and torque using sequence in the service manuals (& sealer on the threads). Install the correct intake gasket set per the service manual recommendations (I use rtv on the end rails of the block). I'd torque the intake, again using the sequence in the manual. make sure you get the correct bolt in the correct hole so the head of the bolt draws up tight against the manifold; some may be longer than others and could bottom out."
 
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