| Author |
Message |
Ric Rainbolt (Ricrain)
Junior Member
Username: Ricrain
Post Number: 175
Registered: 2-2002
| | Posted on Tuesday, July 09, 2002 - 4:29 pm: | |
I usually test the engine after the heads are installed. I add on the water pump assembly, the crossover pipe (the one in the V) and some of the pipe. I then attach the large aluminum coolant hoses to each other with a long piece of coolant hose. Block off the heater coolant outlet with a cap or plug of some sort. Then temporarily connect the expansion tank. "Fill" and bleed the system like you would if it were in the car. I use an off-the-shelf coolant system pressure tester (essentially, a hand pump with an adapter for the radiator cap).
What you look for is a constant pressure over several minutes. Any leaks will become obvious, except those around the head gasket leaking into a cylinder. Blow compressed air into each spark plug hole and watch for moisture. Sometimes, small leaks form around the outside edges of the head gaskets on brand new gaskets, this is somewhat normal. After a few "heat cycles" these tend to seal up.
I usually look for less than a 1 PSI drop over 10 minutes. |
Burnell P. Curtis (Burnell)
New member
Username: Burnell
Post Number: 35
Registered: 4-2002
| | Posted on Tuesday, July 09, 2002 - 12:56 pm: | |
You are probably worrying about nothing. Alfa engines are built the same way and I have rebuilt lots of them. Never had a leak because the fit is tight and the O ring has an easy job to do. My 308 rebuild went the same way. Just be sure everything is clean, then oil the O ring, and slip everything together. I will bet you will not have a problem. |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1902
Registered: 12-2000
| | Posted on Tuesday, July 09, 2002 - 12:39 pm: | |
If it leaks past the liner O-Rings, you'll see coolant dripping out the bottom of the block.
Other leaks will be obvious to diagnose. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 215
Registered: 11-2001
| | Posted on Tuesday, July 09, 2002 - 9:48 am: | |
So
When the heads and blocks and intake manifolds are together, and you pressurize the water jacket, how do you tell there is a leak, and where? |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1899
Registered: 12-2000
| | Posted on Tuesday, July 09, 2002 - 12:47 am: | |
I know this question is directed to Ric (and he should reply to this), but according to the WSM, testing of the cooling system should be done with heads on the block and the "water outlet manifold" installed (that's the cast, branched pipe joining the two heads, leading to the thermostat/W.P. housing). That's page B31 of the GT4 WSM.
They begin by instructing you to assemble the bottom-end first, then install the heads. I suppose if that were the case, you'd better pray you did a good job installing the O-Rings... (If not, you got a hell-of-a-lot of work ahead dismantlling the engine, to repair those leaky O-Rings. It would be kinda like hitting your head against the wall several times)
If you want to test the block ALONE, you could make up (machine) testing plates, to take the place of the heads. But, this is my guess... |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 214
Registered: 11-2001
| | Posted on Monday, July 08, 2002 - 4:25 pm: | |
Ric
I had originally thought that I can pressure test the block alone, but the machine shop I am dealing with is not equipped to handle that. They can test the heads individually, but not the blocks, it is too big to go into the water tank.
So, my question to you is:
1. Given the fact that I am going to change the liner O-rings and that i want to ensure a leak-free seal, when during the assembly process is the best time to pressure test the water jacket?
2. How to test the sealing capability of the water jacket at that time?
thanks
Mitchell |
|