2000 V70xc Crankcase pressure after head gasket replacement

pbob42 · Post by **pbob42** » 28 Apr 2014, 10:08

Long road getting this back running. Bought this and PO had covered multiple issues. Blew the head back in November. Pulled the head and got it machined and did the valves. Got it all back together working on the weekends, and ran great, except for oil coming out from under the oil cap. Did the PVC/breather system including the PTC. It was about 3/4 clogged. Blew back into crackcase to check and could hear air bubbling up through the oil in the crank case. Still getting oil under the cap and smoke from dip stick.

Got a leak down kit, no air coming through tail pipe, radiator, or intake. Some leakage in rings. THe cam cover is off and the cams are out. The leak down was run cold at TDC on #1.

These are the numbers with input at 100 psi
1 - 91
2- 84
3 - 90
4 - 84
5 - 92

Thoughts?

Post by **JDS60R** » 28 Apr 2014, 10:17

Those numbers are good but Can your clarify if you moved the crank so that you tested each cylinder at TDC? (not just cyl 1 at tdc and check all)

If not - we need to check each cylinder with the piston in the top inch of the cylinder (TDC for each) as the cylinder gets distorted and worn there and leakage can be significantly different when tested in that portion.

If results are different we can look at them. If its the same then you have a blocked Oil vapor system ( Yes - I know you replaced it but if you don' t have blow by and she is spouting pressure then the pressure system has an issue) .

Lets do the leak down test at 100 psi with each cylinder at tdc or close and report back. Its ok to turn the crank with the cams off as the valves are fully sealed/raised. Just remember to put the crank back to its timing mark before installing the cams.

Let us know

pbob42 · Post by **pbob42** » 01 May 2014, 21:31

These are the numbers at TDC and 100 psi
1 - 91
2- 76
3 - 90
4 - 92
5 - 92

but now #2 is pushing water out of my cooling lines. Guess the head is coming off. Don't understand. It was dry before. Would 100 PSI cause a head gasket failure that was impending before? I don't believe the head gasket leak on #2 explains the oil cap leak.

I can check the breather system when I pull the head.

Post by **Ozark Lee** » 01 May 2014, 23:19

pbob42 wrote:Would 100 PSI cause a head gasket failure that was impending before?

The pressures are much higher than 100 psi during normal operation with a properly operating engine.

Did the machine shop do anything other than surface the head and re-lap the valves? I wonder if the head has a crack. I would think that the machine shop pressure tested it but that won't necessarily tell the whole story.

...Lee

pbob42 · Post by **pbob42** » 01 May 2014, 23:55

I'll pull it and have them check it out. Keep you posted.

pbob42 · Post by **pbob42** » 06 May 2014, 08:31

Pulled the head and took it to my regular machine shop guy. (He was on vacation when I needed this done). Head was bead blasted. He said the head was ruined by bead blasting. Then he said I needed to polish the area where the cam sits or my cams would heat up and be ruined. He had no problem with the seals or the valves.

There was oil leaking through the second cylinder and it was not black like the other 4. This was also the cylinder that leaked through the radiator.

He is thinking the oil leaking through number 2 and the crankcase pressure is a sign of blow by and the need of a ring job. With all that he is saying, pull it and rebuilt it or replace it.

He asked how hot it got. It was run dry until it stopped.

Post by **Ozark Lee** » 06 May 2014, 19:19

A used engine might be the path of least resistance. I have a spare head but I don't know if it is any good or not. The engine that it came off of had scored cylinder walls on cylinders 1-3. The history on my old engine sounds much like yours. It was overheated and blew a head gasket. The guy paid a shop to rework the head and replace the head gasket only to have it bust a radiator hose 3 weeks later. He tried to drive it home and that didn't work out well.

The trick is to find a good used engine. I searched for about a year until one popped up on Craigslist locally and I was able to pick it up, with all accessories and manifolds, for a few hundred dollars.

Good luck with it - at least you know what is wrong.

...Lee

pbob42 · Post by **pbob42** » 07 May 2014, 06:43

So you would concur with the rings? Oil leaking in #2 and crank case pressure gives the verdict? And one last thing - what is up with bead blasting the head? Is it ruined or can the cam supports be polished?

Post by **Ozark Lee** » 07 May 2014, 08:19

Since I can't see the engine it is hard for me to render an opinion on the rings. The original pressure tests did indicate a disparity on cylinder 2 and the original post indicated excessive crankcase pressure so either bad rings or bad cylinder walls is a good bet.

The problem with polishing the cam bearing surfaces after the head got bead blasted is that the dimensions change and they likely won't change uniformly. The tolerances there are critical and the camshaft journals will wind up getting scored if they aren't right. The camshafts ride only on the aluminum surfaces and they don't have split sleeve bearings like the crankshaft does. If the head got bead blasted then it is pretty much scrap metal IMO.

...Lee

Post by **JDS60R** » 07 May 2014, 09:24

In my opinion,
Stop working on the engine. If it ran dry it has been my experience that you will have an oval bore due to heavy wear. There are some ring packs that can slow the oil blowby once the cylinders are round but with machining costs its a no brainer to get a good used engine.

Sometimes engines can be had cheaply from a car that crashed or blew a trans and the owner wants to move on.

I would not put time ,effort or money into the current motor.