This afternoon I performed a cylinder leak down test on the original 99 Max engine to get to the bottom of the reported compression loss issue.

This was the first leak down test that I have performed. I found my "China Freight" cylinder leak down tester regulator valve was cracked so I hooked up the hose that came with the kit to my 120 LBS small air compressor that has a couple of gauges for tank and line pressure. I connected the air line chuck to the leak down tester hose and where I surprised at the benefits a leak down test can provide. Since I already had the engine sitting at TDC on CYL1, when connected the air line there was a quick rush of air through the intake port. That indicated leaking intake valves. I continued on through the test and only found 2 cylinders that could hold any pressure. Next I pulled the heads to get a closer look at the failing intake valves.

The disturbing part came when I found scored cylinder walls. Based on the way the previous owner SAID he cared for the car, I'm surprised. However, I found the previous owner had tried to cover up a bad radiator with stop leak that I found soon after buying the car so I'm not really surprised.

I would like to take the heads to a local machine shop and get them resurfaced, new valves, springs, seals, and etc., to end up with some good heads that I can use on the newer engine. Hopefully I will find cylinders in better condition than the ones below.

Here are pictures below. The cylinder pictures are not for the faint of heart so view with caution. Ha!

Questions:

1) Can anyone spot the cylinders with the intake value issues below? The cylinders that held pressure look different from the ones with failing intake valves.

2) Does anyone know why the cylinders are so badly scored for a car with 177,000 miles?

3) Would I be better off buying some "re-manufactured heads" at $250 each than trying to salvage the ones in the pictures?

Leaking Intake Valves on 4 Cylinders







Scored Cylinders

 

Thanks for the post.
Good to see tear downs and hear about leak down tests.

 

Damn dude, you went ALL IN on the motor rebuild. Much envy, I have

You might be better off posting this thread in the all motor section to catch the eyes of those with deeper expertise.

 

Thanks TH and DW!

Maybe a Mod will stop by and move this one to the engine section.