Valves leaking. Take a look and tell me if Im missing something - Competition Diesel.Com

Nbdiesel · 10-17-2020, 10:36 PM

So this isn't right is it? I have 103 hamilton springs , well I bought them and the head shop was supposed to put them in. So backround was, I was looking for a boost leak and when charging the turbo at 20psi I could hear a leak in the valve cover. So I took it off and could hear a leak in number 5 or 6 cylinder. This is 3000 miles after I just had Source Automotive check the head and oring. They send the head work out to some one else, so not source fault. I took the head off and made a plate to pressurize the intake to 20 or 30 psi and all the intake valve leak except like 1. How can 20 or 30 psi of boost open the valves and leak in if the head is good???? I wish I had another head to test. I would think the springs would hold the valve shut and the air would not come out.

5.9 cummins leaking valves - YouTube

ComnRailPwr · 10-18-2020, 08:24 PM

It needs a new valve job. Whoever did it sucked.

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TheHammer · 10-19-2020, 11:16 AM

I’ve seen the guides and valve stems wear out so bad it has caused this issue but that is very rare. Otherwise, what happens is some of these machine shops use the wrong tooling/cutter, the seats in these heads are more difficult to cut compared to most automotive applications and the end result is a choppy finish on the seat and/or valve. The shop didn’t lap the valves to the seat nor did they vacuum test them. I’d put money on the seat being very un smooth. One of the very first builds I did years ago that burnt me in many ways was do to this exact issue, poor machine work.

10-17-2020, 10:36 PM	#1
Nbdiesel Name: Nbdiesel Title: Rookie Status: Not Here Join Date: Apr 2020 Member`s Gallery Posts: 17	Valves leaking. Take a look and tell me if Im missing something So this isn't right is it? I have 103 hamilton springs , well I bought them and the head shop was supposed to put them in. So backround was, I was looking for a boost leak and when charging the turbo at 20psi I could hear a leak in the valve cover. So I took it off and could hear a leak in number 5 or 6 cylinder. This is 3000 miles after I just had Source Automotive check the head and oring. They send the head work out to some one else, so not source fault. I took the head off and made a plate to pressurize the intake to 20 or 30 psi and all the intake valve leak except like 1. How can 20 or 30 psi of boost open the valves and leak in if the head is good???? I wish I had another head to test. I would think the springs would hold the valve shut and the air would not come out. 5.9 cummins leaking valves - YouTube

10-18-2020, 08:24 PM	#2
ComnRailPwr Name: ComnRailPwr Title: Too Much Time Status: Not Here Join Date: Jun 2009 Location: Stoutsville , OH Member`s Gallery Posts: 3,293	It needs a new valve job. Whoever did it sucked. Sent from my SM-G960U using Tapatalk

10-19-2020, 11:16 AM	#3
TheHammer Name: TheHammer Title: broke Status: Not Here Join Date: May 2012 Location: juneau wi Member`s Gallery Posts: 738	I’ve seen the guides and valve stems wear out so bad it has caused this issue but that is very rare. Otherwise, what happens is some of these machine shops use the wrong tooling/cutter, the seats in these heads are more difficult to cut compared to most automotive applications and the end result is a choppy finish on the seat and/or valve. The shop didn’t lap the valves to the seat nor did they vacuum test them. I’d put money on the seat being very un smooth. One of the very first builds I did years ago that burnt me in many ways was do to this exact issue, poor machine work.