Valvetrain Knock When Warm After Cam Swap
04-08-2008, 11:17 PM
#1
TECH Enthusiast
Thread Starter
iTrader: (5)
Join Date: Feb 2004
Location: Pearland, TX
Posts: 520
Likes: 0
Received 0 Likes
on
0 Posts
Valvetrain Knock When Warm After Cam Swap I just got done installing my ECS blower cam and Paxton kit yesterday. When I first fired it up I had an oil leak that spilled ~2 quarts of oil on the ground in ~2 minutes. After remedying it and re-starting it, it developed a knock on the drivers side head towards the front. Today I leveled the car out and topped off the oil, it was ~2 quarts low. The knock was gone initially but re-appeared after ~5 minutes of idling. Coolant temp was ~175 and oil temp was ~155 when it started.
At first I thought the knock may have been due to oil starvation on that initial startup but after thinking about it, the sound started yesterday only after it warmed up too. When I got the car it had a 238/242 605/610 on 112 cam, dual valve springs and HD push rods in it (7.400" chromeoly from Crane) and it still has the springs and pushrods. I started thinking tonight that it may be the pushrod length, maybe too short for the smaller blower cam it has now. I haven't taken the valve cover off yet as it got late on me tonight but I wanted to get some input as to what the problem could be. I kind of doubt its anything serious because it's not constant.
At first I thought the knock may have been due to oil starvation on that initial startup but after thinking about it, the sound started yesterday only after it warmed up too. When I got the car it had a 238/242 605/610 on 112 cam, dual valve springs and HD push rods in it (7.400" chromeoly from Crane) and it still has the springs and pushrods. I started thinking tonight that it may be the pushrod length, maybe too short for the smaller blower cam it has now. I haven't taken the valve cover off yet as it got late on me tonight but I wanted to get some input as to what the problem could be. I kind of doubt its anything serious because it's not constant.
Last edited by 5 Liter Eater; 04-09-2008 at 08:51 AM.
04-10-2008, 02:01 PM
#5
TECH Enthusiast
Thread Starter
iTrader: (5)
Join Date: Feb 2004
Location: Pearland, TX
Posts: 520
Likes: 0
Received 0 Likes
on
0 Posts
After talking to my father I pulled the cover and stuck a feeler gauge in-between the valve tip and rocker. All but one were very hard to do sedge in there (obviously discounting the ones that were compressing the springs). One (#7 intake) was loose, although the rocker was tight. The feeler gauge slid in-between the valve tip and rocker very easily. If I pressed on the pushrod side of the rocker I could move it, I could not do this with any other valve. So the lifter is not pumping up. I had sort of resigned to pulling the head and replacing it but then I ran across this thread:
https://ls1tech.com/forums/showth...t=669000&pp=20
And this thread:
https://ls1tech.com/forums/showthrea...cylinder+oil+o
So now I'd say it looks like the oil pump pickup o-ring as I used my old one and I wasn't uber careful when I put the pump back in. I just got everything buttoned up, now I have to go and tear it all down again...
https://ls1tech.com/forums/showth...t=669000&pp=20
And this thread:
https://ls1tech.com/forums/showthrea...cylinder+oil+o
So now I'd say it looks like the oil pump pickup o-ring as I used my old one and I wasn't uber careful when I put the pump back in. I just got everything buttoned up, now I have to go and tear it all down again...
