Rebuilt 408, bad piston ring seal???
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Some is OK
Some hissing is ok,, but this is as others stated through the rings and could be just end gaps. If you have the bottom down ,, did you pull a main cap and inspect for wear.. You could plastigauge one just to see where you are. This will also tell you a lot on the engine.
Cylinder leakdown and compression wet/dry test will give you data to answer your concerns. Good luck,, 99 Nassau Blue
Cylinder leakdown and compression wet/dry test will give you data to answer your concerns. Good luck,, 99 Nassau Blue
Drifting
Joined: Aug 2001
Posts: 1,500
Likes: 0
From: Holliston MA
Cruise-In VII Veteran
You need to do a leakdown test. Hearing that hiss with the pan off is normal. Problem is a 20% leakdown hiss will sound about like a 2% hiss. The 2% might even be louder because of more cylinder pressure from the better ring seal.
Good luck, and I wouldn't sweat it yet.
Good luck, and I wouldn't sweat it yet.
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Break it in
If you have a freshly rebuilt in engine with only idle time you might not have the rings seated and need to drive it a bit to do a run in. I would just repair the bottom end leak, then drive it for at at least 1000 miles checking the oil and engine frequently. Then you will have a better read on the condition. 99 Nassau Blue
