Top End rebuild on a 964 ????
02-15-2007, 11:15 PM
#46
Nordschleife Master
If the cylinder has cracked, then detonation has most likely occured. If the cylinder/head has been melted, then it is most likely a result of running lean. Both issues could exist together or separately, especially with old fuel. A leakdown test will give an indication of whether the intake or exhaust valve is not sealing, and whether the piston rings are good or not, and it will also tell you if something is cracked and leaking ie cracked cylinder or burned through.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
02-15-2007, 11:47 PM
#47
Rennlist Member
Originally Posted by Indycam
Fixing what does not need fixing is very foolish .
If he has good leak down numbers , why fix ?
.
If he has good leak down numbers , why fix ?
.
On other parts like heads it would be to bring all of them up to same starting point again. He should at least get them all inspected.
02-16-2007, 12:15 AM
#48
Nordschleife Master
If the light stuff has gone , its not the same fuel anymore , when it is sprayed in it does not mix as well with the air , what is going to happen is lean .
02-16-2007, 07:26 AM
#49
Advanced
Thread Starter
Join Date: Feb 2007
Location: Orlando, Florida
Posts: 94
Likes: 0
Received 0 Likes
on
0 Posts
.
He speaks the truth...............
The turbo system was removed on my last visit. The motor should be pulled out today. the leak down test showed that only #4 had any signs of a leakage. So we are going to start there to find out how this happened. When the leak down was proformed on #4 the air sounded like it was getting forced out of a crack behind the cooling fan blades on the right side. Maybe a ring is @ fault maybe not. The garage is very busy. So I should have some better info early next week.
The turbo system was removed on my last visit. The motor should be pulled out today. the leak down test showed that only #4 had any signs of a leakage. So we are going to start there to find out how this happened. When the leak down was proformed on #4 the air sounded like it was getting forced out of a crack behind the cooling fan blades on the right side. Maybe a ring is @ fault maybe not. The garage is very busy. So I should have some better info early next week.
Originally Posted by Geoffrey
If the cylinder has cracked, then detonation has most likely occured. If the cylinder/head has been melted, then it is most likely a result of running lean. Both issues could exist together or separately, especially with old fuel. A leakdown test will give an indication of whether the intake or exhaust valve is not sealing, and whether the piston rings are good or not, and it will also tell you if something is cracked and leaking ie cracked cylinder or burned through.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
02-16-2007, 12:35 PM
#50
Nordschleife Master
"#4 the air sounded like it was getting forced out of a crack behind the cooling fan blades on the right side. Maybe a ring is @ fault maybe not."
If you hear air behind the fan , thats not a broken ring . A broken ring would be inside leak . What you hear is an outside leak . The cylinder has been "ventilated".
Are you going to get the oil test done ?
If you get the top end done and then find you should have done more later , penny wise ...
If the oil test comes back with bad news , you can fix up the problem now while the motors out .
The oil test is next to nothing money wise .
If you hear air behind the fan , thats not a broken ring . A broken ring would be inside leak . What you hear is an outside leak . The cylinder has been "ventilated".
Are you going to get the oil test done ?
If you get the top end done and then find you should have done more later , penny wise ...
If the oil test comes back with bad news , you can fix up the problem now while the motors out .
The oil test is next to nothing money wise .
02-16-2007, 12:45 PM
#51
Drifting
Join Date: Jun 2006
Location: Dallas/FortWorth Texas
Posts: 3,438
Likes: 0
Received 1 Like
on
1 Post
For what its worth, I generally send out an oil sample to Blackstone every other oil change just as normal procedure. I'd rather have a running record of how my engines are wearing than wait for something to happen. Having a history of sample reports also gives you a good baseline so that if something does start changing on the next sample, I know what was "normal" for that engine from the previous samples. Its also helpful on resale to be able to supply a prospective buyer with several years of sample analysis. 
02-16-2007, 04:26 PM
#54
Drifting
Join Date: Jun 2006
Location: Dallas/FortWorth Texas
Posts: 3,438
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by stevepaa
I'd like to do the same. 
Who is Blackstone?
Who is Blackstone?http://www.blackstone-labs.com/
02-23-2007, 07:29 PM
#55
Advanced
Thread Starter
Join Date: Feb 2007
Location: Orlando, Florida
Posts: 94
Likes: 0
Received 0 Likes
on
0 Posts
Bad Gas Sucks
Originally Posted by Geoffrey
If the cylinder has cracked, then detonation has most likely occured. If the cylinder/head has been melted, then it is most likely a result of running lean. Both issues could exist together or separately, especially with old fuel. A leakdown test will give an indication of whether the intake or exhaust valve is not sealing, and whether the piston rings are good or not, and it will also tell you if something is cracked and leaking ie cracked cylinder or burned through.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
Since initial diagnosis has determined that there is a problem with #4, the engine has to come out anyway. From there you can make a determination of what the cause is and what needs to be done. For now, anything else is just speculating...Simply replacing the parts is not sufficient, you'll need to determine exactly what caused the problem or it will happen again on a new engine.
Bad old Gas on a high boost motor
I'm getting ready for a top end re-build after I find a 3.6 C-2 cylinder. My only worry is if this kind of destruction happened in cylinder #4 will the other cylinders fail in the future if I don't replace them now. I really don't have the funds for all new cylinders. The pistons looked fine. I'm going to have the shop measure them to make sure they are round. I look over the #4 piston and it looks just fine no nicks. The only thing that makes me feel ok is that the leak down test on cylinder 1,2,3,5, and 6 came back OK. But I'm still a little worry about the future of those cylinders. I think the shop should tear down and inspect the rest of the motor and inspect the cylinder and heads before I go searching for just 1 cylinder.
Last edited by Red Line; 02-25-2007 at 10:55 AM. Reason: .
02-23-2007, 07:56 PM
#56
Burning Brakes
Since you didn't get an oil test, you need to check that #4 bearing. I don't know if a single detonation can smash one, but if it did, you're then looking at a complete rebuild as you'd have little metal bits in your oil system. It also may be just damaged and need replacing. Also, a good guy can put calipers into the case spigot and give the rod journal a quick measurement.
If the engine is out of the car, removing the other bank (leaving the cam housing attached to the heads) is not a lot of work - 1 hour tops. You can then take a peek at the heads, pistons, and cylinders.
If the engine is out of the car, removing the other bank (leaving the cam housing attached to the heads) is not a lot of work - 1 hour tops. You can then take a peek at the heads, pistons, and cylinders.
