Higher Octane?
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Re: Higher Octane? (62fuelie)
My SWC's L-76 used oil for the first 10K miles. Back then the OE top rings were chrome plated and took some time to break in. I also think I may have been too easy on it. Nowadays, moly faced rings break in very quickly.
I can't remember all the details on the earlier oil consumption figures, but when I tore it down at 115K miles it used about a quart every 1500, which was certainly reasonable, and most of that was probably going down the valve guides.
Duke
I can't remember all the details on the earlier oil consumption figures, but when I tore it down at 115K miles it used about a quart every 1500, which was certainly reasonable, and most of that was probably going down the valve guides.
Duke
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Re: Higher Octane? (66ragtop owner)
It's difficult to descibe - part of the mechanical cacophony of a SHP engine. It's best when blended with the subtle mechanical ticking of properly adjusted mechanical lifters - kinda like a hundred old Singer sewing machines.
The only thing that sounds better is an old SOHC Columbo V-12.
Duke
[Modified by SWCDuke, 10:06 PM 2/8/2004]
The only thing that sounds better is an old SOHC Columbo V-12.
Duke
[Modified by SWCDuke, 10:06 PM 2/8/2004]
Racer
Joined: Feb 2003
Posts: 445
Likes: 47
From: Reading Pa
Re: Higher Octane? (SWCDuke)
Duke,
The reason I asked about the noise is my 327 makes a ticking noise that I have been unable to diagnose.
It's a 327 bored 030 with flat top TRW forged pistons, hydaulic cam, roller tip rockers, headers and about 5000 miles on a rebuild. The noise sounds just like mechanical lifters. It is most noticeable at about 2000 rpms and up. It is not as bad when the engine is cold.
I have tried swapping to conventional rockers and several times adjusting the lifters. Since I bought the car with the motor aready done and didn't know what kind of lifters it had (fast bleed or standard hydraulic) I pulled the intake to check the lifters. They were regular hydraulics but 2 where dished pretty bad. I didn't think this was the source of the noise because it sounds like it is coming from both sides equally and more than 1 or 2 cylinders. I installed a new hydraulic cam and lifters due to the worn lifters. The noise is the same.
I have sealed all exhaust leaks, run it without the belts on, disconnected the tach cable and the noise is still there. It is not very objectionable just puzzling.
Any thoughts?
Thanks
Brian
The reason I asked about the noise is my 327 makes a ticking noise that I have been unable to diagnose.
It's a 327 bored 030 with flat top TRW forged pistons, hydaulic cam, roller tip rockers, headers and about 5000 miles on a rebuild. The noise sounds just like mechanical lifters. It is most noticeable at about 2000 rpms and up. It is not as bad when the engine is cold.
I have tried swapping to conventional rockers and several times adjusting the lifters. Since I bought the car with the motor aready done and didn't know what kind of lifters it had (fast bleed or standard hydraulic) I pulled the intake to check the lifters. They were regular hydraulics but 2 where dished pretty bad. I didn't think this was the source of the noise because it sounds like it is coming from both sides equally and more than 1 or 2 cylinders. I installed a new hydraulic cam and lifters due to the worn lifters. The noise is the same.
I have sealed all exhaust leaks, run it without the belts on, disconnected the tach cable and the noise is still there. It is not very objectionable just puzzling.
Any thoughts?
Thanks
Brian
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Re: Higher Octane? (66ragtop owner)
It's very difficult to get a feel for engine noise without hearing it in person. You mentioned that you have TRW forged pistons. If they are the same alloy as the OE forged pistons they should be installed with about .0035" clearance rather than the .001" typical for cast pistons.
This loose clearance causes a mechanical noise similar to mechanical lifters, and it's part of the "symphony" of a SHP engine. If the clearance is looser than the nominal .0035", they will be noisier.
Years ago a friend of mine followed "racers" advice (ill-advice in this case) and had the cylinders honed for about .006" clearance with the OE pistons. They were definitely noisy, and so loose that the rocking motion broke a skirt in about 10K miles!
Duke
This loose clearance causes a mechanical noise similar to mechanical lifters, and it's part of the "symphony" of a SHP engine. If the clearance is looser than the nominal .0035", they will be noisier.
Years ago a friend of mine followed "racers" advice (ill-advice in this case) and had the cylinders honed for about .006" clearance with the OE pistons. They were definitely noisy, and so loose that the rocking motion broke a skirt in about 10K miles!
Duke
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Re: Higher Octane? (66ragtop owner)
Yes, "piston slap" is usually more noticeable when the engine is cold. As
the pistons warm the clearance is reduced and the noise usually gets quieter.
Another cause of ticking can be sloppy wrist pins, or a pin beating out the bore in the piston.
Duke
the pistons warm the clearance is reduced and the noise usually gets quieter.
Another cause of ticking can be sloppy wrist pins, or a pin beating out the bore in the piston.
Duke
