How long on average should it take for moly rings to seat up? This is in a 351w built basically stock except for intake and carb. I've put something like 8000 miles on it already, but am still getting blowbye. Any tricks to speed the process?? Thanks!

 

My experience is that they seat immediaatley or they never do. Wish I had better news. Let's hope somebody else has a suggestion that works for you.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 LWB 4x2, XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 4x2, 3.0, 5 speed, 3.73 posi

 

They should have been seated by 500-1,000 miles...did you break in the engine for at least 500 miles with regular oil? If you used synthetic oil as a "break-in" oil the rings will probably never seat.

Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro

 

No synthetic oil....doesn't look good for me does it?

 

Moly rings, and other types, will seat when using synthetic oil from the get-go. The Corvette C5, Z06 and a bunch of Euro cars all come from the factory with synthetic oil in the engine, trans and differential. Most individual engine builders use dino oil for startup after a rebuild only because it's a lot cheaper to flush and refill after startup and at 100 miles. The no-no is to go to synthetics in an older engine with wear and hardened gaskets.

At 8,000 miles, excessive blowby sounds like you could have a broken ring, ring land, rings ends all at the same spot on a piston(s), or cylinder wall(s) that weren't properly cross-hatched. Is it using more than a quart of oil every 1,000 miles?

Do a compression check on all cylinders and record the numbers. Then pour a couple of tablespoons of motor oil in each cylinder and do another compression test. If a cylinder(s) shows increased compression with the oil, your rings aren't holding compression and you can identify which cylinder(s) are the problem.

Do you have an egr hook-up? If not properly connected or with a faulty valve, that can give you serious blowby out the oil filler tube and/or oil breather by not venting the crankcase.

 

I just have to disagree with the last post. Any repectable builder will advise against breaking in with synthetic oil. I suspect the C5 is run in at the factory with regular oil.
The EGR does not connect to the crankcase. It diverts exhaust gas to the intake. It's operated by intake vacuum.
The PVC system on the other hand can in some cases suck flying oil out of the valve cover and burn it. Especially if you have no baffle or a high volume oil pump.
A compression test is not a good indicator of oil ring seating. You need a leak down test for that.

1977 Ford F-100
400m/c6/4:11/Gear Vender O.D.
Crane hydralic roller, forged, ported polished,Deamon,Edlebrock, yada, yada, yada
280,000 miles
Stock on the outside
modified/rebuilt everything

 

No egr. No emmisions at all on it at this point. I was planning on making it legal again with fuel-injection and all emmisions, but I'm not gonna spend the money till everything else is right. I'd say my oil useage is probably more than one quart per 1000 miles. This is also with a very small leak out of a valve cover though. How about the emmision hookups on the back of the heads? I just blocked each one of individually. Could a leak there have anything to do with it?

thanks for the help!

 

I stand corrected on egr/pvc and agree a leak down test is the final answer for for ring sealing definition. Oil in the cylinder during a compression check does provide a quick method of determining if severe wear/breakage has occured with the rings or if high oil consumption is due to valve guide wear.

C5 and ZO6 engines and various Euro cars (perhaps some of the ricers but I don't follow them) with synthetic oils are not run in at the factory. Nor are LS1 engined Z28s and WR6s that option for synthetics. Synthetic lubricants offer the same basic qualities as dino with superior lubrication under much higher operating heat ranges.

Ring seating is based on the ability of a denser surface, the top compression ring (chrome, moly), using spring pressure against the cast iron cylinder wall or liner to create a seal. That's how cylinder wall wear occurs over a period of time. The second compression ring supports top ring functions while the oil ring distributes oil to the cylinder wall to reduce wear and heat during piston travel. For purposes of lubrication, synthetics just do it better than dino. Ring seating is not affected by oil. As bsprowl commented, either they seat or they don't.

 

I know someone that used synthetic oil in a rebuilt engine and the rings never sealed. He had to tear it down and hone the cylinder walls again. I think the manufacturers run the engines for a little while before the car gets to the dealer. The cam has to be broken in at about 2000 rpm right? The newer cars dont smoke or have problems with the cam or idle real high when you get them.

 

I have never heard of any professional rebuilder that says synthetic is ok to use for break in. The whole point of the break in process is to WEAR parts together at normal operating temps as quickly as possible. Auto manufacturers very well may put synthetic in from the factory but I'm sure it has additives in with it to make it less lubricating. I just got a cam kit from crane and it came with a bottle of additive to break the cam in faster and properly.

 

Hydraulic cams should be broken in above 2000 RPM's for several minutes, but not the new roller cams. All the new engines have full roller cams. As for the stuff that comes with the cam shaft, it is designed to stay on the cam and lubricate it better, not worse. Camshaft lobes are lubricated by splash only, therfore the cam manufacturers send the moly-goop to put on the lobes, because it will stay on longer and allow the cam to break-in without galling/scoring/grinding off the lobes. If a block in properly honed, (each type of ring requires a different stone with a different crosshatch pattern), you shouldn't have any problems using synthetic oil to break it in. You also should drive the car properly for the first 10 miles to get the rings to seat. The rings should be pretty well seated within 2-3 miles of driving. Synthetic oils are better than dino oils but they are not good enough to keep rings from seating.

 

Well I can tell you that Crane and Crower say in no uncertain terms that their new cams are not to be broken in with synthetic oil. They claim it doesn't have the resistance to shear that regular dino oil does. Not sure what ramifications this has for the rings but I can tell you everything I've ever read and heard says don't break a new engine in with synthetic.

 

Moly coating, for the reasons pointed out by bigsnag, is recommended and required by cam grinders/engine builders for new engines and cam changes.

In all the information I've ever read on dino vrs synthetic oils, superior resistance to shear under high operating temps providing extended engine life through reduced wear of metal parts is what makes synthetics shine. Stop and think about the fact that virtually all NASCAR and Indy engines use synthetics. Military fighter aircraft have been using synthetics for a long, long time. Would any of those users accept anything but an oil with the highest shear point?

With rings, seating has little to do with oil. Oil is a lubricant which provides a buffer between moving metal parts to keep them from galling. Cylinder wall prep and ring on piston installation are the determing factors in ring seating. Either they seat, which is creating a seal between compression ring and cylinder wall, or they don't.

 

So if looks like I'll probably need new rings and a hone job as a minimum right? If that's the case I think I'll see the truck. Just don't have time...

 

Motorcycles are delivered with synthetic oil as well. (except HD, but they aren't considered 'real')

My own personal opinion would be after 100 miles anything goes.

Also I bet you have a damaged intake gasket or head gasket, not the rings.

Josh