Propane 454 Ring Break-in
Propane 454 Ring Break-in
(OP)
I am freshening up a Gen 6 454 for my daily driver.
Boring and honing are not in the budget, and the stock bores are ok, so they will be de-glazed with my 320 grit ball hone. I am using plain cast iron rings, and new small dome pistons to achieve a bit over 10:1 compression.
I would like to break it in on propane.
I would rather not use abrasive powder (Bon Ami) in my engine.
There seems to be a number of opinions about bore preparation, and the best way to go about seating the new rings.
Everyone agrees on a 45 degree crosshatch, and thorough cleaning, but aside from that, are there any suggestions to quickly seat these new rings?
Should the bores be left as is (rough) after the ball-hone de-glazing, or should something more be done to them?
Boring and honing are not in the budget, and the stock bores are ok, so they will be de-glazed with my 320 grit ball hone. I am using plain cast iron rings, and new small dome pistons to achieve a bit over 10:1 compression.
I would like to break it in on propane.
I would rather not use abrasive powder (Bon Ami) in my engine.
There seems to be a number of opinions about bore preparation, and the best way to go about seating the new rings.
Everyone agrees on a 45 degree crosshatch, and thorough cleaning, but aside from that, are there any suggestions to quickly seat these new rings?
Should the bores be left as is (rough) after the ball-hone de-glazing, or should something more be done to them?
RE: Propane 454 Ring Break-in
I've never done anything fancy with the deglazing process.
Initial engine oil fill should be on 5w30 regular oil, not synthetic. Do one initial start-up to make sure everything works properly and check for leaks. On the next startup, be prepared to drive it. Get to somewhere that you can do the following. At about half rated max RPM (probably 2500-ish in your case), accelerate hard for a couple of seconds, then let it coast back to the initial speed, and repeat that about 10 times. Then come back to the shop and drain the oil, and refill it once again with non-synthetic. Drive normally but avoid lugging it down and avoid long periods of full throttle for the first few hours of operation.
RE: Propane 454 Ring Break-in
RE: Propane 454 Ring Break-in
RE: Propane 454 Ring Break-in
Evidently, factory oil recommendation for the 454 was 10w30.
RE: Propane 454 Ring Break-in
modern engines usually come from the factory with no specific type of running-in oil - but of course the virgin mating surfaces have been treated in such ways that easy run-in will take place on the prescribed oil under normal driving conditions.
in your situation it might help to temporarily use a rather thin oil with a somewhat lower specification as wear reduction is concerned. a lower viscosity oil will assist in cooling not yet fully run-in parts and also might "allow" somewhat more wear.
the complete running-in process has two sides to it: you want temporarily accelerated wear with some extra cooling capability of the oil used (which is accomplished by the use of a lower quality thin oil) and you want the load to actually provoke the extra wear you want. thus, once you have checked that there are no leaks etc and oil is getting to all the parts that need lubrication, you will need to apply a load to actually get that wear. applying a more or less "excessive" load within the mid to high rev range will generate that wear and is helpful in getting the result needed. you should initially be careful not to apply that load too long, because local overheating of not yet fully mating parts might occur. hence the advises to vary the load for a while.
a relatively short running in period should suffice. after say 2000 km the engine should be fully fit for
normal use and the prescribed lubricant with the standard oil change interval can be used.
new engines usually come with a cross hatch pattern. the pattern plays a role in oil retention on the cylinder wall to aid in lubrication of the rings and to prevent excessive oil consumption, but the pattern has no specific role during running in. if you roughen up the bores with a ball hone, you might get the same effect, just do not overdo it.
RE: Propane 454 Ring Break-in
5W-20 oil in new cars is for faster cranking (starts) on the EPA emissions cycle and a bit less viscous drag for fuel economy. Since film thickness is proportional to viscosity, thin oil in a new engine might keep the parts closer together for faster break-in. Is that a good thing?
Better cooling with thinner oil is owing to increased flow through the bearings?
RE: Propane 454 Ring Break-in
Cast rings are recommended in old propane training manuals. I used to work in the industry during the 80's and 90's.
I know moly is a bit better, but I thought plain cast might seat in quicker. I might be wrong, but I doubt it's a deal breaker for this build.
RE: Propane 454 Ring Break-in
Before you posted that, I was going to question if non-faced rings were appropriate for propane, having listened to stories about how gaseous fuels can be kind of tough on some components.
Now I would only ask, was the wording "recommended for use in" or "acceptable for use in", along with some qualifiers in the context, like, in used bores with measurable taper and out-of-round?
I figure unfaced rings simply can not provide nearly as long service life when subjected to the flash bore corrosion and condensation at start up, until the cylinder walls get up to temperature.
Of course other factors might make iron the only choice.
RE: Propane 454 Ring Break-in
This might take some analysis.
And some special attention to oil delivery, since your fuel does not have any lubricity.
New engine clearances are ridiculous, my wife's new Toyota V-6 uses 0-W20.
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P.E. Metallurgy, Plymouth Tube
RE: Propane 454 Ring Break-in
JMO but the best break-in method by far is good old fashioned motoring either on a motoring dyno or simply using a large electric motor. Spin it up to 3k RPM, make sure there's good oil pressure, and let it go for 20-40 hours. If you'd prefer a running break-in, I've never been a fan of stressing new engines with various heat and speed cycles and usually recommend a few roadtrips with hours of highway driving. Keep the RPM relatively low (<3k) and be slow on throttle acceleration. I'd use standard oil viscosity for that engine (10W-30?) but see if you can find it formulated for gaseous fuels, worst case ask either a Cummins or Cat dealer.
RE: Propane 454 Ring Break-in
jack vines
RE: Propane 454 Ring Break-in