Need replacement for Workhorse 8.1 L engine

[Charlie 5320]

You are less likely to burn a piston with E-85 than you are with E-10 as alcohol burns cooler than gasoline, the higher percentage of alcohol you run, the cooler the engine runs.

I agree, but the unit isn't set up for E85, and it takes a lot more fuel. I've ran E85 in my race cars for the last 5 years. Don't think the stock injectors can flow enough fuel.

 

[kdbgoat]

Wouldn't E85 cause the engine to run lean?

 

[Larry N.]

My 2007 F-150 is a "Flex Fuel" vehicle, so does fine, but vehicles that are not, yes, they'd be lean, plus there might be some rubber or plastic components in the fuel system that don't like ethanol.

 

[Charlie 5320]

Wouldn't E85 cause the engine to run lean?

Yes, it would be very lean, lean enough to burn pistons because the injectors can't flow enough fuel. The fuel map in the ecm isn't even close enough to run E85. There are guys out there that could tune one for E85 however.

 

[gwcowgill]

A lot here believe lean cylinder may be the problem but on the 8.1L stuck valve is also a consideration. You can look at the plug and get a good idea. You really need to get the engine out and inspect the cylinder. The heads on the 454/8.1 engine were known to get a stuck valve when setting for long periods of time. A lot of the 8.1L's are out there with well over a 100,000 miles on them and some with over 300,000.

 

[morefun]

Update!

This morning the shop scoped all cylinders and did compression checks on all as well.  The result is that only the one piston (#2) is damaged and as far as they can tell the cylinder walls are OK.  All other cylinders have good compression.  The final part of the testing is the oil sample that was taken and will be sent out to be analysed.  This will tell us if the wear on the engine is normal for the mileage (44,500), if there are any foreign particles such as from a bearing or other component, or perhaps water that shouldn't be there.  Apparently this test can be used as a guide to determine when the oil in your engine needs to be changed, rather than the general default of every so many miles or so many months.  It could very well be that we don't need to change our oil nearly as often as the manufacturer says.

So if the oil test shows everything to be within normal limits (given that there is a hole in #2 piston), we'll pull the head on that side, drop the pan and change the one piston and rod.  I can't wait to see the piston that has caused all the trouble.

 

[PCarillon]

sounds good keep us posted

 

[jglass]

A lot here believe lean cylinder may be the problem but on the 8.1L stuck valve is also a consideration. You can look at the plug and get a good idea. You really need to get the engine out and inspect the cylinder. The heads on the 454/8.1 engine were known to get a stuck valve when setting for long periods of time. A lot of the 8.1L's are out there with well over a 100,000 miles on them and some with over 300,000.

I'm sure glad you said that.  I also have an 8.1 workhorse and was beginning to wonder if I'll have problems with it.  Even though our MH sits like so many others,  I take it for a 30 mile drive every month and run the heater and AC.  Run the slides in/out, generator and run the leveling jacks up/down a couple of times.

Seems like the driver could have detected the engine running on 7 cylinders instead of 8.  Seems like any time a spark plug wire failed I knew it right away.  Just curious, Jim

 

[WILDEBILL308]

Update!

This morning the shop scoped all cylinders and did compression checks on all as well.  The result is that only the one piston (#2) is damaged and as far as they can tell the cylinder walls are OK.  All other cylinders have good compression.  The final part of the testing is the oil sample that was taken and will be sent out to be analysed.  This will tell us if the wear on the engine is normal for the mileage (44,500), if there are any foreign particles such as from a bearing or other component, or perhaps water that shouldn't be there.  Apparently this test can be used as a guide to determine when the oil in your engine needs to be changed, rather than the general default of every so many miles or so many months.  It could very well be that we don't need to change our oil nearly as often as the manufacturer says.

So if the oil test shows everything to be within normal limits (given that there is a hole in #2 piston), we'll pull the head on that side, drop the pan and change the one piston and rod.  I can't wait to see the piston that has caused all the trouble.

Looking for an update. Need pictures of that piston.
Bill

 

[Daffy]

Agreed on the pic of the piston, more specific as to where on the top of it the hole is. (tells a story)

Scoping is all good and fine but did they have one that could look at the valves and the combustion chamber as well without pulling the head?

Hate to see anyone throw good money after bad.

Good luck on the oil testing....

 

[DonTom]

My guess of the cause of the hole in the piston would be pre-ignition, perhaps caused by  using too low of an octane gasoline for the engine conditions at the time.

Did it happen under a very heavy load, such as going up a hill , espcally if towing?

-Don-  SSF, CA

 

[morefun]

Finally got the oil test results back from NAPA:
"Engine wear levels appear satisfactory for the first sample.  Light concentration of water present" (but not coolant).  My shop thinks the water (0.20%) is probably from condensation rather than an engine problem as it does not have coolant mixed in.  They say that this can happen with vehicles that sit for long times (like an RV).

As a result I have decided to have them try to repair the engine rather than replacing it - assuming nothing untoward is found when they open it up.  At this point we are planning to pull the oil pan, removing the head, replace the piston, rod, and fuel injector for that cylinder, and install new gaskets and hoses.  We'll examine the head and check the cylinder walls for any scoring.  Naturally we'll change the oil and filter (I use Castrol Edge synthetic). 

If the compression in this cylinder is back to normal (all others were), then I'm planning to do some driving to test it out.  I now have a ScanGuage so I can monitor the actual water temperature and any codes that come up.  After about 1,000 miles I'd like to test the oil again, and will change the oil and filter again just in case.

I don't have a picture of the piston yet, but should have the actual piston sometime next week when the work is to be done.

 

[PCarillon]

You may have to wait until the Motor or should I say the new piston rings have seated until you run synthetic oil might have to wait until the first oil change

 

[morefun]

Why should I wait?  Would the new rings seat better with regular motor oil than with synthetic?

 

[WILDEBILL308]

This is one of those old wives tales. Many new engines ship with synthetic oil. They don't require special brake in oil.
Glad they are making progress. I would bet your rod would be fine but if it makes you feel better change it.
Bill

 

[driftless shifter]

It's not the rod, it's the rings. Won't harm it to use dino oil for break in. Might not seat the rings properly if you use synthetic for break in. It's kind of a no brainer for me, use cheaper dino for the break in, then switch to synthetic.

Bill

 

[WILDEBILL308]

It's not the rod, it's the rings. Won't harm it to use dino oil for break in. Might not seat the rings properly if you use synthetic for break in. It's kind of a no brainer for me, use cheaper dino for the break in, then switch to synthetic.
Bill

My comment was "I doubt the rod was damaged" It had nothing too do with brake in. Just like there is NO need to use anything as a break in oil. You can run synthetic from the first crank and be just fine. Please explain how all the new cars shipped with synthetic oil manage.
Bill

 

[driftless shifter]

New car engines are built with new metallurgy. We're talking about older cast iron engines. Redline oil, a synthetic oil manufacture, recommends dino oil for break in of 1000-1500 miles. Summit racing recommends dino oil for up 4000 miles. GM crate engines also recommend dino for break in. Specifically for seating new rings. Why would they suggest that? Don't believe me, google it. My point is why spend money on synthetic that is only going to be disposed of in a short time, particularly when there are questions about the superior lubricity of synthetic interfering with proper seating of new rings. Running dino oil for break in won't harm anything and may be the wiser choice.
Synthetic oil has it's place, but me personally, I would never use it for break in. Nor would I start using it in an engine that is either old with low mileage or newer with high miles.

Bill

 

[driftless shifter]

On another note anybody ever heard of ZDDP additive for break in. It is a zinc additive added to oil to protect new cams and tappets/lifters during break in. Zinc has been in motor oil for a long time but is being reduced for the EPA. It's a good additive for flat tappet  cams that need to work harden each other during break in. It's not needed in modern engines that use roller cams. Roller cams use a tappet with a little wheel on the bottom that rolls on the cam surface instead of hard metal scuffing on the cam. If you put a rebuilt long block 454 or 460 in your rig you might be crying in short time due to a flat cam or wiped out tappet.
Some people with old school hot rods add a bit of ZDDP very oil change or use racing oil that still has it. It's not so much a pollutant as it is a problem for catalytic converter longevity.

The original poster won't need this as his cam and tappets aren't being replaced.

Bill

 

[Charlie 5320]

The later 454s had roller lifters too, not real sure when they changed. Probably when they started calling them vortech. I know GM didn't recommend  synthetic oil in my 95 454, with flat tappets. I would also use regular oil in it for the first change. I used synthetic in my race engines but only after a break in with dino oil for a couple weekends, with no additives.