803A engine help

[kloppk]

Use TM 9-2815-253-24P to get the LPW4 engine part numbers for your 803.

 

[spark500001]

can anybody help us identify the proper letter designation of this engine so when we have to order parts we get the correct stuff.
thanks

That is the data plate for the engine. How useful it is might be a different item. What parts are you ordering?

There's ordering MEP-803A parts, there are Onan specific parts, there are Lister Petter (LPW4) model parts, and of course generic parts. The most specific is always going to be MEP-803A parts, but more general parts may match, e.g., Lister made a variety of engine versions, but bear in mind that not all versions share the same components, so some care is warranted.

All the best,

2Pbfeet

thanks

 

[spark500001]

You have a Lister LPW4 in an MEP 803A that was made for Onan & they name it the DN4. Don't use the China copy parts, it is not worth it.

thanks for the help

 

[spark500001]

Use TM 9-2815-253-24P to get the LPW4 engine part numbers for your 803.

thanks

 

[spark500001]

Use TM 9-2815-253-24P to get the LPW4 engine part numbers for your 803.

thanks

 

[spark500001]

That is the data plate for the engine. How useful it is might be a different item. What parts are you ordering?

There's ordering MEP-803A parts, there are Onan specific parts, there are Lister Petter (LPW4) model parts, and of course generic parts. The most specific is always going to be MEP-803A parts, but more general parts may match, e.g., Lister made a variety of engine versions, but bear in mind that not all versions share the same components, so some care is warranted.

All the best,

2Pbfeet

thanks

 

[Mark T]

THANK YOU FOR ALL THE HELP on this we are just making sure that we order the right parts when to time to ( like a gasket kits )

 

[Ray70]

Not sure if everything comes up when searching the US Ebay site, but in the past I found a lot of OEM engine parts on the UK Ebay site.
You can also get some parts direct from Cummins' on-line site.
Also if you suspect a problem with the Cam shaft, I have a couple used ones with the gear attached in my parts stash.
As well as pushrods and rocker arms etc.
If you end up pulling the head off you could set the engine at TDC and see where the lifters are at ( both valves closed ) then you can better watch the cam location and lifter as you rotate the motor.
Looking at the Cam picture it looks like the gear is pressed on ( and may have slipped ?)
I was thinking it locked into that slot on the end, but that is the governor apparently. ( I haven't been that far into an LPW4 in several years )

 

[Mark T]

Not sure if everything comes up when searching the US Ebay site, but in the past I found a lot of OEM engine parts on the UK Ebay site.
You can also get some parts direct from Cummins' on-line site.
Also if you suspect a problem with the Cam shaft, I have a couple used ones with the gear attached in my parts stash.
As well as pushrods and rocker arms etc.
If you end up pulling the head off you could set the engine at TDC and see where the lifters are at ( both valves closed ) then you can better watch the cam location and lifter as you rotate the motor.
Looking at the Cam picture it looks like the gear is pressed on ( and may have slipped ?)
I was thinking it locked into that slot on the end, but that is the governor apparently. ( I haven't been that far into an LPW4 in several years )

Hi Ray
We are going to put the engine at TDC fist then pull the head . To confirm we are at TDC with number one piston up all the way. if it is the cam gear that slipped on the cam . We would be interested in your used camshaft and gear , could you send us pictures of this part ?
We thank you for all the help on this matter .

 

[Ray70]

Mark, FYI your rational isn't going to tell you what you want to know. The pistons will always be at TDC based on the timing marks because it isn't the crank or the gears that may have slipped.
The only thing that would be off would be the position of the valves when the piston is at TDC if the cam has slipped in relation to the cam gear.
Perhaps we can also find a way to compare aa accurate picture of my cam/gear assy. to yours to confirm if the valve lobes are not correctly indexed to say the dot on the cam gear, or something like that??

 

[Mark T]

Mark, FYI your rational isn't going to tell you what you want to know. The pistons will always be at TDC based on the timing marks because it isn't the crank or the gears that may have slipped.
The only thing that would be off would be the position of the valves when the piston is at TDC if the cam has slipped in relation to the cam gear.
Perhaps we can also find a way to compare aa accurate picture of my cam/gear assy. to yours to confirm if the valve lobes are not correctly indexed to say the dot on the cam gear, or something like that??

Hi Ray
We were thinking we need to start out at TDC , before we start on removing the head . Just so we know were we are at .
Thank you for the help this may take a week to do first time do MEP803A engine and need to document and take pictures of everything to put it back right . We have the TM on it .

 

[2Pbfeet]

Hi Ray
We are going to put the engine at TDC fist then pull the head . To confirm we are at TDC with number one piston up all the way. if it is the cam gear that slipped on the cam . We would be interested in your used camshaft and gear , could you send us pictures of this part ?
We thank you for all the help on this matter .

I don't know if this helps, but if you think about how a 4-cycle engine works, every piston is at its own TDC twice. Once at the peak of compression, and the second at the end of the exhaust stroke.

If you bring the #1 piston up to the top of head, and both the intake and the exhaust valves are closed all the way up, that's TDC for #1. If you watch the valves, while slowly rotating the engine, you should be able to carefully watch the valve motion to see if the valves match where the piston is in the cycle. As a check, since this is an inline 4, when cylinder #1 is at TDC, cylinder #4 will also be TDC, but only one of the two will be at the end of the compression, and the other will be at the end of the exhaust. If the camshaft is off, piston #1 will not be at the top, with both valves closed, at least once in two rotations.
Animation here: https://en.wikipedia.org/wiki/Dead_centre_(engineering)

I think that my concern here is that if your camshaft is off, you won't have a #1 at TDC with both intake and exhaust valves closed on the end of the compression stroke.

All the best,

2Pbfeet

 

[Ray70]

Humm, I just thought of something. The slot for the governor is cut into the camshaft, the gear appears pressed on and the alignment dot is stamped into the gear. If I take a picture of my camshaft from the end, you should be able to judge the location of the timing dot relative to the slot cut in the cam.
Compare mine to yours and see if you can see an obvious difference between the two!

Also, from earlier in this thread, I assume you verified your starter is cranking the engine clockwise when looking at it from the radiator end??
I don't think you ever mentioned confirming the direction of rotation.

 

[Mark T]

Humm, I just thought of something. The slot for the governor is cut into the camshaft, the gear appears pressed on and the alignment dot is stamped into the gear. If I take a picture of my camshaft from the end, you should be able to judge the location of the timing dot relative to the slot cut in the cam.
Compare mine to yours and see if you can see an obvious difference between the two!

Also, from earlier in this thread, I assume you verified your starter is cranking the engine clockwise when looking at it from the radiator end??
I don't think you ever mentioned confirming the direction of rotation.

Hi Ray

Yes that is a great idea on the pictures , we will take a picture of the governor slot and the timing marks with a straight edge reference .
Thank you

 

[Ray70]

Well Houston, we have a problem! I have cam/ gear assemblies for both an 802A and an 803A but neither have that slot in the cam face. They are both solid on the end. I assume this must be something related to LPW4 Vs DN4M ?? I don't recall which this cam was from, but assume both are interchangeable.
There doesn't seem to be a good way to verify alignment without removing the cam.
About all I can say is that with the timing dot held at the 6:00 position, the first lobe on the cam would be at approximately 1:00 ( looking down from the top as seen in this pic.

 

[spark500001]

Well Houston, we have a problem! I have cam/ gear assemblies for both an 802A and an 803A but neither have that slot in the cam face. They are both solid on the end. I assume this must be something related to LPW4 Vs DN4M ?? I don't recall which this cam was from, but assume both are interchangeable.
There doesn't seem to be a good way to verify alignment without removing the cam.
About all I can say is that with the timing dot held at the 6:00 position, the first lobe on the cam would be at approximately 1:00 ( looking down from the top as seen in this pic.
View attachment 950476

thanks for all your help. it's too bad that you didn't have the camshaft we were looking for .

 

[Ray70]

Well, it may not be that its the wrong camshaft, it just doesn't allow us to easily determine if your camshaft has spun within the gear without removing it.
I say continue with your investigation. If you find that Both #1 valves are not closed at TDC ( and for approximately 90* crank rotation after TDC ) Then that would indicate a problem with the cam.
I think you can still use the approximate location of the 1st lobe relative to the timing dot to confirm if it has indeed slipped, but you have to remove the pumps, lifters and the cam to do that.
I also think my cam will work in your motor, if in fact yours is bad. I don't think the slot in yours is used for anything and was just a design change at some point, but that can be further investigated later, if we can first determine if your cam has a problem.

And one last time, ( sorry to keep asking but didn't see a response ) you're turning the engine clockwise looking from the front while observing the valve movements?

 

[spark500001]

Well, it may not be that its the wrong camshaft, it just doesn't allow us to easily determine if your camshaft has spun within the gear without removing it.
I say continue with your investigation. If you find that Both #1 valves are not closed at TDC ( and for approximately 90* crank rotation after TDC ) Then that would indicate a problem with the cam.
I think you can still use the approximate location of the 1st lobe relative to the timing dot to confirm if it has indeed slipped, but you have to remove the pumps, lifters and the cam to do that.
I also think my cam will work in your motor, if in fact yours is bad. I don't think the slot in yours is used for anything and was just a design change at some point, but that can be further investigated later, if we can first determine if your cam has a problem.

And one last time, ( sorry to keep asking but didn't see a response ) you're turning the engine clockwise looking from the front while observing the valve movements?

Ray, yes we are turning the motor clockwise and the starter did indeed turn clockwise as well. our next step is as you say check the first lobe in relation to the timing marks on the gears . also we are planning on pulling the cylinder head off to see if we can figure out why the engine gets hard to rotate when the pistons come up to their high points and check for any damage from piston to valve contact.
many thanks for all the helpful information you provided.