LDT 465 Multifuel. Andy3's Broken Camshaft

[o1951]

Why chance all the bearing if just one is the "issue"?
QUOTE]

Since the camshaft is one piece, it is good practice to change all of them at the same time. I have never heard of just one being replaced. If the other used ones reach the wear limits faster than the new bearing, then you could have the same situation in a different spot on the camshaft.

On that type of cam bearing, I have only done engine out of vehicle cam and bearing replacements.
From personal experience, once you have it opened up, the cam out, with the proper cam bearing tools, not that much more to replace all of them. I do not know about this engine, but whenever I bought cam bearings, you had to buy a complete set - could not buy just one.

When doing crankshaft, always replaced all main bearings, when doing double overhead cam engines, which have split bearing inserts and bearing caps, always replaced all the bearings. Just say'in.

 

[oddshot]

Replacing freeze plugs are no big deal IF you can get to them. Would an access hole in the fire wall be in order?

No. If there is a plug back there, it's behind the flywheel. You'd have to pull the trans, clutch and flywheel and whatever else is back there to get it out that way.

Sometime this weekend I should have the engine off my truck and in a position where it would be a bit safer to pull the side covers off the block, remove the cam followers, pull the remainder of the cam and get a look to see what I would have to do to get the last bearing out from the front of the block.

Driving in a new one is easy.

 

[Keith_J]

A Spark Test confirms that this cam shaft is of steel and not cast iron.

Even the best steel has an endurance limit, the question would be what is the average stress as designed compared to the actual stress when the bearings have worn.

 

[oddshot]

Why chance all the bearing if just one is the "issue"?
QUOTE]

Since the camshaft is one piece, it is good practice to change all of them at the same time. I have never heard of just one being replaced. If the other used ones reach the wear limits faster than the new bearing, then you could have the same situation in a different spot on the camshaft.

I agree, especially since the camshaft is one LONG piece subjected to constant loading and unloading forces at individual places ( the lobes) along its length.

The only foundation it has are the bearings that support it.

Unequally worn bearings will subject the camshaft to stresses it was never designed to handle.

These bearings need to replaced as a set.

 

[oddshot]

Why was there a change in cams?

I don't know ... and, unless we "hobbyists" find an order somewhere in a TM or can do our own side by side comparison of the two shafts, ... I doubt we will ever find out.

I sincerely doubt that contacting White, Hercules or Continental or anybody else for that matter will get us any information.

These manufacturers did NOT produce these vehicles for civilian use, and these trucks are long past any warranty, if there was ever one to begin with.

The LAST thing any manufacturer would want is to open a door and expose themselves to ANY type of liability or responsibility for these products.

 

[JasonS]

I don't know ... and, unless we "hobbyists" find an order somewhere in a TM or can do our own side by side comparison of the two shafts, ... I doubt we will ever find out.

I sincerely doubt that contacting White, Hercules or Continental or anybody else for that matter will get us any information.

These manufacturers did NOT produce these vehicles for civilian use, and these trucks are long past any warranty, if there was ever one to begin with.

The LAST thing any manufacturer would want is to open a door and expose themselves to ANY type of liability or responsibility for these products.

But Continental/ White/ Hercules, etc did produce these engines for farm tractors and prime movers for generators (diesel and spark ignition). Somebody certainly knows the engineering history and I would bet that the military knew of a change order.

 

[Jeepsinker]

This has been discussed before though. The new cam is the same as the replacement cam for the LDS 465-1a engine. They wanted one replacement cam for all of the engines for parts compatability. I think it is safe to assume that one cam design had a problem in one particular niche and someone on high said " just replace them all with one if it'll work."

 

[rustystud]

There where three cams used in this engine. Just speculation but maybe the early ones had problems and the later one which had better flow became the standard one for all. I cannot remember the date of the last cam change, but I believe it was in the early to mid seventies. Like 1974 . It was written down in the engine TM.

 

[RAYZER]

Don't know if it's been mentioned, with the multifuel lacking oil pressure for about 5 sec after starting, it's a possibility that these dry starts could cause exsessive ware, especially on top end components.

 

[oddshot]

Don't know if it's been mentioned, with the multifuel lacking oil pressure for about 5 sec after starting, it's a possibility that these dry starts could cause excessive ware, especially on top end components.

Very Good! I hadn't added that into the equation.

I sure can't see where the low oil pressure would be helping anything.

 

[bchauvette]

http://engineprelube.com/

http://www.prelube.com/


or

cranak the engine fuel off to build pressure then kick fuel on?

 

[RAYZER]

A spin on oil filter kit with anti drain back filters do the trick!

 

[gimpyrobb]

A spin on oil filter kit with anti drain back filters do the trick!

Not really, the oil will still drain forward. Thats why I use the small can filters instead of the big mama-jamas.

 

[clinto]

So we should probably consider this:

Most of our trucks have between 13,000 miles and who knows how many. The gauges aren't trustworthy because they get swapped when they go bad, so unless you have all the maintenance records for your truck, you really don't know how many miles it had.

Regardless, what I am trying to say is that by the time we get them, 90% of their mileage has already been accrued. Unless you're driving your truck 5-10K miles a year, putting the spin-ons and a pre-luber now is like waxing a car after the clearcoat has begun to peel off.

I'm not saying it's not a worthy upgrade, I have 2 of them on my personal trucks. But you aren't going to fix the 20+ years of dry starts that the engine has already had.

 

[Coffey1]

Or the gauges are right and you do nothing to help yourself.
So a ounce of prevention is way better then a pound of cure.

 

[doghead]

I just pulled my cam to replace all the bearings.

Are you saying I should clearcoat the cam, or the bearings or just use wax?

 

[o1951]

I just pulled my cam to replace all the bearings.

Are you saying I should clearcoat the cam, or the bearings or just use wax?

I'd use something like this: [h=1]Permatex[SUP]®[/SUP] Ultra Slick™ Engine Assembly Lube[/h]
Proper lubrication of metal mating surfaces is essential prior to starting a new or rebuilt engine. Ultra Slick™ adheres to component surfaces to prevent scuffing and galling during initial start-up. This high quality formulation meets or exceeds OEM performance specs for engine assembly lubricants.

 

[Jeepsinker]

DH, when we build engines down around here we normally just use Lucas oil stabilizer. $13/quart and it pretty well stays where it is put, although it is a bit messy.

 

[barefootin]

Not really, the oil will still drain forward. Thats why I use the small can filters instead of the big mama-jamas.

I'll agree.... Even with spin-on filters, if mine sits more than a week it still takes about 10 seconds to build "full" oil pressure if I don't crank it for a few seconds with fuel off. However, mine does start really fast...

 

[rustystud]

Maybe it's time to dust off that old plan to build an engine preluber.