Synthetic oil and roller cam failure?

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I have a 98 GMC k2500 pickup with vortec 454. It was a warden government truck, never worked and had every 3000 mile conventional oil changes with 5w30 until I got it with 103k I ran M1 10w40 in it from then on, and used it to to a car trailer at highway speeds. I am in Florida so very hot all the time. Changing oil about every 5k with mobil filters. These have injector issues and intake gasket issues, and I changed the injectors out with bosch units and ac delco factory gaskets. Also had the computer re flashed for more timing and to increase shift firmness and have OD come on at a higher speed.

I started getting a lope or miss which progressed to a tapping, I narrowed it down to a cylinder, it had slop in the rocker arm. Pulled the intake and found several chewed up lifters. So I changed the cam and most of the lifters, it was a terrible job, had to drop the front axle, pull the core support, ac, ect. I don't want to do it again.
It is all back together and running great, on m1 10w30 this time.

I know GM used roller lifters and M1 oil since 92 in corvette without issues. But these 454 engines use exhaust rotators and have very low spring pressure. They also have less lift than the LT1 corvettes, which is absurd. And I have read that some of these 454s had cam hardening issues causing them to go flat.

So is there any chance that synthetic oil could cause a roller lifter to glide rather than roll and cause failure?
 
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Originally Posted By: DONWATERS

So is there any chance that synthetic oil could cause a roller lifter to glide rather than roll and cause failure?


It's not likely that synthetic oil is related to the cam and roller wear issues. In fact, most people believe that roller cams are indestructible, and operate very well no matter what. That's simply not so. From GM, Ford, to VW, to Lycoming aircraft engines, roller cams and roller problems are unfortunately quite common.

And again, it's contamination that kills roller cams and cam chains. Things like fuel dilution and particulates are known issues with roller cams. VW had highly loaded roller issues in the PD diesel engines. The solution is always the same, a more robust oil and more frequent oil changes.

And, just like flat tappet cams, once the wear problems start, they continue to worsen.
 
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Thanks for the reply. Yep it had a problem with fuel dilution, factory rochester injectors leaking down not holding pressure. Probably were leaking for many years. The engine is spotless inside though. I had to drop the pan, take off the valve covers and the intake manifold. Not a spot of sludge. 180 compression too. I thought when I bought it hey great the cam will last forever! Soo wrong. And I wanted US made lifters, bought some TRW old stock ones, turned out to be from China anyways.

My plans going to be M1 10w30 every 5k. It is not a daily driver, only used to tow and carry weight.
 
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I would be using a 15w40 diesel oil or a 20w50 PCMO...Rotella and Valvoline VR1 come to mind. Either one has more anti wear additives vs. your current oil which will help prevent failures like the previous one. If it was mine I would be using 20w50 VR1.
 
Originally Posted By: DONWATERS
Yep it had a problem with fuel dilution, factory rochester injectors leaking down not holding pressure. Probably were leaking for many years. The engine is spotless inside though.


Don, removing as much sarcasm as humanly possible because pulling that cam sounds like it sucked, you do know that gasoline is a very good solvent, right? High levels of fuel in the engine would almost be like using a continuous "engine flush" treatment, yet also be very bad for surfaces under high loads (cam lobes, roller lifter wheels, bearings, etc). So the engine surfaces may be spotless at the expense of the engine itself. Hope your luck improves from here!
 
Originally Posted By: JLTD
I'd say all your damage occurred before your ownership.


Probably do 15w40 Delo or Delvac and a Fram Ultra … 5k OCI … that Fram better on microns …
 
The advanced timing brought the thing to life. It had base timing of 8 to 10 degrees on the scanner, with 20 total! The timing and other computer mods brought it from 6.7mpg loaded with 9000lbs at 80mph to 8.7 at the same speed with the same weight. Now it has 18 degrees no load base 36 degrees total, retarded by the knock sensor if needed and runs at 1 percent long term fuel trim or less. Its the same timing curve I run on Carbed big blocks with vaccuum advance. Basically advance the base timing until you get spark knock then back off 2 degrees. The FI with computer and knock sensors protects the engine with 2 degrees retard when the sensor activates.

HAHA, yes I know gas is a great solvent, especially this ethanol 10 percent stuff. I have several big block cars, and searched for this truck for years, wanting the big block power for a tow vehicle but having no interest in a diesel because I know nothing about electrically controlled diesels, only old school mechanical detriot diesels. I thought hey a roller cammed fuel injected 454 should be trouble free! Even when I bought it, I thought wow this is a long cranking cycle before it starts. Then after doing research and putting a fuel pressure gauge on after it sat all night I realized these injectors were bleeding down big time!

That is a good point, the engine is spotless because of fuel dilution. I bought it with about 100k miles, swapped the injectors for equivalent bosch ones around 120k, and the miss which turned out to be several cam lobes wearing down which I discovered and fixed around 154k. I thought it was a burned valve for a while until I heard the ticking of the pushrod rocker. It is at 157k now.

I would be afraid to run anything thicker than 10w40, this has a factory oil cooler with several sections of rubber line. It runs at least 20 psi oil pressure at hottest idle and 60psi at 80mph under load. I think thicker oil would burst a line, with pressure running close to 100 psi under load.
 
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10w40 and 15w40 are basically the same thickness and should be plenty stout for a BBC … might start looking at comparisons of zinc levels etc …
 
10w-30 is fine for that engine. Not sure what the thick oil folks think they have to gain by putting such thick stuff in there.
 
BBC Chebbies can handle a fair amount of timing, even on pump regular. I have seen some roller failures in BBC's due to skidding, but it was always with needle bearing trunions and either on Comp or Lunati cams ...

I'd say that the warden use left it idling a LOT. Not good for any V engine with the cam in the valley ... They are all lubed by sling oil off the crank, and it takes a minimum of 1,800 RPM to get any appreciable oil onto the lobes. If they let it idle for hours with the radio on while "spotting" poachers, it was not lubed
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Truck motors like to spend their time above 2,500, and at that point, they are slinging plenty oil.

BUT, the synthetic can have a few issues. A lot of synthetics have drain-off if they sit for days/weeks a time. It's due to the lower surafce tension which does not favor capillary fill. That same lower surface tension helps them get their xW-40 spread w/o VII's (good), but it can leave an engine with somewhat sloppy clearances w/o a robust film on cold start (bad).

Not that there is no film, there is. It's just thinner until things get slinging. And wardens, like a lot of police, will go out and start an engine, do a walk around, let it warm up, etc. Then drive off. So there is your cam running on thin film w/o new sling oil. Then they buzz out to the patrol area and start going slow and quiet while they look and listen for illegal activity. If they make a stop, they let the engine idle so it'll keep the radios and lights working, maybe 1/2 hour, then slow onto the next area.

All that slow time is really hard on a V8 cam/lifters. Howards and Crower make lifters with a direct lube channel that allows some pressure oil from the lifter gallery to drip down onto the lobes. But GM and the others do not do it as OEMs. So 100K on a "pursuit" vehicle and it goes to auction. The Dept and the MFG got their mileage, you got the left overs.

What to do? Can you drop the pan easily? Some you can, some you can't ... If so, I'd put a HV pump in there. That way the worn clearances will have a lot more flow to "sling" at the cam. You don't need pressure, just volume.

I'd also run Delo 400 15W-40 or similar. It's a tough oil and can go a long ways between changes (big rigs go 20K between changes). It's not that I think there is inherently anything wrong with M1. But it has shown drain off in my high mileage V8's and they rattle on it on cold start. Delo is usually dead quiet. So that tells me that there is a more robust residual film. And that is what your cam is looking for. Good oil film all the time, at idle and running down the highway.

I have M1 in F-150 right now, but it only has 85K. My Bronco will not stand it. Rattles like a can of marbles on cold start with M1 (225K), and then at idle when hot. I always try it. But sometimes it does not work. When in doubt, switch up the HDEO.

I have built a number of high HP BBC's, and I can say without a doubt, that they love thicker stickier oil. The last three I built had clearanced cranks (0.0045+ average), and ran HV pumps, and they are all still on the road. They get beat on pretty mercilessly, but seem to hold up. I'd say they and yours are not that far apart ...

So tell me, were the lifters that failed nearer the front?
 
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Originally Posted By: dogememe
10w-30 is fine for that engine. Not sure what the thick oil folks think they have to gain by putting such thick stuff in there.


Thickness? Just a wild guess.
 
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