Motor oil weight for triton v10

427435 wrote:
Relative to the cam tensioners, I don't believe they are very sensitive to oil pressure. Looking at their design, they appear to just be something to minimize chain slap. Regardless, they do their job at relatively high oil viscountcies during the 20 minutes or so that it takes for oil to reach it's operating temps and minimum viscosity.

Anyway, I'm at 80,000 miles on the V10 and 120,000 miles on a 4.6 (similar cam tensioners) in my toad without issues. They've always had at least a 5w-30 oi in them and, in the case of the MH, at least a 5w-40. The V10 also has around 30,000 miles with a 15w-50. Prior to that, I had a 4.6 in a Grand Marquis that was still running fine at 175,000 miles. It also never saw any oil less than a 5w-30 viscosity.

Mark,

Your Triton engines are very likely fine. I've heard of some going 300-400k. Mine apparently quit at 118k and I have only owned it for about 5k. The details were a long story, and if I ever find the link I'll get back to you since you seem more interested in these engines than most here. FWIW, I liked, and trusted, the V10 well enough to replace it in an older 2000 Excursion. Ford has the best deal at competitive prices with an outstanding 3 years warranty, unlimited mileage, commercial or not, dealers everywhere. There also was no immediate towing restriction, a plus should an engine need replacing during a trip.

The tensioners do minimise chain slap of course. With such a lengthy chain, just a little wear on each pin translates to a lot of slop. Actually, without adequate oil pressure to the tensioners, a worn Triton chain saws against the aluminum timing case cover and the nylon rub block falls (is hammered) entirely out after littering the oil with aluminum and nylon debris. Meanwhile, the debris goes through the pump and lodges in the oil filter... unless the filter pressure limiting bypass is open because of thick, possibly cold oil. An open filter bypass means debris keeps going unfiltered and this is true of any engine. In case of a plugged filter, dirty oil is deemed better than no oil. Using 5Wxx is a wise choice even if for only this filter bypass avoidence. As your chart pointed out, all oils have similar hot viscosity. The filter bypass is not to be confused with the 30# galley limited oil pressure bypass.

Any debris may lodge in the cam oiling meter orifice in the head, further limiting adequate oil supply/pressure to the hydraulic tensioner... after starving the cam. For this reason Ford has refused to further warranty engine failures caused by faulty generic oil filters (disintegrating, plugging) thereby requiring customers to buy quality Ford Motorcraft filters. I suspect they spec'd 5W20 while sorting this cam "oiling" problem before they pinned it down. Engineers found filter debris as a cause of engine failure, and that may be what occurred in my V10, as the last oil change (1300mi prior) did not use a Ford filter.

Almost always, the RH cam side fails first, as the LH side gets direct oiling from the pump right below it. The heads are semi-symmetrical. As one views the head from the intake ports, the block-to-head oil port is to the right. So the LH gets direct oil at the front, but the RH tensioner only gets oil after it has traveled back past the all the leaky main bearings and then forward past all the leaky cam bearings... until whatever is left finally reaches the tensioner piston.

According to my knowledgable Ford shop supe, one exceptionally bad leak is attributed to well worn split main thrust washers that occasinally fall out into the pan. After that, the crank suddenly clunks from too much end play, and so much gallery oil leaks away, that the RH hydraulic tensioner collapses and the death throes began, although it will keep running for the unwary. The Tritons have two main thrust washers, one of which is whole that fits over the rear end of the crank, the other a split washer that is inserted piecemeal to the front of the rear main. The Tritons do not have the center saddle-shaped main thrust bearing we grew up with, but rather have main inserts and thrust separate.

I'll never be sure what happened to my V10. It lost all oil pressure while idling. It would have cost $2000 to pull the pan on a fishing expedition and later, the Ford dealer "conveniently" forgot to pull it, like he had agreed, for a look-see after the engine was removed. To pull the pan normally at least requires that the intake be removed to make cowl room for lifting the engine high enough to clear the truck cross-members while dropping the pan below the oil pick-up. The $ dilema is similar to the necessity of engine-service cab removal on Ford F-250's... the engines are 1/3 back under the windshield. Nice short hood styling-wise though.

Wes
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