4.0L SOHC Metal Reinforced Timing Chain Guides Possible?

[swshawaii]

Novice question. Must be a reason an aftermarket manufacturer hasn't made them. "If" the engine wasn't destroyed when the plastic tensioner guide(s) failed, seems like it would be a very lucrative business for those choosing to rebuild rather than replace their engine.

In my opinion the main deficiency with the Ford SOHC V6 4.0L design is not the use of plastic tensioner to chain wear surfaces but the use of plastic as a structural element. Due to heat cycles and mechanical stress cycles the plastic eventually fractures and then breaks. The cassette guide assemblies should have been built of metal with plastic only used for chain to guide wear surfaces.

why the plastic guides on timing chain? | Ford Explorer and Ford Ranger Forums - Serious Explorations

 

[Tech By Trade]

Asked myself this many a time as well. Planned obsolescence probably.

 

[swshawaii]

TBT, isn't it baffling? Would think with the HUGE parts aftermarket for these aging SOHC's, someone would have made them by now. Don't know about planned obsolescence, that would seem to be on Ford's end. Besides that, most Ford owners that have lost an engine due to failing plastic tensioner guides will lose brand loyalty in a heartbeat. Dorman (Gulp!) comes to mind first, after all this is their claim:

What is Dorman OE FIX?
Engineered solutions designed to correct known OE failures

• Engineered improvements to eliminate known OE failures
• Replacements for only the failed original component rather than the entire assembly
• Designed to solve the original problem, saving time and money, and creating “customers for life”

What is OE Fix?

 

[Tech By Trade]

Tell me about it. I lost all brand loyalty after owning my pile of crap. Had I not bought a 400k house shortly after buying it, I would be driving something else by now. Only a year left in my plan to get something new though, as long as all holds together, it wont be a Ford product.

 

[96eb96]

Fords reason was probably cost. Those tensioners look real cheap,and over millions of engines that could be some nice money. Designed to barely last the warranty.But as we know many here have run these engines to very high miles with few issues. So they may have put that on a spreadsheet with customer loyalty.The newer SOHCs are *supposed* to have the problem under control, I guess the failure rate isn't that high, so they keep the original design in the aftermarket. You can also make an argument with the 5R transmissions too, far from perfect..

When I bought my ex used in 01 the salesman was an ex-Ford tech and told me the SOHC 4.0L is a terrible design and to avoid it, and nothing could be done to assure reliability. Of course we know the engine has to be pulled to fix the issue, and he felt it was almost maintenance that could be a 60-100K mile job. He said choose an OHV engine. Of course back then the problem was worse.

BTW, Audis V8s of that era have all their timing chains in the back, and they fail in a similar way. They designed it that way because they felt it would be a lifetime part vs the old timing belt. Lifetime to an automaker could be 120K miles, maybe even less.

 

[FF_RSQExplorer]

No one to my knowledge nor have I ever seen a metal to metal guide in 17 years in the auto dealer service buisness.

The reason is that the chain would wear heavily on the guide and also the chain itself.

I have seen a metal bodied guide with poly guide surface molded to it. But the vast majority of the timming chains I've seen from GM, Ford, Chrysler, Volvo, Acura, Honda, LR, BMW, MB, Jag and Aston Martin are plastic with poly runners molded to them. Yes I've work for all of those.

Most T chain complaints are noise and rattle from clogged tensioner oil feed orifices.

There likley was some low tolerance plastics and polys early on with the 4.0, but what kills them mostly is bad maintenance.

And do I wish they were more robust, sure in my Sport 4x4 I just picked up, it was heavily bronzed and not sludged with decent maintenance history.

I had a cold start rattle, tried the TSB, but the tensioners were covered in sludge. Timming chain bit it this morning 5 days after new tensioners. 140k

 

[swshawaii]

Interesting old thread from TRS, surprised I've never seen it.

Ford used 3 different grade plastics between all their OHC tensioner/guide designs. The grade 1 plastic was extremely lightweight and used in only a few applications. Those grade 1 pieces would absorbe the minerals and detergents in the motor oil and brake apart and fail as early as 30,000 miles.

Grade 2 was a revised version of grade 1 after Ford realized what was going on. Grade 2 suffers from the same fate but not as quickly as grade 1.

Grade 3 was what was initially used in the 4.6L and alike engines where lightweight wasnt so important. Grade 3 lasts the longest but still suffers the same fate as 1 and 2.

Ford AJV8 Family of engines used in Jaguars 1997-2008 are the best example of these cheap tensioner/guide design failures. The 4.0L was first given grade 1 and had so many failures but never issued a recall which was and still is dick on their part. They revised them with grade 2 in 2001. Then in 2003 when the 4.0L was revised into the 4.2L grade 3 plastic with metal backing plates came into production and those are the only ones that fixed this issue.

The Ranger Station Forums - View Single Post - 4l sohc timing chain rattle

 

[FF_RSQExplorer]

Interesting old thread from TRS, surprised I've never seen it.

That sounds about right, jags were forever getting tchain work and the improvements were about that same evolution

 

[koda2000]

Am I correct in assuming the Land Rovers that used Ford the 4.0L SOHC suffer the same problems? Don't see why they'd be any more durable, unless Land Rover re-engineered something.

 

[Tech By Trade]

Land rover uses the same garbage. Over in the EU they actually get their ford parts from land Rover because it's cheaper over there. As for a running face of course it would need to be synthetic,were talking the structural portion of the cassettes and their flimsy plastic design.

 

[FF_RSQExplorer]

Am I correct in assuming the Land Rovers that used Ford the 4.0L SOHC suffer the same problems? Don't see why they'd be any more durable, unless Land Rover re-engineered something.

Yes Jaguar and LR and Aston Martin s of the same vintage use either simply rebadged Ford Powertrains or derivatives therein. That is when FoMoCo owned and operated the Premier Auto Group which they owned thoae makes and also included Volvo. Volvo eacaped having alot of Ford infusion as they were light years ahead in platform and powertain development along with advanced saftey features. The collosion mitgation systems that are now in a new F150 or Expedtion or Explorer is what Volvo was using in 2008.

Remember the 4.0 SOHC is a European engineered 4.0 OHV converted to SOHC. The demand was to increase power and efficiency on platforms that used the existing 4.0 OHV engine, without having to modify the platform chassis. Thats why it has a wierd setup .