How bad is the SOHC timing chain problem, really?

[engine]

Under the hood, nothing is easy these days. It helps to have done it before.

 

[JohnnyO]

I don't want one, don't think I've ever even go to see one, but i wonder is there an easy way to replace the chains like use the old chain to run to new chain around the sprockets?

The problem is there is one on the front of the engine for one head and another on the back for the other head. Can't do the rear one without pulling the engine.

Been spending most of my time the last few years on the Sport Trac boards and FB pages. Lots of people with older models are running into timing chain problems now. Also a lot of people are well over 200k miles with no issues. My opinion is regular and frequent oil changes will minimize the problem. My Trac has had oil changes every 5k since new with synthetic. One guy on the Sport Trac board has rebuilt a few and claims that 5w-30 oil is best because if you go heavier like 10w-30 the oil won't flow through the small holes in the chain and tensioners well enough and cause premature wear. My Trac just turned 156k and so far it runs like new. Tranny did crap out at 132k despite fluid changes but that's par for the course.

 

[Craig0320]

The problem is there is one on the front of the engine for one head and another on the back for the other head. Can't do the rear one without pulling the engine.

I watched my buddy do a few on his lift and instead of pulling the engine he pulled the transmission out.

 

[adsm08]

I watched my buddy do a few on his lift and instead of pulling the engine he pulled the transmission out.

I have done a few of these chains, always engine out. I have talked to others who have done it both ways and say it isn't worth leaving the engine in, too much trouble. I agree with them.

 

[adsm08]

I don't want one, don't think I've ever even go to see one, but i wonder is there an easy way to replace the chains like use the old chain to run to new chain around the sprockets?

No, you can't do that. The chain isn't open, it's a loop, and there isn't a lot of room to work, so the chain has to go in with the lower sprocket.

The front set isn't bad to work on, no worse than an OHV timing chain set, just one or two extra pieces. The rear set is complicated by the fact of it being at the rear of the engine. It means that half the bolts you need to get at are inside the bell housing, so the transmission is in the way, and just like everything else at the rear of an engine, it is stuffed up against the firewall.

Taking the engine out is only a few extra steps to pulling the trans, and gives you a nice open working space where you can move freely around the engine, rather than contorting yourself around the body of the vehicle.

 

[Denisefwd93]

I don't study engine design, but I know enough to know I don't want one of these beasts in my Beast LOL.

but, thinking back in the 80s was it? weren't GM's dual overhead cam engines also a nightmare with timing belts?
https://www.wardsauto.com/news-analysis/gm-may-mothball-dual-cam-34l-dohc-v-6

 

[Vincenthdfan]

I don't study engine design, but I know enough to know I don't want one of these beasts in my Beast LOL.

but, thinking back in the 80s was it? weren't GM's dual overhead cam engines also a nightmare with timing belts?
https://www.wardsauto.com/news-analysis/gm-may-mothball-dual-cam-34l-dohc-v-6

Yes, my wife has an 07 Suzuki XL-7 SUV that has a chronic check engine light.

When I check it with my code reader it states there's a cam/crankshaft timing anomaly.

Turns out the General Motors V-6 in her Suzuki is of the overhead cam variety with multiple cam chains in the front of the motor.

A quick check of the Suzuki Web Forum verified that it is indeed a known problem with these rigs...terrific!

Stretched timing chains, worn guides, etc...

Problem is, its a transverse mounted engine and the only way to remove it is through the bottom of the vehicle.

I only have a 4 post lift in my shop, not the 2 post type lift required to lift a body off of an engine/drivetrain...so, it sits awaiting repairs.

The actual chain replacement isn't a big deal, something I could easily do...if only I could remove the motor to gain access!

I've never been one to pay anyone to work on our vehicles, ever...I always do all my own maintenance, so this is an especially frustrating fix we're in with the rig.

 

[engine]

Timing chains, done well, are not a problem. I have a '93 BMW six with almost 200K miles. It's self-adjusting timing chains make the same "motor music" it did when it was new. It plays a "major triad" that rises in pitch with engine speed. And it calls for 20-50 weight oil!