98 SOHC Startup POP-chain

[RustyMacintosh]

My 90-year-old mom is driving one of my Exploders. A SOHC version with 205k. The engine sounds pretty good for a high mile motor. But, I heard it start the other day. Cold start.

I heard a POP--noticeable pop from the underside of the Explorer. OK, so the chain is now in trouble. Moments after starting the oil pressure came up, engine sounds normal (for a 205K motor).

So the tensioner that is controlled by oil pressure.....Right?

Fatal soon? Will it go for a while? Mom is active for a 90-year old (today is her birthday btw), she only drives it around town. My gut tells me to let it ride. Go until it breaks. Send the whole ride to Pick a Part, give her my 2WD which just had a 40k motor installed.

I can, and do have a good tech that can pop that motor out. Do the chains. With this POP or SLAP which in only happens one time, on cold startup, (overnight), then it sounds fine....drive it?

 

[donalds]

I suggest a manual tensioners read all of this therad
4.0 SOHC Timing Noise

 

[koda2000]

I'd let it ride. It may last a good long time if driven gently. I'm doing the same with my POS SOHC '01 Sport Trac. It's been making noises since I got it 4 year ago (and has other engine issues) and I drive it daily. When it finally goes I'll decide what to do with it. To me it's not worth my time/effort to fix it and I'm not about to pay someone else to do the work. If/when it craps out I always have my mint '01 Eddie Bauer 5.0L to drive.

 

[RustyMacintosh]

I'm really leaning towards what Koda2000 has suggested. The engine really sounds pretty good. But that startup, Both that Ex and my 99 Explorer when cold start tends to rev to 1600 maybe more than settle back down within a few moments. I can hear all the rods knocking momentarily then the oil pressure hits.

My 01 doesn't do that. It starts quietly then sits at 1200 for a moment, settles down to 1000 until warmed up a tad.

I am looking at that thread which has the manual adjusters as the Brazilian demonstrated on YouTube. That seems like a logical method to tame noisy chains.

I would guess, the same method can be done to the back #3 chain.

 

[koda2000]

It might be a little hard to teach a 90 year old to do, but what I do to avoid the chain noise at cold start-up is to crank the engine with my foot to the floor on the accelerator (which prevents the engine from starting by turning off the fuel injectors) for around 6-7 seconds during cold starts. This gets oil pressure into the tensioners and may prevent the timing chains from jumping during cold start, which is sudden death for a SOHC. It's become second nature to me to start my Sport Trac this way, I don't even have to think about it anymore. Has run none-the-less for wear for nearly 17,000+ miles/4 years. It's kind of a poor-man's pre-oiler system.

IMO worn hydraulic chain tensioners certainly contribute to the cold-start TC noise, but so do stretched chains and broken guides, so the actual problem contributing to the noise should be determined, rather than just installing the manual adjustable tensioners. It's also a real good idea to remove the SOHC's lower oil pan and check for debris which may block the oil pickup. Broken pieces of tan plastic indicate TC guide failure and sludge may also be blocking the pickup screen.

 

[donalds]

I never said not to check to find out what the problem was
A manual tensioner is a good option in a lot of cases
Like stretched chains over extended tensioners
Most likely why your chains are rattling now
Yes pull the valve covers and look that's a obvious task of you have spent any time reading on this forum


By the way manual tensioners have been used and being used on engines for years won't hurt anything

Just thought you need all info on this problem your not alone and this is one option before doing anything

 

[RustyMacintosh]

I had some success yesterday on a 130k motor which just had chains both front and rear replaced. It has been a frustrating task to find out why when it starts, cold start, with no oil pressure, you can hear everything rattle for a moment.

I've tried replacing MAF, IAC, TPS, thermostat, still, morning you can hear everything in that motor rattle until the oil pressure kicks in.

My 01 starts quietly, the 99 starts cold, sounding like a diesel...

KODA told me something I did not know. Flooring it then crank the starter--the injectors are switched off. Yesterday, cold, I floored the 99, cranked it for maybe 6 seconds or slightly more than took my foot off the gas pedal, it fired, and it was without all the noise...it had oil pressure...it sounded like it should.

As KODA did say, it is sometimes a hard concept for a 90-year-old to understand, and it was, I explained about 5 times to my mom, to do exactly as I did above on my 99.

She said she thought she just had to floor it once like the old T-bird V-8 390 she drove years ago. Dad always told her to floor it once then start it. At Dennys yesterday (Her birthday, she wanted a free Grand Slam), I demonstrated on her 98 how to cold start it.

I shared with my shop who does my work the video from the guy in Brazil. The tech's only comment other than he liked retro-fit, and he told me to find a couple of sets of adjustable tensioners which he said he would install for me, was, that his only concern is if you over-tighten the adjustment. He said it could cause other issues such as cam bearing failures. I figure it is worth the risk on a 205k motor.

SO----now to find several sets of adjustable cam tensioners ---which will be installed ASAP.

AND, I got my eye on a used 95 White XLT V-8 that might be for sale, I turned down a 00 Mercury Mountaineer V-8 Premier simply because the owner would not budge off 3000--while I liked the Merc, it was not the end of the world to walk away.

.

 

[koda2000]

@allmyEXes is the member who first found/tried the Polaris manual tensioners. He reports "so far so good" using these, I think he only installed one on the rear chain. I don't know if it works on the front chain, as the front tensioner is very different/longer than the rear one. You can find these manual tensioners on eBay for around $40-$60 last time I looked. Search the forum posts for allmyEXes thread on the subject and part numbers. @donalds may also know.

I think that if your problem is stretchered chains and/or worn/short tensioners the manual tensioner may work, but your mechanic should be very careful not to over-tighten the manual tensioner to avoid causing damage. Also, please drop you oil pan (easy to do on a 2WD, a bit more difficult on a 4WD) and make sure there's no debris around the oil pickup. Removing the valve covers can also give you an idea of what going on, but that's more work to do.

BTW - The reason your father told your mother to floor the gas pedal once before starting her old T-Bird when cold was because it had a carburetor and doing this allowed the automatic choke to set and the accelerator pump to squirt a bit of fuel into the engine.

 

[RustyMacintosh]

14-16 POLARIS RZR 1000 XP & S - NEW MANUAL CHAIN TENSIONER & GASKET timing cam | eBay

 

[donalds]

14-16 POLARIS RZR 1000 XP & S - NEW MANUAL CHAIN TENSIONER & GASKET timing cam | eBay

 

[allmyEXes]

I have had the manual tensioner installed for the rear chain since the first week of September. All still seems well with "Flo", the blue '97. A few weeks ago I purchased another '97 with the 4.0 SOHC. It is a clean white with graphite or dark metallic gray on the bottom. It has 130K on it and rattles severely, but it runs. It's a solid salt free, southern truck from just across the Ala/Tenn border. I don't have it far enough apart yet to determine what is causing the intense timing component noise. I need a chain wrench to hold the HB damper to break the TTY bolt a loose. I am hoping that it is a primary timing chain guide or tensioner issue, but what I have been reading I am under the impression that it wouldn't make the very loud noise that I am hearing. This lovely weather that we have been experiencing this Fall has kept me from working on it.