4.0 SOHC Timing Noise | Page 4 | Ford Explorer - Ford Ranger Forums - Serious Explorations
  • Register Today It's free!

The tensioners I am talking about are used for Polaris machines but compatible with our Ford SOHC engines (same cloyes body)
You see Polaris used the same Ford tensioner to tension the chains in the Prostar OHC engines.
I own three of these, a 2014, a 2015 and a 2018.
The 2014 and 2015 had timing chain rattle at cold start right from new
Installed manual tensioner(s) and the noise/problem is gone
The tensioners have come way down in price since I installed them

It is not solid, there is a stiff spring inside

There are several styles, Team Alba, Boondocker, Sparks Racing even some manual ones on Ebay:
$64 manual style

Boondocker "worm drive" style

Looks like the oil galley feed is plugged or at least bypass' this style tensioner

Timing chains are ALWAYS under tension with these, fool proof, Why would you ever want slack in your chains????

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Damm!! it is an actual and reliable solution?

I sold my 98' XLT to a friend, with the rear chain noise.
He still using it, and this mod looks easy to do..

We do not know yet, that is why its here up for discussion
In theory it would work, the dude from BRazil did a similar thing in the video above
I have installed them in my Polaris Rzr engines and it fixed all chain noise on startup

If I had a sohc engine I would try it
Maybe we can get @Stic-o to be guinea pig here with his sohc/sport /ttb project? Lol the manual style tensioners (Like I have but I paid way more $250 ea because they are brand name and were new concept at the time) are down to $65 ea on ebay, just need two

I would try it but I already solved the rattle with a pre oiler

and I would like to see it work before I put it on my brand new engine

I'd about find some $400 truck again and put a set in to test, since here people junk stuff for the simple thing of it looking rough (Bought one that way). If it didn't work so what? Junk it and you got your money back.

I've had my 1999 Explorer 4.0 SOHC professionally rebuilt with the stipulation that I would have to install the timing components myself - which I did using the OTC timing kit and a new timing kit with balance shaft tensioner and chain from Evergreen (which is apparently not worth buying) and have had the same noise after doing it twice.

The first time I probably drove the truck 25 miles and was too nervous that I was about to destroy a $2000 rebuild and put it in the garage and pulled the engine within a week or so of parking it. When I pulled it everything looked normal other than the balance shaft chain tensioner which was rubbing the chain on the edge. I ordered another one which also turned out to be Evergreen brand and noticed it also did not mount properly, so I bought a $30 Ford tensioner, and it fit perfectly. I also bought both Ford brand hydraulic tensioners and installed them while it was out.

Well, I reinstalled the engine and it still has the same timing metal on metal rubbing noise from under the engine and I'm beside myself. I'll post a youtube link of it running below. A few small details/thoughts: everything on the engine has been replaced/rebuilt except the cams and lash adjusters/lifters, the crank was perfect, all new bearings, pistons, oil pump (ford brand), new oil pump drive/camshaft sync, I mean everything was done, so I don't think the noise would be anything other than a timing noise.

Any insight would be appreciated. I have a neighbor that's a Ford tech with 20 + years that I'm going to have look at it AGAIN. The first time he said it almost had to be a timing noise and in part was right considering the condition of the balance shaft tensioner.

From today:

THAT is nothing compared to the 99 SOHV I own, it is a quiet motor when cold, cool, but run it on the highway for a hour or so, let it idle, you can hear from the rear of the engine what at first I thought was the cat converter tin plate banging around occasionally.

When crawling up under the Ford, you can hear that rear chain banging around once every 30 seconds. It will only become worse as it goes along...what the guys at the shop said.

SOHV! Wicked cool

I get SOHC engines in here all the time, if I get a good running one that needs a transmission or somethng I will spring for two of the manual tensioners and do some testing.
My stepson's wife drives a SOHC sport trac...maybe we will use that truck for testing :)
I have wanted to do this since 2015!

These are photos of front and rear guides and hydraulic tensioners from my ST. As previously mentioned they are in good condition. Having said that I had the death rattle in the right rear and thought it may be weakened/damaged. I got rid of the rattle by pre-oiling, prior to my rebuild.

The photo of the hydraulic tensioners shows the actual part that goes in the head to the guides is almost the same. The long hydraulic tensioner is that way to hold extra oil because of its orientation, facing down, with restrictor helping oil retention.

To retain oiling capabilities a modification to two (2) of the short tensioner could be done. Using them at front and rear, drilling and threading a hole through the tensioner head. With used tensioners there are scuff marks showing where the tensioner operates. These marks could be used as a guide on how far that the bolt is screwed into the tensioner.

From what I can see it would stop rattle and retain some movement in the tensioners, with oil pressure, provided the bolt isn't screwed in too far. Judging how far to screw the front left tensioner bolt in should be taken off the original long tensioner.

Here is the 2015 "Polaris" Prostar 999cc engine timing chain tensioner
Look familiar?
Next to the new manual chain tensioner (aftermarket, Alba Racing, Sparks racing, several people make a similar tensioner now)
Direct replacement for the short side (pass head) should work just fine in drivers head also


Note to Polaris as one of your shareholders:
If you are going to use parts from other vehicles already in production, CHOOSE THE GOOD PARTS not the one part that sucks the most

Nothing like spending $24K for a off road machine that goes tick tick tick cold start right from the factory........

From my research but limited experience I rekon that the front left drivers side guides rarely fail as they are well reinforced. The problems at the front are the old style primary tensioner with 2 or 3 leaf springs. This said rattle can still be a problem at cold start.

Explorer sohc owners who have rattle on cold start are the "lucky ones" as this means especially the rear all plastic guide probably has not broken. Those owners who have scaping/rattling at 2000 to 3000 rpm means the rear plastic guide is broken. Inevitably the broken guides will cause the engine to jump time and bend valves +++.

Owners with cold start rattle at the rear passengers side and not able to pull engine to repair are prime candidates to try this fix, at their own risk of course. IMHO I think it would work and give them more motoring miles than without this fix.

Yes it looks like Polaris had problems with Ford tensioner and designed a manually adjustable tensioner, which would work for sohc Explorers, if so a very simple fix for non damaged secondary tensioners! Problem solved........

I have read pages and pages here and there and my Wife's '97 has the 4.0 SOHC. Even though it has over 200k, and has the rattle at start up, it quickly goes away. This leads me to believe that it doesn't have much guide damage however the next time that I change the oil I am going to use a clean drain pan and filter the old oil through an automotive paint filter to check for debris. So tell me if I have gathered the information that I need to change out the tensioners:
There is a tensioner on the right cylinder head at the lower rear part of the head accessible through the wheel well
There is a tensioner on the left cylinder head at the top front part of the head accessible from overhead near the intake manifold
The improved
POLARIS design spring loaded mechanical type can be used in the 4.0 SOHC engine and use the crush washer that comes with the new part for $64 each.
EDITED 10-08-19: The aftermarket mechanical replacement Polaris tensioner does not contain a spring.

QUESTION: How many foot pounds do I torque the Polaris tensioner (the outer body part) to in to the head and how many inch pounds ? (I assume) of preload do I tighten the inner tension bolt of the device ?
Has anyone used the Polaris part ? and if not, I volunteer to be the first
And, Am I missing any important information ? or are there two more tensioners for the long chains ?

I would torque both to 35 fp with gasket
We don't know how much to adjust the Polaris
Tensioner s as you are the first to try it

I would tighten...adjust...it until the rattle stops then a LITTLE more

Be sure to retract the Polaris tensioners all the way be for install then tighten it up
You can use your old tensioner s as a reference as they will have wear marks where they were rubbing

I can't wAit to hear your results

Retract as in turn counter clockwise.
I'm not familiar with the internals of the Polaris engine but I assume that the "chain" is a lot shorter so Polaris specs wouldn't be of any use.
I'm concerned about the Polaris spring inside of the tensioner. Will it be durable enough for the 4.0 SOHC chain ?
also, The picture on Ebay is of the tensioner and a gasket, not a crush washer and the part number on the package is for the gasket.
Recently Polaris constructed another manufacturing plant in the Huntsville/Madison Alabama area, 25 miles from me. I don't think that they manufacture the engines there but they do a lot of other production tasks there.
Polaris Locations - Headquartered in Medina MN

If you go with polaris tensioner, you should check it against the ford tensioner to check it will push in as much as the ford tensioner does.

The centre theaded rod and lock nut should be not contact inner part of tensioner till you've put main body in and torqued it up.

I'd suggest finger tight for inner rod, then back off 1/2 a turn, then tighten lock nut.

What I don't know is if there is a hole for oil pressure to assist spring inside polaris tensioner.

I don't think it has a oil galley
As far as the tensioner adjustment unscrew the adjuster all the way out install torque
Then adjust hand tight start up truck then do the final adjustment
And like said above compare to old ford tensioners to be sure they are the same dimensions

Thanks David, Donalds and others. I do not believe that the Polaris tensioner relies on any oil pressure to function however it may need to be temporarily installed to index where an oil hole should be, removed, then disassembled and drill an oil hole (then reassembled) to keep it oiled so it will not wear out prematurely.
I ordered the Polaris tensioner this morning an will be here by September 5th. I will install it on the right lower rear part of the head first. I guess "Flo" will be the "test rat".
Speaking of prelube... I am going to coat the tensioner parts with some of that green cam lube that I have left over from an engine build.

As non of us know how this will workout exactly, you could install at rear and position threaded rod and tighten lock nut in what "feels" like correct and start the engine without oil hole.

I don't think 2 or 3 minute run will damage anything without oil, as that's how it's starting now from a cold start. The difference is it has a hard stop, from threaded rod, which should stop rattle.

Drilling oil hole can be done once your satisfied it's going to work as hoped.

That chain is gonna sling oil all over that tensioner
I don't think oil is needed at all on a manual tensioner

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Ok. I will go without the hole on the RH lower rear one since it points in at an upward angle. When I purchase the one for the top of the left head pointing downward one, I may consider a hole so oil will run through it and lube it and the chain and tensioner too if y'all think that it would help and also not screw it up adding the hole. What makes me consider this is the top left original FoMoCo one is longer with the reservoir section built at the top. All input is appreciated...
Added: But then again the reservoir is for the hydraulic fuction of the Ford tensioner