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        General >> Problems >> 24V Timing Chain Tensioner
        
(Message started by: 12reps on Nov 11^th, 2006, 7:00pm)

Title: 24V Timing Chain Tensioner
Post by 12reps on Nov 11^th, 2006, 7:00pm

Hi there,
My timing chain has started to rattlle at start up after 136,000 miles. I tried to remove tensioner today but the head of the torx screw looks like it is stripped. Is there any other way of removing the tensioner?
Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 12^th, 2006, 10:08am

Yeah just undo the 2 bolts & it will come out.
When you turn the torx it compresses the spring, if you don't do that the tensioner will want to spring out of the hole as you take it off but it's not much force so you can hold it with your hand.
I usally fit them without compressing the spring ;)

Title: Re: 24V Timing Chain Tensioner
Post by wickedteen on Nov 12^th, 2006, 4:16pm

mine has been rattling for ages, i just turn the engine over with out it firing, then it dosnt do it, is there a way of stopping it altogether

Title: Re: 24V Timing Chain Tensioner
Post by solarpanel on Nov 13^th, 2006, 9:30pm

fit upgraded tensioner about £89.00 plus vat from fmd

Title: Re: 24V Timing Chain Tensioner
Post by Dave on Nov 14^th, 2006, 7:53am

Can a new tensioner be put on used chains safely?

Title: Re: 24V Timing Chain Tensioner
Post by Dave2302 on Nov 14^th, 2006, 8:42am

Hi,

I'm curious ??? ,

Ever since I got it (about 12000 miles ago), mine had a slight, (timed at 2 - 3 second), rattle on start up. I spoke to my mate, workshop foreman at FMD, he said don't touch it, it can make them worse. ???

I changed the oil and now only use the proper Ford Synthetic and genuine filter. After the second oil change I noticed the rattle was much less, (timed 1 to 1.5 seconds), and not every time, mostly only after standing 2 days. I have left it alone and it has got no worse.

However, does anyone know if this modified tensioner really does work, and if so has anyone got the finis code, cos I'd rather not have the rattle at all ! ;D

Regards

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 14^th, 2006, 11:08am

Basically the tensioner has a one way valve in it.
If you use the wrong/cheap or don't change the oil regular it gums up & allows the oil pressure to drop in the tensioner once the engine is left a few hours. They don't actually wear much.

The uprated tensioner is longer, still has the same valve.
In short it has a longer reach that's all, for when the timing gear gets to the end of it's life as the older version can drop out if extreme.

A proper cure is to strip the engine & clean/flush all the oil ways.
Temporary is to clean the valve on the tensioner or renew.
Prevention is good quality oil regulary changed of the right spec.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 14^th, 2006, 8:00pm

Hi there,

How much longer is the uprated tensioner and which part of it is longer? Is it just the piston part of the tensioner that is longer? I am currently in the process of modifying my tensioner at the moment, will let you know how I get on.
Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 14^th, 2006, 10:07pm

There are two, are you just going to change the off side one. A pair cost approx £185 with gaskets, I am thinking of changing the pair on my 98 cosworth.

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 15^th, 2006, 12:36am

The only tensioner that was uprated was the right one for bank 1.

The big spacer washer is bigger to allow the slightly longer plunger to go back flush & a different spring too. Just means the plunger has a bigger range that's all.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 15^th, 2006, 5:25pm

Hi there,

I am not changing the offside tensioner, I am only modifying it.
I have no intention of paying over £100.00 for a new one.
To be honest I dont actually know if I have the origonal style tensioner or the uprated one, how can I tell?

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 16^th, 2006, 12:11am

The longer later tensioner should have a white mark on it but few have.

You need to remove it to be able to tell.

There is a big chunky washer, if the plunger slides in side that washer it's the later one if not it's the earlier one.

Title: Re: 24V Timing Chain Tensioner
Post by Octavian_P on Nov 16^th, 2006, 11:41am

Sorry to bug in, but i'm a cosworth newbie, is it possible to take the tensioners out without striping the whole engine out ???

Cheers

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 16^th, 2006, 1:53pm

Hi there,

I have the offside tensioner out now. The hole in the middle of the chunky washer is about 6mm and the plunger diamter is about 14mm, I guess I must have the earlier style tensioner. I removed the tensioner (problem one) with the engine still in the car although I had to take the alternator off and take the bolts out of the power steering pump bar one so that I could move it forward for access. I am now experimenting to see how I can modify the tensioner.
Thanks for your advice Dave.

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by camaro on Nov 17^th, 2006, 7:37pm

Iv just bought a cossie and was wondering what the best engine oil is to put in this sort of engine. I have the famous start up rattle but only when the engine has not been driven for about one day. I have always used castrol gtx in aother cars, is this any good for the cossie. I was thinking of a 5w-30 syn castrol to help aid with the tensioner problem. Any comments, guys?

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 20^th, 2006, 8:04pm

what is the mod that you are doing .

Title: Re: 24V Timing Chain Tensioner
Post by deconick on Nov 20^th, 2006, 9:34pm

hi mine seems to rattle more now since i put in new oil fully syn, i used to use gtx so im still in two minds wether to change the oil again,hay if what ever oil you use let me know cheers.ps mines done 133000 miles

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 21^st, 2006, 12:48pm

Hi there,

I haven't finished the mod yet, I am still trying different things. I will let you know when I am happy with it. My chain started to rattle with the oil that was in the car when I bought it, I don't know what it was. I changed it to fully synthetic but I don't think it made much difference.

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 22^nd, 2006, 5:49pm

I use Halfords fully synthetic and that has made no diffrence, mine has only 85,000 on the clock, but I do the wide open throttle method of starting. The engine runs very sweet when hot even after a 720 mile run.

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 23^rd, 2006, 1:19am

You need to do at least 2 changes within 1000 miles.
First use just some cheapy oil of the right spec then your good stuff.

If that has no effect either:

1. The tensioner valve is not sealing due to oil gunge.
2. Timing gear badley worn or guides broke. (tensioners at limit of operation)
3. Low oil pressure due to wear etc.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 27^th, 2006, 8:13pm

Hi there,

Modification Update
The mod that I have been working on is to replace the spring and cylindrical piece of steel with spaces behind the plunger inside of the sleeve.
With all the chain slack at the tensioner position and the tensioner removed I measured the depth of the tensioner blade, this was 38mm.
I started off with a 12mm spacer behind the plunger giving 38mm , this produced a rattle on start up.
I then increased the spacer size in increments of 1mm, leaving it for 24hrs to allow the oil to drain out.
At the moment I have a 20mm spacer behind the plunger and I still have a rattle at start up until the oil pressure builds up, 2 to 3 seconds.
What is puzzling me is that with the 20mm spacer behind the plunger I could barely get the tensioner screws in as the chain/blade is holding the tensioner off the head by about 6-7mm.
When I measured the depth of the blade after having the 20mm spacer in it was still 38mm; as it pushes the tensioner out as the screws are undone.
My question is this: why have I still got a rattle on start up when my plunger is set to a depth of 46mm (20mm spacer) yet the depth of the blade with tensioer removed is only 38mm? What is causing the chain to be pushed back against the tensioner?
Any comments greatly appreciated.

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by Tobbe on Nov 28^th, 2006, 11:23am

I think you should be careful not to have to much tension on the chain since this might cause failure/wear on the guide.

The force that is pushing the chain back towards the tensioner is the one originated from the exhaustvalveprings, forcing the camshaft to turn when it is in certan positions. Are you sure that it is the rhs that is giving you the trouble?

On one of my 24v it was the lhs that were the bad side. Snapped chain, worn camsprockets, broke guides. The condition of the rhs were very good actually, no visable wear on it, and the tensioner did seal tight when testing when it still were assembled in the engine.

In my everyday car I use a 600w electrical heater mounted in the engine block, when I use this for a few hours there is no rattle. My personal opinion about this rattle issue is that it all is the effect of a worn chain and not a mailfunction tensioner.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 28^th, 2006, 3:58pm

Thanks for your reply Tobbe,

After sleeping on this problem I am now beginning to think that it is the LHS tensioner that is causing the trouble; is it possible to tell which side it is by listening to the engine? I am now going to put the RHS tensioner back to the way it was with no spacers in. I only hope the LHS tensioner is easier to get to than the RHS one!

Well, its back to the drawing board or should I say the wind and the rain!

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by Tobbe on Nov 28^th, 2006, 8:03pm

I did test my tensioners like this, the elbows comprises one way fittings, I did fill the hose up with oil and pressed it into the tensioners by compressed air. You will hear if the tensioner is leaking. If one would want to be very serious about it, just mount some guager aswell, but the make sure you evacuate the air, otherwise the result will not be accurate.

I learned the hard way that you really should not put your fingers into the tensioner hole in the head and press onto the guide when gently turning the engine. Be aware of black nails...

http://hem.bredband.net/tobhed/tensionerpress.jpg

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 28^th, 2006, 8:34pm

I think it is the n/s chain that is the one that is the problem on my cosworth. I have the later tensioner on the o/s, the number on the engine is above the mod number.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Nov 28^th, 2006, 10:24pm

Hi there,

I am very impressed with your photograph Tobbe. Was the purpose of your test to check for oil leaks? I am doing my tensioners with the engine in the car. I have been able to make adjustments to the RHS tensioner and run the engine. However, it doesn't look like it will be possible to do this with the LHS tensioner.

Just removed the black cosworth hood and had a quick look at the LHS tensioner; I could just see it poking through. What needs to come off to gain access to the LHS tensioner?

After some more calculations I have decided to refit the RHS tensioner with a 5mm spacer and the rachet/spring, these spacers have a hole in the middle for the oil flow and for releasing the ratchet. A 5mm spacer will allow me to fit the tensioner without it being under compression and thus release the ratchet.

A900one, when you fitted the RHS uprated tensioner what was the result regarding the rattle?

Cheers Allan

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 29^th, 2006, 12:37am

The uprated tensioner only has more travel that's it, it does not put more force on the guide & works just the same as the old one.

The two chains run at different tensions which I think is a flaw.

I also think that the n/s is the main problem but could not prove this as the results I have gathered showed either one could go, there is no trend ???

I have done some major work to mine but I dare not share as it's a whole package, if you copy part of it your engine will eat timing gear. All or nothing & it is major work.

As I have said before the best thing is to get the one way valve nice & clean so it does it's job. Test it by filling the tensioner with oil & pushing the plunger in.
Should be a fair bit of residence & hardly any oil leaks from the plunger it's self.

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 29^th, 2006, 8:45pm

My engine came with the updated tensioner, it was built in april 98. If most of the problems are down to the one way valve has anyone cleaned these with good results. Can a engine flush improve the problem ?. At the moment I crank the engine untill the oil light goes off and then start it, with most times no noise at all.

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Nov 30^th, 2006, 11:27am

Yeah I have done loads :P

Look at it like this.

Engine left over night, first start = rattle for 2 - 5 secs.
Run engine for 10 mins stop then restart 5 mins later, no rattle at all.

Think about the two things above what are the differences?
Tensioner has oil pressure in it ;D

What stops the oil draining out of the tensioner?
A one way valve.

Why does a greater time let the chain rattle?
Because the valve is leaking or the tensioner is worn (very rare)

Fix
Clean the valve & test the tensioner ;D

Why does it happen?
If you don't change the oil regular you get bad deposits inside the engine.
This starts to block up your oil ways including the tensioner valve.

Will it come back?
Maybe as if it's got blocked it means your engine has oil deposit problems which could block the valve again. Engine needs to be stripped & cleaned.
If you change the oil regular then that will help to both clean the engine & help stop the tensioner valve blocking up again.

Think I will just fit a new tensioner :)
All your doing is fitting a tensioner with a nice new clean valve in it.
Sure it will stop the rattle but as above there is a chance that will get blocked up too & why pay £90 when the old one just needs a clean probably.

Will engine flush work?
It may have some effect but probably not.
The tensioner is at the end of a oil chain, the only flow is where oil is forced under pressure around the plunger which all adds up to very little flow.
Engine flush usally does not stay in the engine long enough to try & clean the tensioner as the oil is fairly staic in that area.

Live with the rattle & the engine will eat it's timing guides.
Then it's all downhill from there :o

Title: Re: 24V Timing Chain Tensioner
Post by a900one on Nov 30^th, 2006, 6:38pm

Time to clean the valves then.

Title: Re: 24V Timing Chain Tensioner
Post by Tobbe on Nov 30^th, 2006, 9:35pm

Let us know the result. I will replace my chains next month, not touching the tensioners, still my rhs is almost new. And if my rattle doesn't go away I guess the lhs tensioner will need some attention. Here we are checking two different causes, that's very good, we will get some interresting results from both methods I hope.

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Dec 1^st, 2006, 1:11am

Strip the whole tensioner down & clean/soak with STD thinner. Has to be powerful stuff so wear gloves ;)

Tobbe sure the chain can stretch/wear but not sure how you figure how it causes the start-up rattle?

The real soluction to all this is the tensioner should have had a ratchet system on them so they self adjust but don't push back like the old 12V's did.
Then they don't need the crappy one way valve at all.

Title: Re: 24V Timing Chain Tensioner
Post by Tobbe on Dec 1^st, 2006, 7:50am

I did get one chain measured and every link were off by several 1/10 of mm, the chain comprises of 95 links I think so this will effect the length quite much. I think this is causing the tensioner to operate at it outer limit, and from this you get start up rattle since it won't seal propertly between the sleeve and the plunger. That's my theory, we will see what happens with new chains.

Title: Re: 24V Timing Chain Tensioner
Post by 12reps on Dec 1^st, 2006, 10:09am

I have had a closer look at the cylindrical piece of steel that fits inside of the plunger and its looks like that is the self adjusting rachet system. There are grooves up the side of it where the pin sits that is inside the plunger. There is only about 10mm of self adjustment though. This could be another problem with the tensioner as this cylinder could be slipping off the pin inside the plunger.

Title: Re: 24V Timing Chain Tensioner
Post by Tobbe on Dec 1^st, 2006, 10:58am

Those bits you are describing are just for locking up the spring inside the plunger during assembly/disassembly. It's not necesary to use that function. It's even better to mount the tensioner as Dave describes it. I would prefer his way since then you know for sure that it is released.

Title: Re: 24V Timing Chain Tensioner
Post by howiedintheplace on Dec 1^st, 2006, 1:14pm

Yeah the tensioners do not have a ratchet system, they rely on the oil pressure, the spring in there don't do a lot either.

I have found that some tensioners don't release properly following Fords instructions so I do not fit them compressed but fully out.

Tobbe yeah I see what you mean that was the reason the longer later tensioner was fitted as combined with sprocket wear the plunger can fall out.

Must add that the wear on the timming gear must be looked at first if there is alot then indeed you have a problem & the gear will be at the end of it's life.

Every car is different & needs to be assesed individually.