Knocking noise

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scottchristian_
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Knocking noise

Post by scottchristian_ »

Hello all,
I have a 1981 2.8i 4 speed, only today have I started to notice a problem , in reverse and 1st gear there's a harsh clunky noise as I pull away , and you can feel the car lurching. The same thing happens in 2nd gear as you accelerate, it starts lurching. I haven't noticed it in 3rd or 4th and when its going it seems to be running smoothly, I suspect there is an issue somewhere from the gearbox back to the diff. Has anyone got any suggestions on what may be causing this and how I could possibly diagnose it ?

Thank you scott
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stevemarl
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Re: Knocking noise

Post by stevemarl »

Hopefully it will be `just` a clutch problem, maybe broken springs in the driven plate, although I`d have thought that would be in all gears. When you try to select 1, 2 or reverse, does the gear lever feel stiffer or different than it used to? 1,2 and R are the same synchrohub which, if that was breaking up, would explain a harsh clunking noise in those gears only, absent in 3 & 4 ? That`s less good I`m afraid. Layshaft bearings also possible, although you`d expect that all the time?.
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Re: Knocking noise

Post by scottchristian_ »

Hi Steve thanks for your reply .

Now you mention it , selecting 1st does feel stiffer than the other gears. It almost feels as though it snags then drops into gear , if that makes sense .
I managed to squeeze my shoulder under the car to have a feel of the drive shift, there's very minimal movement which I assume is normal, and nothing seems to broken or sheered off . So that seems to be okay.

Based on that then do you reckon there's an issue with the 1st 2nd r synchro?

Thank you
Scott
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Bug
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Re: Knocking noise

Post by Bug »

Before you get too deep into it, are you sure it's a mechanical clunk, and not a knock being generated by driveline shunt due to the engine faltering?
It is quite easy to think it's a mechanical problem when in fact that is just a symptom.
The 2.8i is very susceptible to weak mixture, which can give symptoms very similar to what you describe.
I would quickly check the mixture. One exhaust will be quite a bit leaner than the other, but take an average of the two and it should be around 2.8 (funnily enough) in order to get the engine running really sweetly. Yes this sounds higher than ideal, but take it from me, the car will run much, much more smoothly like that. If it has been tuned to the standard 1.5-ish with a sensor up the richer pipe (RH I believe) then the other side will be running on fumes.
Not saying it's your problem, but I would check it first.
Oh and if your gearbox is stiff to get into 1st and reverse then congratulations, you have a genuine Ford one. :D
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Re: Knocking noise

Post by stevemarl »

Scott,
I`ve never had this in a Ford `box, cos they`re quite rugged, but I did in an old Vauxhall RWD: the hub is splined onto the mainshaft and they would crack around the `webbing`.
Image
The inner part is the mainshaft, the outer ring slides for and aft to engage with the gears on either side of the hub. The hub can crack where marked. The selector fork stops it all falling apart, but theres so much play the engagement is very `draggy`.and there will be lots of your clunking noisees. Let`s just hope it`s your clutch, whatever, it`s very likely a gearbox out job.
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Re: Knocking noise

Post by scottchristian_ »

Hi guys thanks for the response,

Yeah to be fair the gearbox has always been a pig to get into first and reverse, like you say thats just old ford 😂

However I'm reckoning it is a mechanical issue , the noise it makes is quite distinctive i.e it doesn't sound good, and the feel just isn't right , as you accelerate in 2nd its really lurching. the only way I can describe it is that it feels like your accelerating while repeatedly dumping the clutch up and down . If that makes any sort of sense ? Then 3rd and 4th just feel fine .
So from what your saying it does seem to be the synchro.

However I am going to bare in mind what your mentioning Steve about the mixture, its going to a shop Thursday to diagnose it .


On that note , in the event it is a gearbox issue , do you guys know where I could source parts such as a new synchro or possibly a clutch ? I've had a quick look on the capri club and don't see any gearbox parts there . Have you got a place you could recommend that are pretty speedy ?

Also one more question is anyone here sort of south London area / surrey ? It would be good to have a contact of someone with a capri that has a bit more knowledge than I do that can possibly help me in the future, I've got a few jobs id like to do on the car and it would be great if there's someone I could meet possibly ?

Thanks scott
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Re: Knocking noise

Post by pbar »

There is a Surrey Capri club, should be details online but I can find you contact details if you wish.
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Re: Knocking noise

Post by stevemarl »

The synchro though wouldn`t really explain the violent surging as you just described it `dumping the clutch`, that`s much more like a clutch, or even engine/gearbox mount - which I guess could also make noise? Or as Martin said a fuelling issue?
The rubber mounting for the propshaft centre joint would be another suspect, but you said that feels OK.
You can get a complete clutch kit from Eurocarparts fro £120 (there`s always a promo code, currently 40% off) https://www.eurocarparts.com/clutch-kit
it`s the labour that costs though and you need to get `box off just to see what`s what.
Hopefully you`ll find that it is just clutch: if it is the gearbox, realistically you need to be looking for a good second hand one (Caprigear maybe? Tel: +44 (0)1507 343148 (workshop)) Maybe even look at a 5 speed conversion, the type9 are probably more common too?
if you could get the parts, they`d be expensive and very few garages will repair a gearbox.
I think that`d be useful Paul.
Here you go http://www.surreycapriclub.co.uk/
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Re: Knocking noise

Post by scottchristian_ »

Okay thank you, there's alot to think about there for sure
I'll give you guys an update when the mechanic has had a look , I think this is beyond my skill set. Fingers crossed its just the clutch .
Cheers Scott
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Re: Knocking noise

Post by Peter-S »

scottchristian_ wrote: Sun Mar 28, 2021 5:04 pm

Also one more question is anyone here sort of south London area / surrey ? It would be good to have a contact of someone with a capri that has a bit more knowledge than I do that can possibly help me in the future, I've got a few jobs id like to do on the car and it would be great if there's someone I could meet possibly ?

Thanks scott
Certainly south of London - S.E. Kent so might be a bit further than you want but meeting is not impossible.
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Re: Knocking noise

Post by Major_Tom »

Bug wrote: Sun Mar 28, 2021 1:41 pm Before you get too deep into it, are you sure it's a mechanical clunk, and not a knock being generated by driveline shunt due to the engine faltering?
I had something similar years back - turned out to be the coil breaking down.

But if it is something like that, how come he's only getting it in low gears?
I'm the one who leaves all those shoes in the carriageway.
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Re: Knocking noise

Post by Bug »

Major_Tom wrote: Mon Mar 29, 2021 11:18 am
Bug wrote: Sun Mar 28, 2021 1:41 pm Before you get too deep into it, are you sure it's a mechanical clunk, and not a knock being generated by driveline shunt due to the engine faltering?
I had something similar years back - turned out to be the coil breaking down.

But if it is something like that, how come he's only getting it in low gears?
Not saying it is that Tom, just an easy check before spending big bucks.
But I found it was at its worst when the car had to work hard. At higher speeds the inertia helps the engine to overcome it a little.
Disappears completely at Warp Factor 9, so you've probably never noticed it. :poke: :D
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Re: Knocking noise

Post by Peter-S »

Bug wrote: Mon Mar 29, 2021 2:13 pm
Major_Tom wrote: Mon Mar 29, 2021 11:18 am
Bug wrote: Sun Mar 28, 2021 1:41 pm Before you get too deep into it, are you sure it's a mechanical clunk, and not a knock being generated by driveline shunt due to the engine faltering?
I had something similar years back - turned out to be the coil breaking down.

But if it is something like that, how come he's only getting it in low gears?
Not saying it is that Tom, just an easy check before spending big bucks.
But I found it was at its worst when the car had to work hard. At higher speeds the inertia helps the engine to overcome it a little.
Disappears completely at Warp Factor 9, so you've probably never noticed it. :poke: :D
All those years ago when I trekked up for the Bomber Meet I had a bit of a misfire but only on the country lanes, pulling out at junctions and the like. We suspected a cracked plug but as it was happy cruising on the motorway for 4 hours I left it alone but it was indeed a cracked plug I found once home. Strange the way some faults manifest themselves.
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Re: Knocking noise

Post by pbar »

A little while ago I had a bad juddering when setting off in first gear only, fearing clutch or propshaft etc. I changed the spark plugs and it completely went away.

Hope this fix is just as easy.
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Re: Knocking noise

Post by D366Y »

I had similar issues with the GL - was always only running on 3 cylinders, took out the spark plugs and problem solved, now it doesn't run at all, but is a lot more consistent!
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Re: Knocking noise

Post by stevemarl »

D366Y wrote: Mon Mar 29, 2021 3:30 pm now it doesn't run at all, but is a lot more consistent!
:lol: :lol: :lol:
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Re: Knocking noise

Post by Mc Tool »

Huh , I typed out this big long post (like I do ) and fucked if I know where it went and I cant be arsed doing it again so........check the u joints too , they can clunk away at low speed but sorta sort themselves out a bit at speed , specially if it locked up , like the joint is real stiff . Sometimes the needle rollers get munched ,turn sideways and the joint goes from floppy and loose to tight and stiff............drove all the way from Queenstown to Invers in a mk3 2 door cortina /302 with the rear uj hammering away ......
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scottchristian_
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Re: Knocking noise

Post by scottchristian_ »

Hello all , thanks for the responses

Peter ill definitely have to take you up on the offer of meeting at some point . Kent isn't too far so that would be amazing at some point.

So it seems there's a multitude of possibilities, my plan is on the long weekend coming up to get the car up on some Jack's as I've got to put new mud guards on anyway and while I'm the ill have a proper good look over her , and while I'm at it ill change the spark plugs too just to rule that out .

Ill give you all an update on the progress
Thanks
Scott
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Re: Knocking noise

Post by scottchristian_ »

Saying that what decent spark plugs would people recommend , preferable ones i can grab from halfords or euro car parts ?
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Re: Knocking noise

Post by Mc Tool »

NGK AP6fs 🙂
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