series 3 petrol "popping".

Aye up, Acquired a popping noise from the end of my exhaust when letting of the accelerator. It's beginning to get worse I have replaced the exhaust
manifold and new exhaust but it is still popping.. Has anyone any other ideas what it could be , Has a Webber carb fitted and runs on both petrol and gas and makes the popping sound on both..
Thanks Adrian Ford
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
sounds like the mixtureis too weak or the timing needs adjusting.
Richard

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It's backfiring through the exhaust. The most likely cause is that you have an air leak somewhere in the exhaust or exhaust manifold. Have you checked that the exhaust is sealing well, and that the manifold is sealing well?
Backfiring on overrun doesn't normally cause any damage to anything. Most series exhausts tend to pop a bit when hot. The chances are you've go a poor seal somewhere.
If it starts backfiring under load, then I'd look at checking the timing. Backfiring under load tends to be far more destructive, often being powerful enough to blow apart silencer boxes...
Weak mixture only causes backfire through the inlet. This isn't your problem.
Andy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Cheers lads, Going to have a good look tomorrow as I have noticed that my water temp is lower than normal when I went out in it today.
Adrian Ford
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adrian,
My '85 110 V8 had done it for years, pop's and splutters on overrun, and not really been too concerned by it. Over this period (for usual reasons) it had new carbs, timing checked severel times, new exhaust etc and it never cured it, although the new exhaust gave the pop's a more metalic note!!
I always knew the engine was getting tired and through more of a hobby than necessity I got an old V8 off e-bay, re-built it and pop'd it in (well I say pop'd, it took a week of shearing bolts to get it in) and the popping has gone completely. Bearing in mind I used the same carbs, manifolds etc, it must have been caused by something in the engine. I had noticed on removing the manifolds to put on the new engine, there were signs that the head gasket on the V8 was leaking, but couldn't say if that was the cause! I'm hoping to find the time to strip my old engine for some clues to this and other things.
Bottom line is, she ran for years like it, and would probably run for many more.
Have you tried a compression check?
Regards,
Darren C V8110CSW amongts others.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.