Bristol Cars - Owners and Enthusiasts Forum  

Go Back   Bristol Cars - Owners and Enthusiasts Forum > Bristol Forums > 6 cyl Bristol cars

6 cyl Bristol cars Type 400 to Type 406

B 400 - backfire

Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 05-06-19, 05:34 PM
Join Date: Jun 2018
Posts: 39
Default B 400 - backfire

During measuring the voltage at 3000 rpm all the carburettors produced backfire. I'd heard that backfiring while driving before but not as many as during that test. Any hints?
Reply With Quote
  #2 (permalink)  
Old 05-06-19, 10:51 PM
Join Date: Jul 2008
Location: Sydney, Australia
Posts: 294

Have you balanced the carbies accurately?
Are the idle mixtured adjusted?
Is the ignition timing correct?
Have you replaced points and condenser?
Does the engine run smoothly at idle ?
Are all the jets clear and not blocked?
Do the have the sparkplug leads connected as per the firing order?

These are just a few of many things to check.
Reply With Quote
  #3 (permalink)  
Old 06-06-19, 06:10 AM
Join Date: Jun 2018
Posts: 39

Hello Geoff,

I'd hoped the difference between running idle and under load would give an idea.

I guess the smoothness during idle is not that what could be expected from 6 cylinders. But the heart of the car is an old engine.

The car got a 468 GBP service before I bought the car. Since that service the car ran 260 mls. NOS contact set, rotor arm, ignition condensor, new spark plugs (NGK C6HSA) and piece of H.T. lead are on the bill. A new NGK coil is also mentioned.

The carburettors have been inspected and ignition timing was checked.

Idle mixture srews, throttle butterflies synchronisation and throttle linkage had been set to correct idle speed.

Setting the valve clearance was also part of labour which all has been done by a motor engineer.

It seems I should go the steps again as far as I'm able but I'm sure my skills are much lower than that of the motor engineer. I hope I will get in contact with some one who really knows. Most mecanics are searching the connection for a diagnostic tool.

On the other hand the specialist inspected the Enot one shot lubricator but there was a lot of oil along the chassis. No words in his report. It is not the oil line going out of the Enot pump and I still investigate to find the failure.

I'm supported by ear phones so any sound is difficult for me - e.g. I did not remark that only one horn is working and it was my son in law who made me sensible for the backfire during driving the car. Getting old does not have benefits allways ;-)

Last edited by Bela; 06-06-19 at 06:17 AM.
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT. The time now is 07:15 PM.

This is the live site

Search Engine Friendly URLs by vBSEO 3.6.0 PL2