Where to start if your CF is misbehaving and you're not sure where the problem may be.

Exhaust valve issue?

Post by [email protected] » Subscribing Member » Sun May 13, 2018 8:43 pm
Joined: Sun Sep 13, 2015 9:12 pm
Posts: 12
Heading home from a great weekend in my Bedford CF250 Autosleeper 2.3. We got stuck in some traffic and after 20 minutes or so I noticed a reduction in power from the engine. Managed to get off the main road and just in time, lost all power and freewheeled to a stop. It was a very warm day although temp gauge was running at normal. Tried to restart every 15 minutes and at the 45 minute point she turned over and we were up and running. Went a different direction, van running great and then we hit roadworks. Instead of letting her tick over I decided to keep the revs up thinking that this helped the water-pump move the coolant through the engine better (not sure if I was fooling myself or not). Heater full on with blower. Stuck in roadworks for 40 minutes and she moved on without any further issues by doing this.

Given the loss of power and 45 minute wait to restart I am suspecting valve issues. Currently 30000 miles with original cylinder head.
Any other ideas on this issue?


Paul

Re: Exhaust valve issue?

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Post by Phil Bradshaw » Club admin » Sun May 13, 2018 10:03 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3701
Clearances too tight on the exhaust valves can cause power loss and hot starting problems but it's not the only cause.

If the valve clearances have not been adjusted for a while then they probably will need checking at least before looking for other problems.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Exhaust valve issue?

Post by [email protected] » Subscribing Member » Sun May 13, 2018 10:25 pm
Joined: Sun Sep 13, 2015 9:12 pm
Posts: 12
Thanks Phil,
I will try to get at this week. I will keep you informed as to how I get on.

Paul

Re: Exhaust valve issue?

Post by johnnyonions » Subscribing Member » Mon May 14, 2018 8:51 am
Joined: Tue Apr 28, 2015 11:33 am
Posts: 297
Paul , I've had loss of power , with similar circumstances , this was caused by condensation in the distributor cap , worth checking if it happens to you again ,

Re: Exhaust valve issue?

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Post by VDUB384 » Club admin » Mon May 14, 2018 9:59 am
Joined: Wed Sep 12, 2012 9:01 am
Posts: 1362
Hi another possibility could be the coil overheating as that would have the same effect always handy to carry a spare coil and if it does it again swapping the coil should sort it out straight away, but like Phil said check the valve clearances as they may be out of tolerance
Dave
Whilst good maintainece is the best prevention"If its not broken don't fix it."
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Re: Exhaust valve issue?

Post by [email protected] » Subscribing Member » Mon May 14, 2018 9:20 pm
Joined: Sun Sep 13, 2015 9:12 pm
Posts: 12
Hi Dave, I fitted an Aldon electronic ignition system with a new coil last year. Do you still think the coil may be a possible issue?

Paul

Re: Exhaust valve issue?

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Post by Phil Bradshaw » Club admin » Mon May 14, 2018 10:39 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3701
Ignition coil could be at fault if a winding has a break in it that opens up when hot then 'heals' again when cold.

Failure tends to be more abrupt than losing power first but not always - sometimes a faulty coil can stagger along for a bit before going terminal.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Exhaust valve issue?

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Post by VDUB384 » Club admin » Tue May 15, 2018 9:10 am
Joined: Wed Sep 12, 2012 9:01 am
Posts: 1362
Hi Paul So you have an Aldon ignition system on that's a good choice but which coil do you have fitted, I found with my Aldon system it didn't like intermotor coils a brand new one would last 2 months max then it was fit for the bin. I found an old 12v non ballast Lucas coil to be the best with the Aldon and used with a 12v ignition feed from no 3 fuse, apart from that the only ignition trouble I had was condensation in the dizzy cap.
Dave
Whilst good maintainece is the best prevention"If its not broken don't fix it."
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Re: Exhaust valve issue?

Post by [email protected] » Subscribing Member » Tue May 15, 2018 4:20 pm
Joined: Sun Sep 13, 2015 9:12 pm
Posts: 12
Hi,
I fitted a flamethrower coil from Aldon and moved the coil from the top of the rocker cover to the bulk head on passenger side to help keep it cooler. Wired in a direct 12v feed from fuse 3 to coil as described in some of the threads on this site. Will be checking valve clearances tomorrow and I will have a look for the condensation issues.

Many thanks for your help.

Paul

Re: Exhaust valve issue?

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Post by Phil Bradshaw » Club admin » Wed May 16, 2018 12:56 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3701
The Aldon on Dave's van worked well, just the coil that let it down (more than once!).

Condensation inside the distributor cap usually collects after the engine is soaked, e.g. running through deeper puddles that splash over the front end. Engine may continue to run until water lodged in the distributor evaporates then condenses inside the cap. Remedy is to leave the cap off when the engine is warm (if need be run the engine until it staggers to a stop). Repeat as necessary until no condensation is evident.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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