Author Topic: Timing Chain stretch according to Forscan  (Read 1470 times)

0 Members and 1 Guest are viewing this topic.

Offline Bradbasford

  • S Class
  • *
  • Posts: 1
  • Gender: Male
  • Colour: Aurora Blue (34J) Metallic
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: Sport
  • Year: 2010
Timing Chain stretch according to Forscan
« on: March 16, 2023, 05:50:36 pm »
Hi all.

I am hoping someone can help.

2011 GH 2.2d (180hp)

Currently sitting on 166000 miles.

Chain done at around 80k by mazda main dealer

Now, I have done a Forscan scan and the reading on the chain stretch is showing at 13.74.....

I have been told this should be less than 10.5, but when asking on FB forums, they have not heard of a stretch as high as I have.

So, is there something that could explain this reading?

Full dealer service done yearly, car runs clean and quiet (as much as a diesel can be) and no errors, flashing dpf lights etc.... Confused!

Don't want to spend £1000 on getting it done if it doesn't need doing.

Help oh wise ones!

Offline mareng73

  • Sport Class
  • ****
  • Posts: 163
  • Gender: Male
  • Colour: Blue Reflex Mica (42B)
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: SE
  • Year: 2014
Re: Timing Chain stretch according to Forscan
« Reply #1 on: August 26, 2023, 05:30:05 pm »
Google chain stretch for that model. I think I read about 10° also.
Your car may be serviced but they only do whats on their list (if you are lucky) and checking the timing chain stretch is not one of the items, though given the history of chains on  sub 2013 models then it doesn't take much to check if they have their laptop plugged in to reset your oil counter when the engine  is up to temperature.
I normally have that PID saved along with Fuel Dilution, Number of Regens, Battery SOC as when I go for fuel take those readings  with mileage, and the dash mpg and log it in my ruled notebook as the car is usually up to temp at that point.

What you have to decide is if the chain snaps what is the cost of damage (new engine) or have it changed before damage is done.
There has been many cases of timing  belts and recent chains (after it was decided to change back but to fit necklaces rather than a decent heavy duty chain)  letting fly and bent valves, holes in pistons ensuing from the wreckage. The engine may still run ok but whats the longevity of the chain. You pays your money, you takes your chance. 

My brother has just changed the chain on a 1932 Daimler 15 (hp),  it was a double widith chain and they used the dynamo to tension it. There was no more adjustment on the dynamo. When the timing was checked it was way out but I assume the engine still ran at some point. He managed toget 30 psig oil pressure turning it over on the starter motor and compression pressures 50-100  psig, so a runner. He just has to make sure the  block is sound and no cracks on the water side.
Engines may run with a stretched chain, but how efficient, clean and does it start easily.
Previous Cars
Rover 45 TDI
Rover 400 DI
Nissan 200SX
TR7
TR Spitfire

Offline mareng73

  • Sport Class
  • ****
  • Posts: 163
  • Gender: Male
  • Colour: Blue Reflex Mica (42B)
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: SE
  • Year: 2014
Re: Timing Chain stretch according to Forscan
« Reply #2 on: August 26, 2023, 06:06:58 pm »
Could not edit and add, so have to start a new post.
What sort of rapport do you have with your service manager, ( not the flunky at the reception desk),  do you trust him to give you an honest answer bearing in mind he can earn £1000  for the dealership.
As you seem to want to keep the car as it is running well and probably looks good body wise is it worth treating it to a £1000  chain to keep it running.  Granted the resale value cannot be a lot, but the car means a bit to you  and there is not much out there these days to choose from if you buy another of any model.

As chain stretch can be measured as opposed to belts changed on mileage it would seem you are on borrowed time with that amount of stretch. It could be a case of a 'stitch in time save nine'.
 
Previous Cars
Rover 45 TDI
Rover 400 DI
Nissan 200SX
TR7
TR Spitfire