Mazda Inline-six Engine Timing Chains?

[John B]

I just watched a video on the CX-90 in-line 6 which I assume is the same engine for the CX-70. The "mechanic" indicated this engine has 3 chains, 1 for the camshaft(s), 1 for the crankshaft and 1 for the fuel pump. However, he stated that these chains were located on the rear of the engine and if they ever needed to be replaced the engine would have to be removed from the vehicle. If true this probably would be very expensive. This would be a big consideration in purchasing one of these Mazda's IMO. I will probably stick with my 2023 CX-5 2.5 turbo .

 

[markfm]

How often do timing chains fail (as opposed to timing belts)? I'd expect them to be essentially life of the vehicle items.

 

[John B]

How often do timing chains fail (as opposed to timing belts)? I'd expect them to be essentially life of the vehicle items.

I suppose a Mazda mechanic with years of experience would be the best person to ask about the life span of their timing chains on other engines.
I have rebuilt a number of American V-8 engines over the years and without exception every chain had stretched over time, some to the point of jumping a tooth or two on the cam gear. However, I know technology has gotten a lot better so maybe this isn't an issue but the "mechanic" in the video pointed out the possibility. Maybe Mazda uses an internal tensioner on these chains?????

 

[youri]

I have kept my two previous mazda’s (mazda 6 2004 and mazda 3 2010) to 10 years/125 000 miles and 13 years/110 000 miles and none of them needed timing chain work. Some sources says timing chain should last for the life of the engine, others have told me to around 125000 miles, but some engines have known recurring timing chain issues (looking at you Audi). My experience with Mazda’s previous engine is that your cylinder head is more likely to crack before you have to work on the timing chain. Fuel pump may be another factor to consider, but I also never had to replace a fuel pump on my previous two cars.

Unless you plan to put that much more time and mileage on the car, then I would say the timing chain accessibility isn’t that big of an issue.

I am curious to know how they get to those last two spark plug though.