Avensis 1.8 GLS 7AFE Engine Cambelt failure

[Burimi]

Hi, 

I have a 1998 Avensis 1.8 GLS. My mum was driving on the motorway doing about 50mph. The engine suddnely died and she came to a halt. No juddering, no breaking noises or anything like that. I got the car towed to the garage, they said the cambelt has snapped. 

Here's the thing, from research I  can see that 1.8L Petrol 7AFE engines were "non-interference" engines. However, the mechanic says he did a compression test and says there was no compression at all, and says that the valves have been completely smashed by the pistons... The engine was absolutely fine and could barely be heard at idle before, so there shouldnt be compression issues, and from my understanding, the pistons should not have done any damage to the valves. 

Question: could it be true that when the cambelt/timing belt broke, that the pistons would have smashed the valves, despite the fact that this is a "non interference engine"?

If anyone with knowledge or experience in this area could shed some light on this topic, I would be eternally grateful. This is my late fathers car, and I want to keep it on the road for as long as I can, it has a lot of sentimental value. 

Many thanks

[Harry Carri]

I think as you do that a non interference engine can suffer a cam belt failure without damaging valves.

[Harry Carri]

 

Hi again, I found this thread which is relevant. Answers from Frostyballs and Konrad suggest 7afe 1.8 is non interference and should withstand a timing belt failure with little damage.

Best of luck, I hope you can keep the car on the road.

 

Matt

[Konrad C]

The 7A-FE should be non-interference. 

The mechanic who carried out the compression test, did he put a new belt on, and was the timing correct?

Not knowing what he did, I hope he did not test without a belt fitted correctly. A couple of teeth out will cause a lot of problems. Also replace the tensioner. The belt only drives one camshaft via the tensioner from the crankshaft. This limits the components that can affect the belt. It is possible that something broke in the cylinder head, like a valve, spring or camshaft itself, which caused the belt to break. Let's hope not.

There are posts saying the engine was fine after replacing a broken belt. You may have already seen these:-

 

I once had a BL Maestro and at 50 mph the plastic tensioner disintegrated by boring through the timing cover and I watched it bouncing in the mirror. Got towed home, and the next day got a new tensioner. The engine started fine. The Avensis uses metal tensioners, so less likely to happen!  

 

 

[Burimi]

Thanks for the reply everyone. The link above was useful. I had seen it before, but it just confused me all the more since the mechanic was talking about compression. 

He hasn't touched the belt, therefore I am not sure what or how he did, to do the compression test. Or how it would even make sense to do one with the timing being completely off and no link between cam and crankshaft. 

I will tear it open, reset the timing and fit a new belt myself this weekend. Fingers crossed, hopefully I will have the same luck as the guy in the other post.

I'm still very confused on how the valves could have been damaged on a non-interference engine. Or how a compression test would work in this scenario...let me know what you guys think.

I will keep you updated on the outcome.

 

[Konrad C]

9 hours ago, Burimi said:

Thanks for the reply everyone. The link above was useful. I had seen it before, but it just confused me all the more since the mechanic was talking about compression. 

He hasn't touched the belt, therefore I am not sure what or how he did, to do the compression test. Or how it would even make sense to do one with the timing being completely off and no link between cam and crankshaft. 

I will tear it open, reset the timing and fit a new belt myself this weekend. Fingers crossed, hopefully I will have the same luck as the guy in the other post.

I'm still very confused on how the valves could have been damaged on a non-interference engine. Or how a compression test would work in this scenario...let me know what you guys think.

I will keep you updated on the outcome.

 

That is what I thought about the mechanic doing a compression test - before installing a belt. Once a new belt has been installed correctly, with everything timed up, the car should start fine!

I will be polite and advise you to go to another mechanic. You have the info, so all you need is the cambelt kit from Gates K015386XS or belt only 5386XS.

Here is a link to one of the eBay sellers show a diagram of how the timing belt is routed: 

http://www.ebay.co.uk/itm/Timing-Belt-Cam-Belt-Toyota-Celica-Carina-Corolla-Avensis-Gates-5386XS-/111457422768?fits=Plat_Gen%3A_T22_&hash=item19f3614db0:g:IxEAAOSwHnFVoB-6

While the belt is being fitted, I would check and obtain the 3 drive belts for the ancillaries. 

[sproutdreamer]

I have been following this thread and I am interested in the outcome after replacing the cambelt. It should be understood on the forums that questions asked and answered are followed up with feedback which adds to the general knowledge and understanding of the forum!

[Konrad C]

Keith,

I like to know the final result of any post. If you read my posts, you the result and details. 

Keep an eye out in the the spring when Waqar (who has an estate 1.8 TR) and myself meet to swap notes on our cars. My reason is to later post our views. This may influence people who may come to ask the question - Late Mk2 or early Mk3. 

I hope the cambelt has been sorted.

Konrad