Ke70 Timing Chain Replacing?

[abatom]

Would anyone know if I need to remove the sump to replace a KE70 timing chain. I have a Sep 1983 Toyota Corolla manual sedan.

 

It looks like I can just remove the flywheel, timing cover and replace the chain that way but I just wanted to make sure I'm not missing something.

 

Thanks

[altezzaclub]

Only if you have the front studs in the timing cover replaced with bolts.

 

As it came from factory, the vertical studs going down through the sump stopped the timing cover from sliding forwards, so you had to drop the sump

[abatom]

Thanks. I don't suppose you know whether this takes a single or double width timing chain?

 

This is a KE70 built September 1983. I just bought a timing chain kit with gears but it's a single width. It says on the box it's for 3k,4K and 5K . I know the 4K was in vehicles prior to 1981 when KE70 came in. Does this mean I need to take it back?

[B.L.Z.BUB]

single, they're all compatible.

Edited December 30, 2013 by B.L.Z.BUB

[abatom]

Hi, thanks,,but I just pulled my timing cover off an it's a double. It's been in the car since I bought it 12 years ago and it looks bran new with some wear on the tensioner despite the fact that I'm having timing chain issues. I would say that has been in the car from the beginning . Looking at the chain it looks like there's nothing wrong with it. Are stretched timing chains visibly stretched or is it something slight and unoticeable?

[B.L.Z.BUB]

It probably been changed to a double, 3Ks came with double row. You wont be able to tell its on the way out until it snaps.

[abatom]

Possibly so. I spoke with toyota in Sydney and Melbourne today and they both confirm it's a double chain for this model. They could be mistaken , possibly due to the age of the car.

 

I've attached some photo's of my tensioner and chain. Does this look to loose to anyone? It's hard for me to tell because I've never replaced one before.

 

Thanks

 

 

[B.L.Z.BUB]

Actually I think I'm way off track thinking of the 5K motor only having a single row timing chain? I havent messed with a K motor for a while ;)

Edited December 30, 2013 by B.L.Z.BUB

[altezzaclub]

I don't think double-rows snap. For the Celica there is a factory method of holding the chain sideways, horizontally, and measuring how much it droops. They give you a limit of wear as a droop distance. Those chains are longer than the 4K, but you might be able to chase that down.

 

Why do you think it might be stretched? I've heard of them rubbing on the timing chain cover until they make a hole in it...

[abatom]

I have all the classic symptoms of timing chain stretch. This initially happened on the way back from a long trip. The cars timing is set correctly and since the problem I've had everything from the head gasket to all the electricals replaced.

 

For some time I was getting bumps when driving. Like the engine was jerking. On this one day after driving for 10 hours, something went and I was getting blowbacks and sparks flying out of my muffler. I could drive the car but only at low speeds. Any accelleration would bring back the problem. Basically the spluttering only occurs under load. After letting the car sit for 2 days the problem died down allot and a that's when I cleared all the fuel lines, rekitted the carby and all the electricals (everything), replaced the head gasket and replaced all the filters.

 

I tried to do a trip recently and after about 2 hours when things heated up, the bumping came back and then the spluttering under load again. The car has done over 300,000 k's and has probably never had the timing chain looked at. All the symptoms of a stretched or even partially stressed timing chain are there and this time any big accellerations the spluttering starts. The car runs rough now. I suspected it some time ago but didn't touch it as I thought, like most, that timing chains don't need replacing. But given the age of the car and the amount of miles it's done (probably more than 300 as I suspect the last owner disconnected the speedo cable) the probability is quiet high. The gap between the tensioner pad and base is quiet large as you can see from the photos above. I can't see any breaks in the chain but when I push the tensioner in with my finger, the chain is quiet loose. Probably enough to create some lag between cogs. Does that make sense?

 

Also.. When using a timing light and marking fan belt with a white marker, the white mark doesn't stay in one spot. It seems to jump back and fourth which is also an indication of a bad timing chain. OR, it could also be worn gears.

 

It looks ok overall but there is literally nothing else it could be, given that I've replaced everything. And,, as mentioned above, it's hard to pick up a stretched timing chain. The symptoms though are classic since I've learned allot about it lately. The probem comes back badly when I've been driving for a while. The real problems start on the long trips. I would assume that a hot timing chain would stretch to some extent and then contract when the car cools which would explain why the problem goes away if I don't' drive the car for a day at least.

 

I suppose I hoped someone would recognise whether or not there is a large gap from the tensioner pad to the base in my photos above.

 

Photo of the camshaft sprocket below.

Edited December 30, 2013 by abatom

[jay_howie]

Every ke70 engine i have looked at has been double, but it doesnt matter as u get new single row gears in the kit anyway. Timing chains don't usually snap they strech, belts snap. Do the chain, its cheap and easy. I don't think it will solve your issue but at least your timing will be correct (after timing light and dizzy adjustments. Which means sorting out other issues is far easier!

You will need to drop the sump due to the studs (replace with bolts).

[abatom]

Thanks, found that today. Had to drop the sump. Why do you think it won't solve my issue?

Do you think the problem is somewhere else?

[jay_howie]

After reading your post again I think its definately worth a shot, needs to be done anyway. Do your valve clearances too.

[snot35]

Have you considered that if the timing mark is jumping around it might be an ignition problem? The light is triggered by ignition events after all.

 

I would have thought if the chain was stretched then the timing would be pretty consistently out, rather than erratic. I'd be checking everything for wear or binding while you have the chain off. Oil pump and shaft up to the dizzy. The dizzy, cam etc.

 

Also, the chain will be loose when the engine isn't running. Oil pressure pushes that shoe out to give it tension. Make sure that isn't binding and check the cam/dizzy/oil pump drive setup for any damage to teeth which might be making things erratic.

 

I hope you're patient, this may take some chasing.

 

It's actually sounds like a dodgy condenser to me, but I take it you've replaced that (assuming you're still running points)? When you replaced it, did you clean up all the electrical contact points? If you haven't, it might be worth going through the ignition system and check it. Things like, where the condenser bolts to the pad, that can be tidied up with a little sand paper for better contact.

 

Let us know how you get on.

[abatom]

Yep, cleaned every contact, replaced the condensor. I even dismantled the dizzy and checked for broken teeth. When a chain stretches the timing becomes erratic. If it's consistently out you've jumped a cog.

 

I have spent a very long time on this which is why I'm where I'm at now. Definetly not electrical. I know the bolt you're talking about and that does cause problems when loose. It also causes starting problems I discovered not so long ago.

 

So, let's say for arguments sake that it is the condensor. This problem is less of an issue after at least 24 hours of letting the car cool down. I just assumed this has something to do with heat and chain stretch though would a condenser do the same thing?. Can a condensor go suddenly when driving over a long distance. You're right, the symptoms are the same. Can't accellerate too hard or I'll get blowbacks and no power. If I can get to 4th gear on the highway I can roll along at about 70kph. This jump was happening for a while before things went. I kept snapping the ceramic spacer in the contact because of this jumping.