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abatom

Ke70 Timing Chain Replacing?

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Thanks for the tips but unfortunately I'm in Melbourne in my unit car-park. haha. Haven't pulled the engine out or anything like that and won't be pulling out the cam unfortunately.

 

I can adjust the camshaft and crankshaft to align but do to the offset of the notch (dot) on the crankshaft sprocket not being able to align with the camshaft dot, I noticed on a second check that the keyway on the crankshaft is about 5 degrees right of vertical when the number one cylinder is at top dead centre. Why would this be? I thought the keyway would be vertical at top dead centre? If I turn it until I get top dead centre, then everything lines up (but the keyway on the crankshaft will not be vertical, it will be right of vertical by abour 5 degrees).

 

Thanks

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I've never worried about the links in the chain, the main thing is to get the two gear wheels into alignment.

 

You will get TDC on number 1 cyl from the crank key, no matter where the timing mark is, and the mark on the cam wheel will do to make the straight red line in your photo.

 

The rockers on #4 cyl should be about equal as they go past one another, exhaust closing and inlet opening. You can only be a tooth out either way, which is a noticeable amount (about 10deg I'd say) in either the marks on the gears or in the tappets. Turn it all by hand afterwards to make sure the rockers look like they should as they open and close at the right times.

 

If you were keen you'd redrill the cam gear wheel with three new holes a few degrees out from each other so you have a cam timing wheel adjustable in 3deg increments.

 

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I thought the keyway would be vertical at top dead centre?

I would think so too. Maybe you could check the other cyls and mark the TDC of #2 and #3 as well.

Edited by altezzaclub
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Thanks, but that's really the point. I have the compression stroke and place a small screwdriver in the number 1 spark plug hole (on the compression stroke). I turn the crankshaft and it reaches it's peak (the top) at around 5 degrees to the right of where the keyway on the crankshaft is vertical. If I move it to vertical, it's not possible to align the dots on the camshaft and crankshaft because the keyway is too close the the dot 120 degrees clockwise from the keyway (on the crankshaft) and I'm not at top dead centre. So, I suppose I'm asking, is it safe, as long as I have found top dead centre, on the compression stroke, to align the dots between the sprockets (the red line on my previous diagram). The end result will look like this: (see photo). My top dead center definitely isn't when the keyway is vertical and the positioning of the dot from the keyway slot in my crankshaft sprocket is testament to this. If the dot on the crankshaft was a little further around in a clockwise direction they a vertical keyway would also align the dots. Because it is not it is not possible to have a vertical keyway and aligned dots.

 

post-20082-0-93615600-1388736897_thumb.png

Edited by abatom

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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.

 

post-20082-0-20695100-1388407715_thumb.jpg

 

Aside from any other issues you're having - you need to mark the harmonic balancer on the notch to check the timing.

 

The length of your fan belt and the time it takes to do one revolution has no correlation to #1 TDC, so yes - a mark on the fan belt will jump around.

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Well its odd, and I've never really looked when I've had one apart, but go for the dots and the TDC, not the keyway.

 

Ideally you woud find crank TDC and cam TDC and just fit the chain to that as best as possible.

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Thanks for that. That's what I'm going to do.

I can't see any other way it can go.. :)

I'll take a photo of the flames if it all goes wrong.

 

A couple of hours later.......

 

Something which has given me a surge of confidence in my alignment strategy is the timing mark on the crankshaft pulley. When the keyway on the crankshaft is in the position mentioned above, the TDC timing mark on the inside of the crankshaft pulley is at 0 exactly (which is where it should be) The marks on the pulleys also align when at this position. I'm very pleased.

 

I was thinking earlier that this double chain in my KE70 is not the original which is why I may have some differences in the standard way it is set. It could also be the difference between genuine Toyota parts and generic parts made by other companies. The ultimate test will be when I turn the key (once put back together) though I'm pretty confident things are right.

Edited by abatom

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The symptoms certainly sound like a bad condenser to me, if you have no luck after the timing chain i would look at changing this, maybe the new one was faulty?

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Well, the job is done.. I can't believe it. I think the worst part is getting the sump rubber back on..

 

It looks like my assumptions about the timing and the keyway position were correct. At top dead centre the keyway is not necessarily vertical. Another reason why this might be the case is sunken engine supports (moreso on the left side). I'm sure they've never been replaced.

 

I also changed the condenser. It's hard to say if it was the condenser or the timing chain because I did them both at once, but what I can say is that the car runs allot smoother now, it sounds smoother or something.

 

But this car has always tested me and after driving up the driveway after taking it for a spin, the tailpipe snapped. Probably an issue caused by all the blowbacks from my past problem. I'm quiet relieved it works. When I first started the car it wouldn't start. There were a few small jumps which I would assume was caused by my turning of the crank shaft by hand several times. Maybe air or something, not sure.

 

I've placed some photos of the final job below. It's hard to get a good angle but I figured these might help someone considering all the help I've received on this forum.

 

 

Note the spacing on the tensioner compared to my original picture.

 

One Question: The timing kit came with a tensioner pad with a hard rubber surface. The previous one was like nylon plastic or somthing. Does this make a difference? Is rubber ok.

 

cheers.

 

post-20082-0-47038600-1388828362_thumb.jpg

Keep in mind that the keyway on the

crankshaft is not vertical and everything worked out fine.

 

post-20082-0-04156900-1388828388_thumb.jpg

 

post-20082-0-33498900-1388828409_thumb.jpg

 

post-20082-0-52716200-1388828430_thumb.jpg

 

post-20082-0-21498100-1388828472_thumb.jpg

 

post-20082-0-59009400-1388828451_thumb.jpg

Edited by abatom

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Nice- everything looks good there.

 

The foot is always bathed in oil so hard rubber or plastic will work. I hadn't thought about the tilt on the motor, maybe if it was upright the crank key would be vertical, as you say.

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Old topic, but i have similar or somewhat similar symptoms on my winter beater. 

Old dizzy was too worn (bearings were done or something was defo done because it was opened) and damaged the dizzy cap. Replaced it with modified (centifugal advance cut away a bit for 11:1 CR engine) 5K electirc one.
Tried to tune it somewhere reasonable, but wont run with factory timing numbers. Wants like +30 degrees advance to run properly. Vac adjuster works and centrifugal adjuster too, but limited of course due to the mod. Now sits around 35 and runs decent, but when gets warm (like an hour or so) starts to backfire a bit.

Any ideas? Engine is 4K out of KE70 -82,  188k kms driven. 

I think i should replace the chain.

 

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I doubt replacing the chain will solve anything, unless you can hear it rattling at idle. There are plenty where the chain is so slack it hits the timing chain cover at idle but they still run OK.

Have you got a timing light you can measure the advance at idle and all the way up??  I painted extra marks all the way out to 40deg with white paint and graphed the timing each 500rpm to get a curve. I know the motors will stand a lot of advance, but backfiring is the limit.

The 5K dizzy I bought had an abysmal timing curve set up for a forklift, so I ended up changing the springs to get a wider curve. That's all covered here-

https://www.rollaclub.com/board/topic/49927-how-to-fix-your-brand-new-ke-motorsport-electronic-distributor/?tab=comments#comment-511594

I think you'll find that is your problem, you just can't get a big enough range in timing with your dizzy.

 

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On 1/5/2020 at 10:09 PM, altezzaclub said:

I doubt replacing the chain will solve anything, unless you can hear it rattling at idle. There are plenty where the chain is so slack it hits the timing chain cover at idle but they still run OK.

Have you got a timing light you can measure the advance at idle and all the way up??  I painted extra marks all the way out to 40deg with white paint and graphed the timing each 500rpm to get a curve. I know the motors will stand a lot of advance, but backfiring is the limit.

The 5K dizzy I bought had an abysmal timing curve set up for a forklift, so I ended up changing the springs to get a wider curve. That's all covered here-

https://www.rollaclub.com/board/topic/49927-how-to-fix-your-brand-new-ke-motorsport-electronic-distributor/?tab=comments#comment-511594

I think you'll find that is your problem, you just can't get a big enough range in timing with your dizzy.

 

True, usually it rattles like hell if needs replacement. 
We measured the timing with two different lights, yes. It runs the best at around 30-35 degrees at idle and gets like 10ish to 15 more advance with centri and vac adjuster.

I jumped the dizzy twice and ended up filing the slot a bit, to get it decent. Something is now off. Been looking for a whole new dizzy now, eBay offers Boursin (should be good) for a good price. 

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" 10ish to 15 more advance with centri "

It should be 8deg at idle and somewhere just over 35deg at 3000rpm, so the weights add 25deg of advance. The vac takes it off when you boot it, then it advances again as you lift off. The vac can't add any advance ahead of the weights.

The springs in the dizzy are much too strong. Try taking one out & running it with one spring, see the difference.

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Running without a spring on the advance weight is not a good idea. You need some type of damping. If the weight swings out and make hard metal to metal contact, it will bounce, causing erratic timing. Find a lighter spring or try to dampen the contact with rubber.  davew7

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