Ke70 Timing Chain Replacing?

[altezzaclub]

Yes the foot does stick out of the mounting on the chain tensioner more than I would expect. Noticed it yesterday but didn't comment on it.

 

It will be interesting to see what difference a new chain makes. I would've thought dizzy for that sort of problem too, wear in the dizzy shaft or weight pivots, poor condensor, dirty points, but it seems you've covered that.

 

You don't get a constant degradation of timing on the cam because of the valve springs acting on the lobes. They push the cam backwards as the follower goes up the ramp, then push the cam forwards as the follower goes over the lobe nose and down the other side. So each valve is doing that as it runs, and it affects the dizzy too as that is driven off the cam.

 

That pulsation workng on the slack in the dizzy gears will make the white marker bounce around on a timing light.

 

The problem of a long trip is very interesting.

Edited December 31, 2013 by altezzaclub

[abatom]

It's interesting indeed. By the time I've solved this I will have practically rebuilt the car.

I'll consider that next time I try to fix something. Thanks for the comment on the tensioner. I can't waite until this is over.

 

Is there a particular type of condenser for the 1983 Toyota Corolla KE70 model (4KC motor). Because this sounds so much like a condenser issue too (now that I've looked it up.) but I know there are issues with the timing chain. Either way I'm going to check this again with another new condenser, they don't cost much.

 

I replaced this before but I seem to remember having difficulty finding one so I'm not sure what I ended up settling for. Are they available in capacitance or is there a range of condensers I can use?

 

Sorry for drawing this out. Thanks

 

 

Edited December 31, 2013 by abatom

[altezzaclub]

I haven't heard of a range being available, so I assume they are all the same. That would work if all coils are pretty much the same, which is what I reckon they are. So if you have a new condensor in there and it is not a dud, then it won't be that.

 

The Gregorys manual says-

""Using a spring scale pull the timing chain outwards at a point opposite the tensioner pad with a tension of 10kg. Measure the clearance between the rear of the pad and the body. If the clearance between the tensioner pad and the tensioner body exceeds 13.5mm, closely inspect the sprockets for wear. Renew if necessary.

 

Anchor one end of the chain on a nail and using a spring scale apply 5kg to the chain. Measure the doubled over length between anchor points and if this exceeds 272.7mm the chain must be renewed.

 

Measure the thickness of the tensioner pad. If 12mm or less renew the timing chain tensioner as an assembly.

 

Similarly measure the vibration damper and if less than 7mm it should be renewed.

 

Dismantle and inspect the tensioner. Check the spring for lack of tension and the oil holes for blockage.""

 

For the capacitor they specify 0.2-0.24mfd.

Edited January 1, 2014 by altezzaclub

[altezzaclub]

Ths can't be a problem of fuel starvation when hot?? The pump gets airlocks and can't supply enough.

 

Is it worth pulling the top off the carb and seeing the fuel level next time it happens?? Just switch it off immediately, push the clutch down and coast to a halt so it can't idle. Pull the fuel line off the outside before undoing the carb top so no more fuel can get in as you lift the float.

 

Then compare that level to when its idling.

 

What is it like around town on a hot day?? The only times I remember the Datsuns giving trouble was after a hard run when you idled around town and the fuel would boil, leading to vapour-locks as the pump couldn't pump vapour.

[abatom]

Plent of fuel in the Carby. I cleaned and rekitted the whole thing. If anything, with the problem, it ran better after that but it didnt' fix the issue. I just though I may have put a dud condenser in there but I know the timing chain needs replacing too. Even if it's not the chain, it's the tensioner which has some grooves in the surface and has probably never been replaced. While everything is off, I might as well replace it. It will probably be better on fuel in the end and easier to set the timing on.

 

I have the same gregories and all those details. I'll do those checks once the chain is out, but first I'll waite until I have a new one in my hands.

[abatom]

If you call want a good laugh I just though I would share this. The condenser in the photo above is a Bosch condenser for a Bosch distributor. The majority of Condensers SuperCheap Auto has are around $7 to $13. This one, the last time I looked (a few years ago) was around $8.95. I saw the same condenser on the shelf today for a whopping $26.50, more than double the price of the most expensive condenser they have. I don't know anywhere in the electronics world where you pay that kind of money for a small capacitor such as this. Maybe I'm a bit mean but that is ridiculous. I didn't buy it, was just looking... and almost choked.

 

Bosch must be thinking they have the only one that will fit a Bosch Distributor.

I have no doubt all of you will have a similar experience with another part of some description, but I just thought I would take the opportunity to ridicule this case just a little.

Edited January 2, 2014 by abatom

[camerondownunder88]

Hi,

Just read over your topic and have you re-installed a new chain yet? What change was noted?

 

After reading it I'm keen to know what the change was as I feel your problem ISNT the timing chain.

 

I once had a K motor the 1L OLD KE10 engine. It made a HORID noise when running. It was the timing chain hitting the cast aluminium housing it had streched THAT much. Was a single row also. Reason I eventually swapped the motor (was easier than timing chain) old K motor developed an oil leak...where...from the timing cover where the chain hit it that much wore down then cracked it....The whole time this was happenign car did NOTHING like that. I just turned dizy did best tune I could engine ran FINE.

 

How ever I have had a few similar things happen to my KE15 once was a snapped cam shaft other time was coil issues on ignition system.

 

So cam shaft issue. Bought a 5K put in my KE15 was told rebuilt. So poped a new dizzy on after engine swap and car was out like 15 degress...mmm funny. Electronic dizzy due to cast of housing can only be retarded so much. So at full retard I couldnt even get factory spec. So I pulled out dizzy re aligned mmm no go....So got a points dizzy put in forced it to factory timing. Car started great....Try to drive. DAM got over 2000RPM power drop then push rods 1 got bent. So fixed rod though ah tune is out. Drove again back fired through carby while driving no power once warm wouldnt start after turning off only JUST start when cold.

 

So out comes cam...I found the pin in the front of the cam shaft had sheered. With nut on big timing gear couldnt see this. But gear was slipping on cam. I fixed issues with other things and then slipped more and problem got worse. So not a "worn" timing chain but when removing it cam was out equivelent about 2 teeth. But I played with SO many sub systems engine did run....Not well. So see if anything is broken...

 

The second time was an ignition coil. After a few RPM car would miss pop out carby lose power then be fine get hot and stop etc.

 

Coil was jsut STUFFED. was an original coil put a new one on ran like a dream so id be tempted to go dizzy also. Check the earth strap on advance plate. Seen many they contact when stopped but is actually broken. As dizzy advances comes apart car pops and stalls so lose vac advance or if you put foot flat on go pedal dizzy retards wire touches bang engine runs. OR seen many a seized dizzy advance plate from no one putting lube on them when serviceing so is dizzy advancing properly. Earthing out etc.

 

To me seems electrical. But am keen to see what your new chain does.

 

But a side note Toyota do have a few limits to determine the wear on a K motor timing chain they are:

When installed the gap from front of tensioner housing to back face of the rubber shoe is NO MORE than 13.5mm when 10kg of pulling force is pulled on chain at link in middle of tensioner.

 

ALSO

 

With chain removed with 5kg pulling force max limit is 272.7mm

 

To find wear on sprockets throw chain around small one so rollers fill the sprocket and throw micrometer over it diameter should be 59mm for large cam sprocket limit is 114mm.

 

Also thickness limit on tensioner shoe is 12.0mmso from front of shoe to back face of shoe with vernier.

 

Chain damper thickness limit is 4mm.

 

So with those messurements see what you go. Might find chain is still good. Id definatly go dizzy issue then.

 

Cheers

Cameron

[abatom]

Thanks for all that. I will let you know if it's the chain and whatever else I discover.

As for the distance between the back of the tensioner pad and the tensioner body, it is definitely large. Whilst I haven't noticed the chain rattling against the case, without putting the 10kg force on the chain it is a little over 13.5mm. The whole interior of the crank case looks rather new though. There are grooves in the tensioner pad but the chain and cogs look alright. The dampener is definitely less than 4mm though and it' has grooves in it. If I hold in the tensioner against the spring there is a good amount of slack in the chain. In the end, it may be an overkill doing the chain but it will fix my timing problem and probably save me a bit of fuel. The timing is hard to set because the white mark jumps around as mentioned.

 

I replaced everything else, all the electricals etc. Even the head gasket so I've pulled out all the rods and they look fine.

 

The problem goes away if I don't drive the car for a while so the heat of a long trip really sets it off. Could be electrical but I suspect the timing chain expands a little after about 2 hours of driving non-stop which is when the problem comes back. When things are hot. There is an identical condenser to the one I have which is for another car and I could have bought that one without thinking. I've done worse. I can't remember what I bought before but it could be the issue too. I hope not because this time the car has cost me allot of time and some unnecessary money but in the end, a new timing chain kit which is less than $70 isn't allot to pay for the peace of mind and one less thing gone wrong. At least the chain will outlive the car, lol.

 

Will keep ya posted.

Edited January 2, 2014 by abatom

[camerondownunder88]

Cool...

 

Also should note chain dampener is the flat long metal one not the spring loaded one.

 

If gap is over 13.5mm from face of metal housing to back of tensioner show then yeah worn. Worth doing as you said $70 for peace of mind worth it.

 

Grooves in the shoe keen to see pictures. As new shoes have some grooves moulded into them to guide the chain a but so some grooving is ok excessive then bad..lol

 

Cheers

Cameron

[snot35]

Actually, coil is another good point. It certainly sounds electrical to me.

[TRD ke70]

After reading all this, i don't think it's your timing chain causing the problem, but it's a good idea to replace it.

Take the gears off when you do it, so you can check the keyways for wear.

 

Have you replaced the coil? is it the right coil?

how's the balast resistor?

Could have a blocked muffler, or a vacumn leak.

Have you done a fuel pressure test on the pump? could be a soft spring on one of the valves.

 

Last question, where do you live?, maybe someone can cast a fresh set of eyes over it for you?

[altezzaclub]

So out comes cam...I found the pin in the front of the cam shaft had sheered.

 

Dayammm! That's the best one I've heard of in years! The problems change as it moves a bit an you can't see what is wrong...

[abatom]

Coil, fuel pump, ballast resistor replaced. And the leads..

 

I'm part way through the timing chain and I'm having a few issues. It's easy to get in there and coparing the new chain with the old, the old chain is a little bit longer but not by much. When I put the new chain in,it's allot tighter but the alignment is something I'm having trouble with. Here it goes.

 

I'm using a Gregories manual. One thing I forgot to mention is that this is a 1983 Toyota Corolla KE70 'S' High Cam. I don't know if High Cam makes a difference in what I'm doing as I don't even know what it means.

 

Anyway.. the gregories shows that the crankshaft keyway needs to be vertical so I can align everything up.

 

When the keyway is vertical the number 1 cylinder is at top dead centre.

 

There is a small notch about 120 degrees to the right of the right of the notch. At this cog, the bright link on the timing chain goes over this point.

 

Unfortunately this notch on the small cog (camshaft sprocket) cannot be placed in a position to cut a centre line (the big red line) through the two cogs and align with the notch on the far side of the camshaft sprocket (large sprocket).

 

I'm probably getting things confused. Should the center line cut the crankshaft sprocket in half?

 

I think the big question is this. Should this be set up so the dot on the camshaft sprocket and cranshaft sprocket meet in the centre? I notice that this is how some timing chains are installed?

 

Photo's below.

 

 

 

Edited January 3, 2014 by abatom

[camerondownunder88]

Hi,

Are you in the Brisbane area?

 

I usually use the Toyota method as follows:

 

1. Slide in new cam shaft (if you got it reground)

2. Attach thrust plate to hold in cam. Making sure mark on front of thrust plate is on LOWER side closest to crank.

3. Align pin of cam shaft with mark on thrust plate.

4. Grab large cam sprocket and the little mark or some have the TEQ logo stamped on it align this mark with the bright chain link.

5. gram small sprocket align the timing dot on it with other painted chain mark.

6. slide both gears and chain onto cam and crank at same time.

7. Torque and beer.

 

Now if you need a straight edge that goes from crank dot to cam pin and then to large timing wheel dot use dip stick if not bent. Simple

 

Also another tip if your timing chain has ONE coloured link easy hold by that link let gravity do its work and link that is lowest to ground grab niko pen colour. Color is up to users choice. Can recoment a whte one.

 

Remember crank goes around twice for one reveloution of cam so chain is divide by two and links at end are the half way/alignment links.

 

Also when removing a cam useless fact cyclinder head bolts are the same thread and LONG great for screwing in a tad and giving a nice hand grip to SLLIDE the cam straight out the block.

 

As for the high cam badge on car..Marketing. Same as all K motors. nothing flash. Was to try and dress the 4k's up as having a high up cam like an over head cam right???lol

 

Also photo two of yours above hard for me to see BUT to me it looks like your large cam gear is adjustable :S if I'm correct you will need a degree wheel and some wire to dial this in and can be used for "fine" tuning a cam. Not really for a beginner. But hey we all have to learn so if it is think of it as more skill building.

 

Cameron

[camerondownunder88]

Dayammm! That's the best one I've heard of in years! The problems change as it moves a bit an you can't see what is wrong...

 

Yep I think installer drove pin home cocked off to side a bit bolted up cam and it had a weak spot and SNAP. And torque of bolt just couldnt handel it. Have the old lumpy stick in the shed. Needs a regrind as when it was shifting destroyed some of the lash ramps and peaks of the cams and the face e sprocket meets with isnt "flat" any more so needs a dress in a lathe. But yeah from a glance could see NOTHING wrong. Apart from my timing and car runnign like CRAP. So pin can go yes.

 

Cameron

 

P.S. Like TRD KEaid I still think you have an electrical issue....id head for coil and dizzy. Do you run a new dizzy cap? Also run a tacho? I had a cheap 2 inch tacho in a KE30 and it was shorting on the inside made for a few miss f so even try removing things to reduce the amount of problem spots to try to solve issue.