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Buddsy

Cam Belt Change

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Only had time for a quick go tonight

  • Removed big curved coolant pipe
  • Removed the triangular bracket which hold the rear of the alternator (Air con cars)
  • Took off the coolant pump pulley with the belt.

Only a small amount done but its all progress.

9 minutes ago, simon a-b said:

I'm sure my oil filler is at the back of the motor... is mine wrong?

On the later cars I think they were near the back which makes filling easier. On the G cars should be towards the seats rather than towards the boot.

Id check you have the cam covers the right way round and on the right one. They are angle and should appear approx. horizontal across the top where they say Lotus.

 

Buddsy

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8 hours ago, simon a-b said:

I'm sure my oil filler is at the back of the motor... is mine wrong?

 

You must have the Australian version.

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8 hours ago, simon a-b said:

I'm sure my oil filler is at the back of the motor... is mine wrong?

Likewise with my S3 n/a..are all the turbos the other way round, or just Buddsy's??

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22 minutes ago, DaveyT said:

Likewise with my S3 n/a..are all the turbos the other way round, or just Buddsy's??

LC engines at the front with the Elan filler cap, HC at the rear with plastic filler cap.

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One easy tip before you remove the belt, I usually use a light marker or something similar to put a stripe across each pulley and the belt. Transferring these marks to the new belt gives you another insurance that nothing moved.

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And this leads us neatly back to the first post on this thread...the article I wrote for Club Lotus magazine referred to therein...where I make a similar suggestion. i also marked the back of the auxiliary pulley to align with the top edge of the auxiliary housing, so getting the ignition timing right is a lot easier than trying to sight up across the crankshaft pulley and the marks and centreline of the auxiliary pulley.

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I always line every thing up and tie rap the cam sprockets before removal of the old belt it does help.

andy

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^^ that's the way Sparky did it at the Beltfest, couple of cable ties in the right place, simple but effective. ( Ian - before you post I mean cable ties, not Gary!)

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Thinks:  don't remember Colin being in Copenhagen...

Then realises it was the UK-based one.

Yup, I'm simple.  And not too effective lately...

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Best wat to do it on any car, its not just from you accidently moving them yourself, some sprung cams swing round 180 as soon as the last belt tooth leaves the cam :(

cable ties or old folded cambelt on some engines between pullys works also on some motors.

They also state rotate engine by hand once to check nothing hits..... I have always cranked them over by hand no less than about four times to air on the side of caution :P

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In the Ferrari world people are always showing off their latest creation for locking the cams such as two shaped pieces of wood bolted together. It seems to be something people do as a matter of course although I didnt lock them last time I did my Ferrari belts and the professionals in the dealers say they dont lock them. I had never come across people locking the cams on the Lotus engine until this thread and I have never done it.

I like the cable tie idea though. One of the problems with locking the cams solidly is you often need to turn them a tiny fraction to get the new belt on. The cable ties presumably would allow a small amount of flex. Cant do that on the F engine though as no holes in the sprockets. I am going to try that next time on the Esprit.

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I set the cam sprockets to exactly where they need to be, then cable tie the belt to avoid slippage.  These are now the datum; NOT the crank.  Then I can go under and fit the rest, backing off the crank sprocket slightly, fitting the belt, then bringing the crank back round to TDC to achieve initial tension between crank and exhaust.  Adjust and lock tensioner, snip ties, rotate 720deg to check alignment, then start the tensioning process.

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Cam sprockets are easy to align...the dots are very visible. The auxiliary pulley is a lot more problematic, as "the book" says you have to sight across the crankshaft and the centreline of the aux pulley and the timing dot. Not so horrible on an engine stand....but doing that in situ is a job for a contortionist. Marking the aux pulley rear face where the housing top edge is before taking off the old belt means that you can readily align the aux pulley....and that's the one that tends to move about; unlike the cam wheels which need a fair torque to move them, the aux pulley moves with a gentle breeze.... A spot of "tippex" or similar to mark across the cam wheels and belt and the aux wheel and belt keeps all three on their proper teeth...you can mark from the old belt to the new and then the alignment just follows.

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On 14/03/2016 at 13:45, molemot said:

 A spot of "tippex" or similar to mark across the cam wheels and belt and the aux wheel and belt keeps all three on their proper teeth...you can mark from the old belt to the new and then the alignment just follows.

Moley I could kiss you! I forgot I did actually do this as I was following your old guide! ;-)

I have been having fun removing the water pump as most people know the bolt behind the dizzy cam wont come out. I made a drill location guide and used a long series drill to loose the head. Ive just had the fight to get the water pump out from under!

So belt and pump all now out. I know Ive only done about 1500 miles but its been 3 years since I started running. The Evans waterless came out looking very clean. The water pump looks pretty clean with only slight deposits on the iron pump turbine. The pic below is how it came off with no cleaning etc.

IMG_20160320_215430021[1].jpg

I think Ive decided to go with PNM to get the pump rebuilt.

Buddsy

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Got my pump back from PNM engineering today. It's been rebuilt and tested on their rig. I have to say it looks very nicely done. I know you can't tell every thing by looks alone but to me if someone is careful with the details that's usually a good indication as to the rest of the job.

Buddsy

IMG_20160404_213759159.jpg

IMG_20160404_213829020.jpg

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On my back again tonight on the garage floor! Cleaning the mounting face and getting ready to fit the water pump and other bits back again. Ive always had a bit of trouble with a leak from a M8 blanking bolt on the back of the head. I think you can see it in the first pic. I have had a go at fixing it once before when I changed the o'ring which had split for a plastic washer. I think the heat does these in maybe? You can see my bolt I have removed. Anyone else have this problem. I think I may have got this not quite right when I rebuilt the engine? Maybe some sealer on the thread or maybe a copper washer?

Any ideas.

Buddsy

IMG_20160404_221138034[1].jpg

IMG_20160404_221622525[1].jpg

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Buddsy,  I personally would try a copper washer with some of that gasket stuff smeared on it, i think it was called hylomar?  I always used to put it on water pump gaskets but have used it on sump gaskets also, may be worth a shot to cure it. ?

p.s your engine still looks mint enough to eat your dinner off it.! how many miles have you done since the rebuild. ?  :)

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Thanks Dan 

I ve used the Hylomar else where on the the rebuild and think that may well be the way to go with the copper washer.

So far Ive done about  1500 miles only.

 

Buddsy

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I have a question (maybe it is just an observation) about changing the timing belt

I am in the midst of changing mine.  Per many instructions, I used a Sharpie permanent marker to mark the belt and the pulleys (Unfortunately, I did not mark the crankshaft pulley).  After reinstalling the belt, I turned the engine over (by hand, turning the rear wheel).  After 3 "laps" of the cam belt, the crankshaft was at TDC and the alignment marks (dots) on the cam pulleys were aligned, but the Sharpie lines on the belt were shifted by one tooth on the pulleys!  I was thinking I needed to remove the belt and start again, but after looking more closely, it appears to me that the engine is aligned properly - the belt has simply shifted its position.  I decided to go again and after 3 more laps (6 total), it appears that the engine is aligned, but the Sharpie marks have "walked" by 2 teeth.  I assume if I keep going, this will continue. 

Have others observed this?  I was trying to use my Sharpie marks to make sure that everything was aligned but it looks like I need to disregard those once the belt is in place and the engine has turned over.

On a related note, I decided to replace the belt based on age (I've had the car for nearly 2 years but not driven it yet due to other issues), but in the process, I discovered that a) the tension via a Krikit gauge was only 40 lbs and b) the automatic tensioner had a metal piston but was missing a nylon cap.  I ordered a new piston from JAE and its diameter was larger than the original so I had a machine shop increase the diameter of the cylinder in the tensioner.  The joys of owning a unique auto!

Please let me know about the "walking" marks on the belt.

Thanks,

Jim

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If you mark the belt it will only be valid for refitting. As soon as you turn the engine over the marks are no use.

In fact an engine designer would never design such that the belt always rotates to the same position on every revolution or low number of revolutions as that would cause uneven belt wear. The belt has to shift around on each revolution.

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Thanks!

 Jim

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If all the pulleys had the same diameter, they would come back to where they were but the crank one is smaller. I had the same moment of fright when I did mine.

 

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Its to do with the total number of teeth on the belt which is not an exact multiple of the number of teeth on any of the pulleys.

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