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Advise please - cam (re-)timing


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Well I put it off a long time (but not many miles).  Had a go at changing cambelts on my V8 - engine in-situ.  Definitely do-able but it sure is limited access at the front of the engine - made worse by all the coolant pipes and various tubes and wiring!!

I got timing pins made up to exact (lotus) sizes by an engineering firm which saved a few £.

It was slow going - lots of time spent getting from under the car -then climbing into the boot (trunk) and lying over the engine - took ages even getting it locked into place.  Got the old belts off and new (blue) belts refitted - with lots of scratched, cut and bruised arms and hands -  I had to move one or two of the cams a little to align the teeth on the belts - but I believe this is quite normal.

Went to turn the engine over by hand a couple of times to recheck the pins but the engine wont turn over more than probably 1/8 of a revolution (45 degrees) before stopping.  I checked - nothing external I can see stopping it so I reluctantly wound it back anticlockwise and locked the crank in position again and rechecked the (tolerance) pins would go in.

They screwed in but the more I checked (and maybe doubting myself) I am thinking that they didn't go in properly when I changed the belts.  I've poked various sized drill bits (4mm and 4.5mm) down and even a bit of thick wire and then tried moving the cams a little by the 18mm nuts on the end to see if I can feel the cams move through the locking holes but I can't. 

What I'm thinking is that I had the cranks 360 degrees out - on the wrong stroke - and that the pins didn't go into holes on the cams to lock them - but just pressed against the shaft - the did screw in a but but looking again (and again...) at it I'm thinking they should maybe gave gone in further.  I did check at the time and was convinced it was OK!!  This is despite rotating the crank - testing if the pins went in - didn't think they did so rotating another 360 degrees.

So... unless there's a really simple explanation staring me in the face that I'm just not seeing I thing I will need to re-time the cams.

So - for the experts here...

  1. can I do that without removing the engine.  I will if I need to but was hoping to avoid that. 
  2. Is there anywhere offering a simple guide?  I have the workshop manual so I can follow "by the book" if necessary

Any other thoughts...

Many thanks in avance.




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I wish I knew, but there is a guy on Lotus Chat in California, He goes by Gonzo, G. Mendoza is his name, who absolutely can tell you.  He has taken these motors apart and is very generous with his time.  He actually in the last year started a garage to do work on Esprit's.  He has many U TUBE videos of V8 Esprit's that have been modded and also a video showing the complete rebuild speeded up of the assembly of a V8 engine.

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Thanks - he gave me encouragement to do it with the engine in place - he also gave me the exact dimensions of the tolerance and setting pins as well as the crank locking key and the tension adjuster tool -so I could get them made up here. Very helpful guy - I might drop him a note anyway..

Thinking about it now - I'm not too concerned - I think I can do it with the engine in place:  Take the cam covers off, move (might need to remove and refit) the camshafts until they are in the correct position, lock them up, check the belt is fitted properly - then finish the job (put it all together again.

Sounds easy when I put it like that !!  We will see!!

As I said I have the manual so I will just take my time - with the cam covers off I will see what I did wrong and why it happened.

I think it will be next week until I get a chance to try it though - maybe a few hours on Saturday though.

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On 22/01/2020 at 21:12, Grahaml said:

Went to turn the engine over by hand a couple of times to recheck the pins but the engine wont turn over more than probably 1/8 of a revolution (45 degrees) before stopping.  I checked - nothing external I can see stopping it so I reluctantly wound it back anticlockwise and locked the crank in position again and rechecked the (tolerance) pins would go in.

If the engine stopped turning because a piston contacted valves then you may well have bent the stems so they'll no longer seal & you'll have no compression on that cylinder.

Have you watched this video on changing V8 belts, he mentions the engine being on the engine being on the exhaust rather than compression stroke when inserting the pins at 2 mins 30 seconds?

Good luck. :thumbup:

Edited by jonwat


John W

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29 minutes ago, andydclements said:

Hopefully with just turning by hand it will have been insufficient force to damage the valves, 

I managed to bend valve stems when turning the engine by hand on my Europa. 😡


John W

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Ouch, that must have been unlucky along with frustrating. There is the extra bit of force when coming off another cam lobe,  or the size of the valve head meaning there's more bending action from just a light touch (if you mean Europa TC / Special then they're just 2 big valves per cylinder so could bend more easily than 4 per cylinder).

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Many thanks all.  After my initial shock I'd calmed down and I believe it's all recoverable.  

The car isn't in gear  - I checked that first with hope in my heart- but no..,,

Thanks for the suggestion Gonzalo.  I have disc printed already in preparation to check the timing belt tension so I'll follow your advice.  I'm still a bit mystified about how I could have got it 360 degrees out - I did try the pins 360 opposite from what I eventually used but exposing the cams will let me see for sure.  Maybe the cams were mis-time d enough to stòp the pins fully inserting - I'll see though.  

I had already taken the plugs out anyway.

I'm optimistic about it being a relatively straightforward fix now -turned over slowly by hand (there's not much access to do anything else) I wouldn't have expected to do any damage.  Could do with getting it done though ..


Might be a wee while until it's all done but I'll post when its finished


Thanks again all.

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  • 1 month later...


Sorry for the delay - bad weather knocked out the electrics to the garage so no light for a couple of weeks - then other stuff held me up.

However - pleased to report back that utilising the advice from Gonzalo (many thanks) it was pretty straightforward to recover - although a bit time consuming.

Took the boot liner out for access, removed the airboxes - for access to the cam covers, Took the plenum off then one of the cam covers so I could see the cams.  It was 360 degrees out as I suspected - but I really just couldn't tell that the Tolerance pins were bit fully in without seeing that.  Moving the crank to the safe position, rotate the cams until they lined up properly with the setting pins in place it was much easier to see whee I was.  That was the RH bank - I didn't have to take the cam cover off the LH bank as I knew what to expect (feel for) after doing the RH bank.

Access was a challenge as you all know but got the new blue belts fitted OK - tensioning was not at all easy as it was easy to overtension then you need to start again - rotating the crank fully - lots of clambering into the engine bay - then out and under the car (repeat as necessary!!)  However - utilising an app on my phone I was able to get consistent results within tolerance.  I rechecked the cam positions, rechecked the tensions etc - all good.

Yesterday finished putting the covers back on (even that wasn't easy with the limited access) - fitted the new aux drive belt,  and checked all the connections I had removed or disturbed, and - it started fine.  Today I did a wee bit more, refitted the airboxes, partially refitted the boot liner (still to be fully bolted down, topped up the coolant - I'd lost a bit with the header bottle lying loose and low and cleaned around the engine bay and gearbox.

There were a few errors showing on OBD reader  - Cam position sensor and a few others - probably as I'd started it without the air filters initially and I'd rotated the cams independent of the engine.  Cleared them and all seems well.

Having done it once - despite the difficulties I would definitely do it again - much quicker and simpler after the experience gained!

Many thanks for the advice



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20 hours ago, Espritv8black said:

Gonzo is the man. Super smart and super nice. Always giving of his time freely. If I lived closer I would support his shop. 

He never responded to me. Thru YouTube channel when I needed a rebuild. 

Or email I got from JAE when I was looking for a spare key. 


Good to see he is still active. 

On 05/03/2020 at 13:20, Grahaml said:

I've an android phone. I tried lots but the best (easiest) was one called Easy Tension by Hutchinson 

I used the Gates Carbon drive app



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