Alex's v8 re-build thread warning pic whore inside >:)

[Alex Carter]

Thanks rizla me too im just a bit stuck as when all rebuilt and ready roll am I looking at a rebuild every 4 thousand miles . Im really miffed how do I tighten them . I wouldnt mind if it was a budget build and it was done on the cheap but it really was a if it needs it buy it and all genuine parts no copy rubbish and it still went wrong ! So a little disappointed at the mo.....

[j900jpw]

Alex, thanks for letting us all know. I suppose the art in hind sight is to gradually increase the tension to the required tolerance being careful never to exceed the upper level which potentially could damage it? I was always under the impression that the tension could be set more than once - in fact the annual service I think says to check the tension and re tension if required. I'm still amazed that the unbroken belt had stretched so much in 4K. I recently did the cam belt on my Golf Gti and after 55K it hadn't stretched that much compared to the new one (less than 10mm).

 

When I do my V8 I will check, turn the motor by hand several revolutions, check and adjust (again and again until the reading is constant), run the car for 30 seconds and recheck / adjust. I will then recheck after 100 Miles. One reason I want to do it my self is so I can keep an eye on things.

 

Do you think you can get compensation? After all you took advice of others and presumably paid for this to be done "correctly"

 

Just a thought - may be interesting to compare the un broken belt with a new one, to see if it has stretched beyond what's expected.

 

All the best.

 

Julian

Edited December 8, 2013 by julianwhite

[Alex Carter]

Well I have raised the problem with gates and they sent a lovely guy down to see me and the engine he was very professional with what he said and what's basically happened is I've dismantled the engine belts tensioners and idlers for his team to test , he's unsure of what's happened as an "installation error" wasn't really an answer when he realised a lotus technician installed the belts he's not confirmed the belts have stretched or tracked badly but I'm awaiting his reply then I'll know if they'll help fix it or I'm left with the bill . I wait to hear from him .

[Alex Carter]

Also your vws and audis all use self tensioners so as the belt gives the tensioner can take up the slack. With the lotus there just fixed so thats it . When we did mine we used the pins locked tbe cam and crank checked again and again and probably turned it over by hand about 40 times checking again and again . The only thing we didnt do was start it as the engine was done out the car for ease and to check other components.

Just be careful on doing yours to tight and the bearings on the pullies whine. Too tight on the belt and it can snap . Its a shame there isnt a rig with fuel and power for an ecu to run the engine out the car just to do this and test the tension again but then again I feel in adjustment tighter and tighter and tighter just brings the opportunity for snapping closer.

[Günter]

Alex -as you can see by the surface design/cast structure of the heads on front ..there was a plan to create an mounting point for automatic tensioner

 

Maybe you can now be the guinea pig, to test if it is possible/cost effective to install some available modern tensioners there.

 

Or see my topic about a 'redesign/reverse engineering' of the belt drive -with different belts, at least 25mm or even more 30mm belt and '8mm HTD pitch' design that is more common now, and if possible with bigger wheels for the belts to make it a more 'smooth' run with a whider spread load on the contact area

[Alex Carter]

So had the report back from gates they are saying the belts had no tracking issues and that the stretch was within there tolerances , great so I'm footing the cost of the rebuild and no explanation for why the other belt became so slack or why the first belt dived off the cams or why the pistons hit . Just fantastic .......

[rizla603104]

I feel for you Alex - but I reckon a manufacturer would say that - as it is their reputation at stake. I guess it was a long shot. So what to do now?

[Alex Carter]

So how would that work .why would the engine not fail straight away lets not forget I did 4000 miles in it and Would they not report oil contamination or the fact that the belts were still in there tolerances . It makes no sense at all im not at all happy . Solicitors it is I feel its the only answer .

[Günter]

Can you say for sure that the tensioners have been fitted in the right way round ?

 

..in a way that the rotational direction of the belt forces the tensioner to 'run into' the belt in any case, instead of 'jumping off'   (see workshop manual for this)

 

Or how exact was the initial timing position done ?  

 

..as for example I can see that on my rebuild (that was not done up to the highest tension specification (HZ) )  -now with a little over 20.000km on the belts the tension is even not up to the lowest spec. '95HZ' rate anymore. And if I try to re-tension it, it runs notable out of timing position, so it means for a exact position I would need to undo the cam wheels again  

-the 'slack' / tension loss is around one tooth now,  and I'm worried too how long those belts will last in general, even with a 're-tension' set up to 120+ HZ 

[Alex Carter]

I dont blame my lotus guy he did eveything right as per the manual and there were to many qualified people there watching . Its not that I want to point the finger its that I need to understand what went wrong so it doesnt happen again . I used lotus tooling an approved clavis gauge the correct set of timing pins and correct tolerance pins the correct crank tool and it was checked and checked again . I didnt use broom handles for the crank or drill bits for the cams I didnt bodge my way through it I did as per the manual with a trained technician so the fact yours is still running well done you !
But I need to know what happened and I dont believe im being told the truth ok .

Can you explain for me why it went wrong what happened why it failed ???? Maybe I need your B and Q rebuild skills and id have a running engine .
If your belts have slacked off so much your cam timing must be terrible do you still have horse power before mine let go I notice it was nt as quick my cams were retarding badly . This doesn't make sense for a belt in length tolerance does it .
Go see the pic buddsy posted does that look tight errrrm no

[rizla603104]

I think it is important to know what might have happened - because whatever it was has not shown itself to this point clearly enough for anyone to understand and ensure the same issues do not present again in the future.

 

For my 2p worth - I would forget the legal eagles. They'll just suck you dry. And take the money away from the rebuild.

[Günter]

Alex -wasn't it you ..who asked about a warranty and 'factory belt-service' ? ..and Bibs and others told you that this was no general action, carried out by Lotus for all of us, as it was only for US cars related to US consumer laws.

 

It is clear that from the constructive point the drive system of those cams is a fail, or let's say a misconception ..as you can see it by comparison with other 16V- four valve head engines  ..in the end those two banks are just two inline four, and therefore should last as long as the same belt driven engines of ordinary family hatchbacks  (-at least this is my point of view)

 

..there is a mounting point for an automatic tensioner, with a positioning hole in the cast structure -but for some reasons the development team changed its mind -who knows why :/

 

On my rebuild I wasn't sure that it is a good idea to let the cam pins in and turn the crank a little more until you tighten up the tensioner bold ..think it was meant this way up in the manual, there in one section mentioning something like this. So I was just happy that I could manage to set-up the tension within the tolerance band after some tries -as on first try it was 200+ HZ  and it did not work for me to exactly match the frequency  given for a new belt, so as far as I recall in the end it was in the more lower 100 -116HZ area  

-timing itself was there on the engine stand still within tolerance, so I glued all bolts tightened up in place, and fitted the engine into the car ..at least  I was happy that all was running fine.  Even the trip to the UK afterwards, with the track run on the old factory test field worked up fine, no noise from the belts and full power. 

 

Now -with your story in mind, and as the mileage is up for the '20.000km factory recommendation' on re-check ..I just tried to test it, with engine in the car  ..and noticed for example that on the LH side measuring angle of 80° BTDC this belt was 'slack' below the sensitive range of my method with "hit it with the spanner & measure with PDA mic" arrangement.   On most other crank angle positions the LH was barely up to 70HZ (with some inconsistency on several tries)  ..the thing is, if the belt is that loose near the 80°BTDC reference point you can feel and see that the cam-lobe forces the LH inlet cam to "jump" independently into an defined position -a position that is not 'timed' anymore compared to the LH exhaust cam.  The RH side too is a little weak -with a measuring of 90

 

This is a situation where harsh 'peaks' of load could happen and destroy the core of the belt -don't you think ?! 

 

for piece of mind I have now undone the whole LH belt (with a surface / contact face that still looks good on the Nylon mesh on the tooth side)  ..and will undo the RH side too and start over from the beginning like on a normal belt change.. so it means I just try to fit them again on both sides, with all setting-pins installed and crank tool in position to be sure that all is ok for the next 20K km. If nothing helps I have to heat up the cam wheels to undo the bolts there (the factory advice was to use this strong white Loctite sealant as a glue there) and even re-position all of the cam-wheels.

[Alex Carter]

Actually no gunter I didnt I asked about liner warranty try reading the post . More thought less haste!

And your going to refit old belts and re tension them again good luck with that.

And just to add you should nt leave the pins in and tension that Sheering force with easily snap a pin or drill bit.... I took my rockers off and made use of the hex cam shaft and a spanner while I cleaned the cam pullie threads and used new glue to hold the pullies

[Bibs]

Alex, what are the chances of foreign bodies (eg parts of the turbo) making into the engine at causing it to seize and that leading to the problem with the belt? Have you checked the turbos for damage or stuck a boroscope into the cylinders to look for damage/metal etc?

[j900jpw]

Hi Alex,

 

If you take up Buddsy's advice, I have some brand new belts which I can measure if you think that may help? If your belts have stretched a lot then it may be worth investigating the tolerances the belt is supposed to have yourself - instead of just taking the manufacturer's word for it? 

 

Gunter - maybe you can measure your 20k old belts if I understand correctly you have removed them from the car?

 

Bib's no need for the scope - the engine has been stripped down and I don't believe it seized.

 

Cheers

[Vulcan Grey]

I just re-read the posts, and I don't see if it was mentioned about the possibility of the cam pulleys slipping on the cam shaft.  Since the Esprit V8 doesn't have keyed camshafts where the pulley fits on in one orientation, the cam pulleys have no markings, and the belt is now loose... it seems impossible to tell if the cam pulley has shifted on the shaft and the timing was changed, along with loosening of the belt.

 

Now there is no way to verify whether the timing remained in the same place where it was originally fitted.

 

In the last 13 or so years, I have heard of several Esprit V8 engines that failed immediately/soon after a timing belt change, or engine rebuild, and IIRC it was often that the cam pulley slipped on the cam.

 

BTW the cam may feel tight again on the shaft, may not necessarily be "loose".

http://www.thelotusforums.com/forums/topic/52710-thoughts-on-keying-intermediate-shaft-and-pulleys/

[Vulcan Grey]

None of the timing pulleys on the V8 are keyed...

 

 

In order to achieve the optimum accuracy of valve timing, all the toothed pulleys are clamped to their shafts without the

positional constraint of indexing keys. A crankshaft positioning tool and four camshaft setting pins can be used

to set each of the shafts in a ‘timing’ position, corresponding to 10” BTDC no.2 cylinder firing. Great care must

be taken if the cam drive system is disturbed, in order to avoid valve to piston contact.

 

It is important to realise that the positions of the toothed pulleys themselves are not relevent to cam

timing, as there is no indexing of any of the pulleys to their shafts. If the cam timing needs to be checked, it is

necessary to establish the positions of the camshafts themselves, using camshaft position ‘tolerance’ pins

[Alex Carter]

Thanks vulcan I have bought a new belt with the intention of measuring the length for exactly that purpose but I also contacted gates for them to come see how lose the other belt was as I didn't want to disturb the evidence till they had seen it . After their guy had seen it they wanted all the belts tensioners and idlers for testing since they've come back with a report saying no fault found the belts have been cut up into pieces so no chance of that now either .....convenient ! As rizla says basically a waste of time bend over take it up the sh## pipe and fix it . Im just hoping that when its all done I have a sorted car and if I sell it'll be worth it .

[Alex Carter]

Here we go so today had some time to do some stripping of the damaged head and i bought a nice shiney new engine stand to start the strip clean polish fix and well men stuff really 

 

i know you've all missed this bit drum roll the pics.

 

so first port of call the turbos pretty sure as suggested there wouldnt be a problem with these as i bought brand new ones but checked none the less .

left

right

 

as you see pretty good

 

the heads were already off but i wanted to get the gear box and engine separate for the engine stand but look what i found the springs on the intermediate plate on one side had snapped off and been spun round the bell housing causing some damage so new clutch on the list now too.

 

 

as you see two parts broke off and although the faces are not damaged you can see the chipping as it bounced around.

 

then i tried to lock the crank to undo the main bottom pulley buuuuut had and issue turns out my bar and strength were to much for the block a big bang and i managed to snap the sensor holder so ill be borrowing my friends welding skills later .

 

 

then the head and frame not really much else to say than they were pretty bent lol best ive ever seen and what a pain to get out good news is the heads fine just need to source pistons valves and seats and all that jazz.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

hahahahahaha heads off for testing 

[TAR]

a bit off topic but wow, you are allowed to work on the engine in the dining room?

 

Hope it all goes well.

[Alex Carter]

this is my mates garage tar lol 

[Günter]

as far as I recall you told us that you have worked on Ferraris & Lambos in the past ..right ?

 

What is the Nm rating for crank-pulley bolts or lower chain/timing belt drives there ..?    Does it work there to lock the crank on a sensor point, instead of simply fit a bar to the flywheel ??

Edited December 21, 2013 by Günter

[Trevsked]

That amount of damage would worry me that during the rebuild I might miss something and it not be right after the refit. Are you not tempted to source another S/H unit, strip it to check it over and rebuild with fresh gaskets?

Trevor.

[Alex Carter]

No trev itll be fine the valves are proper bent but thats it my engineering firm near to me will test the head for cracks and at the same time fit new seats and oil stem seals . Lapping the valves in is easy and doing gaskets again not that hard .sourcing parts I feel will be the hardest part meaning I will have to change all 32 valves for new and all 8 pistons if I cant find o e . Not a concern but certainly makes the bill bigger .

And gunter im trying to refrain for flying off the handle no I never said I worked on lambo and ferrari engine's wrong again . if your going to just sit and point the finger may I suggest you turn it around and insert it where the sun doesn't shine you may have more knowledge about these engines than I do but at the minute your just being an ass for the sake of it Go Away !

[rizla603104]

Gunter - you are such a knowledgable guy - but you're acting like a troll. I have read Alex's thread from the outset - as you clearly have. I have read time and time again sniping and condescending comments. You've clearly got a wealth of information on these engines - so rather than mocking and calling into questions Alex's working practices - why don't you do him a favour and give some helpful advice? You may or may not agree with what he's doing or how he's doing it - but it is his car. I think you de-value your help by being rude. Maybe it's a cultural thing - I don't know - but please stop the daftness. Or - stop commenting.

 

Rant over.