Esprit Turbo project car - part3 - the further continuation

[Andyww]

Thats about the same condition as mine was. So it will make a difference.

Not sure if that cast iron can be welded? A new valve seat would be good but to me that looks like a pretty tricky job. The pictures dont show how the valve seat is on an internal face of the part not on the external surface.  

[LOTUSMAN33]

44 minutes ago, Lotusfab said:

Have had some experience with lathes. I had initially thought weld new material then recut. I like your solution better! Have never heard of those types of valve seats? Have had someone recommended, so maybe try them and see?

We use these materials all the time in my industry and use them in high pressure steam systems so good for heat. Not cheap and very hard to machine without the correct tooling. TBH you could go for a high quality steel EN16T which would last well and more readily available commercially. I would be interested to know what a perfect seat looks like to understand the profile. A good engineering machine shop with a set of long jaws with a decent size four jaw could set this up, alternatively a boring machine could be used. The machining is the simple part, setting it up is what takes the time, I would remove the studs and set it to the bore and also skim the matting face.

Dave  

 

[Andyww]

I happen to have a new one about my person and this is what it looks like. The seat would need to be perfectly centred with respect to the top hole.

 

[LOTUSMAN33]

Fantastic! I bet that has not been available for some time?

Yes I would have been able to set up and machine it if I could access the right lathe as spent 10 years doing strange shape castings early in my career. 

The grey matter is now on overdrive ?

Just checked SJ's....£587 plus VAT! Reclaiming it looks like the best option Fabian?

[Andyww]

7 minutes ago, LOTUSMAN33 said:

Fantastic! I bet that has not been available for some time?

 

I think they still have a few left. Their website is showing in stock. But the new Alunox system has to be very attractive as it replaces the manifold, adaptor and wastegate, all of which are problem parts.

[Lotusfab]

Nice part! I'm not paying £700! I'll  buy a lathe and repair it myself first! Wonder if Lotus bits have a second hand one?

[Lotusfab]

Have started to look into the wastegate adapter problem. The problem with the repair is there is insufficient thickness of material to put another valve seat in. A. It is possible to build the area up using welds but it's tricky and of course you have to find someone willing to take it on.  B imake a insert with a seat in it and fit it in the hole as a single piece. The cost of this £300app. C Blank of the exit, switch to a modern wastegate and make a new exhaust piece to fit. D buy the adapter new. Don't know which one to go for yet?

I took the wastegate to pieces. The membrane needs replacing as its thin and flaking, although still intact it will not last! Does anyone know a supplier? 

[LOTUSMAN33]

That is expensive for the machining work Fabian, where did you go for that quote?

SJ sell them for £65 plus Vat A910E6571F

 

[Lotusfab]

Local engineering company. The valve seAt can't just be machined because the metal isn't thick enough, so a CUP type arrangement has to be used unless the metal is welded?

£65 seems a lot, looking for an alternative.

[910Esprit]

£65 is cheap as chips!   Were significantly more a few years ago.

[Lotusfab]

Not as cheap as a new wastegate valve!

With this sort of valve could blank of the wastegate adapter, fit this valve and modify the exhaust to connect on. Would be a much cheaper alternative than £600 for a new adapter and the wastegate rebuild costs on top?

Although the new adapter is real pretty! ?????????

[910Esprit]

I think that would be a really good solution and fully reversible.   Are the centres compatible?

[Andyww]

I seem to remember someone having done this already. cant remember if it was on this forum or somewhere else.

[Lotusfab]

Mmm, would be interesting to see how they did it? I'm all for original but think the new set up might be more reliable?

Mmm, would be interesting to see how they did it? I'm all for original but think the new set up might be more reliable? Still deciding the best way forward. The original design is pretty poor.

[910Esprit]

Andy - Whats the distance between centres for the Wastegate adapter and the Wastegate exhaust?

[Andyww]

1 hour ago, 910Esprit said:

Andy - Whats the distance between centres for the Wastegate adapter and the Wastegate exhaust?

Wastegate mounting is 70mm, exhaust 60mm.

[Lotusfab]

We'll have tried a few companies. None of them wish to take on the job! So his leaves two options A buy new adapter and repair the wastegate. B change the system and use a new wastegate. Having thought about it I think the original set up is a very poor design. Having part of the wastegate exposed beneath the car is not good. Far better to be sealed and the valve not directly contacting the hottest bit in the adapter. So I'm going to blank off part of it and use a brand new  Wastegate. When I've worked it all out will put some pictures on here.

[Lotusfab]

The turbo bits have arrived. Interestingly there is an extra oil hole on the flat round bit, with the original Garrett parts! You can see three oil holes in the picture the existing one only has two?Have to wait for assembly lube to arrive before putting it all back together, but the cleaning is all done now. 

Found the thread on the Wastegate conversion. Curious how I had the same idea? Now on the hunt for a suitable wastegate and blanking plate! Would be useful to get some feedback on how this setup works, so have PMd the chap on the thread.

My tool kit has started to appear!

This is exactly what I thought of, spooky!

[Lotusfab]

Yes the wastegate bolt centres are 70 MM and the exhaust 60 MM. On the hunt for a blanking plate and exhaust flange. If anyone has sourced some please post.

[LOTUSMAN33]

Fabian

Send me a card template of the blanking plate and I will see what I can do?

Dave  

[Lotusfab]

Thanks Dave. Will do.

[910Esprit]

I'm thinking about this too as my wastegate is fossilised, alhough my adapter is OK.   As the replacement  wastegates seem to have 38 mm centres but the manifold adaptor has 60 mm.  I was wondering about a square flange that is drilled  60mm across 1 diagonal and drilled 38 across the other diagonal.   The 38mm holes would be countersunk to accept countersunk setscrrews, so the inside of the flange would still have a flat surface with the wastegate attached, while the 60mm will still use the stock studs to connect back to the wastegate adapter casting -  Are you still with me...?!    Anyone see any problems with that idea?   Then as you say, a bog standard blanking plate for the redundant manifold outlet.   Shouldn't be too difficult to fab op the new wastegate exhaust connection, or just delete and use a screamer pipe!!   

NB Its not clear in the pic above how the wastegate is actually attached

[Lotusfab]

Think the turbosmart has 70 MM centres! Interestingly someone has already drilled four holes in my manifold and was thinking of what you described! Much needed easier to by a Turbosmart, it's £220.

[Lotusfab]

Yyou can see four small holes.

[Lotusfab]

Thus wastegate I posted before apparently has 70 MM bolt centers, £55! It will have to be drilled out. But it us adjustable from 8-11PSI. Set for 8psi it would be a simple and cost effective solution. Have ordered one so can test it and check the build quality. As long as the boost guage on the car works you have an easy way to monitor the valve operation.

Can't be any worse than the 34 year old relic that I currently have! 

Ps and it looks nice!?????