Owen's Lotus Esprit GT3 Restoration

[Chillidoggy]

Dunno what your plans are, but I spoke to Gary Kemp a while ago, he told me he can get the original Nikasil liners.

[OwenGT3]

I've continued with stripping the pistons out of the engine. All the bores and pistons are of the same condition as piston one, so really pleased the engine is good.

The next stage is to remove the crank from the engine block, so the lower section of the engine needs removing. This shouldn't be too bad a job, but the rear crankshaft oil seal housing bolts are corroded in.

I've applied loads of penetrating fluid, but they are not moving. Also being hex head bolts, it doesn't take long for them to ring round and then you are stuck. I am thinking of welding a bolt to the hex head dome bolts. The heat might help as well, but it's mostly to get a better purchase on the bolts to remove them. I will need to replace them all.

[OwenGT3]

On 21/10/2019 at 10:47, Chillidoggy said:

Dunno what your plans are, but I spoke to Gary Kemp a while ago, he told me he can get the original Nikasil liners.

Looking at the condition of the liners, they are very good. The whole bottom end of the engine is very good, so I will just replace shell and rings. All of the problems are in the head with the valves.

[Sparky]

Owen, I've rounded my fair share of those hex bolts.  On every occasion (except one that required grinding the head then turning out with locking grips) I've succeeded by tapping in a larger torx bit.

[Chillidoggy]

15 hours ago, OwenGT3 said:

Looking at the condition of the liners, they are very good. The whole bottom end of the engine is very good, so I will just replace shell and rings. All of the problems are in the head with the valves.

Assuming they're the originals liners, there is some cross-hatching visible, but they do look worn and scuffed in places to me. As I understand it, Nikasil should not be honed like cast iron liners. @CHANGES?

I'm interested in this rebuild, as I'm currently mulling whether to take my engine out and refresh it. After all, it hasn't been out for a couple of years, and I'm getting bored.

[OwenGT3]

23 minutes ago, Chillidoggy said:

Assuming they're the originals liners, there is some cross-hatching visible, but they do look worn and scuffed in places to me. As I understand it, Nikasil should not be honed like cast iron liners. @CHANGES?

I'm interested in this rebuild, as I'm currently mulling whether to take my engine out and refresh it. After all, it hasn't been out for a couple of years, and I'm getting bored.

This is my understanding, that they shouldn't be honed @andydclements. There is the odd mark, but I would expect some on an engine that's done 97k. If there were no honing marks then possibly they would need replacing, but from first look I think they still have a good amount of life in them. I am going to measure them to see how much they have worn, but this engine I have never seen it burn/smoke or use excessive oil consumption. Also with a restoration like this, where do you stop? I'm already way over budget so if something can be saved and used a bit longer, then I will keep it.

It's the same with the fuel tanks, they are both out now. One all the powder-coating has flaked off, the other just one small little patch. The tanks are really good condition. So do I add nearly another £1k to the restoration and buy alloy or stainless replacements or just restore the originals? I'm more than likely not going to be the next person who will have to remove them, having sold the car on by then, but if they last another 22 years, then it won't be all bad.

[jonwat]

29 minutes ago, OwenGT3 said:

It's the same with the fuel tanks, they are both out now. One all the powder-coating has flaked off, the other just one small little patch. The tanks are really good condition. So do I add nearly another £1k to the restoration and buy alloy or stainless replacements or just restore the originals?

A good wire brushing & a couple of coats of something like POR15  is what I'd go for. 

[Chillidoggy]

1 hour ago, OwenGT3 said:

This is my understanding, that they shouldn't be honed @andydclements. There is the odd mark, but I would expect some on an engine that's done 97k. If there were no honing marks then possibly they would need replacing, but from first look I think they still have a good amount of life in them. I am going to measure them to see how much they have worn, but this engine I have never seen it burn/smoke or use excessive oil consumption. Also with a restoration like this, where do you stop? I'm already way over budget so if something can be saved and used a bit longer, then I will keep it.

It's the same with the fuel tanks, they are both out now. One all the powder-coating has flaked off, the other just one small little patch. The tanks are really good condition. So do I add nearly another £1k to the restoration and buy alloy or stainless replacements or just restore the originals? I'm more than likely not going to be the next person who will have to remove them, having sold the car on by then, but if they last another 22 years, then it won't be all bad.

Where do you stop? I ended up spending a bloody fortune, and I still haven’t stopped!

If your tanks are good, then reuse them. I say this because the chances are the car will live a much better life in your hands post refurb. Unless you use it as a daily driver, it probably won’t see any rain, unless you get caught out.

What I do know is if you don’t have the correct finish on the cylinder liners, then the rings will struggle to bed in, that’s where I’m coming from. That’s the case with cast iron liners. I understand that Nikasil is a coating, and once it’s worn through, then the rings will be running on aluminium, but I freely admit I don’t know enough about them, having never used them before. Hence me asking others more knowledgeable than me. I wonder why Lotus used them, weight saving, perhaps? Or durability? Or both?

[OwenGT3]

1 hour ago, jonwat said:

A good wire brushing & a couple of coats of something like POR15  is what I'd go for. 

I'm thinking of some light shot blasting to remove rust, then pressure test them. A good coat of red oxide paint and then a nice enamel top coat paint, two coats. Foam replaced with proper non-porous type.

[Barrykearley]

Be very very careful blast cleaning them tanks - media will go everywhere and be very difficult to get out - wrong media will blow holes in the thin plate work.

find a place who will acid dip them for you

[CHANGES]

10 hours ago, Chillidoggy said:

Assuming they're the originals liners, there is some cross-hatching visible, but they do look worn and scuffed in places to me. As I understand it, Nikasil should not be honed like cast iron liners. @CHANGES?

 

On 21/10/2019 at 10:47, Chillidoggy said:

Dunno what your plans are, but I spoke to Gary Kemp a while ago, he told me he can get the original Nikasil liners.

10 hours ago, OwenGT3 said:

This is my understanding, that they shouldn't be honed @andydclements. There is the odd mark, but I would expect some on an engine that's done 97k. If there were no honing marks then possibly they would need replacing, but from first look I think they still have a good amount of life in them. I am going to measure them to see how much they have worn, but this engine I have never seen it burn/smoke or use excessive oil consumption. Also with a restoration like this, where do you stop? I'm already way over budget so if something can be saved and used a bit longer, then I will keep it.

First point of interest, Gary kemp just sold his last complete set of Nikasil liners to me a couple of weeks ago and does not think he will be having any more.. He does have 2 odd 'A' liners for partial or emergency repair needs. otherwise only second hand units. 

South West have a few sets on the shelf but won't sell them .  they are keeping for their own use.. 

Nikasil liners are honed with special equipment, but as the coating is quite thin it is not advisable to re-hone ,  At a push you could just stay within limits if you honed an 'A' liner to a 'B' liner spec,  but this will only allow for max 0.0005'' hone.  In most cases an engine with 97K miles will have worn close or more than that anyway.

The problem as i see it , will be the ware on the liners at the top..  This is at the point where you normally see a step in the iron liners,.  What you tend to get on  a Nikasil coated alloy liner is more of a dent where the piston rocks at the point of the top ring. This dent is formed by the coating wearing and the alloy deforming behind it.  To the untrained eye it can look quite good, until you use bore gauge and measure properly.   The down side is when these coated liners reach the end of their life and the coating just starts to ware though,  They then go south very quickly.   

There are companies that will re-coat the liners , they do it for motor bike engines.  But when they remove the old coating they can not remove the dent without going oversize.  This would then require custom pistons etc etc .  

This is why a a lot of rebuilds now use ductile iron liners .  If your pistons are in spec then all you need is a set of rings suitable for that type of liner.   If your pistons are polished or worn on the skirt , you can order your iron liners a few thou tight and have them honed to spec.. This option is more for when parts are not available ,  personally with this engine  i would just buy new.

@OwenGT3  being over budget on any Esprit restoration is easy.  Owners think we traders who do this for a living are too expensive , until they do it themselves. 

Good luck with the project,  please try not to cut corners  

[OwenGT3]

On 23/10/2019 at 17:43, Barrykearley said:

Be very very careful blast cleaning them tanks - media will go everywhere and be very difficult to get out - wrong media will blow holes in the thin plate work.

find a place who will acid dip them for you

Is a better option.

[Barrykearley]

Yes acid dip is. It will strip the paint and the rust. It does need to be done properly - most powder coating places will have an acid bath hiding out the back

[OwenGT3]

Today (12.10.1) was spent stripping the engine some more. I removed the turbo from the exhaust manifold, this required the nuts being removed with a grinder, but I did manage to save the studs. I also stripped the inlet manifold down to it's component parts.

As well as the engine parts, I did remove the drivers side fuel tank. I can see now why this job is so bad with the engine in, as even with easy access the tank was still tight getting it out. Once the top board, seat belt, cross-over fuel pipe and earth strap was removed, the man issue was the seat belt mount. The tank needed to be forced past this, but once past the tank came out OK.

The fuel tanks are actually in very good condition, even with all the powder coating removed, with just surface rust on the tank. I think with a good soft shot blast and paint the tanks will come up well. The passengers tank doesn't look as bad as the driver side for powder coat removal.

Edited October 25, 2019 by OwenGT3

[OwenGT3]

The job I did today was quite a small one, but needed to be done. As the fuel flap on a GT3 on the drivers side is blank, Lotus glue them shut with bonding agent. The flap needed removing for when the car gets painted, so I had to get a scalpel behind the fuel filler flap and cut the glue. Luckily this was not as bad as I thought it would be and the flap opened.

When this goes back together I am going to fix this with powerful magnets, as I might put a trickle charger socket in this blank fuel filler.

[jonwat]

2 hours ago, OwenGT3 said:

When this goes back together I am going to fix this with powerful magnets, as I might put a trickle charger socket in this blank fuel filler.

Neat idea 😀

[OwenGT3]

6 minutes ago, jonwat said:

Neat idea 😀

It is a good idea, I have heard others have considered this as an option. I don't know whether to buy the actual release if you can still get it, but if not a good set of strong magnets will do. Can't be worse than Lotus sikaflex method, I know it's good stuff for bonding, but not what I would expect on a £50k car.

[Sparky]

I believe @temple has a charge port there, courtesy of previous owner @Advantage.

[Chillidoggy]

1 hour ago, Sparky said:

I believe @temple has a charge port there, courtesy of previous owner @Advantage.

That’ll be for his Mobility scooter, then?

[OwenGT3]

I finally removed all the valves from the head today (17.10.19). This wasn't too bad a job as I had a valve removing tool and they came apart really easily. All the guides are worn, with one inlet valve being very sloppy on number one, but the valves don't look too bad a condition generally.

Some ports you can see blow by on the inlet valves, which obviously would be contributing to low compression. Seats on the exhaust valves were very thin and looked like they were not creating a good seal. I think once all the faces have been machined, new guides and the valves lapped in, the head will be A1 again.

Another job I did was to dismantle the pistons and con rods. Again the pistons are in very good condition as are the rings for the mileage of the car. The pistons came apart easily and are now ready to be cleaned up.

Edited November 7, 2019 by OwenGT3

[OwenGT3]

Today (21.10.19) I finally removed the last rear shock, spring and upper suspension link. The top nut on the shock had to be cut partly to get it to move. This was done with a cutting disc and Dremel, removing a face on the nut. With the part removed and some WD40 the nut started to move with a spanner and was removed. The lower nut came undone without any need for cutting. With the shock and spring out of the way, the upper suspension link was finally removed.

I then moved on to removing the passenger side fuel tank. Similar process to the drivers side, but with less items to remove from the top of the tank. The fuel filler neck was removed along with the passenger side air-duct. Finally with all the bolts, nuts, brackets and seatbelt removed out of the way, the tank could come out of the car. This side was easier than the drivers to remove, it may have been the boot release cable on the drivers being in the way causing problems, but the tank was out.

This tank has weathered better than the drivers side, with just a small patch of powder-coating paint lifting from the tank metal. Even so both tanks will be stripped of coating to have a fresh coat of paint and protection if used again.

 

[OwenGT3]

Today's (30.10.19) task was to remove the crankshaft rear seal housing, allowing me to remove the crankshaft engine main bearing housing. The bolts wouldn't come out using the hex heads, so some other method was required.

I decided to weld some nuts to the head of the bolts, which would give me better purchase on the bolt with a bigger spanner, plus the heat from the welding would help free the bolts. I have to say this method worked a treat and all the bolts were easily removed, I just had to protect the engine from weld sparks so as to not damage any surfaces.

With the seal housing now off, I was able to continue to remove the crankshaft main bearing housing. This came off with ease, gently tapping it to remove it from the studs. With the housing removed I was able to inspect the main journals, which like the con-rod main bearings, are in a really good condition. I checked the end float which was within specification.

With the engine block totally striped now, the final items to strip were the cam carriers. These again were not too bad to strip, with only the camshaft sprocket and end float nuts being the worst items to remove. To do this I used the old cam belt around the sprocket and held in the vice. With a strong bar the nuts cracked and were removed. With the sprocket off, I just had to remove the camshaft seals to withdraw the camshafts from their housings.

The engine is now totally dismantled.

[OwenGT3]

I've moved operations back to the front of the car and have now started to strip the front suspension (08.11.19). I started on the N/S suspension and generally it came apart reasonably easily. Most large bolts needed breaking with a strong-bar, but then removed with a ratchet spanner OK.

The only problematic bolts were the suspension arms, upper and lower arms. The front lower arm bolt has seized in the bush, so the head of the bolt may need to be cut off to drive the bolt out, or using an angle grinder cut down the sides of the arm in the housing to remove the bolt.

The shock-absorber and spring assembly came apart OK and was no problem removing from the car. It will be nice when it all goes back together, being all nice and cleaned up and painted.

 

[Giniw]

On 23/10/2019 at 22:27, CHANGES said:

There are companies that will re-coat the liners , they do it for motor bike engines.  But when they remove the old coating they can not remove the dent without going oversize.  This would then require custom pistons etc etc .  

I have read somewhere that the thickness of the new coating could compensate so the liner would be the original diameter again?

[CHANGES]

3 hours ago, Giniw said:

I have read somewhere that the thickness of the new coating could compensate so the liner would be the original diameter again?

A lot depend on the liners deformity / dent and how much the alloy will need machining to remove it.  The typical thickness is of Nikasil between 100/200 microns ,  You need to measure what was there before , see how much thicker you can actually make the plating,  then allow for the honing .   If the dent is less than this then you are in the pound seats so to speak .. however you usually find they are out of spec..      If you are desperate to stay will Nikasil liners , you can always go out by 0.020'' have them all re-plated / honed to that,  and purchase oversize pistons..