The Lotus Grand Tourers

This has been a job that I've kicked down the road for a while but the exhaust manifold is leaking badly and desperately needs done. Upon inspection at least two studs are missing. I've new replacement studs for the missing ones along with new gaskets and copper nuts to do the job and a pulley block to lift the engine.

I could just ram the two studs in and hope for the best but I figured (reluctantly) doing the whole thing is the only way about it.

What do I need to know to do it the best way possible?

I've read to undo the engine mount, I presume just the one under the manifold is enough, no need to undo both sides.

Where is best to lift the engine? There is a lifting eye at the front on the bracket that holds the timing belt cover (from memory), but I see nothing on the rear, potentially will need to make a bracket? Is there anything that needs disconnected before lift?

Header tank/power steering pump - best to remove these and what else if any?

I've read that the cam carrier removed can be a help, what has been people's experience, worth doing?

I presume that I'll be working above and below the car. Have people done it with no lift? Is most lower work done actually through the wheel arch rather than directly underneath?

Just looking a good plan to go about it. Reading posts about it has struck fear in me

It is best done engine out.

The amount of faffing due to access will slow you down and eventually out way the time spent removing the engine.

Even out my manifold removal took ages due to stud issues.

Best way to lift is remove the carbs and inlet manifold and make a lifting brace.

Hawaiis0 wrote: Wed Jan 29, 2025 17:40 Best way to lift is remove the carbs and inlet manifold and make a lifting brace.

Fancy tool, but wrapping a chain around the runners 1&4 of the inlet manifold worked wel enough for me

I pulled the engine out of my Excel SE last week, I decided to take the engine and gearbox out together rather than splitting them. I used a chain hoist with a load leveller and a couple of nylon lifting straps wrapped around No2 and No4 inlets. I left the carbs on, just followed the workshop manual to the letter and it all went to plan. The only thing I didn't do was disconnect the propshaft. Access was tricky and advice on the forum was don't bother, and the engine and box came out fine.

The load leveller is vital, you can leave it centred until the gearbox comes free of the prop shaft splines, then after pulling the engine further forward you can increase the angle to clear the front edge of the engine bay. Mine came out at about 45 degrees! You need room below the car to do that, mine was on a Quickjack lift to give ground clearance. I don't think you could pull engine and box out without the leveller, but some folks have split the engine from the box in which case the engine can probably be lifted straight up and kept level.

Cheers

John

John wrote: Thu Jan 30, 2025 00:34. I used a chain hoist with a load leveller and a couple of nylon lifting straps wrapped around No2 and No4 inlets.

General note: take care when routing ropes and straps around possible sharp edges like you find on a steel oilpan. I once dropped a 6cyl engine when the rope frayed!

I've done this with the engine in the car, back last spring.

You are correct that you can do this with just the nearside engine mount disconnected, no need to disconnect the other one. I used a jack rather than an engine hoist, raised the engine up a bit and put an axle stand (and block of wood) to support under the sump. The sump is case, not pressed, and can take a reasonable load, but lift/support at a corner, not in the middle. If you do use a hoist, wrapping chain/rope around the inlet manifold is the way to go. Yes, it's good to get the coolant and power steering reservoirs out of the way first, and the screen wash one too.

To get access to some of the studs you'll need to remove the exhaust cam carrier. This is not that big a chore, and as a bonus you can fix any incorrect valve shim clearances while you're in there! When re-fitting the cam carrier be careful not to over-torque, it's easy to strip the threads in the head - I stripped several even just tightening to the correct torque. If you do strip one, no panic, just helicoil it (helicoil is not a bodge, there a several joints on the F1 engines I design as a day job that are helicoiled from new as it is stronger!). You'll also need a E20 Torx/star socket, which I didn't know before I first stripped my engine. Fortunately I was doing so at the NEC Resto Show, so I could just wander over to the trader area and buy new tools .

Even with all this done, getting to some of the studs is awkward and painful. Some are easier from above, some from below, some aren't that easy from either direction! Some of them, you'll need to loosen all the nuts a bit, then move the manifold away from the head, then loosen a bit more, the runners get in the way of removing the nut in one go. There's no useful access through the wheel arch, just from below the car. I did it with the front of the car up on axle stands, so that is possible, make sure the stands are VERY secure. It may be a bit awkward but it can be done, so persevere.

Replace the studs with stainless, to avoid future nightmares, as well as the brass nuts you already have. The studs should have a hex socket in the outer end, so you can put them in and tighten them with an allen key.

First time I did this, I tightened up the nuts good and tight, but still the nuts and/or studs worked loose over a fairly short period of time (which was why I was re-doing it last spring). Therefore, use threadlock, and use spring washers. I've yet to prove if this is sufficient to stop it happening again, but it has to be better than not using these.

Let us know how you get on...

I've done it the three ways described above.

Engine out. Easy to do but probably a long day from start to finish. Would only do it like this if I had other work that required it removed.

Engine canted and cam carrier removed. Fairly easy about half a day. Would probably do this if I'd not had it removed previously.

Engine canted. Bit of a pain but if you're not comfortable with cam belt and opening the top of the motor probably the best. Again around half a day. This was the way i did mine first time.

Be prepared that to fully remove the exhaust manifold, (recommended) you may find some studs coming loose from the head with the nuts still on the studs, which makes it impossible to remove completely withot loosening all the nuts and studs, Note this also for when you are reassembling as all studs have to be installed in the head before you can offer up the manifold, attaching the nuts progressively across all the studs. There are different opinions about using stud glue (Loctite type) as the manifold gets very hot and the glue can deteriorate.

I found I could only fully tighten the nuts , well three of them, from under the car, I had raised the front and put brick and plywood supports under the front wheels.
I loosened both front engine supports.

I also found that the gearbox rear mounting had the rubber separate from the metal plate, worth checking when finishing the job. An easy fix but easy not to notice.


Dave the cog

Thanks gents,

Engine out is simply not an option for me. Just don't have the room to it, and can't afford to have the car off the road as I'm daily driving it. Some great points and thanks to all who have offered advice on here and privately. I only got enough studs to replace the missing one's, maybe I should replace all of them.

I'll probably still lift the engine with the pulley block. Around the inlet manifold seems the place to lift. Loosen off both engine mounts and cant the engine over. Does the gearbox mounting need removed too?

Dwaynem884 wrote: Mon Feb 03, 2025 09:49 Does the gearbox mounting need removed too?

Shouldn't do - unless it's broken and needs replacing too!

Dwaynem884 wrote: Mon Feb 03, 2025 09:49 I'll probably still lift the engine with the pulley block. Around the inlet manifold seems the place to lift.

I'd still be tempted to put an axle stand and wooden block under the sump once the engine is raised, just for extra safety, and also because hydraulic lifts will start to sag down again over a few hours while you're working.

With a pulley block and chain I prefer to use a wide strap, like used to strap down wheels on a trailer, running under the sump, both engine mounts loosened, exhaust manifold side removed to give access to manifold lower studs, hydraulic jack under sump (with wooden batten) to release the strap out of the way of the exhaust manifold, and a woode batten as a spacer between the front of the sump and the chassis crossframe. as a precaution against hydraulic jack seepage.
You do not need to loosen the gearbox mounting as the rotation on lifting the engine is within the flexibility of the gearbox mount.
The best nuts are short brass with in-built captive heads. SJSportscars item number SJ573 as an example.
If you remove the cam covers or camshaft carriers you will have more than a weekend job, particularly if you have to change shims to correct valve clearances.

Dave the cog.

To access the exhaust manifold nuts, does the driver’s side engine support need to be detached at both chassis mounting pad and engine end (3 bolts into the block) to get enough room to move the engine or is there enough space just detaching from the mounting pad?

Can someone tell me the diameter and length of the exhaust manifold studs, please, so I can order some stainless ones.

What is the best material for the manifold nuts, copper coated or brass?

TIA

You want M8 x 40 studs, I used these ones from eBay. They are not expensive at all (£11.25 for 16, which is more than you need). They have a hole for an allen key in one end, which is good, helps you to tighten them up in the head first.

I used brass nuts. Whether this had anything to do with the fact that they worked loose after a while, or whether copper-plated steel nuts would be just as bad, I've no idea. I didn't consider copper plated ones, but I'd be concerned that the plating might not last for ever so they might still end up corroding.

https://www.sjsportscars.com/parts-and- ... /SJ573.htm

https://www.sjsportscars.com/parts-and- ... E2529F.htm

This is what I got from SJ's Not sure if the studs have the allen key head