LT77 into a 4-cyl P6?

W

Willy Eckerslyke

Well-Known Member
As there's a TR7 5-speed gearbox (so LT77 I assume) on eBay locally to me I've been wondering if it could be persuaded to fit a 2000TC without major re-engineering. I now folk have fitted them to the V8 but can't remember hearing of anyone using one in a 4-cyl. Any thoughts?
 
Sowen has fitted one using an adapter plate on the 4 cylinder bellhousing and I think The Rovering Member has one too.
 
I know the club member who did TRM's box. He also did a Ford Type 9 conversion in a 4-cyl. Can you put you in touch with him if you like. He's an ex-AR/MGR engineer. He's not a forumite, but is very helpful.
PM me if you're interested.
Cheers

Michael
 
Thanks both, that's enough for me to drop in a bid or two. Prices seem to vary hugely depending how shiney they look in the photos, so it's anyone guess whether I'll get it or not.
 
Not an expert but the main reason for using an LT77 in the first place is that on the V8 it's a bolt-on with some jiggling on mountings and an auto propshaft and that it is actually man enough for the job.

In other circumstances, I'm not sure it would be many people's gearbox of choice. If you're talking adaptor plates and shortened props then something with better availability and change quality like a Ford or Toyota (BMW?) would surely be a more logical starting point. Must be loads of Sierra/granny boxes still about.

Another issue would be that the 5th gear is very "tall" - certainly in a 4 pot SD1 I had (yes it was me who owned that one), it was a bit of a struggle.

In fact I thought the gearbox was basically horrible TBH. I'm not a Ford fan at all but they really do get their manual boxes right, at least in the RWD days.

Perhaps a V8 diff (wider/taller tyres?) might drop the revs enough for modern motoring? That would be a much easier job.
 
PeterZRH said:
Not an expert but the main reason for using an LT77 in the first place is that on the V8 it's a bolt-on with some jiggling on mountings and an auto propshaft and that it is actually man enough for the job.

In other circumstances, I'm not sure it would be many people's gearbox of choice. If you're talking adaptor plates and shortened props then something with better availability and change quality like a Ford or Toyota (BMW?) would surely be a more logical starting point. Must be loads of Sierra/granny boxes still about.

Another issue would be that the 5th gear is very "tall" - certainly in a 4 pot SD1 I had (yes it was me who owned that one), it was a bit of a struggle.

In fact I thought the gearbox was basically horrible TBH. I'm not a Ford fan at all but they really do get their manual boxes right, at least in the RWD days.

Perhaps a V8 diff (wider/taller tyres?) might drop the revs enough for modern motoring? That would be a much easier job.
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In a 4 cylinder you only need an auto propshaft like on the V8 conversion, no custom one-off propshafts required as it bolts straight up. Also with a bit of jiggling the speedo cable also attaches, the only fabrication you need to do is cannibalise a 4 speed gearbox for the bellhousing, have it machined flat (I used a grinder) and cut a steel plate and drill some holes accurately. The gearlever needs adapting to move it forwards, plenty of ways round that one, and a new mount at the back, again not overly difficult. Biggest issue is they are physically too large to fit the tunnel without basic clearance modifications but again nothing really drastic.

Most LT77's are abused with inadequate oil, yet still work adequately as a gearbox. Decent oil, setting up the lever stops and fitting new selector bushes helps. Ford Type 9's are a lightweight 'box, perfectly adequate for 4 cylinder powered cars, but would need a custom propshaft to fit which can be expensive, and even less info on fitting them, though they should fit within a manual tunnel without modification.

I ran my 2000TC with the taller V8 ratio AND LT77 5 speed, never had any trouble with it pulling 5th from 40-50mph all the way through 70mph. If it can't pull 5th on a slight incline without burying the throttle then clearly there's something wrong with the engine.
 
I'd pretty much dismissed the Ford Type 9 option due to the prices they now fetch. Same appears to go for Toyota boxes too, which were never that plentiful in the UK.
Also I was thinking that an LT77 from a light car like the TR7 shouldn't have had too hard a life (this particular one claims 80,000 miles).
Thanks Simon, your description of the process is encouraging - I have plenty of old gearboxes to cannibalise for a bellhousing. You don't mention the input shaft - is this a straight fit then or just needs a different thrust bearing?
 
I have also considered this modification for years, but until now i just keep using the V8 diff.
Another important aspect of the replacement gearbox (at least for me...) is to keep it in the family, therefore making the LT77 the only choice. If you are going to compromise the originality, you should keep it moderate.
The standard gearbox with the higher final drive is fine with the current use of my TC (open road cruising) but the advantage of a 5 speed gearbox would make the car more rev happy and enjoyable in the intermediate gears.
 
Willy Eckerslyke said:
I'd pretty much dismissed the Ford Type 9 option due to the prices they now fetch. Same appears to go for Toyota boxes too, which were never that plentiful in the UK.
Also I was thinking that an LT77 from a light car like the TR7 shouldn't have had too hard a life (this particular one claims 80,000 miles).
Thanks Simon, your description of the process is encouraging - I have plenty of old gearboxes to cannibalise for a bellhousing. You don't mention the input shaft - is this a straight fit then or just needs a different thrust bearing?
Click to expand...

The spigot on the LT77 is much smaller than the P6, so a needle roller bearing can be bonded into the existing phosphor bronze bush. The clutch plate is an off the shelf item, I forget which one now but they're cheap and readily available. I think the gearlever sits about 2" further back, the original conversion modified the lever, but I shortened the remote assembly on mine. The adapter I made for the bellhousing to gearbox was 11mm thick, I think I found 10mm wasn't quite thick enough and it was binding against the crankshaft. I was quite savage with material removal on my tunnel, as I also pushed the engine further back into the bodyshell, but what I've read is it can be done just by hammering out the required clearance.

PeterZRH said:
clearly there's something wrong with the engine.
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An O-series :)
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I was referring to the 2000TC P6, but the O-series is a fine engine with the later twin cam head and a Garrett turbo hanging off the side :wink:
 
That is always something to be taken into consideration when selling. But it's also why you should work out what you will & will not pay for the item when buying & put your maximum bid in at the start. That way also saves you getting sniped (if your maximum is more than the snipe) & getting caught in the moment & paying more than you wanted to. We've all done it. :LOL:
 
Willy Eckerslyke said:
I was outbid. What sort of an idiot ends their eBay listing at 5pm on a weekday?
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Get a smart phone with the eBay app installed :shock:

I've never missed a sniping opportunity with it yet :p :p :p
 
What about getting an R380 from an LDV Pilot or something, much slicker gearchange than the LT77, and quite readily available on Ebay from breakers?
 
R380 next to a Borg Warner autobox





The R380 differs slightly from the LT77 externally, the gearchange selector is about an inch further back, and the lower tailshaft casing is larger with a steel plate bolted to the underside where the mounts attach. The LDV short remote sits practically on top of the selector, so would be further forward than the SD1/TR7 style long remote, though they are both interchangeable.
 

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