Hi all

My Gt motor needs a rebuild after using 1 lt of oil in 60kms of open road driving

I wanted to put a different camshaft in it and was thinking of the classic 731 cam.

I have also heard that the RE83 is very good and rang GR and had a chat about it. He told me it eats a 731 and will rev to 6000-6500 (this low rev limit doesnt bother me- as it is mainly used for round town.)

No offence to GR, but I was after an independent opinion (somebody whose not making a quid from them )

So i was wanting to know from those who are using the cam their opinions and ESPECIALLY!! those who have also used the 731 (people like the Doc) who can give me a comparison of the two


NOTE!!

my motor will have the standard 1 1/4 twin carbs and standard head. Motor will have probabaly a 40thou overbore (due to the large lip in the bore) and i will get the flywheel machined to lighten it

Thanks Brenton

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I used a 731 for years. any modern cam would kill it.
An RE83 will give much better power, from idle up to 6500, and the 731 wasn't much good past there anyway.

The problem with the 731 was loss of bottom end torque with not much top end gain.. As Vizard said.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

In my opinion (Knowing that this thread is aimed at attaining refrences for the RE83) is that, the 731 is good in a big donk (1380 & upward) for std-ish road use,,, IE: in such a big donk it "acts" like a std cam does in a smaller engine, but with obviously way more grunt than a styd engine because of it`s sheer size,,, but it suits the ""ROad" use Application quite well in a large donk--> Drive around everywhere in top gear sort of thing

I have no experience with (nor have i even seen or "felt with my fingers) an RE83 so i can`t comment , nor compare, sorry

But for a small donk a 731 is ,,, (how should i say this? ) --> a "Niffty" little cam nothing flash, but "Niffty"... "Towy" (when set-up correctly in a good """"Packager""",,, almost sweet actually, but definately not angry by any means

Now that i`ve said all that,,, i`d like to try an RE83 in a few different donks:-)

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I would prefer a Wade 240 , Waggot 509 or Kent 274

but you might like the Wade 121, the Goblins page says

"Excellent performance, low lift. Recessing block for valves not necessary"

valve overlap- 81
Cam Lift-0.276
Valve Lift-0.351
Inlet Open-40
Inlet Close-77
Exhaust Open-75
Exhaust Close-41
Inlet Period-297
Exhaust Period-296
Valve Clearance-0.012
.

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I have the 1098 +.060 but have had the Standard Cam..then to a 731 then up to a RE13. 731 cam was Okay but I do love the RE13. My motor which I'm just running in now has the RE83 as I still like the lumpy sound and i wanted the power on sooner. Added to the correct diff ratio this time it feels much better even with the engine still tight

I can give you a better description for a 1098 with the RE83 shortly

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Stop Licking the Dog...I Don't Care Who Started It

I would go with the wade 240. I just did a moke for a bloke on the west coast of SA and re-built his 1100 engine. The engine was only .040" O/S and fitted with one of my big v/v 202 heads. The exhausts are 29mm dia and the block did not need relief, the inlets are 33mm and fitted with double progressive rate springs. Fitted with a pair of 1 1/2" kei hin bike carbs for testing.
As this bloke does a lot of highway cruising I fitted a 3.7 diff with the 13" wheels.
The wade cam has heaps of low down torque,not too lumpy and a couple of times I pushed the engine up to 7000 + revs and it pulled that high diff easily. It pulled in 4th gear from 2000 revs up to 5000 with no problems at all.
Just do not get some lumpy cam that makes daily driving a pain in the arse.

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

Just be a little cautious when comparing any 'factory' grind these days. It is unlikely that you would get your hands on a geunine BMC / Leyland 731 these days, so the ones kicking about are someones elses copy of these original cams. They are rarely exact copies, not that I'm saying they are worse or better, just that they are unlikely to be the exact same profile as the factory produced, so comparing - by others experience - a '731' to to what ever can produce widely varying opinions.


I won't say if these copies are better or worse than the factory profiles, but the reason I raise this is that one 731 may not be the same as the next 731.

This would apply to all cams of the same basic timing figures but from one grinder to another.

Brenton, I know that you posted this hoping for a straight answer and my post here has most likely tipped a bucket of grey paint over all that, but comparing one cam to another is not that straight forward unless you try different cams in the same engine - back to back - as engine spec also plays an extremely crutial role here.

A tip when trying 'lumpy' cams for road use (or any cam for any use for that matter) is to cautiously play around with how the cam is timed to the crank angle. An adjustment of as little as 2 degrees can 'tame' a wild cam and still give results that you are looking for.

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You mean GR actually makes money from what he does?
I thought he was doing it for the love?

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

I have used the RE83 for the last 12 months and thoroughly enjoy it, the torque is great.

I had my 1310 rebuit at the Mini King in Adelaide. He assured me he was putting in a nice cam. It turns out that he put the 731 cam in. This is probably the worst cam ive had in a mini. All the torque that my engine should have is gone. Yeah i admit top end is good but whats the point of that for the road. this is a good cam if you want to totter around like a nanna. As soon as i have the dollars and the time to get the engine out i will be swapping this cam.

It sounds like your cam timing is retarded, could be at less than optimum setting at assembly or worn timing gears / chain.

Try advancing the Cam Timing a few degrees (say 2 to 4 to start with) and you might be plesantly surprised. If it's at say 110 full inlet lift ATDC, try it at say 106 degrees. You will also need to reset your ignition timing.

This is all quite easily done with the engine in the car of course.

Only alter the timing in small amounts, if your going to try different timings and don't go too far. If you get to say 98 or 100 degrees and it still ain't no good, then look at another cam. Going more than that, you need to be sure the inlet valves are not trying to kiss the pistons.

A 'lumpy' cam I was running recently in one of the fleet I actually had timed at 93 degrees. When 'off' the cam, it has still torquey enough to drive around the street in relitive comfort, but still 'pulled like a train' to beyond 7000 RPM.

BTW, what it the static C/R of your engine?

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I would have imagined that Mini King who have been in the business for 40ys would have got my cam timing right, but ill give it a crack

Thanks carl

Well i can only offer a biased opinion. I have not been in a mini with the RE83 but i have the 731 in my current engine.

from my own research of this subject, the 731 cam is a very old design spec and the RE83 is a much younger spec. This means the development of its ability to derive power from your engine is better.

I have a 1098 bored to 1220, STD 12G295 head, pulsar distributor, 10:1 compression and a 45DCOE weber, LCB's with RC40 and with the 731 cam dialed in at 107 ATDC. this engine recently made 60 HP at the wheels (uncorrected) and i have to say it is quite torquey for its capacity.

it pulls hard from 2500-6000 and although it has a little lump at idle, it is still quite smooth compared to some engines i have seen and heard with non-standard cams.

as a few people have stated, the setup of the cam timing and ignition timing all contribute to how the engine makes its power from what you have. i also heard many stories of the 731 being a crap cam, and stories about it being a fantastic cam from guys who used the 731 cams in race engines for years and years, but at the end of the day, it comes down to what you want from it, how much you want to spend, and how it is all setup when you fit it.

in saying that, i almost binned my cam during my engine build and bought one of GR's, an RE13 or RE83, but for me it came down to cost, and i already had the 731 cam and it was in good condition.

good luck

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'66 BRG Morris Mini Deluxe 60HP ATW

I ran a genuine 731 in my 1293 Mk1 S in the early '70s when I was doing a lot of interstate driving. It was alright, easy to drive, but no ball of fire.

I then went 1310 Mk2 S with a Wade 1760 which was a fireball but a bit of a handful in Melbourne traffic. After a while I swapped it for 240 which proved to be the best of both worlds.

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Slide
1965 Mini Van (1360)
1970 Mk2 Cooper S (1310)
1978 Rover SD1 V8 (4.6)
1996 Land Rover Discovery V8 (4.0)

I am currently rebuilding my 1275 and I think the cam I have for it might be a bit of a waste.
It is a Wade 176 profile.
Timing EX - 46-75
IN - 75-45
Valve lift EX - .376
IN - .378
Duration 244

It says it is for competition and I don't know how it will go driving around town.
Has anyone else got a cam this size they are using on their daily drive Mini?

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76 1275 Leyland S