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Who runs an re83 cam?
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Author:  coopar [ Mon Oct 28, 2013 6:06 pm ]
Post subject:  Who runs an re83 cam?
Im wondering what engine specs and what carb people are running?
I have a 1380 running a 45 weber.
It has recently been tuned and i'm running it in.

I'm finding that wow, the motor really has a whole bunch of nothing below 3k rpm.
It really has to be revved to get going. I originally specced it as I wanted a good low down cam, didnt really expect as little below 3k.

Whats everyone else's take on the re83?
Author:  michaelb [ Mon Oct 28, 2013 7:42 pm ]
Post subject:  Re: Who runs an re83 cam?
Not really sure what version RE? is in my Cooper S but my cam comes on strong from about 2500.
1310 with twin 1 1/2" SU's. Will potter along below this but no real power till it hits the 2000-2500.
3000 does sound a bit high.
Author:  Morris 1100 [ Mon Oct 28, 2013 7:46 pm ]
Post subject:  Re: Who runs an re83 cam?
I'm running an RE83 in my 1368 with twin SUs and I was having the same sort of problems as you.
After a lot of mucking around I eventually worked out it was the advance mechanism sticking in the distributor (Hitachi), now it pulls from low revs quite well.

Now I love it.
Author:  cranky [ Mon Oct 28, 2013 8:32 pm ]
Post subject:  Re: Who runs an re83 cam?
Don't know nuthin about GR's cams, but lots of people like them. I ran a 1380 with an STR930 (basically a Piper 649 copy and the required cam for Mini Miglia in UK), for 20 years, and with careful attention to jetting the 45 weber and timing, could cruise in top at 2500 on a 3.4 diff - would pull from 1500 with foot to the floor in 1st and second. The key is the idle/off idle/low speed transition - needs to be a bit lean, then a bit rich to avoid the hole, then leaning out a little into to main circuit. Suggest you beg/borrow a heap of jets and aircorrectors, buy a Sutton pin vice set (basically a pen that holds teeny weeny drill bits) and get a little soldering kit - then you only have to spend a few weekends changing out/drilling/soldering/changing in about 50 squillion combinations of tiny fiddly $*!@@@ little brass pieces to get it somewhere close to right - but when you do.....lordy lordy!

(or take it to a rolling dyno that knows minis)

Common mistake is using chokes (main venturi) that are too big - i started on 36s, bought 40s cos' bigger has gotta be better, right? Wrong - air speed drops and signal strength in the aux venturis is weak. Fine over 6000, but if you live in the real world, performance and torque between 2000 and 6000 gets the job done. Came back to 38s. Also tried bigger auxiliaries and pump jets - same dumb theory, same disappointing result. Tried idles from 40-65, mains from 145 to 215 (yeah, there was a manifold leak), correctors from 140 -210.

Wound up with Main Vent (38), Aux vent (3.5) Pump bleed 50, long stroke pump rod, idles 60F9, one 0.5 hole in each throttle plate for better idle/signal strength (new webers have an additional adjustable airbleed and 4 transition holes), main jets 185, correctors 210 and 60 pump jets. A proper in cab air/fuel meter is a revelation, and even good rolling road guys can't quite replicate actual driving conditions, eg sitting in a traffic jam for 20 mins.

My advice - start with mains at 150, correctors at 170, venturi as above, and put time and effort into timing the cam properly - get the rocker clearance right, the plug heat (ngk bp6es) and gap right FOR YOUR MOTOR! Every engine is different. there is no guaranteed formula - patience, perserverance, and pizza will get you there eventually. Work it slowly richer. Or start too rich and work down - keep notes. Don't sustain high revs until you 'feel' the engine wants to. Watch the temperature - steady increase and overheating/pinging often means timing retarded/mixture too lean/plugs too hot, low engine temp and 'doughy' engine/blue smoke can mean too rich/timing too advanced. Red and blue lights in your mirrors probably mean you've got it right and wrong at the same time....

Stick with it - its easy to bolt on bits, but chances are you have created your own unique little combination, and it's gonna take time to figure out what it needs. Bon chance!
Author:  drmini in aust [ Mon Oct 28, 2013 8:44 pm ]
Post subject:  Re: Who runs an re83 cam?
I run an RE282 (much bigger duration than an RE83) in the 1360, with a 45 Dellorto and 36mm chokes in it.
It will pull from 40kmh in 4th gear at part throttle without snatching, and take full throttle from 2500 up. And @ 5000 in 1st gear the A008s spin on the road and it surges to 8000 if I let it.

I am running lots of advance due to the bathtubbed head (20°BTDC static, 38°BTDC @3500 up). With a stock chamber shape head I would knock that timing back to 12°/30° approx.
Check your timing and carby jetting. The best thing I did was buy an Innovate A/F ratio meter to jet it right. :P
Author:  simon k [ Mon Oct 28, 2013 9:09 pm ]
Post subject:  Re: Who runs an re83 cam?
there's something wrong with your setup - I ran an RE83 with twin 1.5" SUs and low down pulling torque was awesome. I had an RE13 in it, and swapped it for the 83 because I wanted more low-down and I rarely use more than 6500rpm - definitely more how I wanted it.

I'm using the same RE83 cam with a blower on it now, lovely torques

I'd suggest your chokes are too big too, just not enough port velocity
Author:  Lillee [ Tue Oct 29, 2013 9:20 am ]
Post subject:  Re: Who runs an re83 cam?
Check your carburetor settings as per what Simon is saying. Get an AF meter on it and see if it's running too rich.
Author:  coopar [ Tue Oct 29, 2013 12:33 pm ]
Post subject:  Re: Who runs an re83 cam?
Cheers for the advice guys.
It's been to a carb bloke in Melb that has a dyno to tune it.
It's been there twice and he reckons he had it right.
I'm assuming he jetted and choked it correctly.
Maybe the timing is a bit out. Do people recommend advancing it a little to see what happens?

I currently run this powerspark distributor:
http://www.ebay.co.uk/itm/45D-Electroni ... 53f09b433d

This was purchased because I believed it didn't need/have vacuum advance and also didn't need its curve modified?
I may be wrong.
Author:  drmini in aust [ Tue Oct 29, 2013 1:05 pm ]
Post subject:  Re: Who runs an re83 cam?
Do you know what advance curve it has? You want the advance plate in the dizzy to have no more than 10° range (dizzy degrees) and 8 or 9° works fine.
If there is too much advance in the dizzy, and you set the max timing to 30° @ 3500 up, when you then look at the static figure it will be at or near TDC = poor torque with sports cams + unleaded 98 fuel.
I also reckon your 38mm chokes are too big for civilized traffic running. I had 38s and went back to 36s. Top end is still bloody good (in mine).
Author:  simon k [ Tue Oct 29, 2013 2:02 pm ]
Post subject:  Re: Who runs an re83 cam?
To do what Dr Mini says, mark the distributor where it is, and turn it anti-clockwise 2-3mm to retard the timing. Tighten it up and go for a drive, see what it's like.

coopar wrote:
It's been to a carb bloke in Melb that has a dyno to tune it.
It's been there twice and he reckons he had it right.
I'm assuming he jetted and choked it correctly.


but what has he tuned it to do? has he tuned it to make oodles of power at high RPM, or has he tuned it to provide a nice wide torque band?

Do you have a dyno graph printout?

RE83 is a low revving torquey cam, it doesn't make useful power over ~6300rpm, and whoever tunes it needs to keep that in mind. If I was you, I'd pick up the phone and ring GR, spend 10 minutes on the phone - then take whatever advice he gives you. It'd be handy when you ring him to have the numbers for your chokes, jets etc. written down so you can tell him exactly whats been done.

Also, was the cam timing done properly? RE83's need to be at 105.5 degrees.... dunno how much difference it makes on a 1275 because I always set mine up where GR tells me to, but I fiddled with a mates 1100 and timed it at 106 degrees, then moved it to ~112 degrees and picked up a lot of torque (retarded cam timing is something that 1100's like, 1275's are different).
Author:  Lillee [ Tue Oct 29, 2013 4:15 pm ]
Post subject:  Re: Who runs an re83 cam?
Sort the timing out, and if it's still bad, then it's definitely the 38mm chokes.

I tried 38mm and from memory it lost about 7ftlbs throughout the rev range, and torque only came on at 3500rpm and I am running an RE13 which is supposed to be more aggressive than RE83. But running 36mm still gave me 120bhp, 100ft/lbs so never looked back. I reckon Kev is running about 130bhp on 36mm chokes so I don't see the point of running 38mm chokes for road cars...

Smaller choke = faster air = more torque. Too small, loss of power. Too big, loss of air speed. Yes 2mm diameter makes a big difference.

Having driven a car with RE83, it is far more tame than RE13 but torque comes on much quicker and is still a perky cam. Since my torque comes on at 2700rpm on RE13 and under that it's still plenty drivable, I think you have a problem < my scientific deduction lol
Author:  kiwiinwgtn [ Tue Oct 29, 2013 6:36 pm ]
Post subject:  Re: Who runs an re83 cam?
Send GR you distributor to check and graph to his cam spec, there is no way you can just buy a dizzy of the shelf for your cam / engine spec.
Author:  coopar [ Tue Oct 29, 2013 7:07 pm ]
Post subject:  Re: Who runs an re83 cam?
Thanks guys, plenty to try.

simon k wrote:
coopar wrote:
It's been to a carb bloke in Melb that has a dyno to tune it.
It's been there twice and he reckons he had it right.
I'm assuming he jetted and choked it correctly.


but what has he tuned it to do? has he tuned it to make oodles of power at high RPM, or has he tuned it to provide a nice wide torque band?



Mmmm wondering myself.
I took it to him before I ran it in so he could time it and get it running properly so I could do all the running in.
It seemed strange that he didnt ask much about the motor, specs wise.
I figured he would tune it on the dyno so it ran and idled fine, and then pulled out to higher revs with no troubles.
Too new to it on my behalf probably.
Author:  coopar [ Tue Oct 29, 2013 7:09 pm ]
Post subject:  Re: Who runs an re83 cam?
kiwiinwgtn wrote:
Send GR you distributor to check and graph to his cam spec, there is no way you can just buy a dizzy of the shelf for your cam / engine spec.


Might have to be the end result. I'll see what GR says.
Author:  Morris 1100 [ Tue Oct 29, 2013 7:35 pm ]
Post subject:  Re: Who runs an re83 cam?
Try a different distributor (like a stock one) and see if it alters things. You will know if you are on the right track one way or another.

When my car was mucking up I tried a Cooper S dizzy and found the missing low down power. I knew then it wasn't a fuelling problem!
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