Cam upgrade

Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

In the not too distant future, i'm going to have a go at fitting an aftermarket cam for my G200. Has anyone here played with commercially availiable cams for their Gemini and had good results that they are very happy with ? At the moment i am looking at a Crow cam from their web-site part No.782507 It's a mild performance cam with a range of 2000rpm-6500rpm. At $264, i'd like to know if there is a cheaper alternative with the same specs and results.
The engine wont be wildly worked - mainly external bolt-ons and some match porting on both sides of the head and clean up and light port on the combustion ports.
I'm running a Trimatic (Traumatic), and would also like to know if an upgrade will affect the vacuum in the manifold enough to give the auto problems.
Has anyone played with torque convertors as well ? What were the results from it. I wouldn't want to go any higher than approx. 2200rpm stall, as this will greatly affect my streetability with overheating problems.
I know i'm probably gonna get hit by a barrage of 'get a manual hooked up' posts, but i can only do what the wallet permits at the moment so it's out of the question.
Cheers to anyone with some help & advice.
Jasyn...

Badger · tinkerer Joined: 13 Feb 2002 Posts: 155

surely it would be cheaper to do the manual conversion that change the cam!

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

I have used Crow bump stick in my turbo,
Also CAMTECH, they are quite good, but for a cheap cam for a near standard motor I cannot go past the Wade Cams Gemini regrinds for about $70 if your cam is ok, and they run well, I have changed a few, a cheap alternative, but you will have to change your carbi to a Weber to reap the best from them, otherwise you will have to much around with the vac secondaries,

cheers

Racegem · backyard mechanic Joined: 30 Jan 2002 Posts: 987

Hey Jasyn,
Firstly, (you guessed it) a manual conversion would probably be less than your camshaft! Have a look back through some of the 4 sale posts, you could probably even pick up a whole smashed manual car for that, complete with performance cam!! Kill two birds.....

Secondly, ask around about reground camshafts. Generally cheaper than new 'billet' ones.

Thirdly, If you have to keep the auto, 2000 rpm starting point for the cam is a bit high. The stall speed on the converter you're talking about would be fine for that cam, but what's your revs at cruzin' 60kph? If it's close to 2200rpm you'll always be cruising with the converter slipping.

My 2c,
Yonnee.

Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

O.k, well i've just been enlightened some what. I was under the impression that the TX had a few bug-bears when swapping from auto to manual. Does the floor-pan need the shit knocked out of it or should a manual tranny tunnel be welded in - excuse my ignorance, i'm a beginner at this.
I was assuming that a cam upgrade would cost approx. $200 max. if i did the instalation. Whereas a manual conversion would run me into the vicinity of $5-600 and alot of cursing and swearing,as i dont have the tools to rip the engine out for the swap. I have to admit that the idea of a manual conversion kinda scares me as i assume it's a very big job requring more knowledge than i have. Is it really as easy (and cheap) a job as you guy's are telling me ? How long would it take ? And what are the basics involved after i have bought a 5 speed, clutch, pedals, etc. ? Is there any tricks in hooking up the fluid resovoir - i'll probably be hung for that question ?
Any advive on this project would be great, i'm gonna start looking for the bits needed around this site.
Yonnee, could you get me a price on a heavy-duty clutch for the 5 speed as well, it would be appreciated. I kinda like to abuse my clutch like the next bloke.
O.k peoples, start throwing all the advice you can at me - i'm damn well gonna need it... : o )
Cheers,
Jasyn...

Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

I was just searching through the general chat past posts, and came across a dude doing the same thing as me with a TD. The advice in those posts should be enough to get me started.
So right now, i'll have to save towards a conversion. How much would this cost to have professionally done ? I dont have access to a block & tackle or an engine crane. I'm going to supply all that's needed as far as parts though.
This is what i meant by thinking the manual conversion would cost more... That cam upgrade is starting to sound good all of a sudden.
Yonnee, what was meant by convertor slippage ? Again excuse my ignorance. (ask me about a Nissan engine and i'm fine - these old school gemini's have got me learning all over again). : o )
If i retained the O.E torque convertor, should i have any dramas with the cam i mentioned ?
Cheers,
Jasyn...

Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

Also, after doing more searching on this site. Is it a relatively easy job to remove and replace the spigot bearing over without removing the engine ? This would make the job so much easier and quicker for me.

Racegem · backyard mechanic Joined: 30 Jan 2002 Posts: 987

SHEEESH you ask alot of questions at once!! lol

Firstly, the only mod to the tunnel should be an enlargement of the hole a bit further forward. Costs will be determined by what you can buy the parts for. By far the cheapest would be to buy a smashed manual wreck for as little as you can pay. This will give you all the parts you need, including some of the bits people have forgotten like screws for the manual centre console, etc. You'll even be able to make a template for the hole you need to enlarge.
The motor need not be removed for the exercise, just put the car up on jack stands or ramps. The box can be removed / installed from underneath. Geminis come with a cable operated clutch by the way,.....no fluid.

Torque converters have a "stall speed" built into them. It's primarily designed to allow the motor to idle without stalling while the vehicle is stationary. While the motor is running below the stall speed, it's is "slipping". It's a bit like driving at 60 kph with your foot just putting pressure on the clutch pedal. If your camshaft has an optimum range from say 2000rpm, and your factory converter has a stall speed of 1500rpm, the car will "bog down" off the line. Ever tried dropping the clutch to do a burnout with the motor revving at 1500rpm? With your auto, go out to the car, with your foot on the brake, gently rev the engine. Your stall speed will be about the point on your tacho that the car tries to launch a bit harder. Usually around 1500 for a standard Trimatic. Changing the converter to one with a higher stall, will allow the camshaft to be working in its range before the converter "locks up".

The auto won't have a spiggot bearing to remove, just purchase a new one and put it in. Might I suggest getting a Gregory's workshop manual. They will give you step-by-step instructions on removing the auto from the car, and re-installing the manual. You'll have to hurry, the TX one is out of print, my supplier had one left two weeks ago.

Hope I haven't missed anything.

Yonnee.

Woz · tinkerer Joined: 05 Oct 2001 Posts: 126

yon, i think when you say 'The auto won't have a spiggot bearing to remove' do you mean the thrust bearing for the clutch?? auto engines have a different bearing (spiggot bearing) that sits in the crank at the back, that the drive shaft from the gearbox sits in. auto's have a slightly different sized one. you need to remove the old one and chuck in a new one.

this is what ive discovered from the auto engine i have lying round out back; im only assuming that its the same through all autos.

feel free to correct me if im wrong Smile

-Woz

Racegem · backyard mechanic Joined: 30 Jan 2002 Posts: 987

Most autos I know of don't run a spiggot bearing in the crank because they bolt to the drive plate. If anything, some torque converters run a bulb shaped cap in the centre to help it centralise. Unless this cap has become dislodged in your crank??

Hey...correct me if IM wrong. Surprised

) All mine are manuals.

Yonnee.

Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

He he he, you sound just like teacher i had at an engineering course i did. He said the same thing after about my 2046th question.
Thanks for all the advice and info you've supplied, it's appreciated. I've been doing alot of searching on this site for answers to this conversion, and am a hell of alot more confident doing it myself than before. The wreck is a good idea that i never thought of, unfortunately i have nowhere to put it so i'll have to take a trailor and a tool-box to unbolt everything i want. It wont be for a few weeks until i can actually convert it as i'd rather pay for a quality clutch that will be up to my driving style.
Cam will have to wait for the future, once i'm getting bored with power & dropping the clutch at 5000rpm.
New thing i learnt today No. 16, Gemini has a cable operated clutch - not hydraulich.
I did have a Gregory's manual for the Gemini, but a mechanic that did a bodgy job decided he liked it more than i did. So i'll have to purchase a new one.
Converter info shone more light on the subject - thanks.
I should be pretty alright once i get started on the conversion. Good to know that help is only a dial up connection fee away.
Cheers,
Jasyn...