Need Help! 1977 20R motor? - Toyota Nation Forum : Toyota Car and Truck Forums

roliverii · 04-08-2009, 04:21 PM

Im building a race car with this motor in it, I have a 1977 celica gt 20R motor that only has 87000 miles on it and we are putting it in a racecar and cant get it to run right, about half of the vacuum lines are there and half are gone, so I need someone that knows these cars well and can tell me what lines I need and what can be capped off.. This will have no need for emissions of course, and I also have another 1981 Celica out back that we are using for parts..! And can part out if anyone needs anything.. If anyone can help me figure this out and get this thing running top notch that would be greatly appreciated.. Trying to keep a tight budget, but would like to know also what carbs maybe would replace that one and intake if needed, kinda want the easiest way to get this thing to perform without all these vacuum lines.. Its a nightmare, just want the basics?? Thanks...

stepho · 04-09-2009, 06:30 AM

You only need 2 vacuum lines - one for the brake booster and one for the distributor.
Both are normally taken from the inlet manifold.
All the rest are for emissions and cold starting and can be blocked off.

On the street many people use a Weber 32/36 downdraft with an adaptor plate.
I suppose a 38/38 would make more sense on the track.
A bigger budget would allow twin 45DCOE sidedrafts or single 48 DCOE sidedraft with a new manifold.

If the rules allow it, swap up to the 2400cc 22R but use the 20R head.
The 20R head has smaller combustion chambers which raises the compression ratio.

Invest in a good cam and fee flow exhaust.

Look around the www.lcengineering.com website.
You probably can't afford the really good stuff but they have plenty of ideas to keep in mind.

Look in the junk yards for a W55 gearbox from behind a 22R engine.
It is aluminium alloy (much lighter than the steel case W50) and will bolt straight up to a 20R.
Take care to get a version with the gear stick in the correct place (different version have the gear stick in different locations).

Which body are you using, the '77 Celica or something else?

- Stepho

roliverii · 04-09-2009, 02:55 PM

So if i go with these carbs or any other carbs, is there some other mods i need to do to make it all work better. Like ignition box, or distributor or anything like that.. Im not sure on the body, its not on the race car, we made our own car, and the body is sitting out back, and we also have a 1981 body and full car also.. ? If anyone is interested! Thanks for the help...

stepho · 04-12-2009, 03:34 AM

I think every version of the 20R already had an igniter, so no need to change that.
The 20R is a good solid engine with no real vices, leaving cam and exhaust as the main priorities.
And the usual stuff for any engine like checking the rings, spark plugs, timing, etc.

Disclosure: I've collected heaps of Toyota info and wield my own spanners but I'm not an engine builder, so my knowledge of racing the 20R is close to its limit.

- Stepho

roliverii · 04-13-2009, 09:16 AM

No thanks a lot for all your help, got the car running a lot better..! This is not a racecar on any series or anything, just one we are making cause we had these cars laying around.. So basically I just need to get this thing running right.. I have the car idling now, but still think there is a problem with the distributor or something cause it is not clean revving yet? Any suggestions would help.. Again thanks for the info..

DCM · 04-13-2009, 02:20 PM

The worst part of the 20R is the tiny stock carb. It sounds more like you have a fuel and timing problem than faulty distributor.

You could switch the distributor out for a 22R one. It's a better distributor, but you might have to swap the wiring plug to make it fit.

***IronNam*** · 04-13-2009, 03:31 PM

he can't use a 22RE right?

DCM · 04-13-2009, 04:00 PM

Distributor no, as it's electronic, unless you wanted to wire it in, but there would be no point to that.
As for using a 22RE, you could put it in but I would keep it carbed which would make it a 22R.

***IronNam*** · 04-13-2009, 04:20 PM

oh yeah, the rules..

Doesn't Ted from engnbldr specialize in the 20 and 22R's?

roliverii · 04-28-2009, 02:55 PM

Well we got it running better thanks to the answers. but still not right.. Rough running. Any suggestions, befroe we go out and buy a carb! Trying to keep it like it is and get it running!? The cheapest way for now!

stepho · 05-01-2009, 05:45 AM

Distributor timing (probably changed due to vacuum plumbing).
Cam timing (unlikely).
Make sure ALL vacuum leaks are sealed in the manifold.
Fuel filter not blocked.
Brake booster vacuum not leaky.

- Stepho