2TG Rocker Cover Guide - With Pics

[sillycar chick]

pm sent

[AE25]

The 2TGEU 88262 Rocker Cover had "Toyota DOHC" on it and the DOHC was not with raised edges

this is a new one on me! the larger 'toyota dohc' has raised lettering

The oil cap surround in the just "Toyota" cam cover have a rubber seal, whilst the cam cover with "Toyota DOHC" non raised edges don't, it's just a flat surface.

to clarify this further: a steel oil cap has an oring seal including the small 'toyota dohc'. the plastic oil cap doesn't (large 'toyota dohc' cover)



another pic of 151E
edited: oops (18rg version)

[w810sc]

i think that pic above is the 16 valve 18R-G (or is was based on it), i say this because the valve cover has 2 bolt holes at the front whilst the 16 valve 2T-G has only one.

16 valve head pics:



fonz

[TheToyman75]

i think that pic above is the 16 valve 18R-G (or is was based on it), i say this because the valve cover has 2 bolt holes at the front whilst the 16 valve 2T-G has only one.

16 valve head pics:



fonz

Nicely Spotted Fonzy. Love that last pic of the 151 head. The Part number still on the label should be enough to quell any arguments 11151-09511

[MorGo]

That must be the T-variant.R-engines don't need be so wide to cover pushrod holes.Remember,T is pushrod originally and blocks didn't change when going to twin-cam.

[hosking1991]

old thread i know but wow is all i can say about that 16v head! the raised/angled intake ports are beautiful and so ahead of its time,

luke

[TheToyman75]

Wow, talk about a thread revival. I forgot about this one. And yes the 151 was a pretty serious engine for its day.

[MorGo]

I think that both the 2T-G/18R-G twin plug heads were failures.Few of them exist and do they win?
If they were good design there will be more of them.
In here very experienced racer tried to run 8-plug 18R-G.No good.The valve size and especially the port size just was too big.Maybe if revved up to 10 000 they could work.
Even in turbo.3000 cc block and they might be player.
I think that same design mistake was done with the 2T-G 8-plug.
Huge port flow doesn't mean huge power.. There is a thing called flow speed..

[71TA22]

MorGo,

I suggest that the 18RG and 2TG were good heads for their type (impressive formula 3 history for 2TG for instance).

One of their issues was not enough valve area for port area - answered by 16 valve 151 and 152 heads.

The other issue was port inclination as they were both true side draft engines which tend to have poorer fuel/air mix distribution to the short side of the intake port at the valve (did they really need round heads on the intake valves?) - answered by the more down draft inclined intakes on the 151 and 152 engines.

Cant answer the twin spark 18RG and 2TG statement but if they are considered as part of a development program the 4TGT that resulted was not a failure - all they were missing was the turbo and perhaps fuel injection.

[J-M kujala]

I think that both the 2T-G/18R-G twin plug heads were failures.Few of them exist and do they win?
If they were good design there will be more of them.
In here very experienced racer tried to run 8-plug 18R-G.No good.The valve size and especially the port size just was too big.Maybe if revved up to 10 000 they could work.
Even in turbo.3000 cc block and they might be player.
I think that same design mistake was done with the 2T-G 8-plug.
Huge port flow doesn't mean huge power.. There is a thing called flow speed..

Old thread but something.. Im really interested at these Green racing celicas and have been try to found info to my own answers but damn didnt archive them better than to my brains

Mostly twinspark 2TG / 18RG was used with Turbo, without cooler. Maybe afterward modified & used as N/A ?

18RG twinspark turbo got 1 overall win in Fuji 1000km race in 1973. There was prototype cars also. Also video from race found in youtube (&prepare&practise)

Interested thing was there was no class told (like grp 2/4) just like other N/A celicas got.
Maybe in same class with protypes ? Or open class? Info is missing.

Second interested thing was, race is driven 29.7.1973 and twinspark engines are homolocated 1.10.73 !!!

Turbo wasnt used anymore in 1974, they homolocated 151E 16v engine in 1974 And use that. Turbo became illegal ?



But yes, 18RG twinspark intake port is to big, i am not man to say if its too big with 10 000 rpm with hot air and low compression.

2TG twinspark port is someting ~39mm from flange and valve i think is ~near stock, bcz stock valve location and combustion chamber size.

Lap times & measured top speeds also found from the web (in japanese)

[steveh]

Just seeking some info regarding:
"The 11111-88222 Rocker cover did not have "1600" on it. It had its EGR valve mounted there so only had "Toyota" on the left Hand Side"

I am not up with the technical aspects of engines and wanting to know if it should be fitted. I have briefly read up on the purpose of the valve so no need to go there.
My restore has some way to go yet but whatever I can accomplish along the way I am doing, hence seeking some information.
I found the following from a forum thread of 2007, so perhaps the valve has simply been removed:

"dont worry about the egr alot of people block them off anyway all they do is use exhaust gases to heatup the motor and most carbon up and dont work anyway
i myself would block it off and make it look like it works

My cover had a filter connected to its vent pipe and having sought out what this filter was there for, I noticed that another option is to use a hose from the vent to the carb's? The benefit in this option being that not having to periodically clean/replace the filter.

Is there any general consensus if it is better for the EGR valve to be fitted, and the use of filter vs hose for the oil gases?

Steve

[sleeektoy]

Correct 222 setup on my TA27

The EGR valve has nothing to do with the breather in the cover - the breather it vents back through the carbs via a pipe on the airbox
The EGR valve opens when the key is switched off and allows fresh air into the inlet manifold to prevent run-on with crappy fuels

[steveh]

Thanks sleeektoy.
A picture and your comments helps me greatly.
I worked out that the EGR was nothing to do with the cover breather but I can see how I confused the two in the post.
Hoping I may draw on your knowledge a little further. The setup the car came with has a Redline air filter on each of the Mikuni's, I see you have what I'm guessing is an original air box assembly.
Is it still possible to fit an EGR given the difference in the air filter setups?
Similarly the cover breather given it connects to the airbox - perhaps this is why mine doesn't have both of these fitted.

Regards, Steve

[sleeektoy]

It is still possible to have an EGR without the airbox - if no hose fitted it just sucks unfiltered air into the engine - not ideal.
A small air filter could be fitted to the inlet port of the EGR. Or some aftermarket carb air filters have optional blanked holes on the back plates that can have fittings added for hoses to be run to.
The same deal for the breather -it can be run back to the air filters with a fitting on the back if available - or a filter/catch can could be put on there.
A filter fitted on the breather inevitably means some fumes in the car and oil spatter on the top of the cam cover

If you do fit the EGR.. be mindful it is OPEN unless it has power.. the engine will not run(or very badly) unless the lead has power to it and the earth lead is working. 4 hours of being stranded scratching my head why suddenly my engine wouldn't run ended with me plugging that wire back in

[steveh]

I'm glad I asked you the question!
I would like to pm you tomorrow so as not to divert the thread from its purpose.
Would that be ok with you?

Steve