comparing 2T and 2T-G standard pistons

[w810sc]

Hi,
i did a search but could not find any info on these pistons so here is what i have.
I am rebuilding a 2T and a 2T-G(222 head) /3T hybrid. here are the pistons i have found in both of my motors:







for starters the piston on the left is from the 2T-G, and the piston on the right is from the 2T. On the 2T pistons it has "2T" written on the left hand side, whilst on the 2T-G it has "ART" written on the left hand side. I would like to know more info about these pistons, like if they are standard and what are the little holes on the sides purpose.

I also have another 2T with different pistons in it. On the top face it has engraved "RA2599A 1,ou. I havent taken this piston out yet, just removed the head.

sorry for the low quality photos. Any suggestions and info appreciated.
fonzy

[merc-blue]

2t, 2tg, 3t, 3tg etc all have different pistons

2t and 3t are off the shelf for bursons sorta items (main difference is the pin height)
But for a twin cam have about 2mm bigger valves stock so you need to have the valve recesses cut out
For a 3TG you will want 3T pistons (different pin height) with valve recesses cut out

[w810sc]

hi,
thanks for the info, I also have these performance pistons for 2T-G:

but these pistons will not suit 2T-G/3T hybrid motor correct.

fonzy

[merc-blue]

pretty sure they wont becasue of the different pin height but wait for someone else to confirm

[Rinmax]

I'll confirm that. The 2TG pistons wont work in a hybrid.

Easiest way about it is to have a set of 3T piston cut for the valve clearance.

As merc-blue says, its the pin height that is differant as the 3T crank has a longer stroke.

[shelldrake]

You could potentially use those pistons with the 2t crank though. You would then have the 1750cc capacity, with the short stroke (fast revving) crank. (I like this idea)

If you are intent on doing a hybrid, you should get some 88.5 mm forgies with the pin height for the 3t crank. This will give you a capacity of around 2000cc.

[TheToyman75]

You could potentially use those pistons with the 2t crank though. You would then have the 1750cc capacity, with the short stroke (fast revving) crank. (I like this idea)

Fast reving ? Have you driven both ?? I know in theory the longer the stroke the slower the Revs (No arguement at all ) BUT in practice the extra torque you get from the increased capacity of the Hybrid more than compensates for the extra stroke. A 2TG with cams and some decent comp is a fun engine but no comparison to the same engine package with a 3T crank.

The extra capacity just makes everything nicer and more responsive. If you were really stressed about the increase in stroke get a lightened flywheel to cancel out the increase in mass of the rotating assembly.

[shelldrake]

Toyman,

hybrid with a 3t crank and 3t pistons = approx. 1800cc

2t with 88.5 pistons and stock crank = approx. 1750cc (as stated on his piston box too)

If I were in his position I would go with with the 88.5 mm pistons with his 2t block and crank. This means that he doesn't need to worry about clearancing his block (if not a late model 2tg) for the 3 t crank, obtaining said crank, rods and pistons, then flycutting the pistons to suit.

Saying this, the hybrid would in theory have more low down torque, while the 88.5 option should be happier to rev higher.

*For reference I have the hybrid option. I have not driven a 2tg with comparible specs. But if someone has some dyno results. Pull them out now...

[SeptemberSquall]

Eddie, my last 2T-G was 88.5mm pistons, 288/288 duration cams with 2T crank and 40mm Solex carbs.
Needed some stick to really perform, yes.

[shelldrake]

Eddie, my last 2T-G was 88.5mm pistons, 288/288 duration cams with 2T crank and 40mm Solex carbs.
Needed some stick to really perform, yes.

Fair nuff! The proof lies in the facts.

[w810sc]

there are some valuable info here fellas, keep up the good work. As feed back I understand:
- going the hybrid setup will require more work than fitting the 2T-G 1750cc pistons in increasing capacity.
- going the hybrid setup will increase torque; the saying goes "theres no replacement for displacement"
- the 2T plus 1750cc pistons will allow a higher rev range.
is there anything else i need to look out for.

fonzy

[merc-blue]

I wouldnt say it will allow a higher rev range, that would depend on the cams, weight and balance of the engine

As it stands if you have a 2T-G it is much easier just to do a rebuilt VS a hybrid build.
not only do you need the parts but there is also a possibility (depending on your block) that you need to machine the block to allow for the 3T chank to clear the block

[TheToyman75]

The rev limit wil be the same on both engines, Its the rotating components that limit your RPM. The cams you choose will dictate how close you need to push it towards rev limit. If you get carried away you can always use a crank Girdle and push it well off the Tacho.

Shelldrake, The comparison I stated below was for the same engine with a 3T crank ie, a 88.5mm 2TG or an 88.5mm 2/3TG. The extra cubes will always win out.

I have never driven an 88.5mm bore 2TG. I have driven quite a few 2TG's and 2/3TG's, most of them in cars I owned. I had had quite a few combinations but it was only the last build that gave me some direct comparisons. I spent allot of coin on my last 2TG trying to get a budget performer. It started as just a built 2TG with head work and cams and the rebuilt carbies.

The second stage was to fit the 3T Crank. It was a massive improvement, not only did the extra cc's give it more low down torque but it came on cam sooner and pulled like a 13 year old boy from around 3000RPM as opposed to 4500RPM.

When you look at the rebuilding prices there is very little difference. Both need gaskets, bearings and machine work/balancing. Typically both will need new pistons and cast items will do the job just fine in 99% of applications. You need to ad the cost of flycuttng a set of 3T pistons if you use them but thats minimal (Get your engine balancer to do it )

So all your looking at is the cost of a 3T crank - cheap from a T18 or around $80 - $200 for a forged 3T-GTE item if you can get one.

So for $100 - $250 more you may as well build the stroker

[river]

Hi,

Can't you do both and get the 2TG stroked and bored, which will get it up to around 1950cc?

seeyuzz
river

[TheToyman75]

Hi,

Can't you do both and get the 2TG stroked and bored, which will get it up to around 1950cc?

seeyuzz
river

Thats always the ideal mate A nice high comp stroked and bored 4A-GE and 18R-G eater