Attn 2TG Guru's info on 88262 head wanted. *now with pics*

[TheToyman75]

Here's a pic of the 88261 and 88262 pistons so you can see the difference in the piston Crown.



And the 88262 Casting.

[Augmon]

Hi to all of you Toyota fans.
Sorry to interrupt you, just want to show you some pictures that i found in the net.
http://www.koti.phnet.fi/crash/2TG/
There is a photo comparison of the 88262 & 88222 heads (and if i am correct and their pistons)

Hope i helped you
George.

[Turdinator]

So i took my head off yesterday and this is what we found...









Its definitely a 262 head. As you can see it has the unusual 'offset' combustion chambers. The piston tops look like they have been machined to suit, with a smaller dome than standard. I've had a few people offer me older heads since i started this thread but i see no reason to change since the car is quick and reliable with its current config. What do people reckon?

[jeffro ra28]

personally, i like the head you have got.
It will optimise your 'squish' alot better then the normal hemi design.

Just from a quick look id say it may also flow better then the standard hemi chambers.

[Turdinator]

personally, i like the head you have got.
It will optimise your 'squish' alot better then the normal hemi design.

Just from a quick look id say it may also flow better then the standard hemi chambers.

I did wonder about the squish area. I have only a basic understanding of it but i was under the impression that more was better? As for the flow, well the head is undergoing a reco process at the mo so i could get it flowed but the previous owner did what looks like backyard porting so it would not be representative of normal 262 heads.

Thanx for your input guys.

[Turdinator]

I found this on the net the other day. Its the newest chrysler hemi head. I believe the technical name for this type of combustion chamber is "polyspherical." Remarkable how similar a 70s toyota head and a 00s chrysler head look. The main difference i can see is the twin sparkplug in the chrysler.

[poida]

Useful info guys, now I just gotta check to see which head i have

[Turdinator]

Was just checking a thread on 5MGE rebuild and it apears they have the same chamber design. LINKY

Also had this said over on the http://www.classiccelicas.com.au where i've got the same thread going.

the high points in the chamber can cause cavitation so if the head were to be flowed better , they would be taken down anyway.
and if you put hich comp pistons in or turbo it to the max , the you may get detonation points from the sharp edjes..but if your just using it stock then it will be fine..
if you have to much time on your hands like i did when i was 18 lol
try clean out the chamber, place the head back on and run for 10 mins half hour or so(say go round the block hard) then take it off again, then you will notice black soot(cavitation marks)
grind them away and you will find it increases power dramatically. mainly at high revs,,

[jeffro ra28]

lol..........cavitation?

[GasedT18]

"cavitation" - doesn't he mean turdination?

[hks7mgt]

So are we saying the "ONLY" way to determine if you have a 88262 head (without pulling it off) is if the head is unmarked from the front and the cams are marked 88262?

If the head is unmarked and the cams are marked 88261 (with the '1' crossing out a 2) then the head is a cross genereational head with 261 internals. Right?

I was told today that the unmarked heads were a Toyota head, not a Yamaha, but these heads mentioned above are all stamped with Yamaha at the front. Could someone clear this myth?

I'll check what markings my cams have to see if its an unmarked 88262 or a unmarked 88261. Going from the talk about these heads with oval shaped combustion designs flowing better as 1600cc might be right as my factory engine (freshly rebuild) and then running ITBs flowed a shit load. If the cams show a 88262 stamp, then i'll post the dyno graph.

[TheToyman75]

ALL 2TG Heads were made by Yamaha.

The ports on the 262 heads are the same as the ports on the 261, 260 etc heads. They flow the same !

The combustion chamber is where the difference is.

[hks7mgt]

Thanks Rod. All clear about the manufacturer - i was under this impression as well, but was told differently by someone who should know better.

So regarding the identification between the unmarked 261 and 262 heads, is the only way to tell them apart is from the cam markings - or don't we have enough evidence to determine this apart from the head examined above???

[71TA22]

So regarding the identification between the unmarked 261 and 262 heads, is the only way to tell them apart is from the cam markings - or don't we have enough evidence to determine this apart from the head examined above???

You need to be careful with Toyota engines and their internals. There is no such thing as an unmarked 88261 head (unless it was a TRD special for a 100E code engine - but even this would be marked 11111-). Only 88262 heads were unmarked.

The cams and cam covers had changes which did not necessarily coincide with head casting changes. Its quite feasible to have an early 88262 head with 88261 cams just like early 88260 heads can have 88222 cams. 88260 heads can have single valve spring or twin valve spring set ups. Some 88261 heads got the same camcover as 88262 heads (with the raised but flat surface "DOHC" lettering).

The list goes on. A lot of these engines have also been molested for various reasons. Factory 88222 cams were best for torque at higher rpm while 88262 cams were best for torque at lower rpm. The cams could be swapped between all head castings. You could also find factory pistons at 9.8, 9.0, 8.8 and 8.4 C/R.

[hks7mgt]

Thanks 71TA22. I gotch-ya regarding no unmarked 88261 heads.
I've been doing more research and i found some great comparison photos from this post;

Hi to all of you Toyota fans.
Sorry to interrupt you, just want to show you some pictures that i found in the net.
http://www.koti.phnet.fi/crash/2TG/
There is a photo comparison of the 88262 & 88222 heads (and if i am correct and their pistons)

Hope i helped you
George.

That link points to a page that shows two heads, one being the 262 and the difference between them. These are the differences i noticed apart from the obvious oval combustion design so you can identify your 262 head appropriately from various pictures i gathered this afternoon;





The top picture shows the 88262 head and the bottom shows a 88260. I noticed these differences;
- there are no walls between the head bolts columns and the valves housings on the 262
- theres a (huge) opening on the front, under where the timing chain support is between the two cam sprockets on the 262





The above two pics (top one being the 88262 again), i noticed the following differences;
- right above the exhaust ports where the heads gets wider, the 262 has meat taken out where as the 260 is almost flat
- on the bottom of the exhaust ports, the 262 head has lots of meat taken away where as the 260 doesn't
- the thermostat housing on the 262 has more meat than it predecessor, especially behind the bottom bolt hole



Above are the two heads side by side with the 88262 on the left and a 88222 on the right;
- you can see the 262 has more meat under the thermostat housing as mentioned earlier
- the 262 has less meat around where the external chain tensioner bolts in

Plus the obvious differences with (as already mentioned) like the different combustion designs (not known unless you remove the head) and the cams being stamped 262, but even this might be misleading as they may have been changed.

I'm convinced my head/pistons is the one of the 88262 generation 2TG's now. I've been thinking more and i don't see the importance of showing my dyno sheet as its using ITBs not twin solexs so it won't show a good comparison. But fark does it have loads of torque.

I hope this can assist sorting out whether you have a 262 head or not without the need of pulling the head off. If any of this info is wrong, please mention it and i'll address it, but it's my findings anyhow... I hope the dude from the above mentioned link didn't mind me using some of his pictures for this post.