Topic: 20R Head on 22R (How's it help?)

[TrikeKid]

I searched and came up with nothing, but, how does running a 20R head improve the performace of a 22R? I've seen a few people with the swap, and D.O.A sells a 20/22R hybrid. I'm guessing it bumps up compression?

[yotaboy79]

it improves the flow of the incoming air fuel mixture where you realy start making the power is when you put over sized valves into the 20r head and then do some other motor work

[Rocksurfer]

it improves the flow of the incoming air fuel mixture where you realy start making the power is when you put over sized valves into the 20r head and then do some other motor work

I'll be moving along, no need to add anything here.

[Willy Mammoth]

I'll be moving along, no need to add anything here.

But, But we wanted to here what you have to say.     

[TrikeKid [OP]]

 Ok, so it's just a better flowing head after bigger valves are installed etc... Is it any better than putting bigger valves and porting a 22R head?

[Willy Mammoth]

I am guessing here, but I would say the combustion chambers are smaller on the 20R which will increase the compression some without having to change the pistons.

[Rocksurfer]

Ok, so it's just a better flowing head after bigger valves are installed etc... Is it any better than putting bigger valves and porting a 22R head?

No it has a better flow from the get-go, will increase compression and gets even better when you add the oversized valves, and a cam to go with it. Throw in a double roller timming chain and you now have a motor that is stronger than the original.
 




You happy now WM.

[kneedownnate]

No it has a better flow from the get-go, will increase compression and gets even better when you add the oversized valves, and a cam to go with it. Throw in a double roller timming chain and you now have a motor that is stronger than the original.
 You happy now WM.

Ditto!  Instead of your engine only making useful power up to about 5,000 rpm, you will now make useful power up to about 6,000 rpm, or even higher if you do more modifications.  I have an 81 22r block with a 76 celica 20r head, stock valvetrain and all, 4 into 1 header and weber 32/36 carb and it will gladly rev to about 6,000 rpm, whereas before it would stop making power at lK less.  The head design on the 20r is better.  You will not see a gain in the lower rpm, but will up higher.  Next time I will be using the biggest valves I can finagle in there, a mikuni cam, NWOR header, and possibly a holley 4bbl intake with a 390 carb, or fuel injection if I ever get around to making an adapter.

[79coyotefrg]

i actually did some measureing with some mineral spirits and the 20R has about a 10 cc smaller combustion chamber,

back me up Nate  i think a stock 22 has like 9.2-1 compression ratio,  the 20/22 has 9.7-9.8 to 1 and better flow,  the ideal thing is to put 22R valves in the 20 head

with oversize 22 valves in a 20 head, maybe shaved a little with arp bolts 38 weber or the 390 holly  1 5/8 headers with 2 1/2 pipe    the cops be lookin for your

[kneedownnate]

I think you're pretty well right on all the specs and such, but I thought the valves for the 2 heads have different length stems?  The guy that is gonna do my head work says he can't do the needed work to fit the bigger valves, but I kinda think he's just lazy!  My truck doesn't exactly rip right now, but once I build it up some it should atleast get out of it's own way.  And I'm a firm believer in having atleast 2.5" exhaust, that puppy hasta breath!

[Duffil]

a mikuni cam,

hmmm, Mikuni makes cams now

[kneedownnate]

Negative capn, mikuni made cams way back when!  I picked it up NOS off ebay last year, guy had purchased a whole bunch for different rigs from a warehouse that had then packed away somewhere!  Can't remember exactly how much, but I think I paid somewhere between $60 and 80?!  272 and .465?  Maybe I can dig up the specs somewhere.

[kneedownnate]

Well, I just went through my paypal records and couldn't find a transaction for the cam so I couldn't see if he had any more, but I did find out that I've spent WAY more than I ever would have expected through paypal/ebay!  I think 4.65 might be a little much too, just can't remember exactly what it was.

[jr9162]

Why does the 20R head breathe better? Can you say 'Hemi'?

Straighter ports and a plug in the center of the head. I was under the impression 22R valves fit a 20R head. Would really perform with EFI.... The larger valves will drop the cc's a little bit, but you'll still have a higher CR than with a 22R head.

[Duffil]

Why does the 20R head breathe better? Can you say 'Hemi'?

Straighter ports and a plug in the center of the head. I was under the impression 22R valves fit a 20R head. Would really perform with EFI.... The larger valves will drop the cc's a little bit, but you'll still have a higher CR than with a 22R head.

a 20R does not have the plug in the center of the head; its in the same location as a 22R.

[Rocksurfer]

20r is a hemispherical chamber and the plugs do come into the head from the side but do enter the chamber in the center at an angle. The term "Hemi" is a Chrysler trademark and refers to the head design being hemisperical.  This hemisperical design has nothing to do with where the spark plug or the valves are located.

[Duffil]

wasnt sayin its not a HS chamber(i know that it is), just that the plug ain't in the center.

[Rocksurfer]

wasnt sayin its not a HS chamber(i know that it is), just that the plug ain't in the center.

Guess you didn't get that I was agreeing with you. 

[79coyotefrg]

the 22 valves are like a mm shorter,  but its not a big deal,  i always spin seat valves anyway  and this gives you back a little of the length

[firekiller]

I have looked into this extensively, talk to Ted Stanwood at engnbldr.com, he'll clarify the whole hybrid motor myths and facts for you.  After my discussion with him I decided to stay with the 22R with a mild port and polish and oversized valves and his 268C cam.  Very happy with the result.

Tico

[kyle_22r]

a 20R head does not raise compression by any decent amount! the chamber is only a few CC smaller than the 22R open head.

i swapped one on my '82 22R bottom end, since the head was warped, and busted a valve guide(sick of fixing the thing).  i put an EB 268c cam in it, and engnbldr's oversized valves(end up just smaller than 22R valves but have correct rocker geometry).  also had the machine shop do a mild port job near the seats to get more benefit out of the valves.  then i put an offy C series intake on with a de-choked weber 32/36, and a thorley header.  with the correct jets, it really flies!

[79coyotefrg]

I have looked into this extensively, talk to Ted Stanwood at engnbldr.com, he'll clarify the whole hybrid motor myths and facts for you.  After my discussion with him I decided to stay with the 22R with a mild port and polish and oversized valves and his 268C cam.  Very happy with the result.

Tico

you can put a STOCK 20R head on a STOCK 22R block  and gain 20HP  i know because i have doen that,  no other mods  , just put the 20 on the 22 and went  if you dont beleive it  thats great  ,  eat my dust