 How hard would it be, and what's involved?, Retrofitting 75/76 engine to 73/74 specs |
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| Carlitos Way |
 Aug 25 2005, 06:37 PM
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I did it MY WAY  Group: Members Posts: 1,337 Joined: 14-September 04 From: Simi Valley, CA Member No.: 2,757 Region Association: Southern California  |
Well, I may have an angle on a 75 (stock, CA) engine coming my way. Wondering if this might be the best solution for me. I believe the 75 has more smog crap and stuff, which results in lower performance.
What can I do to "restore" it to a 73/74 condition/power? As always, your input is greatly appreciated. |
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| Mueller |
Aug 25 2005, 06:51 PM
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None 
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cheapest and easiest is to keep the early exhaust, the smog stuff doesn't really affect the motor in a bad way, it's the lower compression and cr@ppy design '75/'76 exhaust that hurts it the most. |
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| Cap'n Krusty |
Aug 25 2005, 07:03 PM
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
Remove the external smog equipment and the exhaust. Install your earlier exhaust, plug the air injectors by welding or brazing them up. Even better, find 4 caps of the proper thread and screw 'em on! Most people working on these don't seem to realize that the air injectors seal at that ring half way down the tube, and just threading in a valve adjuster or bolt just isn't the right way to do it. Do it right, do it once .........
The air pump drive is probably broken anyway, and the EGR doesn't really need to be there with earlier FI, which runs richer. One thing you need to think about is head breather fittings. You can drill and tap the heads for some screw-in tubes, especially if the tin is off. Watch out for shavings and chips going into the rocker area. You'll probably want an earlier PCV equipped oil filler/breather box, too. The Cap'n |
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| Bleyseng |
Aug 25 2005, 07:30 PM
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#4
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Aircooled Baby! Group: Members Posts: 13,035 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
Its the same compression as the 73/74 2.0l motors if you are talking about 2.0L's. Now if you are talking about 1.8l's I still think they are the same. Capt Krusty said it all. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) |
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| Carlitos Way |
Aug 26 2005, 10:58 AM
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#5
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I did it MY WAY Group: Members Posts: 1,337 Joined: 14-September 04 From: Simi Valley, CA Member No.: 2,757 Region Association: Southern California |
So... would I in fact get close to the 95 ponies on my 74 if I took a 75 and "plugged it in" or am I going to go down to about 75?
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| Mueller |
Aug 26 2005, 11:06 AM
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#6
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None
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Hey Geoff, not sure why I thought the compression was different...my bad (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) If the rest of the internals of the motor are the same year to year, then with the better '74 exhaust, you should have the same HP as you would with the correct '74 motor..... |
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| bd1308 |
Aug 26 2005, 11:07 AM
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Sir Post-a-lot Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501 |
depends on the engine....
my 1.7 has way more power than my worn-out 2.0 |
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| Aaron Cox |
Aug 26 2005, 12:10 PM
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#8
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
the void in the exhaust port from the air injection limits flow.....how much? i dunno... but i can wager that it doesnt *quite* flow as good as a 73-74 head (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) just my 2 cents... |
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| RustyWa |
Aug 26 2005, 02:09 PM
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#9
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Working Member Group: Members Posts: 610 Joined: 2-January 03 From: Kent, WA Member No.: 72 |
Cap'n, Why didn't the '75/'76 cars come with the head breather fittings? Why do you think it is necessary to add them? |
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| Allan |
Aug 26 2005, 04:13 PM
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#10
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
I went the same route you're going with mine.
Started with a '76 fully smogged motor, threw away all the emissions stuff, plugged the injection ports, installed euro P/C's, backdated the exhaust and put in a mild cam. Stock D-Jet fed and it runs really well. At least better than Aaron or Miles cars. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) |
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