 So what does 1.8 heads do for a 1.7? |
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| computers4kids |
 Feb 28 2008, 07:48 PM
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#1
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Love these little cars!  Group: Members Posts: 2,443 Joined: 11-June 05 From: Port Townsend, WA Member No.: 4,253 Region Association: None  |
I have this rebuilt motor that is offered at a reasonable price to me. It has oversized pistorns and 1.8 heads.
As I understand it, a 1.7 and 1.8 have essentially the same stroke, just different bore. How do 1.8 heads effect a 1.7 motor? Thanks |
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| Brando |
Feb 29 2008, 03:23 AM
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#2
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BUY MY SPARE KIDNEY!!! Group: Members Posts: 3,935 Joined: 29-August 04 From: Santa Ana, CA Member No.: 2,648 Region Association: Southern California |
I think the question should be "how do 2.0 heads effect a 1.7/1.8 motor?"
To answer your original question... they won't too terribly much. They might flow a little better. valve sizes for 1.7: In: 39.3MM Ex: 33MM valve sizes for 1.8: In: 41MM Ex: 34MM. |
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| alpha434 |
Feb 29 2008, 04:26 AM
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#3
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My member number is no coincidence. Group: Members Posts: 3,154 Joined: 16-December 05 From: Denver, CO Member No.: 5,280 Region Association: Rocky Mountains |
Lol.
Flow= HP The problem with 1.8s isn't the heads. Well. Spark plug location plays a part. It's mostly the funky fuel injection setup. Is the rebuilt engine going to come with FI? What type? |
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| computers4kids |
Mar 1 2008, 09:46 PM
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#4
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Love these little cars! Group: Members Posts: 2,443 Joined: 11-June 05 From: Port Townsend, WA Member No.: 4,253 Region Association: None |
QUOTE(alpha434 @ Feb 29 2008, 02:26 AM)  Lol. Flow= HP The problem with 1.8s isn't the heads. Well. Spark plug location plays a part. It's mostly the funky fuel injection setup. Is the rebuilt engine going to come with FI? What type? The motor is setup with djet injection for a 1.7 (not L-jet) and is suppose to run very good. (IMG:style_emoticons/default/confused24.gif) He can't find the MPS, and I forgot to see what color the injectors where...should be yellow. The MPS and injection came from a 73 1.7. The guy spent a lot of money having the motor professionally rebuilt years ago. Anyway...should I get excited (IMG:style_emoticons/default/idea.gif) |
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| toon1 |
Mar 2 2008, 12:54 AM
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#5
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Senior Member Group: Members Posts: 1,849 Joined: 29-October 05 From: tracy,ca Member No.: 5,022 |
If I'm not mistaken, the registers is the 1.8 heads are too big for the 1.7's
1.7=90mm bore 1.8=93mm bore |
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| alpha434 |
Mar 2 2008, 08:29 AM
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#6
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My member number is no coincidence. Group: Members Posts: 3,154 Joined: 16-December 05 From: Denver, CO Member No.: 5,280 Region Association: Rocky Mountains |
It's close enough.
Hey. A deal is a deal. It might run pretty strong. It might just be good for a lot of spare parts... |
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| jr91472 |
Mar 2 2008, 12:40 PM
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#7
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"I'm pacing myself sergeant..." Group: Members Posts: 1,205 Joined: 2-August 04 From: McKinney, TX Member No.: 2,437 |
Just a thought...
Don't assume they are 1.8 heads. I have the same setup, but the 1.7 heads were simply opened up to accept the 1.8 cylinders by the PO. I have heard this is (or was) as fairly common thing. I have no way of telling you how to tell the difference between and 1.8 and a 1.7 head without taking them off and measuring the valves. |
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| sean_v8_914 |
Mar 2 2008, 12:48 PM
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#8
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Chingon 601 Group: Members Posts: 4,011 Joined: 1-February 05 From: San Diego Member No.: 3,541 |
in post 1 he states it has a big bore. remove the valve cover and read teh casting number does it end in 371 S
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| Brando |
Mar 2 2008, 09:46 PM
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#9
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BUY MY SPARE KIDNEY!!! Group: Members Posts: 3,935 Joined: 29-August 04 From: Santa Ana, CA Member No.: 2,648 Region Association: Southern California |
go with a pair of happy 2.0 heads and race your shorts off.
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| HAM Inc |
Mar 3 2008, 08:35 AM
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#10
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Senior Member Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None |
The 1.8 heads do flow a little better than the 1.7 heads. If the last four digits of the casting # in the rocker chamber are 371s then they are 1.8's. The increase in flow is enough to make a difference if the cam is updated. With the stock cam you won't see much difference.
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| computers4kids |
Mar 3 2008, 08:52 AM
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#11
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Love these little cars! Group: Members Posts: 2,443 Joined: 11-June 05 From: Port Townsend, WA Member No.: 4,253 Region Association: None |
QUOTE(HAM Inc @ Mar 3 2008, 06:35 AM) The 1.8 heads do flow a little better than the 1.7 heads. If the last four digits of the casting # in the rocker chamber are 371s then they are 1.8's. The increase in flow is enough to make a difference if the cam is updated. With the stock cam you won't see much difference. Yes, the heads are definitely 1.8, in fact the owner has reciepts for all the work...the heads are brand new (not rebuilt). Thanks all for your input... |
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| HAM Inc |
Mar 3 2008, 10:32 AM
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#12
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Senior Member Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None |
If your heads are new AMC heads that are stock then you will see no difference as compared to a 1.7. All of the T4 AMC heads are cast with identical intake ports, regardless of engine size.
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