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Guest Message by DevFuse

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Cam differences EA82

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3 replies to this topic

#1 bgd73


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Posted 21 December 2006 - 08:11 PM

I did a search and nothing relevant appeared (could be my pc- internet returns the same bizarre non-appropriate replies)

I have had 3 soobs and only throttled a turbo version with an ea82. There is something different dramatically about all of them.
the 93 sedan at 84hp really stumped me until I found what oem did with the timing belt sprockets (manufactured off a "half tooth").
I have a guess at this point about the carbed model ea82 (1987 to be precise- I am sure there is a range of years) and there is no doubt at this point the actual cams valve timing is different. Anyone help with oem numbers such as below for a carbed ea82? The stroke is so tiny, the differences shown below are HUGE with a simple run proving it.

  • intake valve timing open 10 degrees BTDC, close 54 degrees
  • exhaust open 49 degrees close at 15
7.7:1 (turbo)
  • 14 intake open, 56 closed
  • 56 open exhaust, 14 close
  • ?
It seems intake opens sooner on the carb, as the thump of an idle is like banging on an empty barrell with the lid on, and the wild response like an old four barrell when floored indicates as well- very full stroke in other words, not necessarily compression (no pings verify clean). would love some numbers.
I have a combo possible:
lower half of spfi block for pistons, carbed model cams in mpfi heads, scrapping mpfi for a carb mount on mpfi intake with carb disty., etc.
(I have mentioned I am not a turbo fan for the ea82-) :)

#2 mikeshoup



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Posted 21 December 2006 - 11:16 PM

The cam differences are more than just the engine compression. Its the year and fuel system.

Here's the breakdown I have:
86 Carb/MPFI Turbo:
Intake: 3 BTDC / 51 ABDC
Exhaust: 47 BBDC / 7 ATDC

86 SPFI:
Intake: 10 BTDC / 54 ABDC
Exhaust: 49 BBDC / 15 ATDC

86 MPFI Non-Turbo:
Intake: 12 BTDC / 58 ABDC
Exhaust: 58 BBDC / 12 ATDC

Notice: In 86, MPFI and Carb were 9:1, Turbo was 7.7:1 and SPFI was 9.5:1

88 SPFI:
Intake: 10 BTDC / 54 ABDC
Exhaust: 49 BBDC / 15 ATDC

88 MPFI Turbo:
Intake: 14 BTDC / 56 ABDC
Exhaust: 56 BBDC / 14 ATDC

88 MPFI Non-Turbo:
Intake: 16 BTDC / 60 ABDC
Exhaust: 60 BBDC / 16 ATDC

Notice: In 88, MPFI was 9.5:1 compression. This is different from 86 which had 9:1 compression with MPFI

There are probably more camshafts out there than just these. This is the only sampling I can provide with my 86 and 88 FSMs.

The 84 EA81T and EA81 Carb has yet other different camshaft configurations, but it will not work in the EA82 for obvious reasons.

#3 bgd73


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Posted 22 December 2006 - 12:57 AM

I knew it without fsm for the carbs...it obviously has a very full stroke. after 8 years of carb I got an spfi and swore there was something wrong... and it wasn't. It was oem pansied (I hope that is ok to say)
The carb cam on spfi pistons in with mpfi heads would be quite a freaky thumper. :grin:
without a turbo... 130-140hp seems very likely. I just kew they added to some things and killed others. 9.5:1 should have been a very realistically powered soob- without any complaints about any hills or any situation. my 9.0:1 carb does and did better the whole run time I had them. all in the cams. jeesh.
Thanks for accurate info.

#4 GeneralDisorder


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Posted 22 December 2006 - 03:57 AM

We have told you this before - the sprocket is SUPPOSED to be like that. It was not manufactured a half tooth off. Damn you are dense. Stop spreading lies and mis-information. You are NOT right. Got it?

Furthermore, all SPFI engines were 90HP.


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