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Guest Message by DevFuse
 

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Using Carb longblock in SPFI Car (ea82)


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19 replies to this topic

#1 Logan K

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Posted 20 November 2017 - 01:03 PM

Hey there, so I am replacing the longblock on my 91 loyale with an engine out of an earlier carbureted car. I will be swapping intake manifolds and exhaust over, is there any other things i need to do to get this vehicle to run properly? From my understanding it should be pretty straightforward, but I am planning on getting this done over the holiday weekend and would rather gather my parts together now. Any feedback would be appreciated. Thank you! 



#2 DaveT

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Posted 20 November 2017 - 04:14 PM

I did this once, long ago. Iirc, the egr pipe is slightly different.

Just look over all those smaller bits closely. The spfi intake should otherwise go right on the older block. Have to change the distributor also. Inside the block, heads, etc. All the same parts, so no problems there.

#3 wagons

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Posted 20 November 2017 - 09:05 PM

Make an egr pipe as Dave said
Also swap disty and coil as you want them to match. Intake manifold will cross, I know this because I'm using a spfi set of heads with my carb block so yes it will bolt together and run. I did this because the new heads don't have asv and it helps clean up the engine bay.

#4 djellum

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Posted 20 November 2017 - 11:15 PM

your lowering the compression going to the carb motor, provided everything is stock.  the other pistons will fit provided the crosshatching is still good, if it looks decent might want to rering it and use the higher comp pistons



#5 moosens

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Posted 20 November 2017 - 11:15 PM

Just basic flat stock metal - you’ll be covering the holes at the exhaust ports that once had the EGR pipes. No need for pipes. I did this about 15 years ago.

#6 DaveT

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Posted 20 November 2017 - 11:40 PM

djellum wrote:  your lowering the compression going to the carb motor,

 

There must be some variations on this.  The one I swapped - the bore and stroke are the same.

 The cams are the same.  Lifters the same.

The heads and valves are the same as far as the combustion chamber.  Only difference was maybe the EGR port.

Pistons the same, as far as can bee seen from the top at least,

 

The swapped one had no noticeable difference in power under any driving situation I experienced.



#7 moosens

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Posted 21 November 2017 - 12:13 AM

Scratch that. I thought maybe he was thinking turbo block.

Edited by moosens, 21 November 2017 - 12:15 AM.


#8 DaveT

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Posted 21 November 2017 - 12:18 AM

oh, yes, turbo would be different for sure.



#9 skishop69

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Posted 21 November 2017 - 12:45 AM

djellum wrote:  your lowering the compression going to the carb motor,

 

There must be some variations on this.  The one I swapped - the bore and stroke are the same.

 The cams are the same.  Lifters the same.

The heads and valves are the same as far as the combustion chamber.  Only difference was maybe the EGR port.

Pistons the same, as far as can bee seen from the top at least,

 

The swapped one had no noticeable difference in power under any driving situation I experienced.

 

Only 3 variations. Bore and stroke are the same, but the pistons are different. Turbo is 7.7:1, carb is 9:1 and SPFI is 9.5:1. Torque is the same for the carb and SPFI engine but the horsepower is slightly less on the carbed engine due to the piston height difference. The difference is something like 5 or 6 horse power, not really enough to notice.



#10 jono

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Posted 21 November 2017 - 02:07 AM

Ski shop you mentioned only three ...turbo, carb and spfi .....fourth XT mpfi ?

#11 skishop69

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Posted 21 November 2017 - 10:32 AM

MPFI ran the same pistons as SPFI though it had a higher torque and horsepower.



#12 Logan K

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Posted 21 November 2017 - 03:01 PM

Any harm if I just block off the EGR? I dont really have the tooling to make a pipe. 



#13 wagons

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Posted 21 November 2017 - 03:42 PM

If you have to pass emissions it might throw them off and give you a fail. Other than that no harm. I run mine basic. No egr, no asv. I have a pcv system and a carb.

#14 Logan K

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Posted 22 November 2017 - 11:03 AM

I am using SPFI however...so will that throw off the fuel/air mixture if the EGR is disconnected



#15 DaveT

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Posted 22 November 2017 - 11:33 AM

The spfi will adjust for the change. You might still have emmisions trouble, but if you don't have that, no problem.

The EGR is supposed to reduce the temperature in the combustion chamber, might reduce pinging in some circumstances. Lowers NO2 emmisions.

It should run fine blocked, if you have noticeable trouble, it could always be added back on later.

#16 Gloyale

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Posted 22 November 2017 - 01:30 PM

your lowering the compression going to the carb motor, provided everything is stock.  the other pistons will fit provided the crosshatching is still good, if it looks decent might want to rering it and use the higher comp pistons

 

only if it's an 85 or 86.  

 

87 carb block just like SPFI, and has the same cams.

 

If it IS a 85/86 block, probably want to keep the SPFI Cams from the old heads.

 

EGR is the same it's the Carbie heads ASV pipes that need blocked.  easy to make a plate, or just screw a Quarter into pipe where it connects tot eh reed valve blocks.


Edited by Gloyale, 24 November 2017 - 01:19 PM.


#17 Gloyale

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Posted 22 November 2017 - 02:11 PM

Just basic flat stock metal - you’ll be covering the holes at the exhaust ports that once had the EGR pipes. No need for pipes. I did this about 15 years ago.

 

Those aren't EGR pipes.

 

They are ASV (air Suction Valve) system parts.  Supposed to prevent backfires and make cleaner tail pipe emissions.

 

EGR port is on the top of the passenger side head.  Above cyl 3.  Exactly the same on all EA82s.



#18 DaveT

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Posted 22 November 2017 - 02:39 PM

They must have changed the cams mid 86? The 86 I used, I measured the cams, they were the same as the 90 something engine I swapped it with.

#19 Gloyale

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Posted 22 November 2017 - 03:01 PM

They must have changed the cams mid 86? The 86 I used, I measured the cams, they were the same as the 90 something engine I swapped it with.

 

 

It's not the lift that changed, it's the valve timing.  

 

Pretty hard to measure that.......you either didn't measure right, or the Cams had been swapped.

 

From the FSM

 

86

IMG_2753 by Dans Subaru, on Flickr

87

IMG_2754 by Dans Subaru, on Flickr



#20 djellum

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Posted 22 November 2017 - 03:33 PM

I hadn't heard that the 87 carbs were higher comp.  Makes me happy though, I was going to put spfi pistons in my carb block when I reseal it, but I dont think I will now.






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