Franken Engine Harness, Lets talk shop

[GeneralDisorder]

well I am not going to argue. I totally understand what all you are saying. and you are right but so am I. its all just personal opinion.

 

using the info from GDs post above I was thinking of.

 

1. Used, good condition EJ25D short block needing head gaskets ~$400

 

Around $500 for high comp. pistons

 

3. Timing belt/WP kit ~$120

 

5. Misc. gaskets and seals ~$100

 

so sorry my option would be a little more. at 1120.00

I was not talking of rebuilding the engine. and neither were you. that is not a fair argument.

You can install pistons without tearing into the bottom end.

I bet the stock EJ25d heads would flow better than the EJ22 heads with cams

so no cams. of course you could spend more you always can.

 

You neglect a couple things - first the timing belt kit for the DOHC heads is about $200, second the DOHC eat valves, valve guides, and stem seals like candy. Plus you will have to do a shim adjustment..... a rebuild on the DOHC heads runs $500 compared to about $175 on the SOHC heads. In either case I AM talking about rebuilt heads.

 

You can't change out the pistons without also changing to the (piston manufacturers) rings and that will require a proper hone for them to seat - which is best done by pulling the short block apart..... which pretty much means it's stupid not to put in bearings.

 

There's also the consideration that the SOHC heads fit better into a lot of the older chassis (EA81's for example can't run the DOHC), and they are MUCH easier to service - plugs, valve adjustment, valve cover gaskets, etc. All around a more pleasant experience.

 

Do what you like - but you will spend more and get the same thing if you use the DOHC heads - they are really designed for forced induction and their greater flow rate simply isn't needed for NA. And flow rate has nothing to do with the cam grind - just because they flow more doesn't mean they do it at the right time.

 

I've built a LOT of EJ engines now. I am well versed in the associated costs and what works and what doesn't work. You go ahead and stick some high-comp pistons in a used block with some used heads and no cams - I'll run circles around you with my SOHC heads

 

GD

Edited July 6, 2011 by GeneralDisorder

[roostema4328]

you are not wrong. I just have a different opinion. I do like how you say you do the frankenmotor to be cheap and then add a bunch of cost to my opinion. You do not have to do all those things you are saying. In most cases it would work out great. of course you would have to inspect your used parts and make sure they are ok. you could look at the valves and check clearance yourself. and also change the stem seals. they are cheap.

 

plus you say more flow is bad. I dont agree. why else would you be buying cams. you obviously want more flow/duration and lift. why else would you do it. more flow equals more air pulled into the cylinder every stroke= more air to compress. more running compression. more flow out means lower cylinder temps. what is wrong with that?

 

yes the sohc is easier to service and would fit easier. and yes parts are cheaper. you could also source a SOHC 2.5 and put highcompression pistons in that. that would be better on all fronts. no shims to adjust. larger valves more flow, cheap cams.

 

the DOHC does fit fine in a EA82. I have one in my 86 GL. and it is easy to service. but that is because I have the 6" SJR lift and the plugs are below the frame rails now. I suppose if you had an EA81 car I would build the SOHC 2.5. actually I probably would do that anyway lol.

 

My car has a twinturbo DOHC in it now. the next build for my RX will be RWD and have a EJ33 with built heads and block. probably small turbo with full compression for less lag. I already have the rear end that I will stick in which is the entire rear subframe of a infiniti G35. I want to build a subaru drift car. I will slowly collect parts then I will start ha ha.

[GeneralDisorder]

you are not wrong. I just have a different opinion. I do like how you say you do the frankenmotor to be cheap and then add a bunch of cost to my opinion. You do not have to do all those things you are saying. In most cases it would work out great. of course you would have to inspect your used parts and make sure they are ok. you could look at the valves and check clearance yourself. and also change the stem seals. they are cheap.

 

It's usually the guides that are shot on the DOHC heads. And yes you can re-shim them yourself - but it won't fix the worn guides nor will it bring the valves back into spec - most times they are too far gone to even do a proper grind on. The 25D likes to eat valves - just what they do.

 

So you would not hone the cylinder and replace the rings? How do you expect the rings to seat properly and not use a ton of oil? It's just a bad idea - if you are going into the bottom end to replace pistons then you should be doing everything. Either do it right or don't touch it.

 

plus you say more flow is bad. I dont agree. why else would you be buying cams. you obviously want more flow/duration and lift. why else would you do it. more flow equals more air pulled into the cylinder every stroke= more air to compress. more running compression. more flow out means lower cylinder temps. what is wrong with that?

 

I never said more flow was bad - I said it's not needed where this engine makes it's power. The torque cams may increase durration - that I don't know - lift is unchanged. The valve TIMING is altered for more bottom-end power - more air at lower RPM. Thus these cams are the opposite of a turbo engine - they flow big at low RPM and taper off as the RPM increases. After 5500 RPM this build runs out of steam - but that's OK because it's coupled to a close ratio gearset that's been geared down with a low ratio final drive. The DOHC heads flow great up at 6 and 7 thousand - nothing we will ever care to hit. Thus they are useless.

 

yes the sohc is easier to service and would fit easier. and yes parts are cheaper. you could also source a SOHC 2.5 and put highcompression pistons in that. that would be better on all fronts. no shims to adjust. larger valves more flow, cheap cams.

 

Sure you could - and blow the budget doing so. Once again - too expensive to source 253's and 251's.

 

the DOHC does fit fine in a EA82. I have one in my 86 GL. and it is easy to service. but that is because I have the 6" SJR lift and the plugs are below the frame rails now. I suppose if you had an EA81 car I would build the SOHC 2.5. actually I probably would do that anyway lol.

 

I care nothing for EA82's - engines or body's. I skip that gen completely. Never-the-less.... the EJ251/253 is a fine engine - but again not readily availible and thus too expensive.

 

My car has a twinturbo DOHC in it now. the next build for my RX will be RWD and have a EJ33 with built heads and block. probably small turbo with full compression for less lag. I already have the rear end that I will stick in which is the entire rear subframe of a infiniti G35. I want to build a subaru drift car. I will slowly collect parts then I will start ha ha.

 

This has what do to with the current conversation? I've built all kinds of weird combo's as well - not germain to the discussion at hand.

 

You can argue till you are blue in the face - it's not going to change the fact that you can't make the HP this combo makes for the same money. Just not going to happen.

 

GD

[NoahDL88]

The Gol' Darn German's ain't got nothing to do with this!!!! /Beuford T Justice

 

 

This engine is going into an EA-81, where frame rail clearance is at a premium.

 

If its not going in there its going into a 94, where the 2.2 heads mean I don't have to do any extra wiring.

 

 

Either way the 2.2/2.5 is exactly what I need/want, so stop going to every Franken Engine thread and poo-pooing the idea

[roostema4328]

sorry. I didnt mean to poo the idea. I just was inputing some of my thoughts. which obviously must be completely wrong so I will shut up.

 

that combo would be good of course. good luck with the build.

[NoahDL88]

You're not wrong, just apples to oranges, and the fans of the Frankenstein are just fans of apples.

[el_freddo]

Propane aside - what have people found to be the best ECU to run the frankenmotor with cams - the 2.5 litre ECU and wiring or the OBDII 2.2 litre ECU and wiring?

 

This thing sounds like it's going to be off its tits once its going!

 

Will be watching this thread

 

Cheers

 

Bennie

[roostema4328]

the obd2 ecus can be reflashed usually so that would probably be the best choice if you could get one to work.

[GeneralDisorder]

what have people found to be the best ECU to run the frankenmotor with cams - the 2.5 litre ECU and wiring or the OBDII 2.2 litre ECU and wiring?

 

Those two are virtually identical - to the point that the 2.2 ECU/wireing will run a 2.5 and the 2.5 equipment will run a 2.2 - easily. They use the same injectors, and all the sensors on the manifold, etc..... everything is nearly identical between the two. Software might change a bit but not enough for anyone to notice when running a mixed combo.

 

That's why the 2.5 to 2.2 conversion is so popular. The engine just plugs right in without a single wireing change.

 

GD

[el_freddo]

Those two are virtually identical - to the point that the 2.2 ECU/wireing will run a 2.5 and the 2.5 equipment will run a 2.2 - easily. They use the same injectors, and all the sensors on the manifold, etc..... everything is nearly identical between the two. Software might change a bit but not enough for anyone to notice when running a mixed combo.

 

That's why the 2.5 to 2.2 conversion is so popular. The engine just plugs right in without a single wireing change.

 

GD

 

Thanks GD, that's great to know!

 

Cheers

 

Bennie

[franklinstower]

I have been reading up alot on the frankenmotor but I still have a few questions. What I want is more power for my Vanagon but without doing a whole new harness. I currently have a '92 EJ22 installed, with the matching ECU and harness all from the same donor Legacy. From what I have read, the two easiest options to get more power are A then B, but what about C and D:

A) just install some Delta Torque Cams - probably looking at 8-10 more HP and more lowend torque. My ECU should be okay with this, but I might have a slight lumpy idle, is that correct?

Swap to a EJ25D block, use my heads with stock cams, intake manifold, ECU etc. get a lot more HP. probably closer to 160-180? And I am correct that my ECU will run this without a problem? What is anticipated CR using stock thickness HG's (.040"?)

C) Same as abouve but with Delta Torque Cams - Will my ECU be okay with that? from what I have read - maybe not? Probably better at that point to make up a new harness to run the OBD11 ECU and intake?

D) finally, what about a 257 block and my EJ22 heads, OBD1 intake, wire harness - A little less compression but still probably in the 160 range? has this been tested yet?

 

And again, my goal is to have the smoothest, most powerful, most cost effecient engine with some more hp using my already modified OBD1 wire harness. I know the OBD11 harness and ECU are a better match, but at this point, I am not quite ready to make up a new harness and I don't have the matching intake and sensors.

 

Thanks,

Paul

[roostema4328]

c

[NoahDL88]

Idle quality can be an issue with the Delta Cam, it's not a bad thing, just kind of a lopey idle.

[GeneralDisorder]

C - you will have to "retune" your idle air control valve (IACV) by rotating the thermostatic air inlet valve inside it to give the engine more air at idle. The larger displacement and duration of the torque cams causes problems with the engine needing more idle air than the 2.2 valve was setup for.

 

25D compression is about 10.5:1. It's actually the lowest of the frankenmotor combo's. There are quite a few people running a lot higher though without any problems - there's a guy on NASIOC running 12:1 on 89 octane and he says his monitoring software indicates no knock and his ECU isn't pulling his timing at all.

 

It will still be a little lumpy with the torque cam - especially when cold. But it's not terrible. And the '92 harness/ECU is fine. Not as sophisticated as the later stuff but you don't need to rewire it just because of that. If you do rewire it I would go with Mega-Squirt.

 

The frankenmotor is big on torque - max NA HP on the EJ22 heads is around 185 to 190 - they just don't flow for beans up high. But the torque curve is INSANE - it hops up to about 200 ft/lbs of torque at 1200 - 1500 RPM, then climbs a bit more to around 220 and stays pretty much flat all the way to 5500.

 

GD

Edited November 12, 2011 by GeneralDisorder

[franklinstower]

For my vanagon, that torque would be awesome! I rarely go pass about 5000 rpms now, and that is only when I am passing someone in a hurry. my typical rpm range is about 2800 to 3800 so having a full 200 lbs of torque through out those RPMS would suite me fine. with my gearing, I am doing about 70 at 3800 in 4th. I am going to go pick up the EJ25D long block next week, I don't know the mileage on it, but it was reported to only have a HG leak. Hopefully no bent rods, spun bearings etc. And Delta is only 30 miles away!

[obk25xt]

C - you will have to "retune" your idle air control valve (IACV) by rotating the thermostatic air inlet valve inside it to give the engine more air at idle. The larger displacement and duration of the torque cams causes problems with the engine needing more idle air than the 2.2 valve was setup for.

 

25D compression is about 10.5:1. It's actually the lowest of the frankenmotor combo's. There are quite a few people running a lot higher though without any problems - there's a guy on NASIOC running 12:1 on 89 octane and he says his monitoring software indicates no knock and his ECU isn't pulling his timing at all.

 

It will still be a little lumpy with the torque cam - especially when cold. But it's not terrible. And the '92 harness/ECU is fine. Not as sophisticated as the later stuff but you don't need to rewire it just because of that. If you do rewire it I would go with Mega-Squirt.

 

The frankenmotor is big on torque - max NA HP on the EJ22 heads is around 185 to 190 - they just don't flow for beans up high. But the torque curve is INSANE - it hops up to about 200 ft/lbs of torque at 1200 - 1500 RPM, then climbs a bit more to around 220 and stays pretty much flat all the way to 5500.

 

GD

 

 

I want my frankenmotor! :-p

[franklinstower]

I know there were some power and torque differences on the EJ25D's with the '96 being the lowest output. So if I am going to build a frankenmotor and I want the lowest possible compression ratio, which block do I want? The '96 or the '97 to '99? And how would I tell them apart?

 

Was the difference in the piston design, head design or both?

 

Thanks,

 

Paul

[GeneralDisorder]

You don't want the '96 block - effectively the compression is actually higher than the 251 or the 253 variants. The pistons have an 8 to 10cc smaller dish in them and it knocks the compression up to crazy levels with 2.2 heads.

 

'99 is the best 25D block because it's actually a 253 with 25D pistons. 8 bolt bell-housing, 52mm rod journals, and #5 thrust bearing. It's the ultimate 25D.

 

'97/'98 are just plain 25D's. Good for frankenmotor's.

 

GD

[impoutback 97]

Those two are virtually identical - to the point that the 2.2 ECU/wireing will run a 2.5 and the 2.5 equipment will run a 2.2 - easily. They use the same injectors, and all the sensors on the manifold, etc..... everything is nearly identical between the two. Software might change a bit but not enough for anyone to notice when running a mixed combo.

 

That's why the 2.5 to 2.2 conversion is so popular. The engine just plugs right in without a single wireing change.

 

GD

 

So are you saying you've driven a frankenmotor with Delta cams and a 2.2 ecu, then swapped the 2.5 ecu and there was no noticeable difference in performance? Or do I have it wrong and the 2.2 and 2.5 share the same ecu in identical production years?

Edited November 24, 2011 by impoutback 97