[Frankenmotor choices]

Ok 

 

engine guy re measured and realised he had made a mistake.

 

compression ratio has been recalculated at 10.2

 

using the components above.

all back on track and happy again.

 

one final question is...-

how can I tell if an engine block that was in the 99 outback hybrid model which has the new block old pistons.

is such an engine???

if it has been removed.

for example I have the chance to look through 26 short blocks. Is there a way I can tell which is the hybrid one. Piston makings??

 

block markings??

 

etc

etc

 

cheers ant

[Frankenmotor choices]

So I’m told

 

standard 2002 ej25

standard pistons

standard head gaskets

ej22 heads with 8 thou taken off.

 

thiughts on what compression ratio that should be

 

thanks

[Frankenmotor choices]

What is the maximum compression ratio you could safely go with these engines??

 

thx

[Frankenmotor choices]

So in the end we didn’t have the choice to use  exactly what we wanted.

 

i will ask the engine man today.

 

im pretty sure he has used standard pistons and a late block

 

he had to take a fair bit off the heads is all I know 

and then did his calculations. Unsure if his method of calculating the ratio but he did mention using kerosene.

is there an easy method to measure the ratio??

 

i will try and get some

sizes of the parts he has used

 

 

[Frankenmotor choices]

Ok

 

do we have advanced somewhat using the advice received in here.

 

The guy who I am working on this with was keen to do a few calculations before assembly.

this is the messsge he just sent me

 

Hi Anthony,
Compression ratio measured and calculated at 12,375 with standard thickness head gasket of 0.55 mm.
Check on line and see what feedback you get it seems too high to me.
Cheers Rob.

 

So is this measurement possible??

is it too high??

should we reduce with thicker gaskets??

 

thanks again

[Frankenmotor choices]

Great

 

thanks very much for all your time and sharing you knowledge

 

much appreciated 

 

 

[Frankenmotor choices]

On 2/5/2019 at 4:18 AM, GeneralDisorder said:

251 pistons sit at or below deck. You use the 642 factory gasket which is .021" IIRC. Don't need any calculations the comp is low 10's. They run fine. 

GD

Going well on all fronts apart from gaskets 

 

the ome 642 gaskets don’t have the same holes as the cometic and appears to block some of the passages 

 

any suggestions on altering etc??

 

cheers

[Frankenmotor choices]

Thanks

 

Yes s i did read about using the 251 pistons.

any ideas where they will sit in relation to the top of deck??

 

i thought using the .051 cometic head gaskets allowed for the 99 pistons to stick out of block and therefore give higher compression ratios. 

 

Which is is what makes the frankenmotor what it is.

 

thanks again

[Frankenmotor choices]

So can anyone help with this final issue??

 

ive sourced a late block. 52mm journals etc etc

 

we are using the cometic head gaskets .051 thickness

 

when searching for the early pistons there seems to be a few different sizes to choose from. 

 

Can someone possibly confirm what size piston will work best and give the most compression but not cause me issues??

I’ve been looking at 1998 outback pistons with a choice of 2.

and how far these pistons should sit in relation to the top of chamber??

 

 

Thanks again

[Frankenmotor choices]

On 1/31/2019 at 3:49 AM, FerGloyale said:

The cranks and rods are not the same.  They are the largest major differences between.  Though the blocks are different too.  

 

 Early DOHC 2.5 blocks have Small 48mm rod journals, and a #3 thrust bearing location.  The water jackets extend all the way down the walls of the entire cylinders.  This leaves the cylinders left very tall and open all around, leading to resonance at the top and contributing to the head gasket failure rates.  The small rod journals are known to fail often too.  I'm not a fan of these blocks, although they do make GREAT power and rev QUICK (small journals, less crank mass) 

 

SOHC 2.5 blocks use larger 52mm rod journals (like all the rest of the EJs) and move the thrust to #5.  The water jackets at the top side of the block around the base of the cylinders is decreased.  This allows faster coolant flow, less stagnant pockets under the crossover.  It also gives more meat at the base of the cylinder to prevent  resonance.   These blocks had pistons that come right to zero at the block deck, later ones with AVLS, the pistons actually come way out of the block.

The 99's were a combo.  They are basically the old DOHC 2.5 pistons stuck into the new 2.5 block.  52mm journals, #5 thrust, sturdy cylinders.   

 

There were some changes in Oil pump rotor thickness too, though I am not clear on which are in what.....but they are all interchangeable, so find a 10mm pump if you don't have one.

Great info thx

 

so just to clarify 

 

what con rods are used in this combination for the frankenmotor??

Do you have a part number or year of engine or length etc??

 

and if I’m buying new pistons do I ask for pistons from a 97/98 dohc outback.

 

or do you have a piston part number.

 

thanks again

 

anthony

 

 

 

[Frankenmotor choices]

3 hours ago, GeneralDisorder said:

Yes just use the complete 25D engine. 251 pistons are from 99 to 05 SOHC 2.5 engines. 642 is the last three of the OEM head gasket part number. Those are for a 2004 STI. That piston and gasket combo will be about 10.5 compression and the gaskets won't fail because they are less than half as thick as the D gasket. 

Any 25D engine or the 99 hybrid that people are talking about with new case old  internals??

 

thx

[Frankenmotor choices]

2 hours ago, GeneralDisorder said:

Just use a complete 25D. Swap the pistons for 251's and use the 642 head gaskets. There's your 170 HP. No problem. 

You'll have a very hard time hitting anywhere near 160 with EJ22 heads. They just won't flow that much NA. 

The 25D manifold is compatible with the harness you are running. Just swap over the electronics. 

22 heads are a waste of time. That's why Subaru didn't use them on the 2.5. Duh. 

GD

Ok

Pretty  new to all this so apologies if I need spoon feeding.

So I need the hybrid 99 model Ej25d or can it be any Ej25d??

swap out the pistons for 251,s 

what are 251 pistons out of??

 

642 head gaskets I’m unsure  what you mean?

 

and which heads are you saying to use?? Are you saying just use the same heads and keep it as a complete Ej25d engine heads and manifold??

 

then swap all my electrics from my current Ej22 set up and put them onto the complete Ej25D engine.

and my current wiring set up will run this engine fine??

 

also what sort or Hp would you get just using ej22 heads and a later Ej25 frankenmotor in comparison to the above set up??

 

appreciate your help on this

 

thanks

 

 

[Frankenmotor choices]

Also read about some idling issues when changing cams. Is changing the cams vital??

thanks

[Frankenmotor choices]

Fergloyal 

Perfect

ive got those heads and gaskets 

 

so now I need to find a 99 block

just wondering what cars they were in in Australia

 

is there a certain engine code I can look for ??

do the heads need altering to increase compression??

 

thanks

[Frankenmotor choices]

General Disorder

 

i appreciate your knowledge and thanks for your reply.

 

i think the sort of power your talking about is way above why I’m after

 

its a frankenmotor I want and it’s the ej22 heads I’m going to use

 

whatvim after is someone’s knowledge on what bottom end is best used to create a powerful frankenmotor maybe 160-180 hp.

 

my old Vw engine was 90hp so effectively doubling it.

 

with anything above 200hp I guess

id rip my gearbox to shreds

 

thanks

 

[Frankenmotor choices]

Thanks for that info

 

what about using ej22 heads?

 

not sure how my current wiring and manifold etc would work with different heads

 

thanks

 

 

 

[Frankenmotor choices]

Hello

 

can someone please point me in the direction of which ej25 engine block will work best for a frankenmotor??

 

ive read Ej25d which I’m pretty sure is from a dohc engine??

 

i read 1999 because of piston size and rod length. Do these have a different crank??

 

is there a specific year or model that would create the higher compression required with the frankenmotor.

 

any engine block years to avoid??

 

would a new ej25 2005 or older up be any better and why??

 

yup I’m a bit confused as to which is the best choice.

 

im running an old ej22  wiring system  from a 1992 legacy.

OBD1

 

twin port  ej22  heads 

 

thanks for your time

 

anthony

[Ej22 heads ej25 block help needed]

Cometic ej22/ej25 hybrid head gasket

[Ej22 heads ej25 block help needed]

Ok had another look.

 

Engine back out.

 

Looks like the left hand head has jammed solid.

 

The timing belt is all torn and wedged under the belt guide.

 

The inside of the rocker cover one side looks very dry and I'm suspecting has had no oil.

 

Not too sure though.

 

Need to try and find the cause and hope no internal damage.

 

Any thoughts thx

[Ej22 heads ej25 block help needed]

Ok

 

Things moved on but not as I would have liked.

 

Got it all together installed. Running.

 

Wasn't totally convinced all good as tapping noise.

 

Didn't sound right

 

Any way test drive lasted about 30 mins. Then I got towed home

 

Only had time for a quick look. Sounds like no compression so thought timing belt slipped.

 

Engine will turn but doesn't feel right.

 

The cam sprockets on both heads appear to be jammed solid.

 

Maybe I should stick to carpentry ????

 

Any thoughts??

Thx in advance

[Ej22 heads ej25 block help needed]

Yes was pretty funny

 

just didn't feel right.lol

 

Ok I've got the plugs

 

BkR6E11

NGK

 

Do we run the 1.1 gap they are set at for this frankenmotor I'm sure I read smaller.??

 

Every day is a school day

[Ej22 heads ej25 block help needed]

Ok

 

Embarrassing moment over.

 

I haven't put new plugs in yet

 

☺️

[Ej22 heads ej25 block help needed]

Thx

 

The engine the heads came off were from a 1993 liberty or legacy Australian spec.

 

They are twin port though.

 

Ok I've just put the heads back on and timing belt. All the notches lined up etc and seems good.

 

Is it normal to not feel the compression on these engines??

 

It does stiffen up when turning it over but doesn't feel the same as other engines I've done before just wondering if the hydrolic valves changed anything or it could be in using a 2 foot bar to turn it over with.

 

Just thought it would be harder to turn over. New rings. Pistons and heads reconditioned.

 

Any thoughts

 

Thx in advance

[Ej22 heads ej25 block help needed]

Another question. Possibly a stupid question.

 

As I said I'm doing the frankenmotor thing and have been doing a fair bit of reading.

 

One of the things I've read is that there are 2 types of ej22 heads??

 

And that only one type will work.

 

The twin port is the one to use apparently.

 

Does the twin port relate to the twin outlet for the exhaust???

 

As I've never seen an ej22 with a single exhaust outlet.

 

Thx

 

Anthony

[Ej22 heads ej25 block help needed]

Great

 

Thanks very much for your reply