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Discussion Starter · #1 ·
Backstory: my buddy picked up a 98 RS ej25d with a blown motor. i disassembled it and find out the shortblock is toast and one head is toast. We sourced an EJ251 from an 01 RS and another ej25d head.

I got new ej25D headgaskets and tensioner as well.

We get the heads on and the timing belt all lined correct and this is where the trouble starts.

We cannot turn the motor over by hand past about one full rotation of the crank pulley in either direction. it definitely feels like something is hitting inside the motor. could it be the pistons hitting the valves?

What would cause this? A relatively simple shortblock swap has turned into a nightmare. We just want this car to run.

Side note: with the timing belt off, we can turn everything over perfectly. all 4 cam gears and the crank gear turn just fine, its just with the timing belt on that something locks it up and it wont turn past a certain degree in either direction.

RS25 please help. Tell me what i did wrong here/what am i missing?

thanks,
Curtis
 

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yep. you heard me.
‘18 E63s AMG wagon & 10 Subarus
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first off, idk about using a EJ251 shortblock with EJ25D heads. you might be looking at some compression changes there.

second, what head gasket did you use? the EJ25D uses a thicker 1.3mm gasket and the EJ251 uses a thin .56mm. you need to use the thicker EJ25D one, otherwise the pistons could be at risk of hitting the head/valves more easily

third, when you did the timing belt, you took the tension off all 4 cams, and the set the crank at the timing mark, which is a small marking/indent on the crank gear. it is NOT "TDC" (top dead center), its the "timing mark". after you set that, you set the other 4 cams to their marks: straight up on the single mark for the top cams and outwards on the single mark for the lower cams (match the double-mark on both cam gears to each other).

if youve done all that correctly i dont see the issue
 

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Discussion Starter · #3 ·
i used the ej25D thicker headgasket.


when i did the timing i lined up the crank gear with the timing mark. How do i find TDC?

also, when doing timing, i used the ARROWS on all 4 cam gears. Am i supposed to use the hash marks? i apparently forgot since doing my ej20g timing belt :(

thanks for the insight!

curtis
 

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Discussion Starter · #5 ·
AHH thank you!

i was indeed using the arrows to line up the cam gears, NOT the hash marks, which you are supposed to use on the 98 dohc.

now, lastly, TDC? i honestly totally ignored TDC and just lined up the crank gear with th mark on the case above it.
 

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AHH thank you!

i was indeed using the arrows to line up the cam gears, NOT the hash marks, which you are supposed to use on the 98 dohc.

now, lastly, TDC? i honestly totally ignored TDC and just lined up the crank gear with th mark on the case above it.

TDC is the arrow mark on the crank, but you used the mark on the trigger behind it which is correct.
 

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Discussion Starter · #8 ·
SO, massive epic update:

i checked the timing and it was wrong, i used the arrows on the cam gears instead of the hash marks.

we corrected the timing and turned the motor over by hand for a few minutes with the belt on. everything looks totally 100% perfect.

Fast forward: motor is dropped into the car, we add new fluids, spark plugs, and wires. we primed the motor by cranking it without plug wires connected for a minute or so.

we start the car and it sounds SUPER rough. its running very bad. after a couple minutes of roughness it INSTANTLY jumps to running super smooth and idles perfect.

its running very weird. it got worse when it started running super rough again. it wont stay running on its own and the flashing CEL appeared, we shut it off asap after that.

what would cause the motor to do that? go from smooth to rough, to smooth again then super rough and flashing cel

can i read a code from a flashing CEL?
 

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'MURRICA!
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Get a code reader and read the code. I'd guess that there's something connected wrong.

Also possible is that the compression ratio is different and is causing some sensor to read strange. The ECU cycles through different fuel maps and whatnot depending on engine temperature, intake temperature, etc. so it's possible that the motor warmed up, hit a different idle map, and smoothed out. Then went to closed-loop operation when it was fully warmed up and said "woah w t f mate?!" and started running rough again.

Best way to check is by pulling the code. Flashing cell just means "Oh crap, you might blow the motor so shut 'er down NOW!"
 

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Discussion Starter · #10 ·
i know the flashing CEL means bad things will happen if it keeps running so we shut it off asap. i never thought about the different fuel maps..that makes alot of sense actually..

can a code reader pull a code from a flashing CEL? or only from solid CEL's?
 

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My thoughts, in no particular order:

The flashing check engine light indicates a severe cylinder misfire. Reading it probably won't tell you much other than that, but it's a good idea anyway. You might get lucky and there might be some other codes present that will help you determine the cause of your symptoms.

The crankshaft sprocket should have an arrow and a mark. The MARK is what you want for timing, usually painted white or a simple notch. The ARROW should be pointing to the RIGHT, to the DRIVERS SIDE when the MARK / PAINTED LINE is up. Again, it's the white painted lines that you want to line up, NOT the arrows.

The camshaft sprockets are the same. You want the PAINTED LINE, not the notches or anything else. They should all be at top dead center, lined up with the notch in the plastic above it.

The sohc ej251 and the dohc ej25d blocks have minimal differences. The compression ratio is the most noted, being 9.8 instead of 10.0. As noted above, you want to use the headgaskets for the ej25d, dual cam motor. The other differences are negligible and won't make any difference in what you're doing.

The compression ratio difference will not cause it to run any different.

Did you run the motor when it was improperly timed? If so, it's possible that you have bent the valves inside the cylinder heads.

Which CRANKshaft sprocket did you use, the ej251 or the ej25d? I don't know if there is a difference in the number of teeth, but if there is, that will be your problem.

What spark plugs did you use? NGKs are the best bet. Are they properly gapped?

When priming a motor, you want to unplug the injectors so you don't flood the engine. Unplugging the spark plug wires will do the job, but the injectors will still fire and now you have a whole lot of unburned fuel in the cylinders. That can cause some serious problems. You only need to prime it for less than 30 seconds. A full minute is excessive.

Report back with which crankshaft sprocket you are using and if you used the correct marks for timing, and if you ran the motor with it being improperly timed, and what codes are present. I might be able to further help you from there.
 

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Discussion Starter · #12 ·
My thoughts, in no particular order:

The flashing check engine light indicates a severe cylinder misfire. Reading it probably won't tell you much other than that, but it's a good idea anyway. You might get lucky and there might be some other codes present that will help you determine the cause of your symptoms.

The crankshaft sprocket should have an arrow and a mark. The MARK is what you want for timing, usually painted white or a simple notch. The ARROW should be pointing to the RIGHT, to the DRIVERS SIDE when the MARK / PAINTED LINE is up. Again, it's the white painted lines that you want to line up, NOT the arrows. [/qoute]

i may have used the physical notch on the crankshaft sprocket. ill have to check that. I used the hash marks, not arrows, on the camshaft sprockets


The camshaft sprockets are the same. You want the PAINTED LINE, not the notches or anything else. They should all be at top dead center, lined up with the notch in the plastic above it.
there were no painted lines on the CAMSHAFT sprockets, there were arrows and hash lines/marks. we used the hash marks after finding out that the arrows were wrong

The sohc ej251 and the dohc ej25d blocks have minimal differences. The compression ratio is the most noted, being 9.8 instead of 10.0. As noted above, you want to use the headgaskets for the ej25d, dual cam motor. The other differences are negligible, or at least insignificant and won't make any difference in what you're doing. The compression ratio difference will not cause it to run any different.[/QUOTE=Supers587;2688952]
I used the proper ej25d headgaskets when swapping shortblocks.

Did you run the motor when it was improperly timed? If so, it's possible that you have bent the valves inside the cylinder heads. If not, then something else is wrong.[/QUOTE=Supers587;2688952]
when we had the timing wrong originally the motor was out of the car and we couldnt even turn it over by hand. before we put the motor in the car we corrected the timing via the cam gear marks(we used the hashes instead of the arrows). we turned it over by hand for at least 2 minutes and everything looked totally good.


Which CRANKshaft sprocket did you use, the ej251 or the ej25d? I don't know if there is a difference in the number of teeth, but if there is, that will be your problem.[/QUOTE=Supers587;2688952]
we used the ej251 CRANKSHAFT sprocket, we did NOT swap crankshaft sprockets, i will definitely check on the number of teeth. thanks for the idea

What spark plugs did you use? NGKs are the best bet. Are they properly gapped?
[/QUOTE=Supers587;2688952]
i used the NGK iridium ones for the ej25d, not sure on the actual ones but they start with bkr5 something or other

When priming a motor, you want to unplug the injectors so you don't flood the engine. Unplugging the spark plug wires will do the job, but the injectors will still fire and now you have a whole lot of unburned fuel in the cylinders. That can cause some serious problems. You only need to prime it for less than 30 seconds. A full minute is excessive.[/QUOTE=Supers587;2688952]

i will definitely remember that, i did not realize/think about the dumping of excess fuel in cylinders when priming a motor
 

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Don't mean to hijack, but does anybody know of a thread to refer to for shortblock swaps? Want to know if there is any reason not to use an EJ25D or EJ253 Shortblock in a 2000 2.5 RS, which originally came with an EJ251. This thread is informative, but would like to have more specifics.
 

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Baby❤Daddy
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use this when lining up the cams. the DOHC sprockets make it super simple.





as you can see above..the intake cams on the top, have a single line that should be pointed up. and two lines that should meet directly in the center with the exhaust cams on the bottom, which have the exact same double line markings on them.
 

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Discussion Starter · #15 ·
Got it lined up properly..turns out the block is bad..sucks doing all that work for nothing.

New question though..can a ej25d manifold fit on a ej257 longblock? We plan to leave it NA for now. Could we bolt on the 25d intake manifold and run it?
 

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My guess would be no, EJ25D heads are phase 1. But if you are using EJ25D heads, its a moot point as far as the manifold is concerned. But I would be more concerned about compression ratios, headgasket thickness, and piston to head clearance.

If you are doing a EJ257 longblock, then I can guarantee that the EJ25D manifold doesn't fit. I know the intake manifold pattern is different from phase 1 to STI.
 

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Discussion Starter · #18 ·
I asked because my friend was going to get a deal on a complete longblock and i was unsure of phase 1 to phase 2 intake manifold differences.

turns out that the bold spacing is different on the intake manifolds.

i know we can do a shortblock swap and use the 25d heads but i REALLY dont want to do the same work i just did less than a month ago..(headgaskets..AGAIN)

so, in mind of keeping things simple, were going to not grab the 257 longblock and find a 25d longblock
 

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Did you run the motor when it was improperly timed? If so, it's possible that you have bent the valves inside the cylinder heads. If not, then something else is wrong.[/QUOTE=Supers587;2688952]
First, a note for splitting someone else's post into multiple quotes. The ending "[ /quote]" should be just that; adding the "=Supers587blahblah" means that it doesn't appear as a quote, which makes your post very hard to follow. Above, I left the "=Supers587blahblah" in, so Super's quote doesn't appear as a quote; below, I took it out, and now his quote displays correctly. :)

Which CRANKshaft sprocket did you use, the ej251 or the ej25d? I don't know if there is a difference in the number of teeth, but if there is, that will be your problem.
we used the ej251 CRANKSHAFT sprocket, we did NOT swap crankshaft sprockets, i will definitely check on the number of teeth. thanks for the idea
I think using the EJ251 crank sprocket could be a problem, but not because of the number of teeth. As you can see in the diagram that George of the Jungle posted:

...there are tabs that stick out from the edge of the crank sprocket. Those are what the crank position sensor picks up as the crank rotates, and I don't know if the trigger pattern is the same on an EJ25D and an EJ251. I wouldn't be surprised if they're different, which would certainly explain why the engine was running like crap.

as you can see above..the intake cams on the top, have a single line that should be pointed up. and two lines that should meet directly in the center with the exhaust cams on the bottom, which have the exact same double line markings on them.
FWIW, having done this a number of times on EJ25D's, the cam sprocket marks may not align exactly. I think pretty much every time I've had to turn one or two of the sprockets slightly to get the belt teeth to align with the valleys on the exhaust sprockets.

Got it lined up properly..turns out the block is bad..sucks doing all that work for nothing.
What's bad about the block?
 
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