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Hi,

 

I'm just curious...I know that both EJ22 and EJ25 motors were converted to solid lifters by the time my 1998 Impreza was produced.

 

Did this design change make them into interference engines? I've seen information that shows the EJ25 is an interference engine, but the EJ22 isn't...but that was for the older hydro-head EJ22.

 

-Jon, worrying a bit about the possibly 75,000 mile-old timing belt...

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If you have a solid lifter EJ22, you have an interferential engine. The '99 is a one-year-only engine. Previous to that, there was a 4 month only version also, but we haven't seen that one yet.

If your date of manufacture was in '97 sometime, you should be ok.

 

Emily

http://www.ccrengines.com

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From reading, it's my impression (and I hope someone will confirm) that, in Subaru engines, the interference comes from valves striking each other. That is, there may (anyone) be no Subaru engine that will hit piston to valve.

 

Also, (again from reading and looking at drawings of engines) the interfderence engines have dual overhead cams (4 cams per engine) and this calls for a more acute valve angle such that they can hit each other under TB failure conditions. I've seen NO mention of lifter 'style' changing this fact. If you have 1 cam per 'side'. It's non-int.

 

Carl

1 Lucky Texan

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Thanx Emily!

 

So, is it the late 2. - wait...

OK, is the presence of solid/hydro lifters an indicator?

 

is there a LIST of EXACTLY which engines are NON-interferential?

 

 

Carl

1 Lucky Texan

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Now I AM Confused !!!! My 1990 Legacy 2.2 went thru a failed timing belt, broke about 40 miles from home on the NY Thruway after waterpump seized...Little or no warning. Had it flatbedded. Replaced Pump and belt, went 160K more before it was hit.

My 2002 Forester (2.5 w/solid lifters) states in the service manual that there are Valve Depressions on the surface of the pistons to prevent interference in the event that the timing belt fails.

HUMMMM.....

If I do my PM, as I have always done, and have a failure, as I did on my Legacy, now I'm uncertain as per the above comment which I should believe as they ARE in the engine business, as to the survival of the current 2.5L......:-\

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I contacted SOA regarding my 2002 Forester. Emily at CCR is correct. I don't like it having gone thru a failed belt on my 1990 Legacy, but here's Subaru's answer:

 

 

 

Thank you for taking the time to contact us. Your 2002 Forester has an interference engine. Therefore, if the timing belt were to break, it would cause further damage to your vehicle. We recommend that the timing belt be inspected at every 30,000 mile service interval and replaced at the 105,000 mile service interval.

Thanks for the opportunity to be of assistance. If you need any future assistance, please feel free to contact us again.

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I wish a list could be compiled as to which engines are NI and which ones are benders.

 

This question always comes up.

 

 

Carl

1 Lucky Texan

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On many vehicles with timing chains or gears extreme over reving can cause valves to contact pistons.

I understand that even my M series BMW can blow the heck up if you select the wrong gear on a downshift.

I have changed valves on even tough stuff like a 534 International when a guy managed to select second instead of fith. (On the freeway no less.)

If one blew a downshift with a 2.2 do they ever tangle?

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My cousin missed a up shift in my dads 90 legacy 3rd instead of 5th the engine at least went up to 7500-8000, rpm, nothing bad happened yet, 100,000 miles later.

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OK, guys. Here's my best shot.

 

EJ22

'90-96. Non-interferential, definitely.

'97 and 98 are a little fuzzy. Seems that somewhere in the late '97-98 MY there were changes, some of which we haven't seen yet. Late '98, if it looks like a 2.5 SOHC (only 2 timing covers on the front), extremely likely it's interferential. One of these is a 4 month only engine.

'99 EJ22 is definitely interferential. We've done 3 in the last couple of months. 1 year only engine.

 

EJ25

All are interferential, no matter what year, both DOHC and SOHC.

 

EJ20

Interferential

 

 

It's valves that hit pistons. We have part of one piston that was hit so hard that the only thing remaining intact (sort of) is the head (flat side) and what's left of the ring landings. The head is actually in 3 pieces and is being held together by the rings which are "mostly" still in the grooves. The wrist pin was in the oil pan.

 

And the failure doesn't have to be as catastrophic as a broken timing belt or failed tensioner. If the belt is off by as much as 3 teeth, it can and most likely will cause valve/piston damage.

 

If I have ever "preached" maintenance and using Genuine OEM parts, I do it doubly for these engines! Change your oil and never, ever, under any circumstances let them overheat! Use the right octane of gas too. We see burnt exhaust valves in 3 out of 5 engine cores that were replaced for a different problem!

 

I'm sure Rick (the Master Rebuilder himself) :clap: could add to this.

 

Emily

http://www.ccrengines.com

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What you are refering to with the downshift destruction, is actually valve "float". This can and will happen eventually on ALL engines with spring valve returns. The engine gets going so fast that the spring doesn't have time to close it before the piston strikes it - in older pushrod engines, this often meant a bent pushrod, and probably a busted valve too. High performace engines combat this with stronger valve springs, but this is a slippery slope. Hotter valve springs cause increased wear on the rest of the valve train, and you end up eating cam shafts, and you need better spring retainers, etc. You end up having to upgrade everything to get them going really fast. SOA got a justy up to around 12,000 RPM's, but it needed a LOT of engine work to get there without blowing up. Back in the day, before electronic ignition modules, this would happen with the points in your disty. You get up to 8,000 or 10,000 RPM's and the points float - then no more spark, so the engine cuts out. They combated this with dual point systems, and even tri-point systems. The tri-point systems required a LOT of patience to get tuned right, cause the tolerances were so close. IIRC, the tri-point stuff was good upwards of 15,000 RPM's or so.....

 

GD

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valve gear. The first time I heard of this was reading about the Desmo Nortons when I was riding Nortons in the late 60s and 70s.

But back on subject, it looks like from what you folks say we should have no fear of valve float on over revs.

By the way that old International I mentioned bent every single valve. With stellite valves that cost a fortune. No holes in those tough old forged pistons though.

I missed a shift on a 327 solid lifter Chevy once and put a pushrod hole through the valve cover.

From what I hear from you folks I will be changing my timing belt

like the pope changes his underwear.

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