Failed leak-down test - next steps?

[cornerbalanced]

Recently purchased an E46 M3 off Bring-a-trailer. Had the car inspected today (w/ leak-down test), and the car failed the leak down test. While cylinder 1, 2, 3, 5, and 6 hand between 3%-9% psi, cylinder 4 had 14%. Strom (the shop inspecting the car) borescoped the engine, and found 'pooled' oil, and some slight scoring (pictures attached).

The engine was initially built by an ex-PTG mechanic. 3.4L, billet marine crank, CP pistons, and what are believed to be pauter rods. The engine was more recently (re)assembled by Strom Motorsports. Strom, who did the leak down test, suggested the tune could have caused this problem (cylinder ring blow-by).

Just wanted to hear some more thoughts. I am extremely ignorant on this subject. Engine needs to be completely torn down now??

[oceansize]

I remember this, a 3.4l stroker.

What you led you to do the test? Are you having performance issues or excessive oil consumption? If not I'd say buy a replacement engine and rebuild it, drive this one until it dies, then swap in the rebuilt. However, I don't know your budget, but you took a chance on a $40k stroker so you ain't broke lol. If you don't want to do that or your having issues then you have no choice but to tear it down and ponder options based off that. Scoring certainly looks significant.

[Slideways]

Man, that is unfortunate OP. As ocean said, is it drivable or does it have some issue that made you do the leak down? Misfire or excess oil consumption?

If you want to save the high priced internal components from damage, you'll probably have to have someone take it apart and rehone the cylinders and rering the pistons. Anri in SoCal is probably who you want to talk to since he seems to do proper rebuilds on these engines.

It is a bit of a toss up. Either you buy a used engine or spend the used engine funds to fix this one. Or trade for a stock engine if there is any interest.

[cornerbalanced]

Man, that is unfortunate OP. As ocean said, is it drivable or does it have some issue that made you do the leak down? Misfire or excess oil consumption?

If you want to save the high priced internal components from damage, you'll probably have to have someone take it apart and rehone the cylinders and rering the pistons. Anri in SoCal is probably who you want to talk to since he seems to do proper rebuilds on these engines.

It is a bit of a toss up. Either you buy a used engine or spend the used engine funds to fix this one. Or trade for a stock engine if there is any interest.

Nothing particularly led to the leak down test - more so wanted to see the overall health of the engine. The car consumed (some) oil…haven’t driven it enough to pinpoint exactly how much it’s consuming. Still pulls extremely strong…but I have never driven another stroker, so it could still be down on power.

[Anri]

The engine was more recently (re)assembled by Strom Motorsports

.


Hi,

Congrats on your New toy.

I am little lost with your statement.

Strom had this engine all apart ?

Strom, who did the leak down test, suggested the tune could have caused this problem (cylinder ring blow-by)

You should log in to your tune and find out assuming
you are on factory ECU ?

Have Strom or I can have Tomba look at your
map and we can see how its tuned. I highly doubt
that the tune can be the cause. Most tuners if not all
do play safe no one wants broken engines for the last
4rwhp.

I am working on a S54 stroker concept of mine
and improved the Issues stroker engines do
face. S54 is a platform taken to the limit and
passing this limit is dangerous but I faced the
challenges.

Not saying this is the case here but In general
when people sell Performance hot-rod in this
case Stroker-S54 is because of a problem.
The previous owner took it to his shop, they did
what you did and the shop says sell it or $40k

For the fun, I would take this car to a Dyno-Jet
and see what it does.


Stroker engines with +1 size over pistons at
87.25mm this combo will increase the engine
temperature. Its no doubt that the side load
is increased via the increased stroke anything
beyond the OEM 91mm (I think Marine is 94mm)

You have issues on Bank-2. I keep preaching
Bank-2 on inline-6cyl suffers from increased
heat and this causes issues...


Regards,
Anri

[cornerbalanced]

.


Hi,

Congrats on your New toy.

I am little lost with your statement.

Strom had this engine all apart ?






You should log in to your tune and find out assuming
you are on factory ECU ?

Have Strom or I can have Tomba look at your
map and we can see how its tuned. I highly doubt
that the tune can be the cause. Most tuners if not all
do play safe no one wants broken engines for the last
4rwhp.

I am working on a S54 stroker concept of mine
and improved the Issues stroker engines do
face. S54 is a platform taken to the limit and
passing this limit is dangerous but I faced the
challenges.

Not saying this is the case here but In general
when people sell Performance hot-rod in this
case Stroker-S54 is because of a problem.
The previous owner took it his shop they did
what you did and the shop says sell it or $40k

For the fun, I would take this car to a Dyno-Jet
and see what it does.


Stroker engines with +1 size over pistons at
87.25mm this combo will increase the engine
temperature. Its no doubt that the side load
is increased via the increased stroke anything
beyond the OEM 91mm (I think Marine is 94mm)

You have issues on Bank-2. I keep preaching
Bank-2 on inline-6cyl suffers from increased
heat and this causes issues...


Regards,
Anri

I might be due for a visit to your shop…

Backstory: Initially this engine was built by an ex-PTG employee (parts listed in original post). A friend of the owner of the car was driving it on track, and overheated the engine.

When the engine was overheated, Strom disassembled the engine, and rebuilt it (invoice attached). The car runs extremely, extremely cool — PWR radiator, AC condenser removed, Motorsports thermostat. It takes me maybe 20-30 minutes before oil temp gets to 180-200 degrees. Coolant tempt stays at first dot no matter what.

Just not sure why there is piston ring blow by…or what I need to do with this engine next. I’m worried the block is toast, since it has been bored out once (when it was stroked to 3.4L)…then the bores were cleaned again when Strom rebuilt the engine.

You think it’s safe to run on a dyno-jet in its current state? (Poor leak down, and that cylinder wall scoring in the pic)…I’m fairly confident the seller wasn’t just trying to dump this car on me. His car collection far exceeds $10,000,000. The value of this car is more or less a rounding error, he is selling one of his properties and needed more space for other cars.

[Anri]

Strom rebuilt the engine.

Hi,

Thanks for your reply.

I am still confused here and please correct me if I am wrong.

So you are saying that this engine was all apart 4years
ago and it has covered what may be 5000 miles? assuming
the car Collector barely drove it.

I am still confused from the build concept. Is this 3.4 engine
requires to be rebuild every few thousand miles ?

I did not see any Milage/Warranty provided ? or none?

For sure you have 55C t-stat and having the AC condenser
removed it helps a lot with cooling.

Just not sure why there is piston ring blow by…or what I need to do with this engine next

Several reasons to have blow by (I don't want to go
in details)So much to say but I prefer to be reserved.

Making pulls on the dyno whit your 14% leak down
is not a problem. In the bill it shows that the bearings
are replaced so assuming they are in good condition.

Go for a Dyno-Jet and let's see how much power it
puts down. But please if something goes wrong with the
engine please don't finger point me ask the engine builder
directly. Let me know if you need DynoJet service I can
sent you to Jery who has tons of E46M3 dynos.


You have 2 options here; a) drive it as is. b) if bothers you that
the condition of your stroked S54 is not what suppose to be then
chose your engine builder and do it right with max of 3-4% leak down
on all 6 holes.

Did you sell your E92M3 to go back to E46M3 ?

Regards,
Anri

[cornerbalanced]

Hi,

Thanks for your reply.

I am still confused here and please correct me if I am wrong.

So you are saying that this engine was all apart 4years
ago and it has covered what may be 5000 miles? assuming
the car Collector barely drove it.

I am still confused from the build concept. Is this 3.4 engine
requires to be rebuild every few thousand miles ?

I did not see any Milage/Warranty provided ? or none?

For sure you have 55C t-stat and having the AC condenser
removed it helps a lot with cooling.







Several reasons to have blow by (I don't want to go
in details)So much to say but I prefer to be reserved.

Making pulls on the dyno whit your 14% leak down
is not a problem. In the bill it shows that the bearings
are replaced so assuming they are in good condition.

Go for a Dyno-Jet and let's see how much power it
puts down. But please if something goes wrong with the
engine please don't finger point me ask the engine builder
directly. Let me know if you need DynoJet service I can
sent you to Jery who has tons of E46M3 dynos.


You have 2 options here; a) drive it as is. b) if bothers you that
the condition of your stroked S54 is not what suppose to be then
chose your engine builder and do it right with max of 3-4% leak down
on all 6 holes.

Did you sell your E92M3 to go back to E46M3 ?

Regards,
Anri

Really appreciate your input as always.

Correct—Strom rebuilt the engine roughly ~4,000 miles ago (all track mileage) in 2020. The engine was only rebuilt because it was overheated. I believe they have a two year warranty, so unlikely they are willing to work with me. It’s far from a true race engine. Has 12:1 compression, was built to be reliable above all else. Not to set any NA horsepower records, or rev to the moon. The collector I purchased this E46 from has 3 others with 3.4Ls (near identical builds) and has put a combined 100,000 track miles on them without catastrophic failure.

And sounds good re: dyno. I typically go to EAS for dynojet, but if Jery is closer, happy to take my business to him. Would 100% want to have the tune inspected before hand to ensure no major red flags.

And correct, sold to get back into an E46–but maybe bit off more than I can chew! I have poor luck with E46s. I had to replace the engine in my last one too.

[Anri]

Really appreciate your input as always.

Correct—Strom rebuilt the engine roughly ~4,000 miles ago (all track mileage) in 2020. The engine was only rebuilt because it was overheated. I believe they have a two year warranty, so unlikely they are willing to work with me. It’s far from a true race engine. Has 12:1 compression, was built to be reliable above all else. Not to set any NA horsepower records, or rev to the moon. The collector I purchased this E46 from has 3 others with 3.4Ls (near identical builds) and has put a combined 100,000 track miles on them without catastrophic failure.

And sounds good re: dyno. I typically go to EAS for dynojet, but if Jery is closer, happy to take my business to him. Would 100% want to have the tune inspected before hand to ensure no major red flags.

And correct, sold to get back into an E46–but maybe bit off more than I can chew! I have poor luck with E46s. I had to replace the engine in my last one too.

1-2 Year/s pass and Warranty is out the window it does
not matter the miles which is normal.

Usually engines which are used hard on the track
needs more attention, meaning checking things more
frequently, lash, compression, leak down, bearings etc.
assuming all begins at perfect set up.

It is also important how hard it has been used at the track.
I will example ButtonWillow track. If one does CW13 2:10min
with E46M3 then it will really last 100.000miles....lol
but if I see lap times on say NT01s at ~1:56min no aero
means the driver really pushes the car to its limits!

I believe EAS is closer to you in OC. Jery is in Canoga
Park.

Used old car problems....No guarantee that something is not
going to let go in the engine unless fully rebuild and you
begging driving it.

Boy no AC in So.Cali is not fun at all....

I am keen from the result.

Keep us posted.

Regards
Anri

[Anri]

but I have never driven another stroker, so it could still be down on power.

Hi,

In most cases when people hear "Stroker-S54"
the mind game is "Big" its going to be a monster.

One must look at the displacement increasement
over stock.

From 87x91= 3246cc

Stroker 87x94=3353cc

This is only 107cc. To take proper advantages from
the 107cc one must alter the VE. Most gains will be
in the mid range, not so much on top. To have gains
on top one must significantly port the head.

Strokers really shy out from idle up to ~5k thanks to the
pistons moves more air pass TDC via the increased stroke
but for max HP the VE must match the CC/BMEP but other
issues will come to play.


With this increased deck height M20 block design taken to
its limits the gains are very small but I can take advantages
from it to improve the mid range punch on S54s.

The limitation on the S54 is the bore and nothing can be done...





Little comparison: Working parallel with the S54 stroker
crank I also completed S38 Stroker crank its sent out for
production.

The std small displacement S38 is 93.4mmx84 stroke=3453cc

My upcoming S38 will be 4125cc. If I get greedy I can push to
4200cc but would not install this on customers car, for my race
car sure. The safe limit is 4125cc.

From 3453 up to 4125cc now that is a massive cc increments.


Regards,
Anri

[digger]

I would just keep driving it without fear (assuming bearings are ok )

[TexaZ3]

Do another leak down test - could be an error, unless confirmed by another test.

[Anri]

Do another leak down test - could be an error, unless confirmed by another test.

Alex,

The amount of oil he has on top the piston
indicates something is going on.


I know how you think, hope dies at last..but it
won't hurt to confirm the first test.


Regards,
Anri

[TexaZ3]

Alex,

The amount of oil he has on top the piston
indicates something is going on.


I know how you think, hope dies at last..but it
won't hurt to confirm the first test.


Regards,
Anri

I know. But LD is rather easy to do so why not? I'm not a huge specialist on the issue, but could the oil be there due to a different issue?