Topic: What is a good top engine additive for our 2.5's?

[Sine Deviance]

I've got some noise coming from my valvetrain under heavy load. It's rattling, sounds kinda like marbles in a blender. Right now I'm looking for a top engine additive to maybe clear out some of that gunk that could be in there causing the rattling. I was wondering if you guys have any recommendations?

[oldjeep]

That's how the 4 bangers sound, not much you can do about it.

[b.hog]

 Ya sine ,mine sounds like that too.Switched to synthetic and no diff.

[Sine Deviance]

That's how the 4 bangers sound, not much you can do about it.

Ya sine ,mine sounds like that too.Switched to synthetic and no diff.

There's always a cause for valvetrain noise, it is not 'by design.' No valvetrain is supposed to sound like this. I can guarantee you that if you bought a brand-new AMC150 valvetrain and swapped it on your engine, your valvetrain noise would be gone. As your valvetrain ages from use, things get worn out or gunked up or out of adjustment, and you get rattling as a result. Rattling in the valvetrain is a sign that something is amiss, be it low oil pressure, gunk in the hydraulic lifters, incorrect lifter preload, worn lifters, gunk in the rocker arms, incorrect rocker arm adjustment, incorrect valve lash, imperfect valve seats, spark knock (aka detonation) and etc.

My oil pressures are dead-on normal according to the local Jeep dealer service department, so I'm going to bypass that possibility and go straight to gunk. If the additives don't help I'll go to new hydraulic lifters, and if those don't help, new valves/springs and possibly a new rocker arm assembly. Somewhere down the line the rattling will go away. I just figured I'd start with some top-end gunk treatments because that's the cheapest option for a possible fix. In a situation like this, you always try the cheapest possibility first, then move up to the next cheapest, and so-on.

So, once again... any top engine additive recommendations?

[oldjeep]

There's always a cause for valvetrain noise, it is not 'by design.' Rattling in the valvetrain is a sign that something is wrong, be it low oil pressure, gunk in the hydraulic lifters, incorrect lifter preload, gunk in the rocker arms, incorrect rocker arm adjustment, incorrect valve lash, spark knock (aka detonation) and etc. No engine is supposed to sound like this. If the additives don't help I'll go to new lifters, and if those don't help, new valves and possibly a new rocker arm assembly. I just figured I'd start with some top-end gunk treatments because that's the cheapest option for a possible fix. You always try the cheapest possibility first, then move up.

So, once again... any top engine additive recommendations?

Ever listened to a brand new 2.5L - seriously.  I've been around jeeps for a long time, and there are some noises that are just common to them from the day they are born.

[sharpxmen]

There's always a cause for valvetrain noise, it is not 'by design.' Rattling in the valvetrain is a sign that something is wrong, be it low oil pressure, gunk in the hydraulic lifters, incorrect lifter preload, gunk in the rocker arms, incorrect rocker arm adjustment, incorrect valve lash, spark knock (aka detonation) and etc. No engine is supposed to sound like this. If the additives don't help I'll go to new lifters, and if those don't help, new valves and possibly a new rocker arm assembly. I just figured I'd start with some top-end gunk treatments because that's the cheapest option for a possible fix. You always try the cheapest possibility first, then move up.

So, once again... any top engine additive recommendations?

you're right - it shouldn't. I have one lifter (i think) that makes noise when cold and goes away (or makes less noise) once it warms up. I don't experience what you describe under heavy load but to what the other guys said the 4 banger is not the most silent engine either - i am guessing by what you say that the noise is not the normal operating noise of the engine. I don't think an additive would make a big difference (or any for that matter) - i think replacing the lifters is the way to go, they are quite cheap and can be done in an afternoon if you have everything ready. But again, if you're just thinking that the engine is noisy (and not actually related to lifters and for that matter rocker to valve backlash) it's not much you can do - "thicker" oil can quiet that down a bit, but there are trade-offs if you go that route.

[Sine Deviance]

Ever listened to a brand new 2.5L - seriously.  I've been around jeeps for a long time, and there are some noises that are just common to them from the day they are born.

You know... now that I'm thinking about it, you're probably right. I just remembered that Jeep engines run lean from the factory. It could be pinging that I'm hearing and not valvetrain rattle.

I don't think an additive would make a big difference (or any for that matter) - i think replacing the lifters is the way to go, they are quite cheap and can be done in an afternoon if you have everything ready. But again, if you're just thinking that the engine is noisy (and not actually related to lifters and for that matter rocker to valve backlash) it's not much you can do - "thicker" oil can quiet that down a bit, but there are trade-offs if you go that route.

Now I'm thinking I need to try bigger injectors first to rich out the mix a little. If it's pinging that I hear, that should help a little. I think it's finally time for me to buy a set of those FoMoCo 19# injectors.

[sharpxmen]

You know... now that I'm thinking about it, you're probably right. I just remembered that Jeep engines run lean from the factory. It could be pinging that I'm hearing and not valvetrain rattle.

Now I'm thinking I need to try bigger injectors first to rich out the mix a little. If it's pinging that I hear, that should help a little. I think it's finally time for me to buy a set of those FoMoCo 19# injectors.

if you hear constant pinging (and not random knocking/pinging) i would be very concerned as it can damage your pistons and chamber. The 19# Ford injectors flow less than the stock ones at the YJ fuel rail pressure.

[Jesse-James]

The 19# Ford injectors flow less than the stock ones at the YJ fuel rail pressure.

Link please.

[Sine Deviance]

if you hear constant pinging (and not random knocking/pinging) i would be very concerned as it can damage your pistons and chamber.

Unfortunately, I don't know for certain if what I'm hearing is pinging or valvetrain rattle. I only hear it under heavy load, like WOT in 5th gear or driving up a hill.

The 19# Ford injectors flow less than the stock ones at the YJ fuel rail pressure.

Link please.

Same, please. I was under the impression that the 19# FoMoCo Design-III injectors were a drop-in upgrade for us.

[Jeffy]

Ever listened to a brand new 2.5L - seriously.  I've been around jeeps for a long time, and there are some noises that are just common to them from the day they are born.

Yup, even new, they sound the same.  Tick*tick*tick...  It's par the course for an Inline OHV engine.

As for FoMoCo injectors it's 17.3psi vs 17.4psi, very marginal difference.

[Sine Deviance]

As for FoMoCo injectors it's 17.3psi vs 17.4psi, very marginal difference.

Yes but isn't it a difference of flow rate? ~16.5lb/hr factory as opposed to ~18.25lb/hr with the FoMoCo injectors?

[sharpxmen]

Yes but isn't it a difference of flow rate? ~16.5lb/hr factory as opposed to ~18.25lb/hr with the FoMoCo injectors?

it's 18.25lb/hr at 43.5psi, your Jeep runs at 39psi so at that pressure flows less - it's been covered many times with both Bosh and Ford part numbers come to the same flow.

it is marginal difference, my point is you won't be richer once you install them but slightly leaner (minimal though)

[sharpxmen]

Yes but isn't it a difference of flow rate? ~16.5lb/hr factory as opposed to ~18.25lb/hr with the FoMoCo injectors?

it's 18.25lb/hr at 43.5psi, your Jeep runs at 39psi so at that pressure flows less - it's been covered many times with both Bosh and Ford part numbers come to the same flow.

it is marginal difference, my point is you won't be richer once you install them but slightly leaner (minimal though)

the stock one is 17.4lb/hr at 39 psi
Ford 19# Bosch 0-280-155-700 or 710 (can't find the Ford P/N) are rated at 18.25lb/hr at 43.5 psi - resulting flow at 39 psi is 17.28 lb/hr (you can go here and put in the numbers http://www.csgnetwork.com/fiflowcalc.html - there are many online calculators or you can use the formula from the FAQ section).

Link please.

Same, please. I was under the impression that the 19# FoMoCo Design-III injectors were a drop-in upgrade for us.

a good list of injectors and their rated flows:
http://www.justfuelinjectors.com/servlet/the-template/efiflowchart/Page#BOSCH_FORD

Unfortunately, I don't know for certain if what I'm hearing is pinging or valvetrain rattle. I only hear it under heavy load, like WOT in 5th gear or driving up a hill.

probably pinging by the sounds of it, so scratch all i said about the lifters, you should def downshift when you hear that what rpm are we talking about?

[Jeffy]

BTW: for a cleaner try Sea Foam.  You can use it for cleaning just about everything.