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Hi I have a 6v53t in my boat that I converted from a truck motor. It is 233hp at 2500 rpm with 5a55 injectors.
I have bought a brand new set of ex military 5c60 injectors still in the box that I am going to install.
My questions are

What sort of gain in HP could I expect to gain. I need to know this to get the correct prop.

What injector timing should they be set at.

What benefits will these injectors have over the 5a55.

Thanks
Gordon
 
There is a lot of this stuff out on the innerweb and some of those blog boys know WAY more than me about THIS. So, you may want to do (if you haven't already) a thorough search before taking anything I say as gospel.

I know that the smaller 5a55 will deliver approximately 58ml per stroke as compared to it's bigger brother the 5c60 at around 68ml...so you got that going for you...as in mo fuel. SOooooo. a swag would put the power increase POSSIBLE at anywhere from 20 to 40hp conservatively....depending....ON WHAT YOU SAY?...well...lots of things.

As in..turbo..blower..you didn't list a B in the headline so I'm guessing it is NOT bypass valved. It's simple really...if you can BURN the additional fuel EFFICIENTLY then you will gain the HP. If not...then you're just pouring money into the atmosphere. So, tune is important as well as air movement. Unrestricted intake + unrestricted exhaust is essential along with no induction leakage and well lubed T-bearings.

I would think, from what I've read, that this should be a good match and provide you with what you seek...a few more MPH on the water?...I'm guessing.

As far as timing these, I have to go with 1.460" because I don't really know. The way it goes when trying to "squeeze" some ponies out of these is that taller (1.465-1.470) advances the timing and shorter (1.450 etc...) retards. 1.460 is a "safe" place to start and, I would think, be near optimum. I read that the 5a55 is at 1.460 so I think the 5c60 would be there too since it's mostly a volume thing that is achieved internally within the injector body.

I know of no gearhead that EVER retards an engine to gain horsepower BUT it WILL run COOLER that way and THAT is pretty important. If you find that your exhaust gas temperature (EGT) goes high...900*F or higher consistently...you might consider making some changes to increase engine life and bring it back down under 800*F.

Of course, if you don't run pyros then you won't know anyway. So there's that.

Like I said, I'm no expert but you asked so I butted in.

Good luck.
 
Thanks jgmo

From what I have seen of your postings you understand Detroits a lot better than me. I am a motorcycle mechanic that has been off the tools for over 20 years. I am in New Zealand and I don't seem to be able to find someone that can think outside of the square.

You are correct I do not have a by pass on the blower.
My turbo is a rebuilt TV6123 and exhaust A/R 1.05

There are no intake or exhaust restrictions.

I have water cooled marine exhaust manifolds so I was unsure about the true reading from a EGT so I have not gone down the expense of installing one.

The 5C60 injectors are brand new and on there way from Canada to NZ as I write this

I have N55 injectors at the moment and no black smoke at all.

So if you can offer some more advise I am keen to learn

Regards
Gordon
 
To get a blower bypass do I need to buy a complete blower with a bypass valve or can I just buy the bypass and fit it to my6v53t blower?

Thanks Gordon
 
While I imagine ANYTHING is possible, I will say that the bypass passages are cast in and are integral to the blower housing. You would need to purchase a blower even though the valve itself is a separate item. I've never heard of anyone modifying an old blower to work with the valve.
 
I just wanted to revisit exhaust temp with you and say that, when bumping up horsepower by adding and burning more fuel, the EGT does typically go up. Other than poor oil maintenance or a weak cooling system, elevated EGT is a PRIME KILLER of these engines.

While I don't think that the modifications you have in mind will do any harm, it will not hurt to keep an eye on the EGT situation. Get yourself an infrared, non contact thermometer and "shoot" the temps on the manifolds or any "raw" metal just aft of the turbo outlet while the boat is being driven hard. If you do this right after your improvements, you would be well served to write down the results in your log so that you have a baseline database.

These little thermometers are handy dandy little "owner" tools and can also be used for troubleshooting. If you have a dead miss, shoot each leg of the exhaust manifold to find the cool cylinder and identify the one that's not firing.

Also, shoot the temps on your gearbox and prop bearings or stuffing box and put that in the log for a database and then sample from time to time to detect trouble "brewing".

You can also use one to fine tune your coffee pot for optimum performance. :~{)
 
I hear what you are saying.
I have ordered a EGT from the states so as I can install before I do any changes and get some readings then start my improvements.

If I got one as you suggested perhaps I could monitor my home brew temp a lot better as well.

The problem here in New Zealand is that there are very fey two stroke Detroit guys that know there stuff.
Thanks for your help and I am sure to be back for more advise.

Regards
Gordon
 
Well don't feel too bad, I don't think there are all that many good 2 cycle guys left in the States any more either.
 
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