So I've got a newly rebuilt "stock" motor with R&D 110 pump and turbo.

One of the features of the R&D pump is the "4K+" governor.

Typically, I like to keep the revs down below 3600, because you lose HP.

However, last weekend in the snow, I kinda revved it high. I was using 2nd gear and reverse to try to get out of being stuck, and I just revved it without looking. I know I pegged the tach at least once(4500+ RPM)(!).
That being said, it didn't sound bad at all from inside. It was smooth and just kinda roared like an engine should(which was why I didn't notice I was getting so high), but I kinda worry about what damage I did or could do.

I am kinda thinking about modifying the pump with a closer-to-stock governor spring, cause 4500 seems a bit high.

Any thoughts?

 

Very good question....

Were'nt the Chevy 6.2/6.5 were governed higher than the 6.9/7.3?

 

I believe they were but also couldn't get out of their own way and blew up regularly. lol you don't see all that many of them on the road these days do you.

 

Mine revs no problem to 4200 on a pretty regular basis, rebuilt and balanced. Another 7.3 i have will start missing about 3300 (right below the factory governor) after talking to some people, seems like valve float.

 

I think that because of the fueling curve and natural rpm derived defueling you'd be just fine. The valvetrain is what I'd be most concerned about and the main reason to avoid ripping it that high. Wish I could hear what an idi sounds like at 4500rpm...

 

Stay tuned to my thread, if it ever warms up enough that my go-pro (read: girlfriend with smart phone) will get in the back for a ride, i need to get a sound clip up with the dual 4"

 

i forget who it was, maybe Dyoungen, but one of the old posters here decide to blow up a 7.3 after it developed a rod knock.. he over boosted and over revved it every day, regularly running 5 grand because the governor in the pump was bad, with over 25 lbs boost.
he ended up blowing clutches and a trans, but pushed the engine for close to two years before finally killing it by blowing a head gasket or something silly

 

That's good.

I'm thinking timing myself... I've had another motor do that on me, advanced the timing and it fixed that.
Chances are that the IP on that engine is wearing, and the timing advance piston isn't advancing as much as it should.

With a 110 pump on there, I don't know about that... My pump benched like 94 CCs at 4K RPM according to the sheet I got with it.

I really should take a video after I drive home one of these days, with everything warmed up and all.


That's... totally awesome. Good old IDIs, just keep working.

 

Is there really a reason to rew it that high other than u can? I thought u are off any good efficiency. More u rew it, the more u stress the pistons, I have seen pistons snap apart right at the piston pin.

 

The dyno is the only thing that can answer that, but according to the pumps and our engines general power band, depending on cam, idea shift point is somewhere around 3600 with a 90cc / 110cc

My 92 with maxxed stock pump and 088 levels off about 2800-3k, but feels level to about 3600 and falls on its face about 3800. Im sure that has alot to do with my leaky 088, im still building boost to about 3500

The sound alone is worth the trip to 4k lol

 

Jan, the camshaft and valve springs are the limiting factor, just like with the gas engines.
a 390 will rev 5500-6000 rpms. a 391 will only rev to 3300 rpm because of the cam and valve springs.
put a 390 cam in the 391 and it will float the valves at 3600-4000 rpm. put 390 valve springs on those heads and that 391 will rev to 5500-6000. the bottom end don't care, it is the top end that makes the difference.

 

So long as you stay below 6k like you said. More than that and you might just wish you did arp rod bolts buddy and i put a way too big cam in his 390 (his idea) pulled really hard to just about 7k. One day i heard him coming up the road, and bang, no more pretty noises.

 

So yeah...
I tried to make a video of how it sounded, and I think(I hope) I broke a valve spring.


I'll be tearing into it tomorrow.
It still runs, fires right off.. but makes a /really/ loud popping noise out the intake. I tried to drive it a little and it worked, but I heard a little bit of a metallic sound when I got off idle, makes me think perhaps the valve is hitting the piston at that point, due to lack of force holding it closed.
This isn't as bad as it could be -- in this engine, the valves are totally square to the piston, so I'm not worried about a bent valve, but am not going to run it like this for fear of the keepers coming loose and dropping the valve.

When I pull the valve covers tomorrow, that should tell me everything.

Either way, that's the answer: If you want to run high revs, make sure your valve springs(I hope) are up to it.

 

Not trying to be an *** but I own a lot of diesels just not in trucks, if you're looking for RPMs you should probably should have just got a V10..... Diesels don't need to rev for power..... Hoping for the best for your engine and good luck!

 

I cant watch vids on this POS, but hopefully you just bent an intake valve or something, and its not closing all the way.