604 grenade......ideas on the how???

[dukesracin]

With my limited budget I decided to buy a used 604 and stick it in my open wheel mod and run points for my first year out. I figured a small track, my rookie driving in open wheel and we might be good finish top 5 most nights.

I found a used 604 in VA, that was being used in a late model for a reasonable price. When we checked out the motor (6 hour drive to VA) I decided to buy the motor after hearing it run in the late model. We proceeded to yank it out and brought it home that night. Everything looked great.

We called the reputable crate guys and got the low down on springs, balancers and headers etc. We put on a good set of springs, Beyea headers and a little balancer. I ran the MR44 plugs and we used Mobil 1 oil like the book calls for. I had a bert trans with the correct flywheel behind it. We turned it 6700rpm on a shorter than 3/8 advertised track and it ran good for 3 races.........then with out warning the oil light came on and I couldn't get out of it fast enough.......BAM.....gone

After tear down we found the block destroyed with 4 fist size holes inside the block and 1 fist size hole on the exterior. 2 Pistons and rods in a million pieces scattered smothered and covered.
The big thing was the BLACK as night crank journals at rods 5/6, it looked like it spun a bearing and then chunked the rods and pistons.

Was it oil pump failure or spun bearing first????

We were able to salvage the heads complete, the intake and valve covers and the oil pan will need a little massaging.....the rest was junk!

Thanks for any thoughts or input you might have

[Dirt Knife]

2 many rpm

See page 9 of tec article.
Not made for that. 5800 to 6200 max max

http://www.chevroletperformance.com/Racing/CT_Tech_Manual.pdf

[Egoracing]

Why did you replace the ballancer and what did you replace it with? The crate motors are ballanced differently than other chevy engines.

[Egoracing]

See page 9 of tec article.
Not made for that. 5800 to 6200 max max

http://www.chevroletperformance.com/...ech_Manual.pdf

We ran one for 3 years above 6200rpm and I know many that run in the 6800 region. I would wonder why it was sold orignally.

[dukesracin]

http://www.jegs.com/i/Professional+P...80010/10002/-1

That is the balancer I used, I replaced it because it was recommended to free the motor up a bit by less rotating mass.

The crate flywheel for the bert trans has the ext balance on it

Thanks for the input

[dukesracin]

Also we bought aftermarket springs lock and retainers, from a reputable crate engine builder, as we were not subject to any sanctioning body or inspections by techs qualified to know what to look for.

Thanks

[Egoracing]

To accelerate something faster you have to look at the moment of inertia which is weight X (Diameter squared). If you look at it from that aspect a 10 lb 5 inch diameter ballancer has a MOI of 250. A 5 lb 5 inch is 125 BUT a 12lb X 4 inch would be 192 so even though it is heavier it will accelerate faster than a 2lb lighter unit.
The problem with the really light units is that they loose dampening ability at higher RPM especially on an engine that is not already ballenced to tight tollerances. This is why people got away from running the 283 chevy ballancer. You may have killed it going to the lighter ballancer.

[dukesracin]

To accelerate something faster you have to look at the moment of inertia which is weight X (Diameter squared). If you look at it from that aspect a 10 lb 5 inch diameter ballancer has a MOI of 250. A 5 lb 5 inch is 125 BUT a 12lb X 4 inch would be 192 so even though it is heavier it will accelerate faster than a 2lb lighter unit.
The problem with the really light units is that they loose dampening ability at higher RPM especially on an engine that is not already ballenced to tight tollerances. This is why people got away from running the 283 chevy ballancer. You may have killed it going to the lighter ballancer.

OK got it thanks......would this balancer kill other standard sbc chevy race motors?
Is it because it lacks the dampening qualities of something like a fluidampner or similar?

[Egoracing]

OK got it thanks......would this balancer kill other standard sbc chevy race motors?
Is it because it lacks the dampening qualities of something like a fluidampner or similar?

Fluidampners don't work well on oval track engines. The engine must be ballanced when built, the more harmonics that it generates the better the harmonic ballancer has to be. If there was a small problem and you went to a lighter ballancer it can allow that problem to grow. I do not trust many ballancers as I have seen all kinds of issues thru the years that have been caused by the ballancer moving, marked wrong, out of ballance, or plain bad. Contact Steve Hendren on here and he can point you into the right direction.

[brad hibbard]

To accelerate something faster you have to look at the moment of inertia which is weight X (Diameter squared). If you look at it from that aspect a 10 lb 5 inch diameter ballancer has a MOI of 250. A 5 lb 5 inch is 125 BUT a 12lb X 4 inch would be 192 so even though it is heavier it will accelerate faster than a 2lb lighter unit.
The problem with the really light units is that they loose dampening ability at higher RPM especially on an engine that is not already ballenced to tight tollerances. This is why people got away from running the 283 chevy ballancer. You may have killed it going to the lighter ballancer.

Ego,
that was a great reply

[dukesracin]

So it sounds like you are saying the balancer killed an otherwise good motor?
I hate to hear that........guess I should have left that alone huh?

Thanks for the ideas

[brad hibbard]

So it sounds like you are saying the balancer killed an otherwise good motor?
I hate to hear that........guess I should have left that alone huh?

Thanks for the ideas

It probably just blew up ---it happens

I was just commenting that Ego made an excellent observation and it may have had an influence on the failure

[billetbirdcage]

So it sounds like you are saying the balancer killed an otherwise good motor?
I hate to hear that........guess I should have left that alone huh?

Thanks for the ideas

Everyone is just throwing out ideas of what COULD have happened. From what you wrote (which is all we have to go on), one thing is obvious it eventually spun a bearing because the rod is black. Now why that happened is only going to be answered by a knowledgeable person taking it apart and inspecting everything. It could be anything from, lack of oil, oiling issues, detonation, and Etc, the only way you'll get an answer is someone to inspect it.

However you do now have some idea on things that could be the cause, which is what I think you where after. But no matter how smart or knowledgeable someone is they can't give you a definitive answer with out doing the inspection. I don't think anyone was implying they could, but I'm just making it clear that if you really want to know for sure what happened, have it inspected by someone.

Hope that helps and better luck in the future. If your close to brad, I'm sure he could inspect it for you as he has a good reputation.

[dynoman14]

Duke,
Ego is right on with the balancer. BTW, that Chinese balancer is pretty much junk, I have spun them up on a Hines and they are 30-40g off on their own ( supposed to be neutral ).

Since we are allowed to balance ASA 604's and they allow a smaller balancer I have seen 10+ ASA engines blow up shortly after the small diameter balancer was installed ( without re-balance ). I have purchased 3-4 of these engines and the reduction in mass on the damper increased the valvetrain harmonics that are pretty bad in these engines about 5200-5300rpms. Valves end up hitting pistons and either a valve head goes missing in the engine or the retainers pop off and lets the valves go flying.

I also followed this up with a similar test on the RCR spintron and the results were pretty wicked just changing from the stock 604 balance to the smaller 6 1/4" GM balancer.

You can reduce some of the harmonics with weight matching on the valvetrain parts. You can also get the valve seats trued up, flat and round and eliminate about 25% of the noise. If you run a little interference on the seat in the head and the valve seat this will also help a lot.

Finding and testing valve springs on a valve spring dyno is a final step and can reduce your valve train noise almost to zero.

[dukesracin]

Everyone is just throwing out ideas of what COULD have happened. From what you wrote (which is all we have to go on), one thing is obvious it eventually spun a bearing because the rod is black. Now why that happened is only going to be answered by a knowledgeable person taking it apart and inspecting everything. It could be anything from, lack of oil, oiling issues, detonation, and Etc, the only way you'll get an answer is someone to inspect it.

However you do now have some idea on things that could be the cause, which is what I think you where after. But no matter how smart or knowledgeable someone is they can't give you a definitive answer with out doing the inspection. I don't think anyone was implying they could, but I'm just making it clear that if you really want to know for sure what happened, have it inspected by someone.

Hope that helps and better luck in the future. If your close to brad, I'm sure he could inspect it for you as he has a good reputation.

I appreciate the input, and yes I was just looking to get ideas and maybe not make the same mistake again. Like Brad stated, it just blew up, it happens.