Thunderbolt V 1999 5.0L high rpm ping

[jy118lfd]

I have a slight ping at Wot 4700 to 4800 rpm. No pinging throughout rpm and throttle settings. Even from when going wot from idle it only pings at the last 5 to 10% of throttle. If I back it down a little it goes away and I can run like that for a long time with no ping. I also can hit the rev limiter and was wondering if this could cause some sort of wierd combustion to make it ping. Timing was set to 10btdc but I backed it off to 8btdc. But really no change as it has the TB5 and can probably add even more timing. It has no knock sensor so how does it know when to stop adding timing? Can a knock sensor and module be added?

I have not checked the timing at wot yet, to see what it is reading but will do so this week.

It has a quadrajet on it and I am going to richen up the secondary side to see if that helps but I needed to understand the ignition side as well.

 

[Haut Medoc]

Re: Thunderbolt V 1999 5.0L high rpm ping

Do you have an OEM manual for your engine or are you just fiddling around with it?......

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

What is that wot supposed to be for the motor anyone know?

You are running this on the water right?

Whats your speed?

What the other gauges doing?

It getting hot?

 

[Haut Medoc]

Re: Thunderbolt V 1999 5.0L high rpm ping

What is that wot supposed to be for the motor anyone know?

You are running this on the water right?

Whats your speed?

What the other gauges doing?

It getting hot?

4400-4800 is WOT.....
Do you have the right plugs gapped to the right gap?....
It should be at 10*, but you have to put it in base mode....
That pinging is detonation, don't run it at rpms that make it ping. especially under load....
Here is the link to your engine manual....
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/24/24covr1.pdf
I would not fiddle with the carb until you look at the ignition side & make sure all settings are correct.....

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Do you have an OEM manual for your engine or are you just fiddling around with it?......

Yes manual 24 1998 to 2001 V8 engines.

The boat is a 24 foot Seamaster walkaround about 5000lbs loaded with a 305 two barrel motor origionally. 220hp V8

With an aluminum 15x 15 prop the boat ran 29knots or about 32 mph(It still hit the rev limiter here but it did not have enough torque to run the 17 pitch prop)

I swapped the stock cast iron manifold and two barrel for a volvo penta 4bbl aluminum intake w/bronze lined crossovers. I built a quadrajet carb for the motor. (I have extensive backround in carbs and worked with a highly reguarded carb shop for the specs.)

The motor now runs better than ever.
I now run a 14 1/4 X 17 apollo stainless prop with a top speed of 35 knots or about 40 mph and it still could use a tad more prop (hits the rev limiter) but I like running it this way cause when loaded for a fishing trip offshore she still averages about 2.2mpg. I barley ever run it wot and was just runing it for top speed fuel burn and rpm when I heard the ping. It does not ping at any other rpm or load. The motor runs 160 degrees all the time and this was verified with my temp gun.

I run 89 octane fuel from the local docks and have no water in the seperator at all. It has the proper plugs and they are gapped to spec

I have no other problems other than the slight ping.

I am having my carb shop machine some smaller secondary metering rods to see if the ping is fuel related as the supply of rods for the quadrajet is getting scarce. This is also the easiest test to see if it is fuel related.

I really just wanted to know how the TB5 adjusts the timing without the knock sensor and how much it can add. The manual shows a chart but it is generic.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Usually with pinging it's the timing. And or dwell not set correct.

However you got the right plugs? Not running hotter plugs than recommended.

Did you build this motor?

Cause maybe valve springs not set right?

 

[Bondo]

Re: Thunderbolt V 1999 5.0L high rpm ping

It has no knock sensor so how does it know when to stop adding timing? Can a knock sensor and module be added?

Ayuh,....

I thought that was a Major selling point for the T-Bolt Vs,..??

All the 1s I've come across are so equiped....

 

[JustJason]

Re: Thunderbolt V 1999 5.0L high rpm ping

all the ones i've seen had a knock module as well...... that's how they get their "MBT" or "mean best timing"... by advacing the engine to induce a knock.... then backing off.
I've heard though..... never seen, just heard.... that early TBV's did not have a knock module.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Ayuh,....

I thought that was a Major selling point for the T-Bolt Vs,..??

All the 1s I've come across are so equiped....

I wish that was the case and I probably wouldn't have even needed to post this problem.


If you note in the link below line 46 (knock module) and 47 (knock sensor) it states 5.0l bravo and 5.7 alpha/ bravo. None listed for a 5.0L alpha. It also lists the 5.0l alpha ing. module and a 5.0l bravo ing. module so it is not supposed to have the knock module or sensor. The thunderbolt 5 module on the motor say 5.0L alpha Gen+ on it. I have owned the boat since new and know it is all stock.

The motor is stock 1999 with 500 hrs and all I did was swap a carb and intake. So I follow the 5.0 2bbl 1998-2001 with the proper serial number when I need parts.



http://www.ishopmarine.com/ishop/js...&isForSupStore=false&cCatFilter=&eCatSupFldr=

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Usually with pinging it's the timing. And or dwell not set correct.

However you got the right plugs? Not running hotter plugs than recommended.

Did you build this motor?

Cause maybe valve springs not set right?

I did not build the motor. The preload on the lifters has not been messed with. Nor would it cause pinging.

No dwell to mess with. Timing is set to 8 degrees btdc with the module in base timing mode. The spec is 10.

Now that I think of it I swapped the plugs this year and put in the correct number plug but they were the NGK Iridium Plugs. Do you guys think they could cause it?

 

[John_S]

Re: Thunderbolt V 1999 5.0L high rpm ping

I checked MercruiserParts.com and it indicated no knock module or sensor on a 98-01 5.0L carb (2brl) alpha. It was common on 5.0L and 5.7Ls prior to vortec heads. Also, when I checked, V6 4.3L carbed, didn't have them.

It will be expensive to add it: sensor, wiring harness, new advance module, knock module, etc. $$$

You need to use an advance timing light to see what the total advance is at wot. I thought reducing the initial advance would lower the total on non-knock module T5s. Also, try running in base mode and see how the wot timing behaves.

Try reducing initial by another 2 degrees, or running higher octane fuel.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

It ran ok with a different brand of plug?

Could be. To hot a plug.

Did you check the plugs before your started with the timing.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

It ran ok with a different brand of plug?

Could be. To hot a plug.

Did you check the plugs before your started with the timing.

Never ran it with the 4bbl and 17 pitch prop with another plug.

I am going to check the total advance at wot.

Then I will swap the plugs to see if it helps. It is not too hard to do on this boat. About a 20 minute job.

 

[98LSWON]

Re: Thunderbolt V 1999 5.0L high rpm ping

I could be a little bit of carbon build up inside the combustion chamber, effectively increasing your compression. Seafoam would help that.....if thats your problem. I'm with everyone else though, pinging is usually timing related, or a bad tank of gas.

 

[MikDee]

Re: Thunderbolt V 1999 5.0L high rpm ping

A metering rod change? Don't do it now, a lean condition with advanced timing, or preignition, is a dangerous combination!

It sounds like you did everything right with the swap.

By the way, that sounds like a lot of boat for a 305?!
I had a 24' SeaRay Cuddy (4000lbs) with a 350/260hp and I was on the edge running a 17" pitch prop, mostly light loads.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

A metering rod change? Don't do it now, a lean condition with advanced timing, or preignition, is a dangerous combination

The metering rod change will add fuel not remove it. With a smaller rod in the secondary's, more fuel can pass by the jet and it will richen the mix. It is a simple change but I don't have the rods, I have to have my friend make them and they have to be shipped to him in Ohio. Detonation can also occur if the mix is to lean. As we said a few years back when I drag raced "Lean is Mean" or the more you leaned it out the more power you could make until you put a hole in a piston.


What makes me think it is not enough fuel is at WOT I am burning 21gph But if the motor no makes an additional 30 to 40 hp with the carb and intake swap. (A consertive assumptions by the speed increase and the need for a prop change) I should be burning between 24 and 27 gph. Not that I want to burn more fuel but it needs the right amount of fuel.



You are right that it is alot of boat for a 305 . I plan on putting a 5.7 in it when this one wears out. I the last 3 years I have put about 185 hours a year on it.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Here is a pic of the boat so everyone knows what we are working on

 

[180shabah]

Re: Thunderbolt V 1999 5.0L high rpm ping

Can we back up just a little bit? I don't see where the fuel has been tested for water contamination. He states that he does NOT have a water seperator. We could be getting way too deep into a problem that doesn't exist.

Run it on an outboard tank filled with fresh gas and see what it does. Then add a water seperator - you need one regardless of the outcome.

 

[MikDee]

Re: Thunderbolt V 1999 5.0L high rpm ping

The metering rod change will add fuel not remove it. With a smaller rod in the secondary's, more fuel can pass by the jet and it will richen the mix. It is a simple change but I don't have the rods, I have to have my friend make them and they have to be shipped to him in Ohio. Detonation can also occur if the mix is to lean. As we said a few years back when I drag raced "Lean is Mean" or the more you leaned it out the more power you could make until you put a hole in a piston.


What makes me think it is not enough fuel is at WOT I am burning 21gph But if the motor no makes an additional 30 to 40 hp with the carb and intake swap. (A consertive assumptions by the speed increase and the need for a prop change) I should be burning between 24 and 27 gph. Not that I want to burn more fuel but it needs the right amount of fuel.



You are right that it is alot of boat for a 305 . I plan on putting a 5.7 in it when this one wears out. I the last 3 years I have put about 185 hours a year on it.

I just reread your post, and realized you were intending to richen it some with thinner m. rods :redface: instead of leaning it, a good idea! Yes, a lean mixture can cause preignition also, as well as an engine running hotter then normal, (but yours is running nicely cool), or under too much of a load. It sounds like you have your bases covered, But I have a question, aren't the metering rods totally out of the rear main jets at WOT? If so, then you need bigger jets, instead of thinner rods, no? I would say yes, you need more fuel with that 305, simply because of the load you're carrying with that heavy boat, that maybe the answer to your problem?

By the way, NICE Boat!

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Can we back up just a little bit? I don't see where the fuel has been tested for water contamination. He states that he does NOT have a water seperator. We could be getting way too deep into a problem that doesn't exist.

Run it on an outboard tank filled with fresh gas and see what it does. Then add a water seperator - you need one regardless of the outcome.

No water IN the seperator not that I have no water seperator. I also changed the filter just to be on the safe side. Ran it on multiple tanks of fresh fuel. It pings the same. I thought it could have been the 87 octane from the gas station. So I switched to the 89 available at the docks and had no change.