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As many know we built a twin turbo with the guidance of Mark Unchained. Got it going late in the season last year. Made way too much power. I was told it would by Mark and Hass. Had a few problems and eventually kept it in one piece.

Spit the belt driven fuel pump drive out one day testing. It lean popped but seemed OK. Had low boost one test session and found a silicon coupling was blowing loose under boost. lol. Lost oil pressure one day testing and found the crank had flexed hard enough to knock the oil pump loose. Had clearanced the pump to clear the crank during assembly. Caps had walked pretty hard. Changed the bearings and took some timing out. Put one piston in the lathe and opened up the ring grrove where it had pinched rings a bit.

Missed the race we were trying to get to.

Got it going again. It ran so hard almost blew it over testing. Killed another set of bearings. Missed another race. Caps walking pretty bad. Crank was not pretty Our friend and Shazam CC Mike Boyce said it has to be timing. Crap we are running methanol 9.4 compression and only have 33 degrees of timing. Called Brodix and they confirmed 31 degrees max with the Head Hunter heads.

Decision time. Wanting to get to the World Finals. Asked Info Jr. what does he want to do? All we have time to do is roll in another set of bearings and back the timing off. We decided to go for it. Make a few passes and check the oil filter. If it's good keep going, if it's ugly pack it up and bring it home in one piece

Set the timing to 27 degrees went to the WF made a couple really good passes. Checked the oil filter and it was ugly. :mad: Has to be an oiling issue.

Brought it home and didnt touch it all winter. Pulled the engine a couple of weeks ago. It had only killed the rear main bearing. Everything else looked great. As it turns out the rear main on the crank was not happy and the block line hone on the rear main was not either.

Analysis. Damaged it with too much timing. Did not have it apart the last time to find out the crank and block was not happy.

Just set the engine back in the boat yesterday. Ground the crank and line honed the block. Put a Titan oil pump on it. Thanks Steven Gearhead. New piston for the one we repaired. Should last all season this year. :shock:

Current challenge: getting control of the boost.

Couple pics of upgrades. Oil pump and bigger oil lines going to the Oberg filter. Moved the corner of the oil pan out to clear the pump. Very lucky it was so simple. Info Jr. getting the boat ready to drop it in.





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steelcomp was here
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As many know we built a twin turbo with the tune up guidance of Mark Unchained. Got it going late in the season last year. Made way too much power. I was told it would by Mark and Hass. Had a few problems and eventually kept it in one piece.

Spit the belt driven fuel pump drive out one day testing. It lean popped but seemed OK. Had low boost one test session and found a silicon coupling was blowing loose under boost. lol. Lost oil pressure one day testing and found the crank had flexed hard enough to knock the oil pump loose. Had clearanced the pump to clear the crank during assembly. Caps had walked pretty hard. Changed the bearings and took some timing out. Put one piston in the lathe and opened up the ring grrove where it had pinched rings a bit.

Missed the race we were trying to get to.

Got it going again. It ran so hard almost blew it over testing. Killed another set of bearings. Missed another race. Caps walking pretty bad. Crank was not pretty Our friend and Shazam CC Mike Boyce said it has to be timing. Crap we are running methanol 9.4 compression and only have 33 degrees of timing. Called Brodix and they confirmed 31 degrees max with the Head Hunter heads.

Decision time. Wanting to get to the World Finals. Asked Info Jr. what does he want to do? All we have time to do is roll in another set of bearings and back the timing off. We decided to go for it. Make a few passes and check the oil filter. If it's good keep going, if it's ugly pack it up and bring it home in one piece

Set the timing to 27 degrees went to the WF made a couple really good passes. Checked the oil filter and it was ugly. :mad: Has to be an oiling issue.

Brought it home and didnt touch it all winter. Pulled the engine a couple of weeks ago. It had only killed the rear main bearing. Everything else looked great. As it turns out the rear main on the crank was not happy and the block line hone on the rear main was not either.

Analysis. Damaged it with too much timing. Did not have it apart the last time to find out the crank and block was not happy.

Just set the engine back in the boat yesterday. Ground the crank and line honed the block. Put a Titan oil pump on it. Thanks Steven Gearhead. New piston for the one we repaired. Should last all season this year. :shock:

Current challenge: getting control of the boost.

Couple pics of upgrades. Oil pump and bigger oil lines going to the Oberg filter. Moved the corner of the oil pan out to clear the pump. Very lucky it was so simple. Info Jr. getting the boat ready to drop it in.





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What block/crank are you runnig? What kind of brg clearance?
Who's doing your machinework??

ha ha...j/k... :D


Mike Boyce...great resource there. ;)
 

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Discussion Starter #3
What block/crank are you runnig? What kind of brg clearance?
Who's doing your machinework??

ha ha...j/k... :D


Mike Boyce...great resource there. ;)
LOL thanks. Yes Mike is. I do know what timing most run on blown alcohol hemi head stuff. And 33 would be too much. Who would have thunk 31 degrees max on a typical Pinch head Chevy? Non LS style. I guess the latest greatest stuff is pretty effecient.
 

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Resident Ford Nut
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Glad to hear you didn't kill it.

One nice project.

check your pm's


S CP :D
 

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What block/crank are you runnig? What kind of brg clearance?
Who's doing your machinework??

ha ha...j/k... :D


Mike Boyce...great resource there. ;)
LOL thanks. Yes Mike is. I do know what timing most run on blown alcohol hemi head stuff. And 33 would be too much. Who would have thunk 31 degrees max on a typical Pinch head Chevy? Non LS style. I guess the latest greatest stuff is pretty effecient.
Look at it this way, you've changed the moment that peak cylinder pressure occurs so you must change the amount of ignition lead to prevent hammering the piston as it approaches tdc. 33 degrees is too much advance with any decent amount of boost, nitrous etc.

13-15 degrees advance is a good starting point when the engine sees full boost then you can read the plugs and add timing advance back in if the engine wants it.
 

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Discussion Starter #7
Interestingly enough. Spark plugs looked great bearings and main caps not so much. pistons looked great also. Except for 1 lol
 

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Resident Ford Nut
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Look at it this way, you've changed the moment that peak cylinder pressure occurs so you must change the amount of ignition lead to prevent hammering the piston as it approaches tdc. 33 degrees is too much advance with any decent amount of boost, nitrous etc.

13-15 degrees advance is a good starting point when the engine sees full boost then you can read the plugs and add timing advance back in if the engine wants it.
I'm thinking if I can pull out up to 12* with a 300hp Nos shot, then 20* ( total )as a starting point with boost seems reasonable.

S CP
 

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You may have a timing issue, but I don't think that is the whole story. I think you had oil issues as well. The greastest tune in the world can't save your bearings if you have oil issues.
Granted, there is a timing factor in a boosted engine. But fuel and flame speed play a part as well, as does charge density.

16 plug Hemis on nitro run 50+ degrees. That chamber is pretty damn efficient. So something else is determining the timing besides chamber efficiency and boost pressure. Think it might be the fuel type and charge density?

I can knock the hell of set of bearings. We did at the Puddingstone race. But the worst damage was the pistons. The closed ring land tells you something. But still not so sure the bearings is 100% timing. I think the oil system changes were a good idea. Wouldn't surprise me if your back around 30-32 when you get it figured out.



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Discussion Starter #10
You may have a timing issue, but I don't think that is the whole story. I think you had oil issues as well. The greastest tune in the world can't save your bearings if you have oil issues.
Granted, there is a timing factor in a boosted engine. But fuel and flame speed play a part as well, as does charge density.

16 plug Hemis on nitro run 50+ degrees. That chamber is pretty damn efficient. So something else is determining the timing besides chamber efficiency and boost pressure. Think it might be the fuel type and charge density?

I can knock the hell of set of bearings. We did at the Puddingstone race. But the worst damage was the pistons. The closed ring land tells you something. But still not so sure the bearings is 100% timing. I think the oil system changes were a good idea. Wouldn't surprise me if your back around 30-32 when you get it figured out.
After I posted the sparkplug response I thought about the piston. It was #8 that pinched the rings and it was the rear main bearing hurt. I doubt we get the timing back up there. It doesnt need it. But we didnt know that until we got it on the clocks.

I really want to get away from 2 injectors per hole. It won't loose a hole if one goes bad. Driver can't tell.

I have both from #8 out and am having them tested tomorrow.

Plan is running Div 2 Lucas BP. Won't see you until the WF unless you go to Marble falls.
 

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steelcomp was here
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IMO those are awfully big heads for what you're doing. That doesn't help the tune-up window, especially with fuel injection.
I probably would have started at about 25* given the rest of the combination.
 

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IMO those are awfully big heads for what you're doing. That doesn't help the tune-up window, especially with fuel injection.
I probably would have started at about 25* given the rest of the combination.
LOL you would for sure now.. :wink2:

I ran low compression blown alcohol with a hat for years at 36* and more. The only thing I had to compare it to.

It was quite an inconvenience but not a disaster.
 

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After I posted the sparkplug response I thought about the piston. It was #8 that pinched the rings and it was the rear main bearing hurt. I doubt we get the timing back up there. It doesnt need it. But we didnt know that until we got it on the clocks.

I really want to get away from 2 injectors per hole. It won't loose a hole if one goes bad. Driver can't tell.

I have both from #8 out and am having them tested tomorrow.

Plan is running Div 2 Lucas BP. Won't see you until the WF unless you go to Marble falls.
i've always liked marble falls. fun place to race.
do you have egt's on each cylinder???
 

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LOL thanks. Yes Mike is. I do know what timing most run on blown alcohol hemi head stuff. And 33 would be too much. Who would have thunk 31 degrees max on a typical Pinch head Chevy? Non LS style. I guess the latest greatest stuff is pretty effecient.
I know comparing our engines is apples to oranges as I'm on gas but Steve Morris recommended I start at 32* which he said was real safe, and then if tuned for max power he said i'd probably end up at 35-36. Thats with the BB2xrta C&Cd heads, C-16,intercooler and about 25psi. Locked Mag.
I've been running at 31-32 and like you I have more than I need so no need to wring its neck.

You know, this could be a whole lot more fun and way less work if we could get some control over the boost.:hmmm:

Hope it stays together for you.
 

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Discussion Starter #15
i've always liked marble falls. fun place to race.
do you have egt's on each cylinder???
Marble Falls is a Div1 and 2 race?

I havent done any research to see if it would work. All 4 cylinders on each bank are blocked at the collector by a turbo. I would think temp is uniform throughout each header.

I have thought about it.
 

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Look at it this way, you've changed the moment that peak cylinder pressure occurs so you must change the amount of ignition lead to prevent hammering the piston as it approaches tdc. 33 degrees is too much advance with any decent amount of boost, nitrous etc.

13-15 degrees advance is a good starting point when the engine sees full boost then you can read the plugs and add timing advance back in if the engine wants it.
I'm thinking if I can pull out up to 12* with a 300hp Nos shot, then 20* ( total )as a starting point with boost seems reasonable.

S CP
20 is probably ok. Is rather err on the side of caution since he's already mentioned an issue controlling the amount of boost the engine is seeing.
Too little timing isn't going to hurt anything. Too much..well that doesn't make the boat faster, just more expensive to operate.
 

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Highaboosta
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The 23# +- of boost your running is not all that high. It's just making too much HP at that level to make the number your looking for in the class you want to run.
I ran 33# timing with 28# boost. It ran great until I had the issue with the MAP sensor hose.
When you get something running at this level there are so many factors that have to be JUST RIGHT to make it survive. It takes time to work out every bug. Cutting the timing back too far will make a huge amount of exhaust heat. I wouldn't go less than 28 degrees no matter what.

I don't see any problem to running dual injectors. I've never had an injector related problem with the Bosch 160# injectors. Getting them checked every season would be cheap and easy.
 

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IMO those are awfully big heads for what you're doing. That doesn't help the tune-up window, especially with fuel injection.
I probably would have started at about 25* given the rest of the combination.
Hey Scott, I follow your thinking on the cylinder head sizing . There are some of the guys on the bullet that seem to be of a different schooling on this. They say "There is no such thing as too big of a cylinder head on a turbo motor..... "

You might enjoy that thread.
What heads for turbo BBC - Yellow Bullet Forums
 

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Ron, do you have any datalogs to show what the A/F looked like on those good passes? I'm wondering if you might have been cramming enough fuel to it to be hydraulic the thing. Would cause all the symptoms your seeing, cap walk(tough caps to make walk by the way), pinched lands, bearings. With those dual injectors it wouldnt be to tough to do.
Just a thought.
 

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Discussion Starter #20
Hey Scott, I follow your thinking on the cylinder head sizing . There are some of the guys on the bullet that seem to be of a different schooling on this. They say "There is no such thing as too big of a cylinder head on a turbo motor..... "

You might enjoy that thread.
What heads for turbo BBC - Yellow Bullet Forums
That must be the guy I got my engine from. lol :)eh:) :D
 
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