Stock engines are not for blowers

[mud duck]

Unfortunately, Saturday afternoon I blew my stock 454. At first I thought just the blower belt broke. However, after closer inpection I found oil spattered around and a few cracks on the front of the block. Something must have snapped in the lower end of the engine. This was a stock Chevy 454 marine grade engine with a B&M 250 blower set at 5 lbs of boost and MSD ignition. We were not pounding on it to hard Saturday, but we hit top end about three or four times. Then the engine just stopped, and I knew from the sound it was not good. I think blowers need more stout built engines, even if the boost is keep low. Perhaps a Whipple or Pro-Charger would be different and more gentle, I do not know. frown

[Blown 472]

Hummmm sorry to hear bout your broken chev. I run a basically stock 460 as high a 9 psi and other than spinning a rod brg I have never broken any thing (knock on wood)

[JLaughreySS24]

Sorry to hear about your motor!!! Im running a 502 with a superchiller and a B&M 250. Does your 454 have a steel crank and rods or are they cast iron? That may have been your problem.

[FASTERDAMITT]

Part of the problem could be the style of boat. A jet is on and off the throttle so often and fast it creates alot more load on the bootom end. A prop boat ussually is accelerating for a while and then decelerating for awhile. Also how long do you let the oil warm up before you hammer the throttle after launching? I see people everyday start it and floor it. NOT GOOD!
A stock motor treated right will last for a long time at low boost. Also intercooling is the only way to go on a boat.

[mud duck]

A few pics of the damage.
http://www.***boat.com/image_center/data/521/452My_Pictures0007-med.jpg
http://www.***boat.com/image_center/data/521/452My_Pictures0003-med.jpg
http://www.***boat.com/image_center/data/521/452My_Pictures0004-med.jpg
cry

[Infomaniac]

Why does the # 2 main cap say 4 on it?
Might be part of the problem.
[ September 10, 2003, 08:02 PM: Message edited by: Infomaniac ]

[Jbb]

Infomaniac:
Why does the # 2 main cap say 4 on it?
Might be part of the problem. Not a good sign....
I am not sure the Whipple would be easier on the bottom end than what you had Proper oiling ,sensible boost levels and driving style plus Forged pistons and crank would help

[Heatseeker]

mud duck, I know how that feels! I blew my 18 year old stocker up on Father's Day(after running it all last season with 7 lbs. of boost). I shredded a piston, bent a rod ,two valves and ventilated #5 cylinder. your damage is certainly more extensive than that!
Lucky for me, my 4 bolter was on the stand and just about ready to be planted...

[mud duck]

cry
http://www.***boat.com/image_center/data/521/452My_Pictures0009-med.jpg
http://www.***boat.com/image_center/data/521/452My_Pictures0002-med.jpg
cry
So, If I go with a 502 this next time, I should be able to reuse my B&M blower, Holly carb, MSD ignition, Lightning headers, etc. What pistons, piston rods, and/or crank do I go with? I thought I would go with Dart heads, any better suggestions? I need all the help I can get.

[HM]

I think your breather falling into the belt theory is probably right - I can't see a crank bending like that from your relatively mild setup.
A whipple will not give you less torque (especially vs. a B&M) - probably more.
502/502 is a nice base motor, but if you want to go higher than 5lbs, your best bet is to do it right.....go to HTP and let him tell you what you need.
I give you a "10" on the nuclear melt down factor!! Damn that thing got tore up!!!

[Blown 472]

You ran something between the belt and pulley and it did all that??

[superdave013]

Mr. Mud, The guy who used to help with my drag boat moved to St. Paul. He might be able to help you out. He's put toghether lots of engines but he does not do it by trade.
Even if he can't he would be fun to hit the lakes with next summer. He's a jet guy too.
I'll PM you his contact info.
[ September 11, 2003, 08:35 AM: Message edited by: superdave013 ]

[Blown 472]

There is also a guy in omro, wi. Goodwin Performance, did a kick ass blown 572 in a tunnel hull that hangs out on shawano lake.