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Search found 202 matches

by CharlieB53
Sat Sep 21, 2019 6:48 pm
Forum: Engine Tech
Topic: Fuel Requirements
Replies: 17
Views: 446

Re: Fuel Requirements

In the marine world a general rule of thumb is fuel required equals 10% of HP.

Like fbird said, 420 HP generally requires 42 gph gasoline.

Your mileage may vary.
by CharlieB53
Wed Sep 18, 2019 11:26 am
Forum: Engine Tech
Topic: Are Exh pushrods more stressed even in NA applications?
Replies: 35
Views: 1187

Re: Are Exh pushrods more stressed even in NA applications?

Would it be advantageous to grind ex valve/seat to maximize low lift flow?

Intake angles for high lift flow?

Is this already a common practice?
by CharlieB53
Wed Sep 11, 2019 2:34 pm
Forum: Engine Tech
Topic: another blown up jetboat motor sbc
Replies: 16
Views: 1038

Re: another blown up jetboat motor sbc

WOT of 4700 is way too tight on the pump clearance, over loading the motor causing premature failures.

Loosen pump to get closer to 5500 and it should perform well and last much longer.
by CharlieB53
Tue Sep 10, 2019 4:57 pm
Forum: Engine Tech
Topic: another blown up jetboat motor sbc
Replies: 16
Views: 1038

Re: another blown up jetboat motor sbc

I’d liked to have seen the valves from the prior failures, perhaps would know more if it was the valve head or keeper failed.

3800 cruising? What was the WOT rpm set by the pump clearance? To tight on the pump can overload the motor creating excessive exhaust valve heat.
by CharlieB53
Tue Sep 10, 2019 10:54 am
Forum: Engine Tech
Topic: Oil on #4 Plug
Replies: 13
Views: 578

Re: Oil on #4 Plug

While the intake is off check the gasket surface with a straight edge .
by CharlieB53
Sat Sep 07, 2019 12:29 pm
Forum: Engine Tech
Topic: Camshaft help
Replies: 18
Views: 1302

Re: Camshaft help

No doubt valve springs are required for rpm but I have a question for the cam guys.

With a lift limit would it make sense to increase cam diameter so as to enable increasing duration in the lobes.

Is there even room in an abc for a larger cam bore?
by CharlieB53
Sat Sep 07, 2019 12:01 pm
Forum: Engine Tech
Topic: Oil on #4 Plug
Replies: 13
Views: 578

Re: Oil on #4 Plug

Can you do a clean shut off then pull the plug and inspect for oil? Compare that to pulling the plug immediately after decelerating and high intake vacuum. High vacuum on deceleration may be pulling oil past intake asker yet not leaking enough at wot to show a problem yet. Have heads/intake surfaces...
by CharlieB53
Tue Aug 27, 2019 10:57 am
Forum: Engine Tech
Topic: Quench safety distance for a 496 MAG gen 7 BBC
Replies: 12
Views: 747

Re: Quench safety distance for a 496 MAG gen 7 BBC

OP didn’t mention RPM this BOAT engine is operated. Generally rod stretch becomes a critical factor with increased RPM, however in the marine application and somewhat less rpm extremes a tighter squish may be allowed. I wouldn’t get extreme, but set up far closer to minimum should still be well acce...
by CharlieB53
Sun Aug 25, 2019 8:15 pm
Forum: Engine Tech
Topic: 2618 Piston Street Use Longevity
Replies: 131
Views: 20957

Re: 2618 Piston Street Use Longevity

Heating a piston in the oven to measure the crown may be fine but measuring the skirt may be misleading. Follow the heat path in operation the contact areas of the skirt should prove measureably less than the none contact areas 90 * off. This difference in temps could transfer a cold oval into round...
by CharlieB53
Sat Aug 03, 2019 9:21 pm
Forum: Engine Tech
Topic: 468 bbc heads
Replies: 11
Views: 1569

Re: 468 bbc heads

I know I am way late to this thread, but I would be looking for the Merc Marine 502 block. this is a 4.5 bore which with the right crank would give you the RPM you want from a very solid block.
by CharlieB53
Sat Aug 03, 2019 9:09 pm
Forum: Engine Tech
Topic: gapping rings
Replies: 7
Views: 512

Re: gapping rings

Gappung over-sized rings enough to fit in the smaller bore will also give an increased ring/bore pressure which would increase both ring and bore wear. Some body makes the right ting, or some body CAN make the right ring. You just have to expand your search and make a few more phone calls. Good hunt...
by CharlieB53
Fri Jul 05, 2019 8:20 am
Forum: Engine Tech
Topic: 327 help
Replies: 45
Views: 1898

Re: 327 help

Verify TDC with a piston stop, degree wheel or good timing tape on the balancer.

Pull a valve cover and start measuring opening/closing points to see just where that cam is installed.

You have already tried multiple carbs and ignitions, my money is improper cam timing.
by CharlieB53
Sat May 25, 2019 7:48 pm
Forum: Engine Tech
Topic: Simple Tunnel ram Question
Replies: 317
Views: 12610

Re: Simple Tunnel ram Question

Fuel droplet size is critical within the air column. Larger particles obviously have more mass and are more susceptible to “fall-out” during those short moments the air column ‘stops’ at valve closing. Gravity. ‘may’ have a minuscule effect on these fuel droplets however I believe inertia to have a ...
by CharlieB53
Fri May 24, 2019 6:49 pm
Forum: Engine Tech
Topic: Darin Morgan LS7 Heads: Data/Results Inside!
Replies: 25
Views: 5340

Re: Darin Morgan LS7 Heads: Data/Results Inside!

No one mentioned the OP also increased header primary tube size. I’ve no doubt this contributed to the numbers increasing.
by CharlieB53
Sun May 19, 2019 8:05 pm
Forum: Engine Tech
Topic: Resumed troubleshooting the ‘99 Suburban...
Replies: 3
Views: 476

Re: Resumed troubleshooting the ‘99 Suburban...

I agree/ testing exh pressure to rule out a plugged cat Also test temp sensor as out of range can cause a false rich when the computer thinks the eng is cold but sensor not so far out as to give a check engine light. May be more than one temp sensor. Desperate sensors for gauges and ecu. Make sure w...