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1972 57 crusader engine

J

jim_rutgersen

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"I have a 1972 5.7 Crusader ma

"I have a 1972 5.7 Crusader marine engine That back fires / spits back out of the carb. even when the coil wire is off. I has a Presttolie distributor. I have have check the frire order and most of the wires were wrong, fonud top dead center on #1 cly mark on the dis. and used the fireing order from a standard rotation engind, dis. clockwise rotation. any one have any Ideas?
you can e-mail me at [email protected]"
 
with the coil wire off I get a

with the coil wire off I get a spit back out of the carb. the enging turns over but when it gets to to the point it seams hard to over come that one spot and I get a puff out of the carb. then the mortor will turn frely agian untill it gets to that spot agian
 
"Wild guess, but maybe a very

"Wild guess, but maybe a very sticky valve guide. It's putting more pressure on the push rod and starter during cranking. A sticky intake valve might send the fuel charge backwards during the compression stroke. I would take off the valve covers to try to ID the problem cylinder. Then, loosen the offensive valve rockers to isolate further."
 
"Similar thought here - differ

"Similar thought here - different detail. I'm leaning towards bent valve(s) in the cylinder with the "lack of manners".

could also be that the exhaust lobe is wiped/pushrod bent and the exhaust valve isn't opening.

Exercise Dave's suggestion; if nothing is visually obvious, run a compression check. Between the two, they should point to the cylinder with the issue."
 
Thanks.

James: You also m

Thanks.

James: You also might have a blown head gasket. I suggest you get a compression test done and get back to us.

Jeff
 
"it might possibly be a worn c

"it might possibly be a worn cam shaft lobe on the exhaust side. during the exhaust stroke if the exhaust valve does't open ,the air having been pulled in by the intake ,compresses,and when it gets by passed by the non-opening exhaust valve skips to the intake stroke ,so that when the intake opens,the exhaust has more pressure than the incoming air,and shoots out the intake. something to think about. turboman ROLL TIDE 12-1"
 
".."ROLL TIDE 12-1"

".."ROLL TIDE 12-1"

As Inspector Clouseau was told after he destroyed "a priceless Steinway!"--"Not any more."

I was rooting for them, by the way.

Jeff"
 
"Hello and thanks for your rep

"Hello and thanks for your replys, I pulled off one of the vale cover and found a broken and bent push rods. I am now just going to pull engine and do a rebuild, thanks all"
 
Unless you have a lot of time

Unless you have a lot of time on the engine I would just inspect the heads. You more than likely have experienced stuck valves. I wouldn't think the timing chain has jumped teeth.
 
"James ,as JOE said unless you

"James ,as JOE said unless you have a lot of hours on it why spend money you may not have to. By chance ,have you buzzed the motor hard recently?Valve float will do the same thing,but ,I believe I would at least pull the heads and see what has caused the problem. THANKS JEFF, we met a team that had a player that willed his team to win. We had a very good season this year,and look to have an even better one next year. TURBOMAN ROLL TIDE 12-1"
 
Jim:

glad you are on the pa

Jim:

glad you are on the path to recovery.

I'd add "thorough inspection of the camshaft (or replacement)" to the "must do" list; especially if you don't know what cause the breaking and bending.
 
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