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454 rebuild

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mrmal56

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"I have an 89 Supra with a 454

"I have an 89 Supra with a 454 crate engine in it. Engine came flooded with water, no extra charge. Anyway, have torn the motor down and am ordering some parts. Is it essential to use marine head gaskets if only running the boat in fresh water?"
 
Does anyone know what the acce

Does anyone know what the acceptable range for play is for the timing chain? Or where I might be able to find the specs for this? I have 1/2" of play on one side with the other side taught. Thanks.
 
You're fine. Just be sure

You're fine. Just be sure the water did not allow any rust to form on the chain or gears.
 
"I have a 395 hp GM 454 with 8

"I have a 395 hp GM 454 with 80 hrs on it she starts & run great up to 32,3300 rpm then it starts breaking down I have replaced the cap & rotor changed out fuel filters the plugs have 80 hrs on them wires are new,the it has a GM HI ign system & a 650 holly, new fuel pump other than changing the ign module & checking fuel pressure what else should I be looking at"
 
"fred:

should have started

"fred:

should have started a new thread.

I'd check the wires to make sure they are on securely and in the correct order. Also, check for full timing advance (if EST system, advance is in the module, done electronically). Also check inside the cap for arcing. If all that's ok, then do the rest of the checks.

If nothing obvious shows up, pull the plugs and see if they are 'colored'. Not as reliable as in the past but will show indicators if running lean."
 
"[b]"what else should I be

""what else should I be looking at"

Ayuh,... You have a Fuel Delivery Issue,....
Changing the Igntion module won't help a thing...."
 
I have checked the fuel pump &

I have checked the fuel pump & lines even ran engine usuing 5 gal fuel can directly to the fuel pump it still will not turn up past 3200 when you try it breaks up & back fires through the carb the timeing is right on would a bad coil be doing it or is it still some kind of fuel problem
 
"change the water separating f

"change the water separating filter, if between the pump and the carb?

Change the carb inlet filter (some holleys have them and some don't)?

put a fuel pressure gauge on with the engine? what did the gauge indicate?

What does "timing is right on" mean; at idle, at 1500 rpm, at 3500 rpm?

If you used an outboard tank to feed the fuel pump, try raising the rpm to 3200 and squeeze the ball as fast as you can. Sometimes the fuel pump will be fine at idle and not produce enough fuel flow at higher rpm. The ball being squeezed rapidly will supplement any shortcomings in the pump up to a point."
 
"[b]"or is it still some k

""or is it still some kind of fuel problem"

Ayuh,... Could be the Carb itself...."
 
"carb inlet filter new,fuel pr

"carb inlet filter new,fuel pressure 5.5 lbs timing at650 rpm with the electronic advance is 12 degs at 4000 no load 32 degs as per spec. for thr est ign just took the carb off will get a rebulit kit from holly & we will see what happens"
 
"check the fuel pressure at 32

"check the fuel pressure at 3200+ rpm, too. I've seen pumps do fine at idle and off idle but fail to deliver enough fuel over 2500 rpm."
 
OK I am back went duck hunting

OK I am back went duck hunting for a while. did have the carb rebuilt & checked the fuel flow at 3200 rpms stayed right @ 5.5. lbs still cant get the eng pass 3200 rpm I guess I am back to the ign.system
 
"yup!

get another pair of e

"yup!

get another pair of eyes and check each wire, for good fit and proper location on the cap.

You never said and I think we all guessed that this issue started after the 80 hour point - true or has it been a problem since the initial startup?"
 
Try hand choking the engine wh

Try hand choking the engine when you hit the stumble point. You will be able to tell if you are leaning out. 3200 is about when the secondaries come into play. Holley has separate needle and seat for secondaries. Also check the linkage for secondaries.
 
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