2002 Crownline 262 CR 5.7 B3 Hydrolocked broken valve trashed cylinder

[Scott Danforth]

My math says 11 to 1

Dome volume 5cc
deck clearance .025
gasket .040
cylinder head 64 cc
Bore 4.030
stroke 3.48

check your math https://www.summitracing.com/newsand...ion-calculator



also, most stock 64cc heads are coming in at 67cc, a bit more if there is a valve job done.

 

[dollar7499]

Oh man, I hope I didn't do something silly
So I would need octane booster or 93 octane?
Is that related to my sputtering and surging or is that still probably my timing or fuel??

 

[scoflaw]

Gotcha , the reliefs would be considered a dish. 9.8 sound high, no room for error or cheap gas

 

[alldodge]

Oh man, I hope I didn't do something silly
So I would need octane booster or 93 octane?
Is that related to my sputtering and surging or is that still probably my timing or fuel??

Not with 9.77 maybe 89
Sputtering and surging is most always fuel supply related

The stock deck height is .045 and unless it was decked to .025 the CR is down to 9.35 and 87 octane

Quench was not messed with

 

[Scott Danforth]

volvo pentas going back to the mid 80's used flat-top pistons (7cc reliefs) with 64cc heads - published 9.4:1 CR. with stock timing you should be fine at 87 octane.

if you run at 14-16 BTDC where I was with the cam I was running, you will need to bump up the octane to 89 or so. I ran 91 originally because it was ethanol free.

agreed, sputtering and surging is your fuel supply

 

[scoflaw]

Higher than normal CR + sputtering/lean condition = tink tink tink tink...BOOM.

Fatten up the fuel or motor #5 is in your near future

 

[dollar7499]

Trust me, i really wanna figure out the fuel issue! Checking fuel filters tomorrow and trying to figure out how to flow and pressure test this 3 month old fuel pump. Want to check the pieces on the tank too.

 

[alldodge]

With a carb, in most all cases its the carb and second is timing so far as lean condition

 

[dollar7499]

Hmm, the quadrajet i just rebuilt without touching any adjustments, I'll have to research how to make that more rich. What timing condition could cause it? It starts in a split second and idles all day, its only under load it struggles. I have been reading about how to check the coil and install separators on plug wires, just heard about crossfire.

 

[Rick Stephens]

I'd humbly suggest redoing the carb rebuild. There aren't any 'adjustments' other than idle mixture screws and how much accelerator pump travel. Carburetor rebuilds are the most common job needing a re-do. Pay particular attention to all the passages. Run wire or fishing line through them, make sure they are perfect. A blocked passage is what makes a carb/motor run lean, not poor adjustment.

 

[Bondo]

Hmm, the quadrajet i just rebuilt without touching any adjustments,

Ayuh,..... Then you mighta taken part of the carb apart, but certainly didn't Rebuild it,......

 

[Scott Danforth]

^ *1.....what he said..... if you didnt touch the adjustements, you didnt "rebuild"

 

[dollar7499]

I'd humbly suggest redoing the carb rebuild. There aren't any 'adjustments' other than idle mixture screws and how much accelerator pump travel. Carburetor rebuilds are the most common job needing a re-do. Pay particular attention to all the passages. Run wire or fishing line through them, make sure they are perfect. A blocked passage is what makes a carb/motor run lean, not poor adjustment.

These are the adjustments I didn't touch because it ran so well before. I did soak it overnight and change out the rebuild kit because I accidentally left it out in the rain... I will be removing the idle mixture screws this time around.

 

[alldodge]

Clarify please, where did the carb your using originally come from, an what is the part number stamped on it?

 

[dollar7499]

The tin tag on front says MCM 260 / 270 1347 8292
The side number says 1708(or 3) 0561 0374
When I purchased the boat, the engine that was sitting in the boat not hooked up (1984 5.7l) had this on it and another same quadrajet in a side compartment. I figured I would try it with the vortec and it started right up and ran good once I added an electric choke (the cold lake water was making it run too cold)

 

[alldodge]

Thanks, the number checks out, and is used from 5.0 to 8.2 motors.

If I have understood the consensus of others, were leaning toward the motor is running lean. A lean motor will burn it self up rather quickly. This being the case then all that's left is either an incorrect rebuild or incorrect metering rods being used.

The secondary metering rods control the amount of fuel entering based on air flow. If incorrect ones have been installed, or a carb removed from a smaller motor was used, this will create a lean condition. Idle circuits have next to no impact on secondary fuel flow. So motor can fire up, idle and rev up in neutral great, but still have an issue.

It would be best to measure air flow ratio, but when you get back into the carb, measure the rod tip in dimensions.

 

[dollar7499]

I'll pull it tonight, I also ordered a fuel pressure gauge to check the pump.
I'll get the numbers off all the rods and measure them too. And check the anti siphon valve. Is there a flow rate I can check, like fills a gallon gas can in 36 seconds or something?

 

[dollar7499]

Anti siphon valve and filters are clean, all carb passages were chased with guitar string and were clean. Secondary rods were DW , I'll have to look that up. I have never done the secondary air door adjustment before, so when i loosened the clamp screw it sprung back so i couldn't see how far it was turned. Reset it to 1 turn and clamped it again. No smoking gun yet!

 

[alldodge]

Here is a great link on the Q-jet. It has sections in how to rebuild and how to tune

http://wildaboutcarsonline.com/cgi-bin/pub9990262549620.cgi?categoryid=9950419967774

 

[dollar7499]

Looks like my DW secondary rods are close to the leanest made! Very similar to DY, DE but DW doesn't show up on later charts, had to get measurements from an old chart: 1334, 1170, 874 (thousandths) L power tip. I am going to check with Jet and see what I should be running in my VERY heavy boat.