Compression test results

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Just checked, old plugs are gapped at 40 - 43. Seem about right ?
 
030BE33D-8CB9-4960-905A-DD396CA540A0.png

Straight from MSD.
 
Looks like a typical holley thats been on an engine for a while. I'd definitely keep that as a spare. You'd pay 200 to 300 for that carb used. I bet with a rebuild it works just as good as a new one with no leaks. The 850 will be nice also.
 
If you decide to rebuild that 750 to have as a spare, lap or flat file the machined surfaces. That'll go a long way in getting rid of the leaks if you decide to use it on something else in the future. I had an accelerator pump housing start leaking recently. A quick lap on a flat surface with fine sand paper eliminated it and only took a couple mins.

Keep us posted on how the new carb works out.
 
mopowers said:
If you decide to rebuild that 750 to have as a spare, lap or flat file the machined surfaces. That'll go a long way in getting rid of the leaks if you decide to use it on something else in the future. I had an accelerator pump housing start leaking recently. A quick lap on a flat surface with fine sand paper eliminated it and only took a couple mins.

Keep us posted on how the new carb works out.
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Thanks & will do. . .a forum member messaged me so when the new one arrives I'll be shipping this 750. . Hopefully I can just get it dry enough enough to ship
 
GREEN GHOST said:
Thanks & will do. . .a forum member messaged me so when the new one arrives I'll be shipping this 750. . Hopefully I can just get it dry enough enough to ship
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The last two new carbs I got (street avenger 670 and 750 DP) came with reusable "blue" bowl gaskets. Those are the cat's meow for taking things apart to rejet, and reassembling without leaks. The stock gaskets are horrible because they stick to the bowl & metering plate. Cleaning off that stuck on material made it a lot more difficult to rebuild. Hope you enjoy your new carb!
 
Plugs gapped to approx. .048 & installed (even #6!). . .now just waiting for the delivery from jegs, in the mean while might tackle the oil pan gasket. . . Will keep everyone posted & continue with the rapid fire questions . . Happy new years in advance
 
Ok so on with the questions . . .. seems like I lucked out and the pan came of relatively easy. The front crank counter weight was all the way up which helped . . .question is I can't get the windage tray off due to the oil pick up. So should I :

Leave on and forget about changing the gasket on top of the windage tray ( might not be attributing to leak as much as bottom gasket?)

Or

Loosen the pick up by hand so it's out of the way and take down tray / order & change gasket. .if I push the pick up out of the way do I have to go through the steps of checking space to bottom of pan ? Or can I just push / tighten back to its original spot ?
 
BTW original reason for pulling pan was because of leaks , bolts also were very loose
 
GREEN GHOST said:
Just finished testing compression this afternoon, results below are cold & dry. From everything I red the numbers seem higher than what I would've expected for a healthy engine. It's a 500ci 440 stroker with approx. 10.5-1 compression and a small hydraulic cam. Are the higher numbers a result of the baby cam ? Or is the CR possibly higher than I'm thinking?. .. . .cylinder 6 will remain a mystery and I'm ok with that lol. Just getting the spark plug out was a hellacious event that took 15min & had me wishing the car had a 408 in it . . .couldn't imagine a hemi in this thing
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Drill a hole in the inner fenders for number 6. I drilled a 1-1/2 hole i think. Then its super easy to get to that plug. But that was with a indy EZ headed 440 in my 73 dart swinger and TTI 2 inch headers
 
mopar65 said:
Drill a hole in the inner fenders for number 6. I drilled a 1-1/2 hole i think. Then its super easy to get to that plug. But that was with a indy EZ headed 440 in my 73 dart swinger and TTI 2 inch headers
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Here is a crappy pic of the hole i was talking about.

Screenshot_20220103-103931_DuckDuckGo.jpg
 
Pan has been off & plugs in. Just waiting for felpro gaskets, new bolts, & carb to come. The moroso gasket while very high quality just looks too thick to sandwich on either side of the windage tray. Hopefully the fel pros are alil thinner. Plan is to get oil pan back on then work my way up to wires, carb, linkage, etc.
20220103_211704.jpg
 
did you figure out what stroke your crank is?
wondering if @PRH was correct with the combo as far as deck height/gasket thickness and getting to that 10.3 compression ratio or whatever it was.
 
cookietruck said:
did you figure out what stroke your crank is?
wondering if @PRH was correct with the combo as far as deck height/gasket thickness and getting to that 10.3 compression ratio or whatever it was.
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Unfortunately no I haven't. I was able to read some of the last digits off the front of the crank which seem to be closest and suggest a 4.150 stroke. BUT that would make the compression way low and the 190 cylinder results suggest higher compression. . The crank most likely is a 4.350 stroke and the numbers I'm seeing could be a date code. . The only way to know for sure is to pull the front cap which I really don't want to do. . .think I'm just gonna take it at face value and say it's approx. 500ci and approx 11 -1 cr . . .gonna work on trying to get this junk dialed in and running right then maybe dyno or see what time it can turn
 
GREEN GHOST said:
Unfortunately no I haven't. I was able to read some of the last digits off the front of the crank which seem to be closest and suggest a 4.150 stroke. BUT that would make the compression way low and the 190 cylinder results suggest higher compression. . The crank most likely is a 4.350 stroke and the numbers I'm seeing could be a date code. . The only way to know for sure is to pull the front cap which I really don't want to do. . .think I'm just gonna take it at face value and say it's approx. 500ci and approx 11 -1 cr . . .gonna work on trying to get this junk dialed in and running right then maybe dyno or see what time it can turn
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What kind of fuel are you running in it?
 
GREEN GHOST said:
Just checked, old plugs are gapped at 40 - 43. Seem about right ?
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.045-.050 is where I run them with msd box.
Try stock heat range and get the timing right 'if it pings now'.

I havent read the entire thread.
I just see fouled plugs that shine like they're eating oil...and 185-190 cranking that should eat 'min 91 octane' pump gas okay.
Seals making it run bad...if they cause fouling , yes .
 
MOPAROFFICIAL said:
.045-.050 is where I run them with msd box.
Try stock heat range and get the timing right 'if it pings now'.

I havent read the entire thread.
I just see fouled plugs that shine like they're eating oil...and 185-190 cranking that should eat 'min 91 octane' pump gas okay.
Seals making it run bad...if they cause fouling , yes .
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Thanks , I gapped new plugs at .048 & only 93. . .I'm hoping as other suggested the issue was the carb and not valve seals
 
GREEN GHOST said:
Thanks , I gapped new plugs at .048 & only 93. . .I'm hoping as other suggested the issue was the carb and not valve seals
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Not to say it isn't a carb tune issue.

Are you carb savvy ?

You might wanna make sure the carb is in the idle circuit..at idle.. and then in drive/brake on have someone neck down the idle mix screws till it coughs and back to where its smooth...and set them both/all 4 the same. Ex. 1/2 to 3/4 of a turn out.
From there you can do a rough power valve rating check with a vac guage and choose one that about 2-3" less than idle vac while in gear...or choose one half the vac if automatic trans. Then you can lean the primary jets till it surges a hair at cruise 50mph or better..and back up 2 jet sizes..that's your primary cruise dialed in....then wot testing with the secondary...usually are close/on but might need a jet bigger....if you run into pinging...again...play with total timing by taking some out, 2 degrees at a time. Try and leave 2 degrees of cushion between you and the pinging, if so.
 
MOPAROFFICIAL said:
Not to say it isn't a carb tune issue.

Are you carb savvy ?

You might wanna make sure the carb is in the idle circuit..at idle.. and then in drive/brake on have someone neck down the idle mix screws till it coughs and back to where its smooth...and set them both/all 4 the same. Ex. 1/2 to 3/4 of a turn out.
From there you can do a rough power valve rating check with a vac guage and choose one that about 2-3" less than idle vac while in gear...or choose one half the vac if automatic trans. Then you can lean the primary jets till it surges a hair at cruise 50mph or better..and back up 2 jet sizes..that's your primary cruise dialed in....then wot testing with the secondary...usually are close/on but might need a jet bigger....if you run into pinging...again...play with total timing by taking some out, 2 degrees at a time. Try and leave 2 degrees of cushion between you and the pinging, if so.
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Wow, lots of good info. I actually wound up buying a new 850, but I will go over all the tunning you mentioned once I get this thing installed
 
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