Moparts

Wow. Slugs are .151" in the hole

Posted By: feets

Wow. Slugs are .151" in the hole - 11/17/14 12:29 AM

I knew the compression was going to be low on this 440 but I was hoping for a bit more than that.

I'm thinking...




Poor old Imperial needs more cylinder pressure. Might have to address that some day.
Posted By: 69Dartman

Re: Wow. Slugs are .151" in the hole - 11/17/14 01:06 AM

Well is there a easy way to get them where they should be? What is it, less then 8 to 1 now as I think they were listed as 8.2 anyways.
My Neon is almost 10 to 1 factory
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 01:18 AM

Doing the math with the cylinder head, gasket, and piston depth I come up with 8.0 compression. That's a bit low even for forced induction.
Posted By: ahy

Re: Wow. Slugs are .151" in the hole - 11/17/14 01:27 AM

Hmmm

Posted By: DaytonaTurbo

Re: Wow. Slugs are .151" in the hole - 11/17/14 01:34 AM

I measured one that came out to 7.8 compression. Talk about a dog!
Posted By: 71birdJ68

Re: Wow. Slugs are .151" in the hole - 11/17/14 01:36 AM

81/2 to one, in the piston airplane world, that's considered high compression, and requires 100LL.
Posted By: RapidRobert

Re: Wow. Slugs are .151" in the hole - 11/17/14 03:26 AM

yeah I've ran into SCR's in the 7's (measured). If you ain't going into the short block (boring) I'd get a Hughes cam to build at least a bit more psi & tweak the dist subsystems dead on.
Posted By: Kern Dog

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:01 AM

Moparts member Jim LaRoy (Formerly "Hey Old Guy", curently "LaRoy Engines") has done several dyno sessions with low compression 440s and has published some impressive numbers even with engines as low as 7.5 to 1. He posts here, FABO and FBBO and even DodgeCharger.com. It might be worth looking into. Well prepped heads benefit any engine, even ones with low squeeze ratios.
Posted By: 340duster340

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:11 AM

what are the plans for the car?
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:50 AM

Quote:

81/2 to one, in the piston airplane world, that's considered high compression, and requires 100LL.




The twin turbo440 was 8.7:1 and ran on 93 octane with 8 psi boost and no intercooler.
It also handled 17 psi with 93 octane a wee bit of rubbing alcohol through a repurposed nitrous needle.



Plans for the car?


It's a 5100+ lb cruiser. Occasionally driven by an overly enthusiastic maniac. Kinda funny. I beat on that thing harder than I beat on the hot rod.
Posted By: Colin Frolick

Re: Wow. Slugs are .151" in the hole - 11/17/14 06:37 AM

My 71 was close to that. When I put aluminum heads on it they were milled a lot to make up the compression. Then when I built the 493, same heads, we used reverse dome pistons to get about 10:1 with 0.039 quench. Runs great!!
Posted By: Challenger 1

Re: Wow. Slugs are .151" in the hole - 11/17/14 02:46 PM

Change the pistons, I bought a short block like that, the seller thought it was 360 because of a nearby air cleaner.

I stuck cheap sealed power 6 pak pistons in mine and sold the flat tops. It didn't cost me hardly any money to do it. No I did not balance the motor, still running great today 10 years later.

Mine had big ole nasty rust circle about 3" around in one of the cylinders from sitting after a fresh bore and hone. I hand honed and it sealed up fine, it didn't even begin to remove the rust stain when I honed it.
Posted By: dynamite

Re: Wow. Slugs are .151" in the hole - 11/17/14 03:26 PM

Dang Kevin ...You're just not catchin a break with that IMP..Sounds like it needs a complete O/H..with better pistons..,, then why not just stroke it, as pistons come with most kits, While you're in there a better cam , then some better heads while you're doin it , $$$$ Why not $$$$$$$$$$$$$..you know how it go's...Good Luck..Larry

Attached picture 8333735-get-attachment(13).jpg
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 04:19 PM

Quote:

Dang Kevin ...You're just not catchin a break with that IMP..Sounds like it needs a complete O/H..with better pistons..,, then why not just stroke it, as pistons come with most kits, While you're in there a better cam , then some better heads while you're doin it , $$$$ Why not $$$$$$$$$$$$$..you know how it go's...Good Luck..Larry





Yeah, I'm fighting that urge. Knowing there is a full EFI system, a pair of turbos, and more 8 piston calipers collecting dust in the garage is killing me.

I'd be installing the EFI system now if there wasn't 84 ounces of R12 in the A/C system. The upper A/C line is a steel, not rubber, and goes directly across the mouth of the throttle body. No way yo put an air filter on it.
If I change the line it would be the proper time to change the compressor.

It's a big ugly slope to fall down. Best to avoid it completely.
Posted By: moparmoynihan

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:21 PM

Well if you're contemplating selling the Parts for the Impy, I'm your guy Feets. A super clean rust free 69 Imperial 2 door is waiting in NY for some parts!! Johnny Brake calipers too!!
Posted By: Mr.Yuck

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:55 PM

so boost it. 6-8lbs should help ya out enough. You can use a carb and wouldn't even need to cool the boost.
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 05:58 PM

I'll never use a carb under boost again. Once you go EFI it's hard to go back.

I'm not selling the parts. I need to get the Imp back together and running so I can concentrate on other things right now.
Posted By: 80fbody

Re: Wow. Slugs are .151" in the hole - 11/17/14 06:26 PM

You can make plenty of power even with the low compression. There's a writeup over at FABO taking that low comp BB and running thru the dyno while adding cam, intake, headers, etc. I think it ended up around 450hp for nearly squat into the build.
Posted By: HotRodDave

Re: Wow. Slugs are .151" in the hole - 11/17/14 06:50 PM

Quote:

Quote:

Dang Kevin ...You're just not catchin a break with that IMP..Sounds like it needs a complete O/H..with better pistons..,, then why not just stroke it, as pistons come with most kits, While you're in there a better cam , then some better heads while you're doin it , $$$$ Why not $$$$$$$$$$$$$..you know how it go's...Good Luck..Larry





Yeah, I'm fighting that urge. Knowing there is a full EFI system, a pair of turbos, and more 8 piston calipers collecting dust in the garage is killing me.

I'd be installing the EFI system now if there wasn't 84 ounces of R12 in the A/C system. The upper A/C line is a steel, not rubber, and goes directly across the mouth of the throttle body. No way yo put an air filter on it.
If I change the line it would be the proper time to change the compressor.

It's a big ugly slope to fall down. Best to avoid it completely.




What we do with R12 is find a buddy who needs some (always someone with an old car who needs some), hook my gauges to the high side on the one car donating the freon and the low side to the recipient, (I use my 134 gauges and 134 adapters on both cars)pinch off the line to the bottle start both vehicles (if possible) and turn on the AC, you can get pretty much all of it out this way (may need to jump the relay to make the compressor keep pumping after the pressure drops too low in the donor car)and it don't go to waste and Al Gore should be happy. When we put the old R-12 system back together we just put adapters on and evac real good and fill with 134. Even if your car is not running you can still get it down under 50 PSI and if you can figure a way to heat the AC system up a little in your car you can get even more out. Whatever you do do not put propane in an AC system ever! there is a shop in town that does and we keep getting exploded condensers to replace
Posted By: HotRodDave

Re: Wow. Slugs are .151" in the hole - 11/17/14 06:57 PM

As for low compression just get a custom cam ground with around 205@.050 and as much lift as possible, then add high ratio rockers to get more flow without increasing the duration. I have seen low compression engines like this one 8.4 compression 5.9 magnum I built get 180PSI with a small cam like that. You could even go with a wider LSA (that cam was 110) to help the turbo and not lose too much cylinder pressure.
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 07:17 PM

You guys must have missed my other posts regarding this car. Here's my new cam card.

Attached picture 8333924-2014_1117_12153500.jpg
Posted By: Vert

Re: Wow. Slugs are .151" in the hole - 11/17/14 07:43 PM

Poor(pour) Man's High compression engine.
Jack up one side of the car until the cylinder is straight up and down. Put a circle of thin card stock around a piston at TDC. It needs to be thin enough to fit between the piston and the cylinder wall. Drill several 3/8x 1/4 deep holes in the piston head and vacuum out the filings. These help anchor the DEVCON. Mix up some DEVCON and pour it in smoothing it as needed. Fill it to zero deck. Let it cure, remove the card stock, and repeat for each cylinder in that bank. Then lower the car and jack up and repeat on the other side.
Let us know how this works out. Its only been tested in a Hypothetical Hemi so far.
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/17/14 08:36 PM

Disturbing.
Posted By: HotRodDave

Re: Wow. Slugs are .151" in the hole - 11/17/14 09:25 PM

Close enough. I would advance it 2-4 degrees to get a tad more TQ. That could help the turbo spool a tad quicker also becaus then the EX valve opens while there is a little more EX pressure. I would still run a higher ratio rocker to take advantage of the better flow at higher lifts.
Posted By: dogdays

Re: Wow. Slugs are .151" in the hole - 11/18/14 12:28 AM

Another way around the problem would be to add 0.300" to the stroke. Or swap in a set of Hemi-length rods.

But realistically, you are either going to crutch it or change pistons.

R.
Posted By: feets

Re: Wow. Slugs are .151" in the hole - 11/18/14 12:38 AM

Quote:

But realistically, you are going to slam a cam and heads on it and put it back to work.
R.





Fixed!
© 2024 Moparts Forums