Looking for Insight & Wisdom for my NSS Ride.

[Ricks427]

Ok Guys, I'm have some issues with a car I just bought, Here's what I know and what's going on..

First off the previous owner didn't have any knowledge to what was done to the motor, Here's what I've found.

The Motor I believe is stock stroke 440 with a big dome piston, Indy SR Heads must have been ported to max wedge since its running 440-25 intake, Edelbrock 750 carbs, Big Flat Tappet Solid lifter cam. North of 600" lift. Ignition is MSD Digital 6.

Notice that the intake has nitrous burst plates, I did find evidence of a minor fire at one point. I'm guessing these intakes have been known to backfire due pooling fuel.

I did a compression test and all the cylinders are between 98-105psi, Seems low to me. guess the cam has a big overlap! Rockers lash is at .022" intake and exhaust. I did the once over on the whole car, Fresh 112 Gas, went through the carbs, replaced some fuel line. new plugs, wires and penn grade 20/50 oil. 70-80 oil PSI.

So my Issues are:

Car will not idle under 1500 RPM... Seems to get hot really fast 10min with the pump and fans running and we're over 220 degrees. I can't put a timing light on it since the ATI balancer had some corrosion and destroyed the numbers and marks also the passenger side lower radiator hose is in the way of the timing pointer.

Tomorrow I'm planning to pull the intake and reseal just to make sure there's no hidden vacuum leaks, tried spraying carb cleaner around potential vacuum leaks but didn't fine anything obvious. I'm also going swap the radiator to stock copper 4 core and change out the balancer to another ATI I have.

What timing recommendations should I shoot for.? Any other recommendations?

 

[RemCharger]

Well ya pretty much nailed it with the low compression numbers. Unless something was wrong with the testing.

 

[Curiousyellow71]

We usually ran a total of 38 w domed pistons. Tried 36 and 40 and slowed a hair.
Something has got to be up w those compression numbers? Are you holding carbs open some?

 

[GTX JOHN]

Aluminum crossflow is way better than a factory copper radiator unless
the Aluminum is partially plugged.
You could put timing tape on the dampener and save changing it.

Low compression is worrisome
My Superstockers with 10 to 1 / 9 to 1 and 700 plus lift are still 150 or more.

 

[Ricks427]

When the compression test was done both carbs wide open.. With all the cylinders pretty much the same compression it seems to me a bad cam choice or cam timing is retarded?

 

[pnora]

Compression that low it should be huffing pretty good out the breathers. Pusher fan is not going to keep it cool.

 

[Rebelrouser]

Ok Guys, I'm have some issues with a car I just bought, Here's what I know and what's going on..

First off the previous owner didn't have any knowledge to what was done to the motor, Here's what I've found.

The Motor I believe is stock stroke 440 with a big dome piston, Indy SR Heads must have been ported to max wedge since its running 440-25 intake, Edelbrock 750 carbs, Big Flat Tappet Solid lifter cam. North of 600" lift. Ignition is MSD Digital 6.

Notice that the intake has nitrous burst plates, I did find evidence of a minor fire at one point. I'm guessing these intakes have been known to backfire due pooling fuel.

I did a compression test and all the cylinders are between 98-105psi, Seems low to me. guess the cam has a big overlap! Rockers lash is at .022" intake and exhaust. I did the once over on the whole car, Fresh 112 Gas, went through the carbs, replaced some fuel line. new plugs, wires and penn grade 20/50 oil. 70-80 oil PSI.

So my Issues are:

Car will not idle under 1500 RPM... Seems to get hot really fast 10min with the pump and fans running and we're over 220 degrees. I can't put a timing light on it since the ATI balancer had some corrosion and destroyed the numbers and marks also the passenger side lower radiator hose is in the way of the timing pointer.

Tomorrow I'm planning to pull the intake and reseal just to make sure there's no hidden vacuum leaks, tried spraying carb cleaner around potential vacuum leaks but didn't fine anything obvious. I'm also going swap the radiator to stock copper 4 core and change out the balancer to another ATI I have.

What timing recommendations should I shoot for.? Any other recommendations?

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I would do a cylinder leak down test, that will tell you if the compression is low due to wear, or cam timing issues. With dome pistons and a big camshaft, I would expect to see 150 to 175 cranking compression. To kind of verify the cam timing set engine to TDC on the overlap of the cam, if the intake rocker is lower it is advanced, if the exhaust is then it is retarded, same height both rockers cam installed straight up.
36 to 38 degrees total timing works on any big block I have messed with.

 

[dvw]

I've run this intake for 10 years. It should idle with no issue. My cam is [email protected]" and will idle at 1000rpm. Seal up the intake. Make sure the adapter plates that mount the carbs are tight. Use blue loctite in the bolts. These plates will loosen up. I made gaskets for them. For the lid file a 1/16"x 3/8" notch on the forward sealing edge. That way you can get a screw driver in between to pop it apart. If not they are tough to seperate. I use Ultra Grey to seal the lid. Jet 113 primary/110 secondary 68/47 rod. It will be very close.use the mid to lighter tension metering springs. 34 degrees total timing. To start the the engine. Pump on to fill the bowls. Then pump off in case of backfire. Hit the throttle to th efloor twice. Now wait 30 seconds. Ht the the throtle again holding it half open. It'll start like fuel injection. Always start with the throttle open. If it coughs it gives the prssure a place to go. If it's below 50 degrees; though a cloth fender cover over the carbs to act as a choke. Once it starts pull it off.
Doug

 

[INTMD8]

What compression tester did you use?

If harbor freight or similar try a quality one before basing any decisions on the numbers.

 

[64HEMI330SEDAN]

im thinking thats way to much intake manifold for that cid engine. they work well on large cid engines and it sounds like it has a air leak to. you are correct about the blowing up and fire thing. i was a victim of that myself. i put a modman with two 750 afb's on mine and it loved it. i had to do a little tweaking on the pump shot to take a small stumble at the hit out. i have a 451 cid engine, 13.5 to 1 compression, 440-1 heads hand ported ,705-710 soilid roller cam and have been low nine eighty at 136mph. nice looking car i hope you get her figured out.

 

[RemCharger]

Compression that low it should be huffing pretty good out the breathers. Pusher fan is not going to keep it cool.

Yes and/or , did the previous owner run it with a baked water pump.
Ruh-Roh scoobs, time to sell

 

[dvw]

Before we all get all worried about the compression numbers. Try a second gauge. The numbers are pretty darn close to believe every cylinder is equally 30% low. That is unless the valve timing is off. Easy enough to check. Bring it to TDC. Either #1 or #6 will be on TDC compression. The opposite cylinder will be on split overlap. The intake valve will be starting to open. The exhaust valve will be closing. If the valves are the same height, the cam is installed straight up and not retarded. Retarding the cam will cause the intake to open later. Thus the intake valve will be lower than the exhaust valve at TDC if the cam timing is retarded. If the intake is higher the cam timing is advamced. How does it look at TDC? Before going over board. Fix the leaks, set the timing, jet it, and run it. See how quick it is.
Doug

 

[not so famous bob]

B

Before we all get all worried about the compression numbers. Try a second gauge. The numbers are pretty darn close to believe every cylinder is equally 30% low. That is unless the valve timing is off. Easy enough to check. Bring it to TDC. Either #1 or #6 will be on TDC compression. The opposite cylinder will be on split overlap. The intake valve will be starting to open. The exhaust valve will be closing. If the valves are the same height, the cam is installed straight up and not retarded. Retarding the cam will cause the intake to open later. Thus the intake valve will be lower than the exhaust valve at TDC if the cam timing is retarded. If the intake is higher the cam timing is advamced. How does it look at TDC? Before going over board. Fix the leaks, set the timing, jet it, and run it. See how quick it is.
Doug

before wasting ur $ on a diff. radiator , move the existing one up to the cradle and seal it , being that far back is stupid , "air going around it instead of thru it !!

 

[Ricks427]

Ok time for an update, after a few days of wrenching here is what I found.

After using a piston stop and finding true top dead center, I marked the ATI balancer and installed some MSD timing tape. As I rotated the motor to TDC I noticed the Rotor pointing to the #1 Terminal on the cap while the Balancer was showing 50 degrees advanced... Really... WTF. I double checked, ya its for real!! Wow 50 degrees initial advance. then looked into the mechanical advance and they had the blue bushing in it adding another 25 degrees by 2800 rpm... No wonder it wouldn't idle..

So I adjusted the mechanical advance to 18 degrees and set the initial at 18 degrees, for a total of 36 degrees all in by 3000 RPM. WOW!! What a difference! NOW It Idles between 900-1100RPM! I also swapped out the Aluminum radiator I think it was clogged, for a good 3 core original water temp never got over 180 degrees after running for 20 minutes..

As for the compression I was using a cheap AutoZone special, so I'm guessing its not accurate. this motor runs to good to have such low compression. I'll do a leakdown test next week. to prove it out.

Thanks Guys for all your help!! You Guys Rock!

 

[Big bill]

That’s great news Good job …

 

[dvw]

The manifold in question Indy 440-25 is a very good manifold. I dynoed one back in the day on my old 498" motor. Indy -1's out of the box, 13-1, .680 roller, 2 Eddy 750's. It made 658@5750 with a factory crossram. With the Indy it made 720@6750. We started the pull at 4000rpm. It was better at every rpm level. My 580" motor currently runs one as well. No one in NMCA with -1 heads has gone faster even using a tunnel ram. Not to mention I'm close to 200lbs heavier. Been 8.96@150
Doug

 

[Ricks427]

Ok here's an update, a few weeks go I took the car to the track. After some shake down passes, the car ran consistent 11.70s @ 114 - 1.62 ' , My erratic idle issues showed up again. Temp was in the mid 80's and coming back the return road water temp was 210-220f.

Since then I have swapped the cooling fan to a puller, locked the timing down to 34 degree's total, Pulled the intake and carbs resealed every possible leak, and seen evidence that is was leaking at the #6&8 ports. I checked all surfaces for flatness, and resealed and reinstalled, found some clearance issue with carb linkage, which was fixed.

However once checking for full throttle.. I marked the throttle cable manually at WOT, and stabbed the gas pedal only to find out I'm only getting 75% throttle. Its running the stock pedal belcrank with an aftermarket universal cable, So my next question what's the best way to modify the belcrank to have more throw? I extended the arm length about an inch which give me 90% throttle. I could change the pedal side clocking 5-10 degrees which might accomplish this.. any solutions out there??

 

[LemonWedge]

Don’t have a solution for your go-pedal issue. But I love that you’re out getting things figured out. based on what I see here, I’m confident you’ll have this thing figured out and running to its potential before long.

 

[dvw]

The trick to getting the throttle to open all the way is to allow the pedal to up further. WIth the aftermarket cable I swapped the rubber spacer for brass. Machined it out of an old carb inlet fitting. Then the supplied nut that threads onto the cable is too thick. Find a thin nut. You can also bend the two arms apart slightly. But use heat on the arm. I cold bent one and it broke at the plug weld at the end of the cross shaft at the most inopportune time. 3rd rd of the Norwalk Mopar race. Also the carb stud that comes with the aftermarket cables can be suspect. Broke that as well. Yup in the burnout box 1st rd.
Doug

 

[HEMI-ITIS]

I went with the lokar adjustable throttle cable bell crank. Also raised the pedal assembly off the floor by an inch or so.That took care of the WOT issue.