Help!! Engine Miss - Page 11

KRatcliff · 06-06-2012, 09:54 AM

Quote:

Originally Posted by Tim Lisson

You mentioned in one of the posts recently it does rev up freely without load? You need to take this to a drag strip and get after it.

Also, i would verify your alternator is working properly along with a seperate ground wire from the alternator to the head. I know what your thinking, it's bolted to the block...

It is funny you mention that. I bought 100' of the braided ground strap material from Ebay. Do you know how far 100' will go?

Lets just say that if I ever crash my car, I won't die from the impact. It will be from strangulation.

Ben Kallies · 06-06-2012, 01:11 PM

Tim,

Leakdown test was performed cold. Engine hasn't been run in 2 weeks.

-Ben

Tim Lisson · 06-06-2012, 01:40 PM

Ben,

First of all, I'm no expert so take this for what it's worth....

1) After dyno session, did you back the rockers off when it sat until you got it in the car?

2) When I do a leak down, I typically run the car up to 140-150 then attempt to zip through the test with warm cylinders. The cylinders that are over 5% I would smoke test, go by a cheap cigar and have it over the carb/intake opening and exhaust port/ header tube when performing this scientific test... don't laugh, it works.

Other than everything else mentioned, get it to a track or bring it up north. My trans builder has a chassis dyno and has had many BBC on it. Sounds like a fun mystery!

Tim

Alan Roehrich · 06-06-2012, 01:42 PM

Now the chassis dyno sounds like an excellent idea, that's even better than track time. you test the whole car, and you can hook diagnostic equipment to it and then duplicate the problem.

Ben Kallies · 06-06-2012, 05:11 PM

I've actually been thinking about the chassis dyno idea for a couple of weeks now. There's a speed shop with an in-ground dyno about 10 miles from my house. I'm not certain how experienced the operators are in terms of diagnostic abilities, but at the very least, I'd be able to see how it responds at full throttle under load.

-Ben

Arnold Greene · 06-06-2012, 11:52 PM

Ben, make sure you have plenty of clutch pressure before you put it on the chassis dyno. Good luck.

Ben Kallies · 06-07-2012, 04:35 AM

Arnold,

Thank you. I wouldn't have thought of that.

SC321X · 06-07-2012, 01:13 PM

Have you looked at the valves to make sure they all open the same as you bump over the motor(no mess that way) If they all seem to open all the way chances the cam is ok. If this car is an automatic I would unbolt the torqconverter and see what difference that makes. make sure you push it back out of he flywheel.

MikeMoller · 06-07-2012, 11:13 PM

Quote:

Originally Posted by Ben Kallies

OK, so the leakdown test is done. I checked each cylinder twice with the same results each time. Results are as follows:

cyl 1 12%
cyl 8 10%
cyl 7 11%
cyl 3 7%
cyl 6 5%
cyl 5 12%
cyl 4 11%
cyl 2 8%

It's my impression that these results are good. Thoughts, comments? Is a compression test still necessary, or do these results verify the health of the engine?

Thanks,

-Ben

Run a compression test anyway. If you have a flatttened cam lobe-particularly intake- the compression may show low on that/those cylinders. Happened to me on a brand new motor.

Mike Moller

Gary Wiegand · 06-11-2012, 10:33 AM

Hi Ben,

This is my first reply on this site, so hopefully I get it done correctly.
Before I describe a similar situation which I had, trying to chase down a "miss" in the engine, and what was causing it, I have one question; do you have a spacer plate below your carburetor?

06-06-2012, 01:11 PM	#102
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 105 Likes: 2 Liked 0 Times in 0 Posts	Re: Help!! Engine Miss Tim, Leakdown test was performed cold. Engine hasn't been run in 2 weeks. -Ben

06-06-2012, 01:40 PM	#103
Tim Lisson Member Join Date: Aug 2003 Location: Solon Springs, WI Posts: 166 Likes: 0 Liked 0 Times in 0 Posts	Re: Help!! Engine Miss Ben, First of all, I'm no expert so take this for what it's worth.... 1) After dyno session, did you back the rockers off when it sat until you got it in the car? 2) When I do a leak down, I typically run the car up to 140-150 then attempt to zip through the test with warm cylinders. The cylinders that are over 5% I would smoke test, go by a cheap cigar and have it over the carb/intake opening and exhaust port/ header tube when performing this scientific test... don't laugh, it works. Other than everything else mentioned, get it to a track or bring it up north. My trans builder has a chassis dyno and has had many BBC on it. Sounds like a fun mystery! Tim

06-06-2012, 01:42 PM	#104
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,907 Likes: 993 Liked 1,032 Times in 270 Posts	Re: Help!! Engine Miss Now the chassis dyno sounds like an excellent idea, that's even better than track time. you test the whole car, and you can hook diagnostic equipment to it and then duplicate the problem. __________________ Alan Roehrich 212A G/S

06-06-2012, 05:11 PM	#105
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 105 Likes: 2 Liked 0 Times in 0 Posts	Re: Help!! Engine Miss I've actually been thinking about the chassis dyno idea for a couple of weeks now. There's a speed shop with an in-ground dyno about 10 miles from my house. I'm not certain how experienced the operators are in terms of diagnostic abilities, but at the very least, I'd be able to see how it responds at full throttle under load. -Ben

06-06-2012, 11:52 PM	#106
Arnold Greene Member Join Date: Mar 2003 Posts: 131 Likes: 0 Liked 3 Times in 2 Posts	Re: Help!! Engine Miss Ben, make sure you have plenty of clutch pressure before you put it on the chassis dyno. Good luck. __________________ Arnold Greene IHRA/NHRA 2420 A/S, B/S

06-07-2012, 04:35 AM	#107
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 105 Likes: 2 Liked 0 Times in 0 Posts	Re: Help!! Engine Miss Arnold, Thank you. I wouldn't have thought of that.

06-07-2012, 01:13 PM	#108
SC321X Junior Member Join Date: Apr 2010 Posts: 55 Likes: 0 Liked 3 Times in 3 Posts	Re: Help!! Engine Miss Have you looked at the valves to make sure they all open the same as you bump over the motor(no mess that way) If they all seem to open all the way chances the cam is ok. If this car is an automatic I would unbolt the torqconverter and see what difference that makes. make sure you push it back out of he flywheel.

06-11-2012, 10:33 AM	#110
Gary Wiegand Junior Member Join Date: Jun 2012 Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Help!! Engine Miss Hi Ben, This is my first reply on this site, so hopefully I get it done correctly. Before I describe a similar situation which I had, trying to chase down a "miss" in the engine, and what was causing it, I have one question; do you have a spacer plate below your carburetor?