The Ford Barn

rick r · 03-03-2016, 02:50 PM

Need Help. have an 8 ba with # 2,3,5,8 cylinders dead . 100 lbs. compression on all cylinders. 10 in hg. vacuum at the intake manifol at idle. lodomatic dist. supplying good spark to all cylinders. double checked firing order and confirmed that all wires are in correct holes. idle mixture screw on dead cylinder side has no effect. have confirmed that there are no external vacuum leaks by spraying starting fluid all around intake and carb base while engine is running. have tried 3 different carbs (94) and same results. confirmed that distributor timing is correct. timing variation either way from spec. does not help. Any and all suggestions greatly appreciated. Thanks in advance.

Midnightcaper · 03-03-2016, 02:54 PM

Are plugs fouled?

Bruce Lancaster · 03-03-2016, 03:04 PM

Those are all fed by one barrel of the carb. Look for a chunk of crud blocking the feed in the carb! On a 94, blocking main jet will shut down both main and idle circuits.

flatheadmurre · 03-03-2016, 03:13 PM

Testing 3 different carbs with same result...can something have sneaked its way down into the manifold blocking one throath ?
If you take the carb of and crank it over do you have air flowing into both barrels ?

Scott H in Wheaton · 03-03-2016, 03:15 PM

What do you mean by dead cylinders?
You said 100 lbs compression on all cylinders
and spark going to all cylinders

If its not mechanical (rings, valves), and its not electrical (spark to all cylinders), it must be fuel related.

Are you doing a cylinder balance test with the engine running?

rick r · 03-03-2016, 03:19 PM

Sponsored Links (Register now to hide all advertisements)

cylinders 2,3,5,8 are not firing. engine is running on# 1,4,6,7.

Bruce Lancaster · 03-03-2016, 03:23 PM

It should pull on both sides (response #4)...if a side isn't flowing, I'd think compression readings would be way off there...?

39topless · 03-03-2016, 03:30 PM

Are the plugs in the "dead" cylinders getting wet when engine is running? If they aren't, and you've tried 3 different carbs, must be as flatheadmurre suggests. Intake malfunction.

George/Maine · 03-03-2016, 04:09 PM

I would say your fir ring order is wrong check cap wires in order

Ross F-1 · 03-03-2016, 05:01 PM

It would be unusual, but if the exhaust crossover has burned into the throttle bore on one side of the manifold, it would suck exhaust instead of thru the carb. Was the manifold bored at the riser? Your problem is in the passenger side bore of the manifold.

19Fordy · 03-03-2016, 05:58 PM

I support the "Check the firing order of the spark plugs" theory.
Also, this might help.
http://www.fordbarn.com/forum/showthread.php?t=184107

flatjack9 · 03-03-2016, 07:11 PM

Definetly sounds like an intake manifold problem.

37 Cab · 03-03-2016, 07:34 PM

With the engine running at idle slowly cover the carb with your hand to reduce air flow. Slowly choke it to richen it up in other words. Will eliminate a lean condition so you can move on to ignition.

George/Maine · 03-03-2016, 08:49 PM

I alway wonder if it ever run good. There is a motors book out there with wrong order check and see if Mercury is what you are using.

rick r · 03-04-2016, 07:55 AM

Problem was the intake manifold. The engine in question is in a friends shop, so I have not seen the defective manifold. I will post an update as soon as I get a chance to look at it. Thanks to all that offered solutions

prpmmp · 03-04-2016, 08:19 AM

Rag in the intake??? Pete

Midnightcaper · 03-04-2016, 12:39 PM

Quote:

Originally Posted by prpmmp

Rag in the intake??? Pete

The ole sneaky shop towel.

rick r · 03-04-2016, 01:09 PM

The manifold in question was a stock aluminum (Canadian) 8ba. Found 2 holes about 3/8 inch dia. in the wall between the heat riser passage and the fuel runner. The holes appeared to be caused by corrosion. There was no sign of any corrosion on the outer surface of the manifold. Live and learn !!!!

Midnightcaper · 03-04-2016, 01:11 PM

Wow nice find glad you got it straightened out

prpmmp · 03-04-2016, 02:17 PM

Quote:

Originally Posted by rick r

The manifold in question was a stock aluminum (Canadian) 8ba. Found 2 holes about 3/8 inch dia. in the wall between the heat riser passage and the fuel runner. The holes appeared to be caused by corrosion. There was no sign of any corrosion on the outer surface of the manifold. Live and learn !!!!

Wow that sucks(ruined manifold)I guess it would have been better to find that ole sneaky shop towel in there

Pete

03-03-2016, 02:50 PM	#1
rick r Senior Member Join Date: May 2010 Location: Woodville Ontario Posts: 227	8BA Dead cylinders Need Help. have an 8 ba with # 2,3,5,8 cylinders dead . 100 lbs. compression on all cylinders. 10 in hg. vacuum at the intake manifol at idle. lodomatic dist. supplying good spark to all cylinders. double checked firing order and confirmed that all wires are in correct holes. idle mixture screw on dead cylinder side has no effect. have confirmed that there are no external vacuum leaks by spraying starting fluid all around intake and carb base while engine is running. have tried 3 different carbs (94) and same results. confirmed that distributor timing is correct. timing variation either way from spec. does not help. Any and all suggestions greatly appreciated. Thanks in advance.

03-03-2016, 02:54 PM	#2
Midnightcaper Member Join Date: Mar 2016 Location: Lake tapps wa Posts: 63	Re: 8BA Dead cylinders Are plugs fouled?

03-03-2016, 03:04 PM	#3
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: 8BA Dead cylinders Those are all fed by one barrel of the carb. Look for a chunk of crud blocking the feed in the carb! On a 94, blocking main jet will shut down both main and idle circuits.

03-03-2016, 03:15 PM	#5
Scott H in Wheaton Senior Member Join Date: Dec 2012 Location: Wheaton, IL near Chicago Posts: 861	Re: 8BA Dead cylinders What do you mean by dead cylinders? You said 100 lbs compression on all cylinders and spark going to all cylinders If its not mechanical (rings, valves), and its not electrical (spark to all cylinders), it must be fuel related. Are you doing a cylinder balance test with the engine running? Last edited by Scott H in Wheaton; 03-03-2016 at 03:21 PM.

03-03-2016, 03:19 PM	#6
rick r Senior Member Join Date: May 2010 Location: Woodville Ontario Posts: 227	Re: 8BA Dead cylinders Sponsored Links (Register now to hide all advertisements) cylinders 2,3,5,8 are not firing. engine is running on# 1,4,6,7.

03-03-2016, 03:13 PM	#4
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: 8BA Dead cylinders Testing 3 different carbs with same result...can something have sneaked its way down into the manifold blocking one throath ? If you take the carb of and crank it over do you have air flowing into both barrels ?

03-03-2016, 03:23 PM	#7
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: 8BA Dead cylinders It should pull on both sides (response #4)...if a side isn't flowing, I'd think compression readings would be way off there...?

03-03-2016, 03:30 PM	#8
39topless Senior Member Join Date: Sep 2013 Posts: 1,027	Re: 8BA Dead cylinders Are the plugs in the "dead" cylinders getting wet when engine is running? If they aren't, and you've tried 3 different carbs, must be as flatheadmurre suggests. Intake malfunction.

03-03-2016, 04:09 PM	#9
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 8BA Dead cylinders I would say your fir ring order is wrong check cap wires in order

03-03-2016, 05:01 PM	#10
Ross F-1 Senior Member Join Date: Nov 2010 Location: NM Posts: 2,438	Re: 8BA Dead cylinders It would be unusual, but if the exhaust crossover has burned into the throttle bore on one side of the manifold, it would suck exhaust instead of thru the carb. Was the manifold bored at the riser? Your problem is in the passenger side bore of the manifold. __________________ '52 F-1, EAB flathead

03-03-2016, 05:58 PM	#11
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,949	Re: 8BA Dead cylinders I support the "Check the firing order of the spark plugs" theory. Also, this might help. http://www.fordbarn.com/forum/showthread.php?t=184107

03-03-2016, 07:11 PM	#12
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: 8BA Dead cylinders Definetly sounds like an intake manifold problem.

03-03-2016, 07:34 PM	#13
37 Cab Senior Member Join Date: Dec 2014 Location: Miami Oklahoma Posts: 535	Re: 8BA Dead cylinders With the engine running at idle slowly cover the carb with your hand to reduce air flow. Slowly choke it to richen it up in other words. Will eliminate a lean condition so you can move on to ignition. __________________ Tommy

03-03-2016, 08:49 PM	#14
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 8BA Dead cylinders I alway wonder if it ever run good. There is a motors book out there with wrong order check and see if Mercury is what you are using.

03-04-2016, 07:55 AM	#15
rick r Senior Member Join Date: May 2010 Location: Woodville Ontario Posts: 227	Re: 8BA Dead cylinders Problem was the intake manifold. The engine in question is in a friends shop, so I have not seen the defective manifold. I will post an update as soon as I get a chance to look at it. Thanks to all that offered solutions

03-04-2016, 08:19 AM	#16
prpmmp Senior Member Join Date: Jun 2013 Location: west grove Pa. Posts: 238	Re: 8BA Dead cylinders Rag in the intake??? Pete

03-04-2016, 01:09 PM	#18
rick r Senior Member Join Date: May 2010 Location: Woodville Ontario Posts: 227	Re: 8BA Dead cylinders The manifold in question was a stock aluminum (Canadian) 8ba. Found 2 holes about 3/8 inch dia. in the wall between the heat riser passage and the fuel runner. The holes appeared to be caused by corrosion. There was no sign of any corrosion on the outer surface of the manifold. Live and learn !!!!

03-04-2016, 01:11 PM	#19
Midnightcaper Member Join Date: Mar 2016 Location: Lake tapps wa Posts: 63	Re: 8BA Dead cylinders Wow nice find glad you got it straightened out