SO I have #4 and #8 dead at idle....and have checked every possible cause..honest. Question: anybody running early manifold on an 8BA? I am thinking about angle of block since the valve angle changed, maybe just maybe a manifold leak internal is the cause? The manifold is an Eddie Meyer repop, 2X2, brand new real 97s. Have eliminated electrical and mechanical possibles.
Have you tried a vacuum gauge? At idle, there should be a high and steady reading. Any leak would show up.
Please tell me how the angle of the valves would affect the sealing of the intake. The intake surface is flat, tighten the bolts, then check with WD40 for leaks. If no leaks, check compression.
I run an early 2x2 offenhauser on an 8ba with no issue. I run the 59ab style intake gasket. Runs great, pulls hard and idles well. I have a motor minder vacuum guage hooked up and it idles at around 18 vacuum inches. Fwiw I also run a pcv valve. Sometimes when people run the early manifold that has no provision for a road draft tube wacky things happen like there is no crankcase ventilation or improper venting. Not sure what you have going on in regards to that.
I assume you already checked those wires with an OHM meter for continuity. I had a rough run condition earlier this year on my 8BA and it turned out the number 2 wire ate it's carbon core about an inch or so from the plug end.
Ha....my brain is mush after fighting this for several hours over a few days. I still don't see how a leak in the valley is found by WD40 on the exterior. 120 compression on every cyl, wet.
Yep, have changed wires around, and even new wires, cap, distributor, rotor, etc from different engine. Thanx for input...it is a mystery that will get solved!
By golly I shall try a 59AB gasket.....maybe there is a difference? And my ventilation is just at the oil filler cap area on this early manifold.....hmm. Still wonder why just 4 and 8 dead at idle but will try gasket change. Thanx.
I run a Navarro blower intake and the first time I assembled the upper end I had a vacuum leak. I immediately suspected the gasket, though Mike included it with the intake it did not cover all that well. I used the 59 style gasket as Adam401 did and there has been no issues. I have to admit I am not fond of the look as you see too much of the gasket in my opinion. In hind sight I should have trimmed the gasket for aesthetics sake but running well trumps looking well ( I will deny that if asked ). Get that flathead running Ron.
If you install an early intake on an 8ba you will ruin that engine. You will block off the internal ventilation by covering the front vent tube which will trap impurities inside. I’ve done this on my 8ba but installed a PCV in it. This will force ventilation through your valve galley and make it happy.
Yeah I think theres a misunderstanding when people use the early manifold on the later engine that the breather on the oil fill is adequate crankcase ventilation. It is not.
Which goes hand in hand on the thread I did a couple months ago on adding a PCV to my intake below the blower. Made an incredible difference.
I'll show you mine if you show me yours https://www.jalopyjournal.com/forum...-pcv-question-retrofit.1201064/#post-13686719
I can't figure out how to post a link from my phone. My thread is titled like " 59ab fuel pump stand on 8ba which pushrod" its all about my putting the early manifold to use on the 8ba
I guess I got lucky, running an Edelbrock SU 359 on an 8-BA for 8 years and 13,000 miles. Pulled the engine and put it in another car, with and early Offy intake, been running since, for 15 years. No PCV on either engine, only a breather at the oil fill at the back. It didn't have an easy life, I ran it on dirt ovals, at least 15 outings. Adding PCV sounds like a good idea though.
Very lucky. Short duration oil changes could help but odds are stacked going against science and engineering. PCV is a cheap easy project for peace of mind. Great looking car Marty.
Is the oil due to ventilation, lack of? I just cut the vent tube off and left it open inside the manifold, hoping maybe that is causing my idle problem at 4 and 8.
Did you run the early gasket for a particular reason? I did not think enough about ventilation for one thing, and wonder if the early gasket maybe seals better for another....the 8BA looked like a perfect match, maybe not?
I was kinda forced into the early manifold due to hood clearance, my focus was on getting clearance for carbs plus air cleaners and it all just barely fits....the Eddie Meyer early unit was the lowest profile I could find, but may be a mistake. Hate to cut holes a nice heavily louvered hood!!
I learned later from a flathead guy I should have removed (or cut down) the tube in the front of the lifter galley that connects to the road draft tube. This would enable the engine to breath like the 59A did. He said the early intake manifold blocked this tube. Give it a look...