Too much, too little?

R

Ronbo

Famous Member
That is the question and here is the rest of the story. I bolted an AUS 250 head on my 200. About 10K on the rebuilt engine, nothing fancy just stock and bored to .040. I never even took the distributor out on this swap and that is why this is so puzzling. The chambers on the head are, I believe, 48cc. The car will not run. It sputters but won't start. I had to cut my own intake gasket so there is a potential problem right there. Plugs are dry, number six gets wet (might be the only cylinder trying to fire). The inside of the carb is wet, accelerator pump squirts so I have fuel to the carb. Question is, is it making it to the cylinders??? Next step will be a compression test to be sure everything is sealed up in there. Could it be too high? Or too low maybe??? I have NEVER had this happen before. Remember, nothing changed with the ignition or valve timing. What would happen if the head gasket was in wrong? I checked and triple checked before buttoning it up but, maybe it was in wrong to begin with?
I'm at MASSIVE vacuum leak at the intake point right now. If compression was too low it wouldn't run but how could it be? GRRRrrrrrr! Frustration. :)

Ron
 
my 250 head was closer to 70cc
Just to get this straight, you spent $10k previously (total engine rebuild). It ran, now you need to swap the head & you have problems?
 
I believe he meant 10k miles on the engine, not 10k dollars. That would be a bit much for what he describes as "nothing fancy" 8)

Well, Ron, I'm thinking vacuum leak. I'm not sure what the chambers where on your old head, but they couldn't be smaller than 48cc on a US head so your compression is likely higher than it was (just guessing, cuz you didn't say). Here's what I would do: Compression test (it'll have to be cold, so questionable results will ensue), re-do the valve adjustment, new plugs, check the float level :?: , check all your ignition wiring and test for good spark, check the torque on the intake manifold and carb base. Try again. Unfortunately, no way to test for vacuum leaks until you can get it to run. As fate would have it, I have an extra OZ intake manifold gasket that Mike shipped me by accident three years ago. It's yours for cost of USPS Priority Mail shipping if you want it (If I can find it..) PM me.
 
Ronbo,
With a 200cid, 0.040 overbore, 0.053 head gasket, 0.030 deck height, 6.5cc piston recess, 48cc combustion chamber, your CR would be around 9:1. Shouldn't be a problem there.

Make sure your rocker arms are adjusted correctly.

Good luck.
 
I've reassembled some engines and found that the hydraulic lifters were pumped up and were holding the valves open. Do a compression check and observe valve operation to see what might be happening.

Oz 200 pushrods might be too long if you're using those. Again, a compression check will let you know.
 
Thanks alot fellas, I'll let you know where this goes. :roll: I'm sure I'm overlooking something as usual.

Falcon Fanatic: Be looking for a PM. If nothing else I'll use that as a template to make some more gaskets. It will definitely be worth the cost! :)

Compression test is in order. Any chance some fluke, wierd, stupid, thing happened to the ignition? Sometimes it buzzes like its arcing. Thats new. Plugs have a great white spark when checked but that occasional buzzing noise is new.

Ron
 
Yup, that would be the sound. Strange I've never heard it before now but at least I know that part is working. The more I think about this, why aren't the plugs saturated after an hour of trying to start it? Brand new Holley. I dont think I can check the floats unless its running? Guess I could have my daughter turn it over and try adjusting from there. Again, GRRRrrrr!! Patience is not one of my virtues! :lol:

Ron
 
rocklord: What if it were 52cc? Sorry, too lazy to look up the formula :roll: Heading outside right now to fool with it some more. Its gotta be a vacuum leak around the intake. no fuel right? OR if the compression is too low it'll still burn up the fuel but not run???
 
If its not even sounding like it wants to start I would try some starter fluid down that carb to see if it is a fuel issue
 
What you really need to do is haul your arse and your car out to Phoenix and stay at my place. We just put our cars side by side and learn from each other until we get them both working the way want!

On a more helpful note, since you put on the OZ head, you obviously got an intake manifold as well. Is that super sealed to the head? That is where I would start looking for the vacuum leak.

fordconvert":9imjn7xg said:
Is the pushrod length the same?
Click to expand...

This was my initial thought as well. If distributor never came out, then you shouldn't have an ignition issue. When I did my swap to OZ Head, I purchased new pushrods, but I didn't compare to the ones that came out of my 200.

I also recall there was a ground strap that connected the head to the body. Since you are getting spark at the plug, it's probably not a grounding issue, but just in case.

As you've already indicated, sounds like fuel not makign it to the combustion chamber to me. I would pull valve cover, turn crank with a breaker bar, and watch valves open and close. This would be a good indication if the valvetrain is working the way it should.
 
Ronbo":20xpx9pu said:
rocklord: What if it were 52cc?.....
Click to expand...

It would still run fine, just wouldn't develop top power. The size of the combustion chambers is NOT what is causing your no-start condition.

The most likely problem is having the valves adjusted too tight, thereby not allowing the valves to fully close. Until you can fully prove you have compression, do not worry about details such as vacuum leaks; it just ain't gonna run with the valves hanging open.
Joe
 
+1 on valves.

Back them all off, crank it so oil pressure builds up and pumps up the lifters, then adjust. At #1 TDC, adjust #1 E & I, #2 I, #3 E, #4 I, #5 E. Look at Distributor, and rotate until #6 TDC. Adjust #2 E, #3 I, #4 E, #5 I, and #6 E & I.
Works. :wink:
 
Ronbo":3tc9whtf said:
rocklord: What if it were 52cc? Sorry, too lazy to look up the formula :roll: Heading outside right now to fool with it some more. Its gotta be a vacuum leak around the intake. no fuel right? OR if the compression is too low it'll still burn up the fuel but not run???
Click to expand...

You would still have around 8.5 CR, enough for it to run.
 
Whew! Alot to digest here. Still haven't done the compression test, that will happen TODAY. I pulled the valve cover and cranked it over, rocker assembly works fine BUT.....my rockers are non-adjustable. Is this a problem with the OZ head? I guess the compression test will tell the tale today, all pushrods were still in the sockets and moving. It could be interference from the valve cover too, I guess. Its a CI special so I really doubt that one. It does try and fire, sounds like one cylinder is trying to make the grade (my guess is number 6 because it has fuel on it). I'll report back later....


Ron

Vin, yup, we'd have both cars tricked out and we'd be broke! :roll: I'm still looking for work down Sierra Vista way, I'm not too keen on cities. I'd end up all night fighting crime in the bat mobile! :lol:
 
In the absense of all else, go back to ground zero. Do everything, even if you think you are all set. I just replaced the wires on my volvo, did it by memory and thought I was all set only to find out I had swapped #2 and #4 wires, and that was with only a 5 minute gap between all wires off and all wires one and the fact that Volvo pretty much cuts the wires to the perfect length so you CAN'T put them in the wrong spot.

Are you 100% sure your wires are in the right firing order on the cap? I would start there. Verify TDC on the distributor and reset the wires.

I'm not sure about pushrods. I can tell you that I used normal US 200CI pushrods on my aussie head.

crank it for 30 seconds to build up pressure. Rotate the crank and make sure the rockers and valves are moving through the entire range of motion.

I would suggest finding some adjustable rockers. It makes things so much nicer to work with.
 
Welp, compression test done and only number three had any compression, a weak 90psi. I noticed some trouble putting the valve cover back on, like there was interference somewhere. Off with the valve cover and I'll see if it'll fire. This is too wierd. I don't have an adjustable rocker set unfortunately :( More to follow....


Ron
 
You must log in or register to reply here.

Similar threads

S
All Small Six Exhaust manifold leaks
Replies
12
Views
621
DON
DON
F
All Small Six Wrong Head?
2 3
Replies
40
Views
2K
philford
philford
A
All Small Six Bored into the water jacket
Replies
18
Views
975
Cox Custom Mechanical
Cox Custom Mechanical
T
All Small Six 250 CR errrr.... mistake.
Replies
8
Views
409
bmbm40
B
xavier296
All Small Six Ignition Timing Map
Replies
5
Views
460
xavier296
xavier296
Back
Top