valve seals

[cmm24601]

couple of questions folks....

Can anyone confirm that the spark plug gap on a 1969 Mustang 250 i6 is 0.02in? I've upgraded to a pertronix 40K coil and the electronic timing, but I'd like to keep the stock gap width

2. Just replaced the spark plugs. 3 - 4 - 5 were covered in ash, so it looks like i need to replace the seals. Is this possible to do with the head on? I'm a novice mechanic. Is this something a professional should do?

 

[bubba22349]

The stock spark plug gap in 1969 for the 250's was .034. Good luck

 

[Econoline]

The valve seals can be replaced with the head on. The main concern is the valves dropping into the cylinder when the springs/locks are removed. There are different ways of doing this, rope shoved in the cylinder, air pressure in the cylinder. If you do some googling you 'll get the idea. Find a good shop or mechanic around you and they should be able to do this for you for a reasonable amount of $$.

 

[chad]

I'm the wrong guy to ask this Q (as may B evident next
but Y go w/standard gap?
One of the advantages of the peppier ignition is to widen the gap for better burn…

 

[CZLN6]

Howdy cmm:

And welcome to The Forum.

How about some more information about your car. How old are the spark plugs? What number cylinders are they from? How is this car driven? Lots of cold starts with very little warm up?

What I'm saying is that it may not be a valve seal problem. Other more simple issues should be explored first. Starting with the questions above. My kids drove a Mercury Comet, 250 with an auto trans, back in high school. It was started up and driven about 2 miles from home to school. Then started up and driven to soccer practice, then work. The point is it never got really warmed up to the point of burning off chamber residue. Result- fuzzy spark plugs. So we ended up cleaning or replacing spark plugs about every three months. We used .035" on the gaps with the stock point distributor and coil. The auto choke worked great even in below freezing mornings. And it never smoked or used any oil. They could have driven it 20 miles every weekend to burn off the fuzz, but they had to pay for their own gas, so that was out. So a ritual spark plug cleaning became a daddy-daughter event. Every other month was my sons turn for some bonding. We also used this time to assess fan belts, fluids, change filters and oil, and just talk.

But, I digress. So, if any of this sounds familiar to you, do some more assessing before concluding you need new valve seals.

On your ignition, why are you interested in keeping the stock specs on the plug gap? I'm assuming that the reason for upgrading to a Petronix Ignitor and coil was to improve mileage and or performance. Or possibly to eliminate points maintenance. All good rationale.

But, with an improved ignition you can gain even more by opening the spark plug gaps to .040" or .045" with no increased wear or any other downside. And you can gain more in power and economy by increasing the initial advance setting to 5 degrees more than the stock specs call for. For example, if the stock setting with an auto trans is 12 degrees btc, try setting the initial at 15 to 17 degrees btc. Listen for any pre-ignition knock. If you hear any reduce the initial advance setting by 2 degrees and try it again.

Again, welcome to this Forum. Great people here and willing to help and offer suggestions.

Adios, David

 

[CZLN6]

Howdy Back:

"Just replaced the spark plugs. 3 - 4 - 5 were covered in ash,"

Sorry, I missed that last night. Fuzzy 3, 4 and 5 plugs could be caused by a rich choke setting. If #1 and 6 appear lean, or look fine, it may be a choke issue and/or too much idle time.

Oil fouled spark plugs are typically black and oily looking. An ash coating may be a by-product of the brand of gas you are burning.

How long/many miles have you had the Petronix and hotter coil? You may need a one step colder heat range spark plugs.

Just more thoughts. I hope they are helpful. Let us know what you find.

Adios, David

 

[cmm24601]

Very helpful info. I will reset my plugs to 0.04 and see how things go.

David - Here's more info about the car:

Very much a frequent cold start scenario. I drive it less than a mile to work. A few trips in to town during the week at about 12 miles round trip.

I have about 1000 miles on the new pertronix setup but most of that is highway miles. I took a road trip across NC a couple of weeks ago.

The engine was rebuilt by the previous owner. ODO read 6000, but the owner said it had at least 2000 more. Still, the engine is in it's first 12,000 miles since the rebuild.

I just put new spark plugs on, they can handle a much hotter spark according to the OReillys guys. I'll post the specs when I get home.

Funny you should mention the carb and choke... A best I can tell, I have the original Autolite single valve. Looks rebuilt, but I haven't taken it off the engine. Back in October a plastic piece on the choke linkage snapped. I safety wired the thing back together, but there are times that I suspect the choke is holding the throttle open longer than it should. It takes several cranks to get the car warmed up in the morning. Frequent stalls until it warms up. Tapping the accelerator while warming it up has different effects each time as if the linkage mechanism is getting hung up.

CJ Pony Parts didn't carry the linkage parts and it seems like most people just replace the carb with a 2 valve anyway. that's my plan. Any carb recommendations?

Also, I think I'm going to take a look at the valve seals with the head still on and see if they were replaced in the rebuild.

 

[drag-200stang]

When you have the valve cover off check if there is a good baffle at the pvc suck point. Oil can end up at those cly. some times. Just something to think about.

 

[CZLN6]

Howdy Again:

FYI the stock carb on this engine should be a very desireable carb called an Autolite 1101. If I were in your shoes I'd work to get it working properly. Once you upgrade to a two barrel carb you should be able to sell the 1101 to help offset some of the upgrade costs.

Thanks for the info. Keep it coming.

Adios, David

 

[cmm24601]

Alright David. Now you've got me rethinking the carb situation. I can see you know this engine well to say the least and you are fond of the Auto lite? What advantages would a two valve carb present? My main goal is reliablilty and was of a cold start.

Can you point me to a good resource on the Auto lite 1100?

 

[CZLN6]

Howdy cmm:

First, let's take on the choke issue on the stock carb. Another issue is choke sticking. The choke is in a very unfriendly environment. I'm assuming that it is still hot air choke. By that I mean that there is a bent tube from the top of the exhaust manifold to the choke body, covered with an asbestos sleeve, because it is hot. It draw hot air through the exhaust manifold into the choke coil. The purpose is to heat the coil and cause the choke to open. But, that is unfiltered air being drawn in by engine vacuum. Depending on your driving environment that air is dirty, unfiltered air being drawn into the carb. Consequently, a good hose down, both inside and out is needed to keep the choke mechanism free and un stucking. Any aerosol spray carb cleaner can do the job. I like to do it when the engine is warm, to lessen the mess. Using a good fuel system cleaner every so often is also a good idea. Just pour it into the gas tank before fueling.

Your 1101 is closely related to the 1100 used on a jillion Mustangs and Falcons. The choke parts are all very similar. Keep an eye out at your local swap meets for a core to glean parts from.

On the two barrel the choice is simple- I'd recommend an Autolite 2100 in a 1.08 size for your engine. That was the easy part. The hard part is, you will need to modify the intake log on the head. There is an adapter that mates a two barrel to a one barrel opening, but that creates a hood clearance problem. Double trouble on a '69 Grande. You may not be ready for a 2V conversion yet. Keep reading and listening for awhile. Adapting a 2V carb along with mating to an auto trans downshift linkage is quite involved.

Other two barrels to consider are the Holley 2300 in a 350 cfm size and the Weber 2V carbs.

In the mean time, while you are studying, get to work on your stock carb to get the most out of it.

Keep it coming.

Adios, David

 

[jimlj66]

Not sure what part you broke on your carburetor, but I was able to find a plastic part for my 1100 carburetor from Daytona Carburetors. The local Napa and Auto Zone was completely worthless for the broken part. They also have rebuild kits if you can't find one locally.

 

[chad]

WoW:

"...the Holley 2300 in a 350 cfm size…"
350 cfm on a 250/4.1 !
didn't know they (that motor) would take that much…
Cool!
(my carb is less than 220 cfm
but I am goin 4 tq not HP)

 

[drag-200stang]

Something to think about is, a 250 has the same suck signal as a 333 V8. 250 has 41.666 cid per suck vs 37.75 for a 302 V8.

 

[chad]

Something to think about is, a 250 has the same suck signal as a 333 V8. 250 has 41.666 cid per suck vs 37.75 for a 302 V8.

kouwell, thought that log intake "killed it all".
thanks,
gunna hafta ck the stats on CI archive (or "handbook") 2 view them all...