Compression test

[Carmine]

Hi everyone. I'm going to do a compression test on my 409 soon. I've never seen or done one before, but I think this is how I should do it. Take all the spark plugs out and connect the tester to a particular cylinder. Turn it over a few times and note the highest compression reading and the cylinder number. Move on to the next one doing the same thing. Would this be the correct way?? I'm not sure what a good compression reading/number might be, but don't they have to be within 10 points or 10% of each other?? Thank you, Carmine.

 

[62impala409]

You will get a more accurate reading if you prop the carb open. Air needs to get into the cylinders to compress.

 

[MRHP]

And I usually put a battery charger on 20 amps or so otherwise on the last few cylinders, it could be spinning slower giving you a lower reading. Make sure to disable the ignition system. Keep the throttle wide open on the carbs. The gauge should reach its max reading after 3 or 4 pumps. Make sure to count the compression cycles, and do it the same amount for each cylinder.

 

[Don Jacks]

As Leo said,block the throttle open.On your engine,about 165-170 psi is likely.A lot depends upon the cam's duration.Yes,you'd like each cylinder to be within 10 or so,in reality,as fresh as your engine is,with in 5 would more likely as to what you'll see.

 

[Carmine]

Thanks everyone. Been wanting to do this for a while. Hate to tell you why, but the engine is still using oil. You have no idea how disappointed and discussed I am with this. The smoke is very, very light and you really have to look hard for it. But, I can smell it as I approach a stop sign and stop. It might not use as much as it previously did, but after about 1800 miles, it should have stopped by now I think. The tail pipes are also a little damp with oil but not like before. I just want to check the compression and if I find something wrong, then I can return to the machine shop and speak with them, Carmine.

 

[Ishiftem]

I think a leak down test would be more accurate if you are looking for the condition of the rings.

 

[Don Jacks]

 

[blkblk63ss]

what is the warranty by the engine builder,mileage and time ??? I would visit them now so they are aware of this . I would drive it to those limit's and see if it quit's first. I would think they would want you to try that. What kind of oil are you using???

 

[Carmine]

what is the warranty by the engine builder,mileage and time ??? I would visit them now so they are aware of this . I would drive it to those limit's and see if it quit's first. I would think they would want you to try that. What kind of oil are you using???

Truthfully, a warranty was never spoken about. Shame on me I guess. This is my 6th engine rebuilt by this machinist and we kind of developed a friendship. So, it's somewhat a delicate situation for me. I already alerted him to the fact that the engine was using quite a lot of oil last year. He is aware of it. I really thought that by cleaning out the oil return passages in the heads and given some more time for breakin of the rings, it would cure things. It did to a certain extent. I didn't see the obvious blue smoke anymore and thought that was it. I really thought this issue was behind me until I stopped at a stop sign not too long ago. The draft from the car caught up with me and I could smell the odor of burned oil. UGH. Yup, knew that smell alright. When I got home, I looked at the tailpipes which were in the sunlight. Didn't see anything. Moved the car to the shade and I could see a very faint smoke. You had to look long and hard to see it, but it was there. Not nearly like it was though. Totally discouraging for me. I haven't been real lucky with my first venture with the "W" engines. My 348/434 likes to run hotter then I like no matter what I do. And the 409 has this smoke issue/oil usage. Sometimes I think these just aren't for me although I really do like them both a lot. I know if this was just any machine shop, this 409 would have been back there last year. I would have insisted on some qualified repair shop pull the motor and let the machine shop tear it down; at their expense. If they refused, I would have then sought a remedy through small claims court. Guess sometimes it's not the best to be too friendly with your repair people. I'm personally not pulling this motor. It's finished off quite nicely in the engine compartment and I'm leaving it. So, I thought I'd do a few test maybe trying to find the problem. The compression test is one of them. I know there was also mention once of a leak down test. I'll try that also but first have to research how that is done.

I changed the oil and filter earlier this year. It had the Joe Gibbs breakin oil still in it. I'm using Castrol 10w-40 oil plus that additive for the camshaft, Carmine.

 

[models916]

Mine had blow by for longer than yours. Went to Dino Oil and put a lot of load on the engine for about a month. Things like up hill in a high gear and engine braking around town. They don't seal up with easy running. I used an Iron ring set. Went to a PCV on the road draft opening and vents in the valve covers. I have heard that molly faced rings can have the ring surface washed off when new with a single flooded carb early on? I wouldn't give up yet. Saw an article couple of years ago from an engine shop that seals the engine and then puts a shop vac to the valve cover to run it in under vacuum to seal the rings up.

 

[blkblk63ss]

Break-In Plan
Although it is not necessary, ATK says the following procedure will help speed up the break-in process:

• Make five or six medium-throttle accelerations to about 4,500 rpm before letting off in gear and coasting back down to 20 miles-per-hour.
• Run a couple hard throttle accelerations up to about 5,000 rpm and once again coast back down to 20 miles-per-hour.
• Let the engine cool, change the oil and filter, and check the coolant level.
• Drive the next 500 miles normally, keeping the engine below 5,000 rpm and minimizing operation at idle.

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[blkblk63ss]

Carmine back in the day car maker's had a recommended break in procedure similar to above . I would do this about every time you drive it. Also 10/40 oil i think i would use something other then that , but that's my opinion .Back when i had a new 64 ss 409 i used Mobil oil because that's what my dad used on the farm . It used oil ,so i switched to Quaker state oil and the oil usage went away almost immediately. Been using it ever since on all vehicle's i own with no sludge problem's or oil burner's. I know guy's here hate that oil but it work's for me.I am not telling you to use this , just stating my experience with this oil.

 

[Don Jacks]

How much oil [mi.per qt] is it using?

 

[303Radar]

What if the valve seals are bad? What's a good test for this versus rings?

 

[Carmine]

How much oil [mi.per qt] is it using?

I wish I had kept better track of it, but I didn't because I thought the usage was all behind me. I would say I'm down about 1 quart and went maybe 500-600 miles. This is about half as to what it once was. I'd have to check some old threads and see what I reported. I know initially it was a lot. I'm relying on my recall but I thought it was better then 2 quarts in the first 1,000 miles. I really thought this problem was gone when I changed the oil, therefore didn't pay any attention to it until I checked it and saw about 1 quart low. Initially, I did run it hard on several occasions and let it back down in 4th gear until it started bucking a little. The engine still runs strong and cool. No missing at all. Just puzzles the heck out of me. I probably should go to the machine shop and advise them that the problem still exist but not quite as bad. I should also find out from them what rings they used.

The valve stem seals I'm assuming are new. Other then physically looking at them, I don't know how to tell if they are defective or not. Something is allowing the tailpipes to have a very light coating of oil. This coating is very light in comparison to the coating I once posted. The newer version also isn't as dark as the old. Much lighter in color but nonetheless, its there.
I can try that breakin plan in thread #11. Nothing to lose doing it, Carmine.

 

[Jim Sullivan]

Carmine, usually, if the valve seals are leaking, you will get a puff of smoke at start up or on accelerating from an idle then will clear up.

 

[La Hot Rods]

Maybe a chance the intake gaskets are sucking oil out of the lifter valley.
T o test for this plug the breather in the back of the intake (if you have a pcv in it remove it) start the engine then remove the oil fill cap and hold your hand over it and see if you feel any vacuum sucking on your had. If so then the gaskets are leaking in the valley.
This test works if you close off all of the breathers and pcv and leave one to check for vacuum.
If that makes any sense.

 

[427John]

Carmine another thing to consider is think back to initial fire up and break-in did you have any carburetor issues that may have caused some flooding or excessively rich running?Even if it just happened for a few minutes it may have washed down the cylinder walls and glazed them,precluding proper ring seat.If this is the case you may be facing honing to break the glaze and new rings,I have heard that there special abrasive break in additives,but have no experience with them and I personally am leery of that whole concept.The importance of having a properly operating carb for initial fire up and break in cannot be overstated.A buddy and I actually have a carb we keep on the shelf just for that.

 

[427John]

After re reading your post #9 the low level of smoke you are observing leaves hope of being able to get those rings to seat.Double check your carbs and make sure that fuel bowl levels are correct,any choke is fully open and that there are no signs of rich mixture.Also you didn't give much detail on the engine,did your engine builder set the engine up to early 60's max.perf. specs if so that in itself may be the cause of what your seeing.In the 60's Ford motor company actually issued a letter included with the purchase of 64 thunderbolts and 66 427 superstock fairlanes that described the oil consumption you are seeing and light smoke as normal for engines set up to race specs.

 

[Don Jacks]

Carmines engine was built to ,basicly 340 hp 409 standards,meaning cast pistons,and a cam that's just a bit bigger.I think that what this engine needs at this point is a 500 mile plus road trip.The constant heat,and the various load and unloading will fix it,no tear down required.