Have Questions on Engine Leak Down Test

[prayers1 153]

Going to Walmart to get rubbing alcohol.

 

I gave it some real thought. I might have 1500 miles on it.

Isn't that a lot of soot on both head and piston. I was really surprised to see how dirty it was.

I change the oil frequently, maybe more than I should and use 90% of the time non-ethenal premium gas.

 

I always had a tuning concern. No matter which way I went, I always wound up getting 3/4 of a turn on all A/F screws.

Because of the bog I always had, Quickfuel said to richen it up so I went up on bleeders and squirt nozzle and readjusted the transition slots.

 

Changed to a MSD box and Dist, same bog and same carb condition and 12" of vacuum.

 

Maybe the above has a self telling sign

 

In any case, I'm going to pull the motor. I don't think I can get the correct torque on the 2 bolts at the bottom near the shock tower, it's a real tight squeeze.

[1969_Mach1 333]

The deposits don't look too bad.  Like most of these cars, they don't see a lot of long distance highway speed driving which helps clear out those deposits.  From your carb jetting and air bleed specs in your other posts, I'd say the carb is not too rich.  If you want much more vacuum at idle you'd have to do a cam swap for something with less valve overlap.  This is accomplished by either increasing the lobe separation angle to something like 112 degrees, or by reducing the duration of the intake and/or exhaust valves.  The drawback of this is your cylinder pressure will increase, thus increase detonation or the chance of detonation.  From my limited experience your cam's valve overlap of 56.5 degrees at the advertised duration is not too much, but at 0.050' lift the valve overlap of 5.5 degrees is creeping up on the threshold of causing some drivability issues with a 351 cubic inch motor.  In my old school thinking mind the lobes seem fairly aggressive.  Also, for the advertised duration, is that at 0.004" tappet lift or 0.006" tappet lift.  It makes a small difference.  I think the SAE standard is to use 0.004" which is what Crane uses.  But some cam manufacturers like Comp and Lunati use 0.006" so their cams always seem a little more aggressive than the specs indicate.  I'm kind of stuck in old school for cams.  I prefer something with a little less aggressive lobe profile so it's easier on the valve train.  This doesn't help your situation, but what I run in a 351W is a more old school straight pattern asymmetrical lobe cam with 286 deg. duration at 0.004" valve lift, 224 deg. duration at 0.050" valve lift, 0.542" total lift, and 112 deg. lobe separation angle.  This gives it 62 deg. overlap at 0.004" valve lift and 0 deg. overlap at 0.050" lift.  It has good drivability and 14" vacuum at idle.

[prayers1 153]

 

[1969_Mach1 333]

Nice work.  Looks like you found the leaking exhaust valve.  Was there also another cylinder with the same issue, just not as bad?  If it were mine, I'd consider taking both cylinder heads to a machine shop, have them cleaned and they can lightly regrind the valves and seats and install new valve seals.  Ask them to also vacuum check for leaks on the valves after the heads are reassembled.

 

After I mentioned to pour solvent in the ports it occurred to me the solvent might leak through the valve guides.  I have reinstalled the spark plugs then filled the combustion chambers with solvent.  Then look into the ports for solvent leaking past a valve. 

[prayers1 153]

I added the rubbing alcohol to #1 & #2 exhaust valves. #2 was a little tricky because of the heat riser hole on the opposite side, so I was able to use a syringe. I had the head lying flat and didn't notice any drops, after a while I leaned the head towards the exhaust side to empty out the fluid, I continued rotating the head until it was upside down, that's when I noticed fluid around the valve. I don't believe any fluid escaped the heat riser hole and feel confident it was leaking at the valve. It did not leak at #1.

[jmlay 80]

How does the head gasket look? Scrape the gasket from the head an the block & check both with a straight edge for warping. 

[ray1970 88]

So  the current train of thinking is that the the head gasket is leaking between cil. 1 and  2??

The head gasket dosent look that bad but it would explane  some of the poor leak down readings if it was leaking.

I would think that a gasket is not one way and you would get the same poor reading on both 1-2 cil ??

 

Having two problems on one cil. is very possible.

.

When you get done fixing your current issues it my not change your past low RPM problem...... Hope it will..

 YES you have a problem but i dont see were its going to change your past issue much.

(Please disregard this message if i am wrong)

 

The clock is ticking 

[1969_Mach1 333]

So  the current train of thinking is that the the head gasket is leaking between cil. 1 and  2??

The head gasket dosent look that bad but it would explane  some of the poor leak down readings if it was leaking.

I would think that a gasket is not one way and you would get the same poor reading on both 1-2 cil ??

 

Having two problems on one cil. is very possible.

.

When you get done fixing your current issues it my not change your past low RPM problem...... Hope it will..

 YES you have a problem but i dont see were its going to change your past issue much.

(Please disregard this message if i am wrong)

 

The clock is ticking 

I'm inclined to think the same.  Fixing this will not affect the low RPM issue.  Unless the low RPM issue was something different than we interpret from the posts.

 

Maybe while the motor is out,  It's time to research cam selections and see if something else is better suited.  Just saying.  It's apart, maybe make certain what you have is best for your application and driving style.

[prayers1 153]

I have been advised by someone who is experienced that by looking at the pictures they believe there was a head gasket problem, I really couldn't tell myself.

 

I pulled the 2nd head and it looks a lot cleaner, not as much surface rust.

 

I'm bringing the head and gasket to the builder and see what he has to say. I can't believe I had this problem with approx 1500-2000 mile motor.

 

Yes, now is the time to decide what to build. If I put the heads back on same problem, if I put in another cam who knows what would happen.  One thing for sure, if I build another its gonna be a Stroked Windsor or Cleveland.

 

I would like to build something in the 500hp range, having small heads that Windsor use would be great, I can fit headers, get a brake power booster, ease of changing plugs etc....

As for the Cleveland, I have most of the stuff, a std bore short block in the corner, manifold, dist, headers etc..  I'll  just need a stroker kit and Alum heads and a torque converter.

 

Food for thought! What's your take!!!!

[Max Power 74]

Usually when doing a leak down test and you hear air going out the exhaust, it's a valve sealing problem more than a head gasket. I suppose it is possible if the adjacent cylinders ex valve is open when you are testing the cylinder, it could work that way. Is previously stated, if a gasket is out between two cylinders, the readings will be equally low in each cylinder.

 

I would build the stroker Cleveland with aftermarket heads.

[MikeStang 247]

When I have done leak down tests in the past, I have always loosened off all of the valves and removed the rockers, then brought each cyl up to TDC and run the test... While it wont tell you if the valves are adjusted properly it will tell you if you have a good seal in the cyl.

Then if I have low readings I figure which cyl it is and then reinstall the rockers and run the test again and see where the air is coming from.

[ray1970 88]

(I would build the stroker Cleveland with aftermarket heads.)Max Power..

 

Did that and never looked back. Got tired of the of the lack of power down low....Cheap it was not......

.Fun factor is YES....Power from bottom to top..

500-550Hp is great for the first year than you start looking for a little more....It never stops!!!

Someone stop me!!!!(Is there a 12 step program?)

[MikeStang 247]

Ray the easiest thing to do after stroking and poking is to buy an N20 Kit that will do 50, 75,and 150 hp shots...THEN on year 1 run the 50 hp shot and be happy till ya want more, then swap to 75 hp shot and a few years later hit it with the 150 shot...that should keep you happy for many years to come haha.

 

Really tho if built right and running a conservative tune a built stroker should handle 125-150hp shot of giggle gas very easily

[1969_Mach1 333]

I know I like the 351W based motors.  But they're a tight fit in that engine compartment as well.  And with the long rod of a Windsor, they are much taller than a Cleveland, so now hood clearance is added to the equation.

 

And Prayers1, 500 to 550hp.  Sounds great.  I don't care what anybody here says.  First mores hp = more tempermental.  Second, more hp = shorter engine life.  I'd be more realistic with a goal of 425 to 450 hp.

 

I agree with MaxPower on the head gasket.  Typically if a head gasket is leaking between two cylinders, those two would both have low and similar compression.  Since the four cylinders on the other side look so much cleaner I would suspect the bottom of the intake manifold is gasket leaking and pulling some oil vapors into the cylinders on the dirtier side.  That would also explain the excessive blow by condition you were fighting from the beginning causing you to remove the PCV.

[ray1970 88]

It my not be normal but my current 408C is far less finicky on tune than any of my last two 351C .

How long will it live? Time will tell..Hopefully one or two more weeks..

[det0326 179]

It my not be normal but my current 408C is far less finicky on tune than any of my last two 351C .

How long will it live? Time will tell..Hopefully one or two more weeks..

Ray I like your sense of humor. If I am ever up your way I will look you up and we will go to the local bar and have a few beers on me.

 

Dave

[ray1970 88]

If its three weeks from now we my have to take your car..If so i will buy.

Better ideal is we show up at P1s place and bug the shit out of him..let him buy the beer..

How could it go wrong???

[prayers1 153]

Just got back from the machine shop, he looked at the head gasket and said it looked fine, that it didn't leak between #1 & #2.

 

He took the #2 exhaust valve out and lapped it.  He found that one side of the valve was barley touching the seat, the valve was not bent, but can see into the guide that one side did not having any wear, the valve was riding on an angle.

 

Further inspection found that the valve stem tip witness mark was wearing towards the edge, as if the roller tip was on an angle and had developed a very tiny mushroom on the edge.

 

As for now he's going to take both heads apart do whatever it needs to be done to fix it.

 

I do not know what the future holds for this Cleveland.  I learned that it will not do me well as a street engine but well enough if raced, where I can keep the rpms high all the time.

 

He suggested for me to build a Windsor based roller type block, stroked to a 393 or 408, using AFR 205cc heads and an Edelbrock  RPM Performer with a 2800-3000 stall converter.

 

Whats your say!

[ray1970 88]

not shore how to respond on that...so i wont...

[LoneWolf2U 136]

See post #25.

Are the valves stock?  Where the guides replaced at some time?  What rockers are you running? Does it have studs and guide plates or is it stock rocker bolt down?

You posted something about shims, Was it checked for rocker to stem pattern?

 

As for going stroked,  It could be all good and well but I don't see flashing your convertor in stop and go traffic is very street friendly. bit thats my 2cts.

[prayers1 153]

Mach1Rider

 

Yes, he did what you suggested in post #25, good call.  He did mention that the other shop messed up on the guide work. IIRC, something like you can still see the drill or bolt mark and one side you don't.

 

The heads were rebuilt by someone else, I just changed the factory valves to SS single groove Valve Stems, new double springs and Scorpion 1.73 Pedestal Roller Rockers.

 

Not checked to Rocker to Stem pattern.

 

Nice to see your still around, how's life in the country at the new place!

[MikeStang 247]

with AFR 205's on a 408 Stroked Windsor and small Hyd roller cam 500hp is fairly easy to do.

and it wont run hot in traffic, will have enough vac for power brakes if cam is ground right and will be a torque monster.

2800-3000 stall is about right long as you have gear and the converter is built RIGHT... No comparison of a 2800 stall from TCI and a custom built unit from Continental... TCI unit will flash under light acceleration all the time...custom Continental will run like a bone stocker till you put your foot in it....

[prayers1 153]

Mike, Thank you for that info.  I'm still investigating on what to do. I have 4:11's.

 

AFR 205 vs. TFS TW 205 what do you think?

 

In a way I'm pretty excited to do a new build and with something I can install a power brake booster. Had few close calls with the manual set up.

I also believe header fitment will be easier than a Cleveland, what is the the best tube diameter?

 

If I decide to go Windsor, I'll have to start another thread.

Thanks!

[1969_Mach1 333]

I definitely like Windsor's.  But, I'd say price out a new motor thoroughly.  Then decide weather to, or when to, pursue a new motor.  Maybe, for now reassemble yours and make certain everything is correct.  Then build the other, and do the swap at a later time.  After your teardown results I wonder if your intake manifold was sealing correctly.  If not, it would cause a host of problems.  Also, you've mentioned shimming the rocker arms to adjust the lifter preload.  So, while your heads are in the machine shop inquire about machining them for screw in rocker arm studs and eliminate the pedestal setup you currently have.

 

As far as power brakes. 1970 Mustangs came with Cleveland motors and had power brakes.  If booster to valve cover clearance is a problem Tuff Stuff offers a single diaphragm booster that is much shorter than the Bendix dual diaphragm brake booster.  So it would provide much more valve cover clearance.  It is 9" diameter vs. 8" diameter on the Bendix.  So on Manual trans cars it might interfere with the clutch rod from the pedal to the z-bar. 

[ray1970 88]

I can say that its very tight having a 351C and power breaks and tall valve covers.(Think big block)

The Z-bar is not an issue..  

I remember my 351W  having more room.