351windsor low oil pressure

[Lemon Owner 11]

Well what a weekend it has been. I have been trying to get this engine back together but the gods are against me.

 

First problem was the cam spocket would not turn smoothly when the retainer bolt was tightened. As it turns out the cam retainer plate was rubbing on the edge of the sprocket so needed about an 1/8th of an inch ground off. So Cloys double row timing chains do not fit straight on.

 

I had to make my own water pump to backing plate gasket because the gasket kit only has one for the timing cover to water pump. After fitting it I found the water pump rubbing on the backing plate. Of course removing it damaged all the gaskets and I had to make a double thickness gasket to stop the rubbing.

 

I went to fit the sump but the gasket in the gasket kit had 2 cork gaskets for the same side. I purchased a new sump gasket but it did not quite fit properly and had to be trimmed at the rear main cap. Also the rear rubber over the main cap was too small. Fortunately the rubber in the gasket kit fit. As it turns out the later 351 windsor with the one piece rear main seal has a different size main cap. Thus making a different sump gasket set.

 

So I finally got around to dropping the lifters and push rods into place. As I did so I noticed a shiny wear mark on the side of one of the push rods. Bent pushrod, which explains the lifter noise.

 

And with that I am off to buy another push rod and all work has ground to a stand still. Until tomorrow when I can get another. I wonder what is in store for me next.....I have a feeling the lifters are going to give me grief. They appear to be different height internally. We shall see when I fire it up. It is going to be a long week!

[Flanders 46]

did the walls learn some new swears over the weekend? :-)

[Lemon Owner 11]

Hahah actually I was quite reserved for a change. I think I have become accustomed to the fact that things will go wrong and to keep expectations low. I managed to track down another push rod but it was too long. So I will keep that one and get in the shorter one today which I have a feeling will be too short. We shall see.....I just hope either way the lifters will pick up the slack.

[LSG 15]

Lemon, you may want to think about finding another shop. 500$ for balancing is more than double what it should cost. Did you check the cam bearings to see if they installed them correctly ? lots of folks don't know how to do this...........

 

LSG

[Lemon Owner 11]

When I put the cam in I spun it and it felt good with no binding or oddities so I think the cam bearings are fine.

 

I have had another interesting weekend with this engine. After running in the cam I finally got to take it for a drive but it did not want to idle in gear and seemed to show signs of a vacuum leak. By this I mean it would stumble a little off idle and it would take 5 seconds for the engine idle to return to normal idle revs. I checked the timing and advance and all appeared normal. There seems to be an odd bark? in the exhaust note too that it never had before. And the engine is louder.

 

I blocked off the vacuum advance to rule out this as a leak. I checked out the carb which is a vacuum secondary 600cfm holley, near new second hand unit and there was a small leak in the choke system. Which was not of a type I am familiar with. I removed the choke and fitted the manual one off the two barrel that was on the engine previously. But the symptons persisted.

 

Another problem is that when the engine is hot it does not want to crank which is a whole new issue. But when I advanced the timing it started to crank over fine. hmmmmm

 

I changed the carb off my coupe which is known to work fine. I started the engine and it ran fine with no bark in the exhaust and return to idle quickly. But the throttle spring would not return it to idle properly so I shut it down and replaced the spring. When I started it again it ran roughly as if there is 2 cylinders down. I have now replaced all the plug leads, distributor cap and rotor with ones off the other car with no change. I removed the pertronix ignitorII from the dizzy and replaced it with the old points with no change. I have run a wire from the positive side battery to the coil to rule out ignition problems. I have run a wire from negative side battery to distributor to rule out earthing problems. I have timed it by ear rather than rely on my new harmonic balancer which could have incorrect marking but still the problem persists and deteriorates.

 

I removed all the spark plugs, 3 of wich showed near black insulators with the others showing near white to a little chocolate. I proceeded to do a compression test with all cylinders in the region of 160 - 170 PSI which is very good. So that should rule out valve leak problems? But clearly there is a problem with a few cylinders.

 

My feeling is maybe a bad earth inside the distributor or a vacuum leak under the inlet ports on several cylinders. But I don't know and intake gaskets are $50 a set and that's alot of money on a big maybe. A vacuum gauge is $70 and they are not that reliable. I may have blown out the power valve on the carb that I put on off the other car but I would not think that would effect the idle circuit but it is a maybe too.

 

So does anyone have any ideas? I am just about at the end of my tether, please help!

[bnickel 10,004]

i would check the breaker plate in the distributor, i've had them start to stick when they get old and the nylon bushings wear. I'd start there, also check to make sure the vacuum advance is actually advancing. the best way to do this is with the engine running and the vacuum advance disconnected and plugged on the carburetor side connect a handheld vacuum pump to the advance unit, and pull a vacuum on it, the engine RPM should increase, if it doesn't the vaccum advance diaphragm is bad. you can perform the test the same way by using your mouth to pull a vacuum and hold it with your tongue if you don't own a vaccum pump, you can also get them pretty cheaply at places like harbor freight.

 

I actually had to replace both the breaker plate on the stang a couple of years ago and the breaker plate and the vacuum diaphragm both on the cougar just last year when I was trying to get it fired up from it's 12 year nap even though the car only has 64,000 original miles. I guess age and probably sitting for so long did it in.

[Lemon Owner 11]

I have already checked the vacuum advance and it is working fine with no leaks.

[1969 Mach1 14]

After examining the spark plugs and finding 3 that are questionable did you install a new set to see if the problem clears up at least for a short time? Check your intake and all other sources for vacuum leaks. Wow, I can't believe intake gaskets are $50 in your area. You have good compression in all cylinders, it should be fairly easy to fix.

[bnickel 10,004]

You should still check out that breaker plate assembly, they can and will stick when they start to get worn out and just because the vacuum advance canister is good does not mean that the breaker plate is in working order. just FYI

[1969 Mach1 14]

I agree with bnickel. I remember many years ago when I was in high school. Worn breaker plate assemblies on two vehicles, a 1969 Mach 1, and a 1967 Fairlane, both with small blocks, caused all sorts of misfire conditions. I remember the point's dwell would decrease significantly every time the vacuum advance moved the breaker plates and the engine's would begin to missfire. I think that's one reason most people move away from these OEM distributors when it's time to replace them.

[bnickel 10,004]

that's probably one reason but honestly breaker plates are relatively cheap, around 15 bucks or so and these distributors are pretty simple to work on as well. I always try to keep the OE dizzy and vacuum advance can too. I have a really cool adjustable vacuum unit that replaces the original hose nipple fitting on the canister that allows you to completely customize the vacuum advance curve with an allen wrench just like the aftermarket advance canisters but you get to keep a concours appearing engine bay with this unit.

 

http://www.cougarpartscatalog.com/adjf01.html

 

have the mechanical advance curved at a good speed shop or do it yourself with a dial back timing light and a helper and one of the Mr Gasket advance spring kits and you're good to go.

 

I thought of one other you might check while looking at the breaker plate too, remove the distributor cap and grab the rotor and see if there is any excessive play also get a helper to crank the engine and watch the rotor spin to see if you detect any play that way as well, if there is more than a few thousandths of play then the bushings in the dizzy are worn out and the unit needs to be rebuilt or replaced. I'd recommend having it rebuilt as opposed to a reman unit from autozone or places like that. the reason is because the rebuilders generally set the dizzy up with a generic advance curve, if you send it out to be restored or rebuilt you'll be able to keep the correct advance curve. if it needs rebuilt or restored I'd send it to this guy http://428cobrajetcars.com/new_parts he's not exactly cheap but I've heard nothing but praise for his work.

[Lemon Owner 11]

I replaced the spark plugs with the old set out of the engine and again there was no change.

 

In regards to the vacuum advance I checked it was operational. First I would connect it to ported vacuum and then manifold vacuum and watch how it reacted with the timing light. I also checked by sucking on it and it was fine. Also by changing from the electronic ignition to points and back again ruled out any dwell problems.

 

I had a little read through the installation instructions for the cam and I read something interesting. If I have too much preload on my hydraulic lifters it will cause low manifold vacuum and a rough idle. Pretty much all the symptoms I have. As I said earlier I was worried that the lifters were internally taller than the originals. Coupled with the fact that the block and heads have been decked with new valves it is a definate possiblity. And about the last thing left to check! So tonight I will go home and stick a washer under each of the non adjustable rockers to test the theory.

 

Wish me luck! and thank you for taking the time to come up with ideas.

[1969 Mach1 14]

Good Luck, that could very well be it. I guess you didn't have the heads machined for screw in studs and guide plates. Thus, making the valvetrain adjustable.

[Lemon Owner 11]

Well after fitting some cone lock nuts that allowed some more clearance for the lifters my problem is solved. Engine now runs smoothly. At least we are done on that front. Now my carb has decided to start leaking out the secondaries. Most likely I have a problem with the needle and seat. It just never ends does it.:wacko:

 

And I did not get the screw in studs because I wanted to keep the engine as close to stock as possible. Kinda regretting that right now.

Edited January 5, 2012 by Lemon Owner

[LSG 15]

Lemon, there is more to the cam bearings than if the cam spins freely or not. A distressingly high number of shops don't understand how the oiling in them works. Normally, the factory installs the cam bearings with the oil supply hole in the 12 o'clock position as you're looking at the front of the block. Some guys who don't understand have the oilholes in the worst possible location, 6 o'clock. You can follow the factory and follow their idea and put the oil feed at 12. OR you can follow the AERA and put the oil feed at 3~4:30, which has a very good effect on oil pressure at idle. LSG

[Lemon Owner 11]

Oh, I didn't know that. Well it is all in and running so now all I can do is cross my fingers and hope for the best. I was hoping that if I went to a reputable machine shop and paid some big money I would not have these problems. But clearly that was misguided, but at the end of the day I cannot do everything myself and I have to rely on others.