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Oil leaks, where to start?


o_rod

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After chasing a few electrical issues with the car I'm now going to tackle the oil leak I've noticed.

 

The engine is a freshly built 350 4 bolt bored 30 over. Seems to me the leak is coming from the front of the engine around the oil pan or crank pulley area. Is it necessary to pull the engine to fix this or does anyone know any tricks? I'd prefer not to pull it but whatever it takes to keep the oil where it belongs :)

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My 71 350 had a leak from the ft pulley area. I had already replaced the o ring once when I rebuilt it. After removing the pulley I could see and feel a groove (actually two) in it.

I purchased a steel sleeve, slipped it over the hub and also replaced the O ring. This has worked well.

To help the sleeve fit, I heated the sleeve and froze the pulley.

These old engines do leak, my rear main is leaking some now as are the valve covers, again. 160,000 miles on it.

Bruce

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Parts houses sell those "speedy sleeves" that fit on the harmonic balancer. I believe I got one from Autozone. They come with sleeve and installation tool. I installed one on my balancer since the seal had cut a groove in it. Problem solved.

John S

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You said it was a new rebuild. Do you know if it is an after market oil pan? I ask because where the timing chain cover and the oil pan come together there is a "horse shoe" rubber seal. There is a thin one and a thicker one. Most all after market oil pans use the thicker seal. Then again some stock pans use the thinker one also. If the wrong seal was used it will leak. Here is how to check...

 

Place a straight edge across the pan rails measure down to the bottom of the lip of the oil pan. If the measurement  is 2 3/8", use the thick seal, if the measurement is 2 1/4", use the thin seal
They made a seal change, thinking the thicker seal would seal better.

 

Dale

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Get it all clean and then check where it's leaking. Brakleen works well for that. Leaks can be hard to find; they leak up high, but drip from down low. For clean oil, or transmission leaks I use baby powder... get it clean and dry then dust the area with the powder and the source shows up quickly. Old dirty black oil is easier to see and the powder probably isn't needed.

Those "speedy sleeves" are wonderful. If your harmonic balancer has a groove worn in it the sleeve will fix it, and it will last longer than the original balancer did. The balancer is cast iron, the sleeve is stainless steel. It's a permanent repair.

I had an old Dodge military truck and it had a driveshaft between the transmission and the transfer case. Every driveline exit; the rear ends, transfer case, transmission...leaked. Those darn sleeves fixed the whole thing. It was impossible to get new yokes for that truck. Thank you speedy sleeve.

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We have a small block that started leaking after changing the timing chain to gear drive and a TPI system. Used a stock pan and timing chain cover and the correct gasket and 10 minutes after it warmed up it would leak. We went and replaced the oil pan thinking that was problem still leaked. We changed the seal in the timing chain cover thinking it might have tore still leaked. Got a sleeve for the blancer thinking maybe a grove and it still leaked. We then though maybe its to much PSI from the TPI system pulled that off and stuck a regular intake and carb back on it and it still leaks once it warms up. One thing I've read there is a bolt hole on the front side of the block that goes into a oil passage and if that bolt is missing the oil could be coming from there. Just a though.

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Thanks guys for the tips, I got underneath it tonight and man, what a mess, my engine decided to paint the undercarriage with it's own lubricant. Good idea with the baby powder!

 

Robert, I think you just made my night!!! I was getting ready to pull everything off the front of the engine when I noticed the previous owner grounded the battery to the very bolt your speaking of near the fuel pump! My young one woke up ending my garage time for the evening, but tomorrow I'm going to rectify that issue and see if it seals it. 

 

The grounding in this car is terrible, the PO used self tapping screws and random engine bolts as grounds :mad:  where should I move the battery ground to, or where is the stock location? I'm going to upgrade the rest of the engine bay grounding as well.  Cheers to more projects!  :2beers:

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I've been told I should get used to the oil stains on the driveway and garage floor with these engines!   :P

 

I've tried to ground the battery to the alt bracket but I realized I have old iron 462 heads with no accessory holes. I'm using a custom bracket for the alt going to the header bolt but it wasn't a good enough ground to even activate the starter. Would 4 guage be large enough for an engine to battery ground? The stock ground isn't long enough to reach any other accessible engine bolt.

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some key things to remember about grounding, you can ground the engine almost anywhere but....

 

you just detailed your engine and freshly painted everything, that paint can cause poor grounding, wherever any part touches the block, you need to remove the paint on the block and the part so it has continuity  

 

where the starter sits against the block....make sure the block surface is clean and not painted/same with the starter, this is how the starter gets its ground

 

upper alt bracket... make sure the paint is removed between the bracket and the intake, also where the ground cable bolts to the bracket

 

lower alt bracket...clean the surface of the head and both ends of the alt spacer, and don't forget the alt itself!

 

grounding is all about cleanliness, no paint, no rust even on the attaching bolts, running a tap into bolt holes to clean them helps dramatically!!!!

 

some dielectric grease on all grounding points wards off corrosion 

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Good tips! I sanded the paint off of the brackets, water pump, nuts, everything and used star washers and voila, dropped the ground resistance dramatically and the car fired up!

 

Another question, do I have to worry about the length of bolts that go into the holes on the front of the engine beside the fuel pump? The higher one is short but the lower bolt is probably 9 or so threads in, maybe an inch. Will that mess with the pumps pushrod? I know the higher bolt can interfere but what about the lower?

 

Thanks again, you guys have been a great assett as I learn about these beasts!

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