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Discussion Starter #1
Hello folks!

-I've been having some water/oil creamy stuff showing up on the breather, valve covers, and top of the oil dip stick.
also quite a bit of water coming from the left tail pipe. (true dual exhaust). No water in the oil when drained or on the bottom of the dipstick.

-I know moisture is a product of combustion but I've not had this problem before.

-did a compression test and all cylinders are at about 60psi after 7 compression cycles. I know this is low but they are all the same.

-PCV system is checked and PCV valve is new.

Could the engine just be tired? could the timing cause the water?

Car is 1965 GTO with original 389 with 95k miles. I don't believe the bottom end has been rebuilt but there is evidence the top end has been opened at some point (Different paint).

Could a different then stock cam cause the compression the appear low?

Car runs ok aside from some valve tapping that I've been trying to narrow down as well.

Any help would be appreciated.

Jesse
 

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60PSI in the cylinders? Either this is written in error, your gauge is faulty, or your engine is blown, but going with an error because all cylinders seem consistent.

Factory Service Manual for 1968 states:
The 8.6 & 9.2 compression engine has 150-170 PSI cranking the engine over at 155-165 RPM.
The 10.5 & 10.75 compression engine has 185-210 PSI at 155-165 RPM.

How long have you owned it prior to having this problem and how many miles have you put on it since owning prior to this problem?

Not knowing what another has done to the engine, you can't guess. Assume original "77" GTO heads and not a swap to something else to lower compression. It is possible pistons could have been swapped to lower compression, but not likely.

You can have some moisture build up, but should burn off as the engine is brought up to temp and driven.

Loosing anti-freeze or having to keep the radiator filled could be a bad sign. You can rent a radiator pressure test kit from most auto stores to test the coolant system to see if it holds pressure.

Could be many things IF there is a problem. 60 PSI IS a problem if that is correct. You could have anything from a cracked block,cracked head,warped head and/or bad head gasket, head bolts loosened up, or even a bad intake gasket allowing coolant to seep/flow into an intake port and down into the engine.

An aftermarket cam can show a lower cranking compression, but not that low. It would also be indicative of a fairly radical cam with a lot of overlap - sacrificing low end power for upper end power.

Timing chain may be worn slap out or timing jumped which could also have an effect on cam timing and compression, but again, I don't think that low and the engine would run very poorly. You can check timing chain slop by watching your distributor rotor and a creating a mark on your balancer so you can watch it. Then advance the crank until the rotor moves, note the mark on your crank, then turn the crank in the opposite direction and note when the rotor again begins to move and how far the mark on the crank has moved. If the mark on the crank moves about 5-7 degrees either way before you see the rotor begin to turn, the chain is sloppy. Any more than that and it is in need of replacement.

However, at 95,000 miles in the average GTO, that is high mileage on an original engine having the high compressions they had. Lower compressions put lower loads on things like rings and bearings so they can last longer. These are not today's cars which go 250-300,000 miles.

Just my opinion. :thumbsup:
 

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Discussion Starter #3
Thanks for the analysis Jim.

I checked the compression tester on my compressor. reads the same as my compressor gauge.

Would it be reasonable to assume that the rings on all cylinders are just equally worn and the blow bye as just too much for the PCV system to deal with?

It does not burn any oil or smoke and both cylinder banks are low compression. I have not yet pressure tested the coolant system.

Considering its a numbers matching car, my instinct is to just do a basic stock rebuild reusing all the hard parts I can.

Any opinions on using modern internals (roller cam, forged internals, etc.) on a car like that? I've read different opinions on the effect on value.

Jesse
 

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Thanks for the analysis Jim.

I checked the compression tester on my compressor. reads the same as my compressor gauge.

Would it be reasonable to assume that the rings on all cylinders are just equally worn and the blow bye as just too much for the PCV system to deal with?

It does not burn any oil or smoke and both cylinder banks are low compression. I have not yet pressure tested the coolant system.

Considering its a numbers matching car, my instinct is to just do a basic stock rebuild reusing all the hard parts I can.

Any opinions on using modern internals (roller cam, forged internals, etc.) on a car like that? I've read different opinions on the effect on value.

Jesse

Well, at 60 PSI, and you know the gauge is correct, I'd say the rings are shot, but it should be burning oil.

You are not at a high altitude like Denver, by chance? Higher altitudes can effect cylinder pressures as well, so it could be OK if you were at altitude.

If it were me, based on the mileage, and knowing it is a numbers matching engine, if money allows I would indeed rebuild it just to know its condition and know it will last another 95,000 miles. Keeping all receipts and taking photos of the engine build (before, during, & after) to document all that is done to it will help keep its selling price up should you decide to sell the car at any time in the future (or even for insurance purposes).

Building the engine depends on what you are looking to get out of it. I would replace the cast connecting rods with forged steel as they are cheap insurance and much stronger then stock. The forged I-beam rods like factory are your first choice and most inexpensive. Then you get into the H-beam which is slightly higher and more rugged - but not really needed if going with a stock or even slightly modified engine.

Depending on bore size determined by your machine shop, you may want to get a dished piston to lower your factory 10.5 compression closer to 9.0 - 9.3 so you can use pump gas. You will lose a little HP, BUT, if you are OK with a few more cubic inches, I would go with a Butler rotating assembly for the 389 which will get you a set of Ross forged pistons dished to match the 72-75 valve chamber cc's of the #77 389 heads to get you at the 9.0-9.3 compression ratio. The additional cubic inches will more than compensate for the lower compression and give you more Torque at the wheels. https://butlerperformance.com/i-24591340-butler-performance447-454ci-balanced-rotating-assembly-stroker-kit-for-389-block-4-250str.html?ref=category:1234862

You are going to need everything in the kit anyway, except for the crank, which you are most likely going to have to get turned$. You can price individually forged pistons, forged rods, rings & bearings and then compare. Balancing is typically $200-$250 which Butler includes. Note that you will need a "neutral balance" harmonic balancer and flywheel according to the website. The factory balances the engine "externally" which uses the harmonic balancer & flywheel to get this done. So you will need a new harmonic balancer and neutral balance flywheel if a 4-speed. Butler can also help you sort this out if you need more info on parts and costs.

Budget is the key here and a Pontiac engine is not inexpensive to build - nor are machine shops inexpensive on their services. The more you can do in assembling the engine, the more you will save.

Roller cams/lifters in my book are a luxury at the prices they get, but can also be a plus when it comes to wear and even a little extra power. The average flat tappet factory style cam in my opinion is just fine as long as you correctly break it in nor use excessive spring pressures and a super high lift number. Heads won't flow much over .470" in stock form, so keeping lift under this number should be no problem with a flat tappet cam. Many choices from stock to street/strip.

For timing chain/gears I like a double roller set-up. Summit or Jegs can be a good source for quality brand parts and they ship free over $100. I have gotten many parts from Summit and have no complaints with them.

I would recommend purchasing the book by Rocky Rotella, How To Rebuild Pontiac V8's. This will give you a really good step-by-step view of what it takes to disassemble and rebuild a Pontiac engine. Very easy read with a ton of photos that walks you through the process. You can see what parts will need replacing and this can help you write a list of parts you will need in order to generate an expense sheet or enable you to ask questions on parts needing replacement.

So this is just the tip of the iceberg and a few pointers if you decide to go ahead and do a rebuild. You can keep the engine as close to stock if that is the route you want to go or make some modifications to improve/enhance the engine and keep the engine streetable & dependable without going crazy on horsepower. :thumbsup:
 

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Also, being in California, you should be able to find a shop that works on older cars and get a second opinion and see what they come up with. :thumbsup:
 

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Just a silly question
are you doing your compression test with the carb butterflys open so it can breath ?

I did that once on my 235 chevy and only got 65-75 lbs and thought my motor was done ...
opened the throttle and got 145's
 

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Discussion Starter #7
Thanks for the input guys.

-I did the compression check with the engine warm, all plugs removed, and the butterflys open. counted 7 compression bumps to get to 60 psi.

- I'm actually in lower alabama now but I think there are some decent old school mechanics around.

- I just dropped the car off for some minor body work so I won't see it for a couple weeks.

- I will plan on redoing the comp test with a different guage for sure (maybe bad schrader valve?). Also, need to test leakdown, and coolant system pressure.

Thanks again for the advise guys.

Jesse
 

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Discussion Starter #8
Does the book you recommended go over the factory correct detailing of the engine? ie: painting etc
 

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Thanks for the input guys.

-I did the compression check with the engine warm, all plugs removed, and the butterflys open. counted 7 compression bumps to get to 60 psi.

- I'm actually in lower alabama now but I think there are some decent old school mechanics around.

- I just dropped the car off for some minor body work so I won't see it for a couple weeks.

- I will plan on redoing the comp test with a different guage for sure (maybe bad schrader valve?). Also, need to test leakdown, and coolant system pressure.

Thanks again for the advise guys.

Jesse
You might have a major engine failure . The fact that all cylinders are low and the same this most Likely rules out heads. Very unlikely you would have a blown head gasket or cracked heads on both sides at same time. I guess my question is how has it been running? How long have you had and how much have you driven it ? Did it start to run poorly or you just noticed the mixed water / oil ? . Its real hard to make a call but this motor is sick we can all agree , I would take to a good shop that can run a few more diagnostic test and keep the fingers crossed . Best luck Doug
 

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If you actually have only 60 psi in every cylinder, it must be a bear to start. That's barely enough compression to run. I would do a cylinder leak down test next, to verify that you actually have worn piston rings/pistons/cylinders. You may have something as simple as a worn-out camshaft. If you have over 30% leakdown, time for a rebuild. I have a big cam in my '65 GTO that bleeds off cylinder pressure while cranking, but still have 175 PSI in every hole after 4 revolutions. Do a leak-down test next, and go from there before you start tearing it all apart.
 

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Discussion Starter #14
Hoping it was just a bad guage. The car is in the shop for the next week or two so I'm dying not being able to get my hands on it.
 

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The most common cause of water in the engine are a blown head gasket, cracked engine block or failed intake manifold gasket. Unless your engine has been through a freeze w/o anti-freeze, then most likely it's a blown head gasket. At 96K miles, I would recommend a complete rebuild. If you can't afford that, then pulling off the heads and replacing the head gaskets is your next best option. Whatever you do, be sure to drain all the fluids from the engine now as to avoid rust in the lower end of the engine caused by the water. I recommend having the heads reworked while off the car with a valve job and new oil seals. Be sure to keep your push rods in the same order you remove them. You can do this using a piece of card board and punching 16 holes with a screwdriver to emulate the 16 push rod positions in the engine block and check the lifters while you are this deep in the engine for wear.
 

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The most common cause of water in the engine are a blown head gasket, cracked engine block or failed intake manifold gasket. Unless your engine has been through a freeze w/o anti-freeze, then most likely it's a blown head gasket. At 96K miles, I would recommend a complete rebuild. If you can't afford that, then pulling off the heads and replacing the head gaskets is your next best option. Whatever you do, be sure to drain all the fluids from the engine now as to avoid rust in the lower end of the engine caused by the water. I recommend having the heads reworked while off the car with a valve job and new oil seals. Be sure to keep your push rods in the same order you remove them. You can do this using a piece of card board and punching 16 holes with a screwdriver to emulate the 16 push rod positions in the engine block and check the lifters while you are this deep in the engine for wear.
Not sure a blown head gasket on one side could cause the comp loss in every cylinder? I am no expert but I would think better chance of block damage ? Doug
 
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