Thread: Opinions on 327 issues

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Hello all,

Looking for some second and third opinions on an issue I'm having with a 1964 block 327 with stock heads, Edelbrock Performer intake and 650cfm 4 bbl carb.

Changed oil last fall before winter and there didn't appear to be anything abnormal in it. Struggled with keeping coolant sealed while working on this throughout the summer (replaced the original carb and intake), lots of blue goo was used and many drives ended with trying to tighten all the hoses that would accumulate a small drip here and there. Temperature also hovered around 200 most of the time, idle or running, didn't seem to matter. Did spit coolant one time after it got too hot, but not a terrible amount.

Anyway, fast forward to a few weeks back when I finally got to fire it up. It started really rough, the whole car kind of shook and it just didn't sound very good. Let it run for awhile in high idle and it smoothed out, trace amount of white smoke was coming out of the exhaust as well. Nothing billowing or choking, but it was visible.

Temp came back towards 200 where it seems to live. Now, I could smell a syrup like mixture in the air as it heated up, so somewhere along the line the coolant is getting on or in something hot. This hasn't been much cause for concern since I still find a leaky hose every now and then. A slight woft of steam is coming out of the oil fill neck just like usual. It drove decently, not an award winner, but it wasn't terrible.

Today I pulled the dipstick a few times. It's clean, no antifreeze.

The coolant level doesn't seem to be that much lower than it usually is, although I haven't kept too close an eye on it.

I took off the oil fill cap (which tends to have a coolant "ring puddle" always present in minute amount where it presses into the intake) and it had some moisture goo with some greenish yellow tint. Obviously this makes me assume it is coolant that has been vaporized.

Is there any other opinions that point to something other than a head gasket? I will also note that for awhile the coolant leaks had dripped into the valve covers, but I can't imagine that any of that would still be burning up at this point.

Lengthy, I know. Thanks!

Welcome to CHR:

I have always loved the 327 as it was among the first engines I ever hot rodded. They buzz to the moon and were always a dependable engine in everything from tri-fives to early Impalas.

Coolant leaks are a bear - one thing you may consider is a leaky intake manifold gasket as water certainly transverses the manifold and with a slight malformation or tear coolant can be sucked into the intake resulting in the symptoms you've described. Your problem may be as simple as tightening the intake manifold to 25 ft/lbs (inside to outside sequence). After that I'd do a complete compression/leak-down test to further isolate the problem. A bad head gasket may also result in obvious bubbles in the radiator fill neck and almost always has steam puffing out the exhaust.

Let's hope you get lucky with the intake gaskets!

Glenn

Would just an intake manifold leak cause it to get into the exhaust as well?

Originally Posted by TIGGS247

Would just an intake manifold leak cause it to get into the exhaust as well?

Yes - coolant is drawn into the combustion chamber and mixed with the fuel charge. It doesn't burn and is expended as steam out the exhaust - also the cause for the nasty/sweet smell.

Using "blue goo" or RTV (or other slippery gasket sealers) on the intake manifold allow the gaskets to slip slightly. The gasket will still look to be in the right place at the outside but the lower edge(s) can slip down and cause a leak. Chev intake gaskets have such a small cross section on the lower edge so it doesn't take much. The slipped gasket allows several combinations of stuff going several directions......none of them good.

Originally Posted by robot

Using "blue goo" or RTV (or other slippery gasket sealers) on the intake manifold allow the gaskets to slip slightly. The gasket will still look to be in the right place at the outside but the lower edge(s) can slip down and cause a leak. Chev intake gaskets have such a small cross section on the lower edge so it doesn't take much. The slipped gasket allows several combinations of stuff going several directions......none of them good.

Good word Robot - I use just a smidge of Gasgacinch on the head side to hold in place, toss the cork pieces and use black RTV on the two China walls (ends) with a blob at the tabs of the flat gaskets at the corners. I can't remember ever having a problem with this method.

Pull all the spark plugs and report back with their condition. The one or ones that look like new will be the ones with coolant in that cylinder.

Get a good quality compression tester that screws into the spark plug hole and follow this procedure.....
Warm the motor up to operating temperature.
Remove the air cleaner.
Wire the primary throttle blades wide open so the motor can breathe.
Disable the coil wire to prevent a fire.
Remove all the spark plugs so the starter can turn the crank easily.
Screw the tester nipple into a spark plug hole and snug it up on the gasket.
Turn the starter through at least 5 compression cycles to maximize the reading on the gauge.
Write down the cylinder number and gauge reading.
Repeat 7 more times.
Post results here.

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