[smakcruiser]

Back in September I was driving around my car like I normally do a few times a week and all of a sudden it just started running terribly. So I took a compression tester to the cylinders and all are in the 130s except for #8. I can't get over 10 psi out of it.

I have recently moved and my new garage is heated so I can work out there all year around, so I would like to take it apart and see what is wrong. The motor has about 40K on it I believe.

Without tearing it apart, obviously I can't determine what is wrong, but when you get symptoms like this is it re-build time or could something else be wrong that does not require a re-build? I am just hoping for the latter because I can't afford a re-build right now haha.

[Stuart]

Have you taken off the valve cover yet? Look for a valve stuck open.

[smakcruiser]

I apologize, I forgot to mention that... yes I have. Nothing weird in there.

[kwt63cat]

With the valve cover off, watch the valve action as someone cranks the engine. If that looks normal, with #8 at TDC on the compression stroke introduce some compressed air into the spark plug hole of #8. (I made an adaptor to do this by brazing a quick coupler nipple to an old spark plug that I busted the porcelain out of.) Listen to the exhaust, Intake, and crankcase breather to determine the source of the problem. You can introduce compressed air into a known good cylinder for comparison purposes. Good Luck

[smakcruiser]

ok. So I put some compressed air into the cylinder this morning and all I hear is a loud hissing somewhere in the crankcase area. I do not really hear anything with cylinder #6. Hmmmm...

[geeteeohguy]

It could be a flat cam, bent pushrod, hole in the piston, or, more likely, a burnt exhaust valve. Try a leakdown test to verify, after you check for a flat cam.

[smakcruiser]

I just yanked the intake and valley pan off. Pulled Rocker arms. All the push rods look ok. Cam looks ok visually...

[Mr Twister]

Originally Posted by smakcruiser

ok. So I put some compressed air into the cylinder this morning and all I hear is a loud hissing somewhere in the crankcase area. I do not really hear anything with cylinder #6. Hmmmm...

You basically did a leakdown test. Air is escaping in to the block through a hole or crack in the piston, cylinder. or gasket.

[smakcruiser]

I think the next step then is to pull the head and see what is happening. What are my best and worst case scenarios here???

[kwt63cat]

At this point it sounds like a head gasket or a problem with the reciprocating part of #8. Pull the head and check things out. Best case scenario? Bad head gasket leaking to the valley area of the engine or to the oil return galley from the cylinder head. Worst case? Broken ring, broken piston, or badly scored block from bad rings or even a wrist pin spiral lock failure. I'm hoping for the head gasket failure. Please keep us informed.

[smakcruiser]

Can I fix any of the worst case scenarios without pulling the block and having it re-bored? I can't afford that right now LOL

I will. I plan to do it this weekend.

[kwt63cat]

It sounds like your not far away from getting the head off, so I would do that and diagnose what the problem is at that point. Then we'll help you make a decision as to what to do. I think you can get the pan off without much of a hassle. #8 is at the back of the engine so proximity to the cross member is a plus if you have to work from the bottom end with the pan off. Pray for a bad head gasket. Ken

[Ragtop Man]

Big failures usually make a big noise. Feels like a head gasket from here, anything that would break a piston or a dropped valve would give a loud report.

Did you check for water in oil? That's a head gasket. Yank both heads, freshen them up, and while you're at it, throw in a new timing set, curve the dizzy. She will run great again.

Hate to say it but my old kar knowledge says to yank the head, a stuck valve would not be out of the question either, or one that snapped a stem/tip and galled into place.

[smakcruiser]

Any tips on getting the exhaust manifolds off??? The bolts to don't seem to be any particular size. The only thing I can get on their firm is a 14mm and I HIGHLY doubt that is the actual size. I've thrown every penetrating oil I have at it and can't budge them. Kroil usually works wonders for me, but not this time!

[Deadhead]

There are probably other tools like this, but I have used Xtractor sockets to get those off. That and the acetone/ATF mixture. I think mine came from Lee Valley, but I am sure you can get them other places too.

[smakcruiser]

Like this ???

http://www.sears.com/craftsman-10-pc...p-00952166000P

[Heybuck]

Originally Posted by smakcruiser

Any tips on getting the exhaust manifolds off??? The bolts to don't seem to be any particular size. The only thing I can get on their firm is a 14mm and I HIGHLY doubt that is the actual size. I've thrown every penetrating oil I have at it and can't budge them. Kroil usually works wonders for me, but not this time!

Can't you just leave them ON and undo the pipes. Then lift the head complete with manifold off the engine.

When you have the heads on the work bench, you can attack them much more easily and the risk of skinned knuckles or broken fingers is greatly reduced.

Just my idea of an approach to the problem

Ian

[Deadhead]

Originally Posted by smakcruiser

Like this ???

http://www.sears.com/craftsman-10-pc...p-00952166000P

Yeah, but the ones I have have MUCH finer splines on them, which has got to be better. You have to tap them on, and then they dig in further as you torque down on them to remove bolt.

[geeteeohguy]

The bolts are 9/16", which is actually 14mm. My recommendations would be to pull the heads with the exhaust manifolds in place, and use rust remover and penetrating oil on the bolts. With the bolt heads clean, you can get a good 6 point impact socket on them and impact them off. Me, I'd let them soak for awhile, and maybe use some heat from a propane torch, too. Again, you may simply have a burnt exhaust valve. Not a big deal to fix.

[smakcruiser]

Originally Posted by Heybuck

Can't you just leave them ON and undo the pipes. Then lift the head complete with manifold off the engine.

When you have the heads on the work bench, you can attack them much more easily and the risk of skinned knuckles or broken fingers is greatly reduced.

Just my idea of an approach to the problem

Ian

I have the exact same problem underneath. I think its going to be a pain either way