The root cause of the flying turd's problems

[Tim Walsh]

I went out to david clark's house today to do a little tune up on our cars. His was running VERY rich but we at least got the dwell angle and the timing right so his is running really well right now.

Mine on the other hand hasn't wanted to idle and is also running VERY rich. We started with dwell and timing and both were VERY off. So we did a compression check. Here's the results

1. 157
2. 140
3. 155
4. 155
5. 148
6. 25


Looks like it's rebuild time for me

[earlycar]

Tim, recheck the bad cylinder, it's very possible to get a bad result if the compression checker wasn't seating properly. then if still bad check the valve adjustment. hope this helps,chris

[Tim Walsh]

The compression checker I used was a screw in type that replaced the spark plug. We rechecked it just in case we didn't have the testing on correctly.

I'll check the valve adjustment though too.


Anyone else had experience with engines that sat for awhile and then ran?

[Bobboloo]

Tim it's also not uncommon for engines that sit to have the carbon that had built up on the crown of the piston fall off from the moisture from sitting. The carbon falls down into a puddle blocking closure of the exhaust valve. A good running of the motor usually blows out the carbon and the valves start seating.

[Tim Walsh]

bobby,
It has about 100 miles on it right now so I don't think it's that.

[1980SC]

Try adding some oil through the plug hole, then check #6 again. If the number rises, then you'll know the rings or cylinder are bad. If the number doesn't rise, it may just be a valve problem.

Rob
1980SC

[Bobboloo]

Tim I just went through a search on Berrymans B-12 to find a thread for you and I see you've already been informed of it's uses. I also read about #6 pouring out water when you removed the plug.

Just a thought. Is it possible that you adjusted the valves and number six had a valve that wasn't seated due to rust on the stem? In other words did it seem to need more turns to get the desired gap?

[Tim Walsh]

I frankly don't remember anything different about the #6 cylinder when I adjusted it.

I never did end up using berryman's but I'm definitly going to have to try it.

I'll give the oil a try as well

[Elombard]

Hook up an air hose and listen for the leak. If its leaking by the rings (oil tank) your bummin, if it comes out the valves might just be carbon, or a way off valve adjustment.

[Paul Thomas]

Tim,
Do what Lombard said, and use a leakdown tester. Eastwood sells a nice one. You can listen for the leaking air and a good tester will tell you where the air is going too.

Before i wrote the motor off, i would strip off the intake and exhaust and look in the port on both sides to see if the valves are seating right.

Worst case, if it is toast, i would look for a nice early motor that someone is dumping for an upgrade. You'll spend a whole lot less and you can take your time disassembling the T.

Paul

[Adam]

[edit] I just properly read the thread and saw the previous reference to Berryman's. Sorry.

I'd try anything before pulling that motor down again...

[beepbeep]

do the "water decarboning" -trick first...it can be piece of carbon lodged between valve and valve seat...

[Bobboloo]

I think there's a good a good chance of a stuck intake valve. I only say this because that's probably how the water got into the cylinder in the first place. You might try adjusting it loose and try the Berryman's trick of pouring it into the intake while the motor runs.

But before you do that, if you have access to an air compressor try the trick of filling the cylinder with air when it's at TDC and listen for the leaks at intake, exhaust, and crankcase. This will point you in the right direction.

The rest of your numbers look pretty good.

[Tim Walsh]

I think you might be right.

Could a broken ring also produce compression that low? That's an incredibly low compression # (less than 2 bar)

[Adam]

Tim,

How does the plug look on that cylinder?

Also ,check your injector on that #6 cylinder. If it's no good, it could be flowing excess (dumping) fuel into the cylinder and "washing the bore". However, that alone wouldn't cause your comp. to drop to 25.

I had a similar problem on my 2.7 with a tight valve (and dud injectors), although my comp only dropped about 60 psi to 100...

[Tim Walsh]

It looked exacly like all the other plugs.. just this side of fouled. They is a ton of carbon deposits on it.

[Mike Kast]

Tim, I have a compressor if you might need access to one. I'd love to hang out and learn something about these cars. I'm getting really good at cleaning the hell out of mine. But it is almost embarrassing to read what some of these pelican people are doing with there cars. While your all preparing to launch, I'm cleaning...lol...

[Tim Walsh]

Mike,
You're welcome to stop by, but I'm in raliegh a fair amount helping (well trying to help) on dtw's car. The next time in raliegh I'd love to stop by or if you're in g-boro give me an email or PM and you're welcome to stop by.

[Tim Walsh]

small update. I pulled the intake valve cover, rotated the engine to TDC for #6 and there is just a hint of play in the rocker, like it's adjusted properly.

I'm gonna try the water and b-12 trick next before having to jack up the car and check the exhaust valve.

[tryan]

bon-ami