1973 340 issues.

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[QUOTE="trigger_andy, post: 1971850737, member: 2230"
By the way, what did you mean by this '' If you think you're halfway happy with it now, you ain't seen nuthin yet.''

Many thanks[/QUOTE]

He means when you get those three cylinders working right you're not going to believe how that son-of-a-gun runs. Pull the heads clean the valves and hand lap them. You can use tooth paste if you don't have lapping compound. you got head gaskets throw back together and then try it again.
The acetone automatic transmission fluid is a neat trick. It is a lot cheaper than using multiple cans of PB Blaster.

If you pull the heads and find them to be Beyond repair for your budget at the moment why not pull the 318 heads and put on it for the time being.

Another old remedy was Marvel Mystery Oil put some in the crankcase put some in your gas.
 
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Jadaharabi said:
[QUOTE="trigger_andy, post: 1971850737, member: 2230"
By the way, what did you mean by this '' If you think you're halfway happy with it now, you ain't seen nuthin yet.''

Many thanks
Click to expand...

He means when you get those three cylinders working right you're not going to believe how that son-of-a-gun runs. Pull the heads clean the valves and hand lap them. You can use tooth paste if you don't have lapping compound. you got head gaskets throw back together and then try it again.
The acetone automatic transmission fluid is a neat trick. It is a lot cheaper than using multiple cans of PB Blaster.

If you pull the heads and find them to be Beyond repair for your budget at the moment why not pull the 318 heads and put on it for the time being.

Another old remedy was Marvel Mystery Oil put some in the crankcase put some in your gas.[/QUOTE]

Thanks for the clarification. :) I’m really looking forward to seeing what it’s like when I get these issues fixed.

I think pulling the heads is next on the list of things to do. Be a good weekend project. :)

I ga
 
I would really suggest you do the check with the air in the cylinder before pulling the head. Once you pull the head, you have lost the opportunity to pinpoint the problem better, and may be back to pure guessing.

IMHO, lapping the valves is not going to do much. It might bring up a few good cylinders a few more points but the guides are probably so worn by now as to render lapping useless. If anything is bad enough to drop #2 to 23-30 psi cranking, lapping is not going to fix it.

And those compression pills were in the same category toilet paper oil filters LOL
 
nm9stheham said:
I would really suggest you do the check with the air in the cylinder before pulling the head. Once you pull the head, you have lost the opportunity to pinpoint the problem better, and may be back to pure guessing.

IMHO, lapping the valves is not going to do much. It might bring up a few good cylinders a few more points but the guides are probably so worn by now as to render lapping useless. If anything is bad enough to drop #2 to 23-30 psi cranking, lapping is not going to fix it.

And those compression pills were in the same category toilet paper oil filters LOL
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Good point. I'll make sure to do the Air Test first. I assume I can use the Compression Tester Hose and a bit of rubber between it and the Air Gun?

Corrently Im running Sea Foam in the Crank Case and done a hot soak in the carb and I away to do a second Hot Soak now then Ill do another Comp Test to see what, if anything the ATF mix and Sea Foam has done. :)

Again, this is more out of curiosity than anything before I start anything serious.

I fractured my thumb last night too and had to go to A&E and Im now in a support with a black and blue hand so I m limited to what I can actually do just now anyway. :(
 
If you can work a hand valve of some sort to manage the air, that would help. You want to test that dead cylinder with the valves closed; i.e., up on the compression stroke close to the time for it to fire. You can use the distributor as a reference by pulling the cap off, and lining up the rotor with the #2 spark tower on the cap.

Good luck on that thumb! Ow...
 
trigger_andy said:
Hey Les,

my '72 340 will be getting rebuilt with 10.5:1 Pistons and a wilder cam as you mention and I simply cannot wait to see what that feels like. :)
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When I bought my 2nd '71 340 Cuda street car, that had the correct stock 340 10.5, 2.02/1.60 headed engine, it had a .484/284 purple hyd cam in it, small hdrs, a dual pane, a 750DP, 3.55 gears and at the track it ran 13.3's@101mph on slicks which = 301hp at the flywheel, on the street it was fast, the fact that you've probably got the 1.88/1.60 valves will not make much difference, you'll love it:thumbsup:
 
Hot Metal said:
When I bought my 2nd '71 340 Cuda street car, that had the correct stock 340 10.5, 2.02/1.60 headed engine, it had a .484/284 purple hyd cam in it, small hdrs, a dual pane, a 750DP, 3.55 gears and at the track it ran 13.3's@101mph on slicks which = 301hp at the flywheel, on the street it was fast, the fact that you've probably got the 1.88/1.60 valves will not make much difference, you'll love it:thumbsup:
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Awesome!lookng forward to that day. :) I’m porting a set of 596 Heads so I’ll get them ready for installing too. :)
 
So after leaving 50/50 mix of Acetone and ATF in the bored over night and today running a can of Sea Foam in the carb including two hot soaks I get the figures below.

Cylinder #1 = 115psi
Cylinder #2 = still 35psi
Cylinder #3 = 110psi
Cylinder #4 = 105psi
Cylinder #5 = 105psi
Cylinder #6 = 85psi
Cylinder #7 = 110psi
Cylinder #8 = 105psi

I squirted in a tablespoon of oil into bores #2 and #6. No difference on bore #2 but bore #6 jumped from 85psi to 95-100psi.

There is a dark patch on the Headders by Port #4 when cool I felt it and it’s greasy. There is also smoke around that bank too so maybe the head gasket is bust?

When I did the Acetone/ATF soak Bores #1 and #7 boiled/bubbled the mix when added. Only those bores though. Poor coolant circulation?
 
DavidLee said:
because a leakdown test can tell you more accurately where the leak is coming from. if you detect air coming from the oil pan it points to rings. if from the exhaust ports from a bad exhaust valve, from intake port it points to a bad or bent intake valve, if from between the head and block a blown gasket or cracked head
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Please explain in detail how the leakdown test will "more accurately" determine where the leak is coming from better than putting air in the cylinder.

Leakdown testing determines HOW MUCH a certain thing is leaking. All he needs to know is WHAT is leaking. He already has the how much.
 
You can make an adapter to air up the cylinders by taking a spark plug breaking the porcelain out of it and tapping so that you can thread in a air hose fitting to hook the airline to.

Years ago we had a triple toilet paper oil filter setup on a diesel tractor it kept the oil as clean as new however those old rolls of toilet paper were wound different than the new are. so it kind of got outdated by the evolution of the toilet paper rolls.
 
Jadaharabi said:
You can make an adapter to air up the cylinders by taking a spark plug breaking the porcelain out of it and tapping so that you can thread in a air hose fitting to hook the airline to.

Years ago we had a triple toilet paper oil filter setup on a diesel tractor it kept the oil as clean as new however those old rolls of toilet paper were wound different than the new are. so it kind of got outdated by the evolution of the toilet paper rolls.
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Thanks for the tip. I'll look into that. :)

Interesting info on the Toilet paper, I thought that was a myth. :D
 
bbrroowwnn said:
sounds like a ring problem on #6 and a valve not seating on #2.....
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Yes, my thoughts on #6.

Could #2 be a Head issue or is that not really likely? All along the Head Gasket I see what seems like oil residue between the block and the heads bubbling/popping away when running, but its not at #2, its from #4 to #6, maybe as far as #8.

Now here's a stupid question. :D When I do the Compressed Air Check tomorrow and I find its either the Inlet or exhaust Valve is there anyway 'dry' lapping that valve in place could potentially bring the valve back? I have heard of people lapping valves insitu with compound but I also hear that this can destroy the bore too.
 
DavidLee said:
boy you did not read my post did you
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Every word. You didn't explain anything in depth. The leakdown test is not really for diagnostic purposes like he needs. It is more of a tool to measure the percentage of wear on certain items. He will have much greater success simply pressurizing the bad cylinder with air.

A leakdown test certainly has its place. He has a cylinder though that would probably not even make a leakdown test register, so for him, it is a waste of time.
 
Do the test that Rusty said now on #2 and see where the air is coming from...just make absolutely sure that both valves are closed on #2 when you check it
 
bbrroowwnn said:
Do the test that Rusty said now on #2 and see where the air is coming from
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I'll get that done tomorrow hopefully after the hospital. Need to go in as the swelling is getting worse and the bruising is spreading up my arm. :(
 
RustyRatRod said:
Every word. You didn't explain anything in depth. The leakdown test is not really for diagnostic purposes like he needs. It is more of a tool to measure the percentage of wear on certain items. He will have much greater success simply pressurizing the bad cylinder with air.

A leakdown test certainly has its place. He has a cylinder though that would probably not even make a leakdown test register, so for him, it is a waste of time.
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Actually i did, you are not smart enough to listen. it would be the air escaping that would tell him where his problem is.
 
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About modifying the compression tester. Probably yes.
If its the type that screws into the spark plug hole.
On mine, the hose attaches to the gage with a air hose type fitting. But I couldn't use it directly. It's at the shop, but IIRC, the check valve would have blocked the air. So, I removed the spark plug adapter end and attached it to a airhose coupler that matches my hose fittings.

I was doing this to change a valve spring, but I think everything applies to what you are going to do. I did the busted one first. When I saw some other springs were pitted, I bought more and a brass 14mm spark plug to npt adapter since I found they are fairly cheap (here) - so that's another option.

Edit: Be prepared - The engine might turn when the cylinder is pressurized -
 
DavidLee said:
Actually i did, you are not smart enough to listen. it would be the air escaping that would tell him whee his problem is.
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Easy boy. You don't know who I am or what I know. Nowhere did I ever insult you. I am merely asking questions. The test I told him to do will do the same you say the leakdown test will, but much faster and he doesn't have the money tied up in a leakdown tester.

Sorry you feel the need to get defensive and fling personal insults. That's usually a sign that your position is a weak one. You still haven't gotten specific. But that's ok too.
 
I think Rusty's point is that a leakdown test overkill. Having the two gages and set up for enough air delivery is additional work and cost. He's asking if, in this situation, there is actionable additional information it would provide over the simple test.

edit: posted this before seeing RRR's reply, but I'm leaving it. Maybe its helpful having it phrased differently.
 
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