Dodge 360-3 compression test

Started by Mlw, October 18, 2021, 06:27 PM

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Mlw

As said i Did something else today, working on the Engine.

I've got myself some new tools today one of them a compression tester.

For reference I will give the results. but reading the Chassis manual I made a few mistakes, so will do a new test tomorrow as given in the manual

Cold engine, No throttle, battery goodish
And of course, ignition coil detached, fuel line detached. (and feeding the fuel in a  Glass bottle.)

The fuel was nice bright and fresh, taking away my worries about the state of the fueltank and the fuelpump works excellently.

Compression test (PSI)

Cyl 1. 123
Cyl 2. 113
Cyl 3. 118
Cyl 4. 110
Cyl 5.   88
Cyl 6. 107
Cyl 7. 113
Cyl 8. 113

As with European cars compression shouldn't get under 145 PSI I really didn't know what to think, but luckily I've read the following thread here on the forum

https://www.classicwinnebagos.com/forum/index.php?topic=965.msg977#msg977

So, anybody any thoughts about the results? and yes, the result of cylinder 5 worries me a bit. but i think it's a valve.

The reason to think this
With this kind of difference the speed of the starter changes, so with V8 lo, lo, lo, lo, hi, lo , lo, lo.

This engine did this just once in the multiple times I started, and then I was allready thinking what's this suddenly?

AOBrodie

88 is pretty low. Probably still run though. Does it have a miss?

Mlw

Hi AOBrodie,

Thanks for responding. Yes the compression is low. It can miss when it dies at a cold start.

I know why now. The head gasket is blown. normally I'm used to white smoke out of the exhaust, but no such thing. I do know this is possible however.

I did a new test yesterday so I've started up the engine. If you prime the carb by putting a splash of gas in the carb you only just have to touch the key and it runs. As I now knew there was a problem I did notice now the engine shook the whole RV. (Rock a bye baby... :))

How do I know I have a Blown headgasket? My Coolant hoses were rockhard and pumping around water altough the waterpump wasn't connected because my alternator was away for refurbishing. Therefore I measured heath by the manifolds but as my heater was on high I started to notice it blew hot air.  ??? ??? ???

I went out, tried to compress the hoses but all of them were rock hard, I had bubbles in my expansion tank and I have sludge on my oilcap. Still no coolant smell from the exhaust.

I still did the compression test (having it nice and warm at a cold rainy autumn day), and here are the results.

Cyl 1. 122
Cyl 2. 116
Cyl 3. 116
Cyl 4. 123
Cyl 5.   87
Cyl 6. 121
Cyl 7, 116
Cyl 8. 108

I'm a bit confused by the results but as I didn't run the engine more then 6 minutes there is a chance the results are unreliable and as we work with bars in Europe the psi numbers are converted from bar to psi

Furthermore the Chassis manual (again thanks classicwinnebagos)  states the compression should not be under 100. the compression ratio of the engine is 8.0 to  one.

So compression is low, but it is how these 1979-360 engines were build to meet emission regulations.


AOBrodie

How does your oil look on the dipstick? Do you think it's leaking combustion gases into the water jacket?

Mlw

Hmm, that's a good one. I actually didn't check that as the oil levels were 100% on the engine oil as the transmission oil and both clean as a whistle. on the other side, the whole engine is covered in a 0.80 inch thick layer of oil residue. I will check next Monday. It will be a good test as the engine has rested for a week then.

Not so strange the oil looks brand new because two weeks ago i ran the engine for about half an hour and my guess is that the engine thought he had to resemble a colander. Seriously all gaskets are gone, valve, oil pan, transmission fluid...

Of course the first time I laid my eyes on the engine it was dirty but perfectly dry, so in Europe we call these engines that were never cleaned "honest engines" and top off the fluids is the least you do to look good at a sale.


I don't know if you have read my other posts also (especially the intro), but if you do you get a pretty good idea what kind of type the former owner was. I bought it from a dealer in American cars who mostly had very good reviews, but also three real bad ones. If he's not going to answer his phone very soon he will receive a fourth. Luckily I still have to pay him transporting costs, but he will get nothing before he talked to me.

Altough it's another setback I'm not to worried yet as it is a known fact that these engines aren't killed easily and parts are (still) cheap, so I don't have sleepless nights yet.

As for your question i think the engine is leaking combustion gasses in the waterjacket, As the coolant hoses were rock-hard and i had bubbles in my expansion tank like a kid blowing in his lemonade with a straw, I think there is no other conclusion. Maybe the gasket was allready bad and finally went the last time i ran the engine for half an hour because i certainly can't remember seeing these problems before.




Eyez Open

As to your concerns on a head gasket leak, pull the plugs and check each one as you go. If you run upon a plug that is exceptionally clean you have your answer. If not you have another answer. Water vapor steam cleans the combustion chamber extremely well a long with the spark plug.

It is highly unlikely a head gasket leak pressurizing the coolant sysytem, first the valves release the pressure and secondly if that was occurring...The cooling hoses would have failed long ago...popped like a balloon. But crazy things can happen.

Mlw

Well, that's exactly the opposite of what I heard from numerous others.

https://www.youtube.com/watch?v=v0U8Iyf0kk4
https://www.youtube.com/watch?v=hZPWLuTftBg
https://www.youtube.com/watch?v=wVDsreabEr8


I've worked for a sailing yacht broker for 5 years. He had a old school mechanic like Scotty who could repair motors you would think would never run again and I learned a lot from him. He told me exactly what's told in upper video's, so that's why i use them as example. Also a good example if you want to learn old engines,

https://www.youtube.com/c/ViceGripGarage

I dare you not to laugh, the guy acts like he's a total idiot (even telling in his intro) but actually is a very cunning mechanic. There is a reason this guy reaches an enormous crowd.


I do agree however with you that the hoses eventually will fail, but I heated my engine just idling, hence providing overpressuring the hoses heavily.

https://www.youtube.com/watch?v=VCYHyioj0W8


As for the water steam comment. If it's going that far, you also will have white smoke from your exhaust. I don't have that, and no that not uncommon. There are numerous ways a headgasket can get blown.

I'm not trying to contradict you, but as I'm going as deep in repairing/refurbishing my motorhome as I'm doing now, we just as well can get the conversation started so others may benefit.

And I have time. The motorhome is not my daily driver so if it's going to take longer it's not more then a little inconvenient. I rather don't make the costs, but if you don't then you shouldn't buy an old motorhome. You know you are buying someone elses problems and it's up to you to solve them.

As i rather deal with the problems now then on the side of the road I'm glad this is happening now. As i wanted to take the engine out anyway so i can refurbish the motorcompartment and the engine itself, because if I don't I'm going to regret it shortly, certainly with the weatherconditions in Northern Europe.


Eyez Open

I had no intention of offending you, only pointing out quick simple method to get at the root of the problem. I agree with all of your thoughts with one caveat...a cracked head might be at the top of my concerns. The hole with the low compression would be my first suspect.

https://barsleaks.com/gaskets/symptoms-blown-head-gasket/

Apologies are offered, good fortune to you and your project.

Mlw

Not offended at all,  :) :) :)

Like I said, all is good to keep the discusion going. This is how solutions are reached. Your tip of the clean sparkplug was golden, but not the case with me. Like I said, headgaskets can go numerous way. I had it one time in my life earlier and I steamed up the road hundreds of meters. It was pretty clear then, but as i was a young lad didn't know as much and the engine was repaired by a garage as it was still affordable back then. As I wouldn't had experienced the knowledge of my former colleague and hearing the same message in numerous video's I would never have started this project.

But now I did and will just go with the flow. and I will get this thing back on the road. We will see what's the case when I open up the engine and I will post the pictures. I had allready ordered a complete gasket set before I noticed this problem, so just need to go deeper. That's just the way life goes.'

as for the cracked head.......... Let's not talk about that... yet  ;) ;) ;)

So apologies weren't necessary, Good fortune to me and the project I gladly accept. as I'm going to need it, and I'm offering it right back at you. We need it in these troubled times.  :)ThmbUp




Mlw

So It took a while unfortunately because of other things to repair and bad weather.

At first it seems that there was indeed some water in the oil. An old mechanic gave me a simple test to check that however, put a flame to the oil with a lighter. As it sparkles, you've got water in your oil, as it gives some form of combustion/ignition there's fuel in your oil. None of them happened.

altough you should be glad, it only adds to the mystery what's going on with Cylinder 5. but as I want to take the engine out anyway for some major cleaning of the engine itself, change the gaskets and everything that pops up, and want to clean and revive the engine bay and stop the water leakages into the cabin.

The engine is running, so I can move Betsy when we need to and as we don't need high RPM to do that I just can't be bothered with this at this time.

Mlw

SO today I finally had the pleasure to bring the stuff I ordered a month ago to Betsy so worked on the engine today,

Place New sparkplugs.
New spark plugs cables.
New air filter
New voltage regulator and sanding the plug connection completely blank again.
Replace the belts
Replace the ballast resistor.
Checking all wiring again after the battery was fully charged by the new charger and finally read 13,50 volts. Still 2 volt lower on the ignition coil and found the last plastic insulate brass connector between the coil and ignition module. Replaced it with a watertight connector as with the complete ignition module wiring. https://www.classicwinnebagos.com/forum/index.php?topic=16254.0

But OK, As the engine didn't run for almost a month put a splash of gas down her throat cranked her and after pushing thru just 2 cylinders,

https://www.youtube.com/watch?v=QuoKNZjr8_U

And I promise you guys, I ran around exactly like that  :P :P :P

Alternator running fine, But, Rock hard  cooland hoses again. They looked like balloons, but no bubble in the expansion tank  ???

So i called one of the other guys at the hobby garage who works on American Cars a lot to take a look and he did something that scared the hell out of me, he opened the radiator cap. ??? ??? ??? ??? ??? ??? ???

Coolant flying in the air 2 meters high and he quickly shut it again. Luckily the engine was not that hot yet still running on the choke.

But: problem fixed!    i?? D:oH!   :D

There clearly was some air in the system because now everything ran fine. Upper hose was now easily to compress till the thermostat kicked and you get the normal resistance. So no blown headgasket  :)clap :)clap :)clap

After this adjusted the timing and the carburetor and I could finally feed her the unions, adjust the stationary to  850 en put her in gear without dying.


After the successes on the cabin and coach wiring and now the engine I can finally and wholeheartedly say:

Betsy is off the Intensive Care!!!




Still to be done:

Change all the fluids and filters.
Give the carb a good clean cause after warming up she's a little hesitant to talk again after you shut her down, although not unfamiliar with these engines.


Let her run again,and warm up and do a new compression test. As I'm a loyal follower of Vice grip Garage, I heard Derek tell multiple times say that rings can get stuck and come around again. Let's just hope this is the case and be done with it. After all if there would really be something wrong she would not start like she does.

Oz

1969 D22, 2 x 1974 D24 Indians, 1977 27' Itasca

Mlw

Well, the follow-up is in the next thread. A lot was explained.

Dodge 360 restoration