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Dry and wet compression test


Iain T

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I bought a compression tester before Christmas and have been itching to use it on my Vitesse MK2. I know unless calibrated the actual values can vary but I wanted to know if all the cylinders were within the ideal 5% of each other. I ran the engine up to normal temperature (only around 70F as that was as hot as it would get), took all the plugs out, lifted the carb air piston and tested with the throttle fully open...I've been reading the instructions on the Forum!!! Values were 128-135psi dry and increased by 15-20psi with a teaspoon of oil down the plug 'ole. Question, is this increase acceptable or an indication that the ring/bore is not in perfect condition?

I did notice plugs 2 and 3 were soot black and 1 was normal colour. Plugs 4,5,6 were all ok. As 1-3 cylinders are fed from the front carb I would assume given all things equal they should be the same colour so the carbon must be coming from valves or rings on 2 and 3. FYI the engine does not smoke on acceleration or in fact any other time. Thoughts please.

Iain

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Its not a new engine so I would say those readings are acceptable as youre always going to get some leakage past rings and dont forget the piston is travelling a lot faster when running so the effect is less.

Why not try weakening the mixture a little on the front carb to see what it does for plug colour? What results do you get using the piston lifting pins on each carb for mixture testing?

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Hello Iain,

Could it be that the front carb is running ever so slightly rich hence 2&3 being a bit sooty ?? Cylinder 1 as is 6 is on the extremity of being fed fuel / air mix and that as a result MAY be benefitting number 1 from not being richly fed compared to number 2&3 ??

Just a mad idea !!

Regards.

Richard.

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As number 1 plug is the correct colour and I have had the engine rolling road tuned I hope the front carb mixture is sort of, probably, hopefully ok. The difference between the colour of 1 and 2,3 plugs is enormous, 2,3 are black soot.

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20 minutes ago, Iain T said:

Doug,

Dry:-

1=130, 2=128, 3=130, 4=132, 5=128, 6=135

Wet:-

2=150, 6=152, I didn't test the others wet as the light was fading and my wife was fed up cranking the engine!

No need to do a 'wet' test, Iain!

The purpose of that is to tell if a bore has a low pressure due to ring or valve seal failure - and your dry figures show no such sign!    In fact it shows a variation across the block of much less than 5%, which is absolutely fine!   No need to proceed any further!      Make her a cuppa, to show your thanks and get on with something else (preferably that earns domestic brownie points!).

The wet test is binary, not a measurement.

If a bore does have a low pressure, then the oil will raise it IF it is due to ring seal failure.   The amount that it is raised has no significance.

OR, if there is a valve seal leak, then the oil will have no effect.

JOhn

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Doug,

I know but she doesn't like the 'aroma' of my car (what's wrong with old car and oil?) plus it was a bit windy on the 5th floor in the multi storey car park. I do wind her up a lot but on her plus side she does like Wheeler Dealer...TR6 tonight.

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Doug,

I'm not allowed to use the washing machine, it has too many flashing lights and options. Customer review, never get a Miele too expensive and doesn't get the washing any cleaner or untangled than makes costing half as much!

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Iain, my Vitesse lets me know when Ive gone too weak on mixture by bogging down at certain revs when driving. Its quite sensitive and once Ive identified which carb it is a quarter turn or two on the jet and I know Ive got the optimum setting....

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we had a   £££££   Miele  it had a fault code  about water level  they arrived and cleared the level sensor tubes ( 2 yr old)  but would not reset the ecu, said they were not to use the reset programme  ...what!!!     no sir its £440 for a new  ecu  and thats with a 5 year warranty    so it went up the tip and got a samsung for £340   

Pete

 

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What annoys me is the water pump, it's too powerful and sucks the water out so fast it overfills the standpipe! I've ensured the standpipe height is within spec but on occasions it still bubbles out the top. WHY make it so powerful??? Our 12 year old Bosch was a third of the price and performed much better.

Same with our superdooper Siemens dryer, looks great but the moisture sensor is bo****ks. My wife has 'dead' fingers which won't activate the touch controls. It's quite amusing to hear her giving the dryer a royal mouthful....better it than me!

Iain

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We've gone through two machines in four years due to door locks not opening. The water level sensor sends a signal to the door when the machine's empty, and when it fails the door won't open at all. I bought an old model off Gumtree for £80 and it worked superbly until some idiot put a hair bobble through it and broke the pump. Being the only short-haired one in the house it wasn't mine...

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12 hours ago, Pete Lewis said:

so it went up the tip and got a samsung for £340 

Our Samsung is 4 years old - replaced a Dyson we had had for about 15 years which after the initial niggles fixed under warranty was brilliant but the bearing went finally. Just had about 5 or 6 weeks of pain with the Samsung. It has a 5 year warranty but has taken 5 visits to fix it (I hope!) 3 with new parts, two with the wrong parts - though the 2nd visit was with "incorrect" parts that were fitted (including a new drum) on visit 5. I suspect if the parts declared not correct on visit 2 were actually fitted then, it would have been fixed at that point and the replacement main board was not needed. Did feel like it was a Land Rover main dealers service department and just had the parts bin thrown at it :) 

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A few years ago we bought a weekend place at Ramsgate and occasionally rented it out. An American guy, who was going to attempt swimming the Channel, and his family rented it and at the end of the rental period phoned us to say the washer was full of water and wouldn't drain so they left with their clothes in it! They flew back to the USA and when we went to Ramsgate to investigate we found a pair of women's tights wrapped around the washers pump. When I contacted them to say what the cause was and we would DHL their clothes to them all they said was in American upright twin tubs this never happens...!!!

He never attempted swimming the Channel because the weather was awful and rained for most of their 2 week stay. Perhaps in the 'New World' trade deal with the US we should all by American twin tubs????? That way Colin you can dress in which ever manner you wish...

Iain

 

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I shouldn’t admit to this we have a DeLonghi Dish Washer at 2yrs old was replaced by the manufacturer because it just kept stopping and when restarted returned to the programme start! 
The replacement new washer. Started the same after 6 months the service guy was pulling his hair out so he checked the power source which I had moved with a flat plug multi point extension board, the reason being one to get the on off switch in a cupboard and to gain  extra room behind the dishwasher so it went in under the bench top. Guess what over nearly 20 years the auto cut out switch of the extension boards spring had relaxed due it hanging vertically, and it was that kept switching the power off.

Replaced the extension lead board and mounted it horizontally and all’s good!

well we did get a new dishwasher to replace the 2 year old one so the clock starts from then. The wife loved the old unit not so keen on the replacement what the heck can’t win.

not telling you how old our top loader washing machine is ( last of the Aussie built units I think) cause it might get a scare !

Peter T

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I've related our appliance threads to my wife......she thinks we are all barmy and need to get out more, I think she has a point. How about starting a discussion about irons or pillows (wife has a large collection, soft, medium, centre infills, Siberian/Hungarian down etc etc somehow none are just right)? Philips Azur always our go to iron, good on shirts!

I must stop this I'm having a gender bender...help someone stop me......

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Iron?  Don’t use one very often.  My casual shirts and trousers don’t need it and my work clothes don’t get it - I used to iron them but by the time you’ve driven anywhere they are creased anyway so stopped about 2-3 years ago. I probably iron something three times a year?

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