GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: Sgt_Lemon on 27 August 2013, 21:15
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What should the factory compression figures be for a 1.8 8v?
If someone can post off the Haynes PDF it might be worth putting the figures down for all other models as I couldn't find it within the section or searching in the MK2 section.
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about 180/190 is good on standard engine. but your engine is cammed yeah. so I would just make sure they are even from cylinder to cylinder.
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Thanks, will check it out tomorrow.
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I just did a compression test, got from 1-4 figures of 150/ 145/ 145/ 145.
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Was that with throttle wide open? Thats low, try a diff compression gauge also
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Throttle wide open. The book says between 145-190 is good. To be honest though I'm happy that they ae all close, not sure the tester I got at a car boot for £5 can be trusted.
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they will read lower at cranking due to the sports cam and modified head you have fitted. but they are very even. when I tested mine one of them was 195 and other 3 were 190. did retorquing the head stop your coolant loss btw?
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How will they read lower with cam & head job? The valves are closed so no difference in compression
145 is too low, try a different gauge
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Agreed okay but would personally like to see a bit higher than 145 soon or later rings or valve stems will need doing sooner than later?
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The tester I used wouldn't hold a value so 2 people were needed so I doubt the accuracy of the figures.
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How will they read lower with cam & head job? The valves are closed so no difference in compression
145 is too low, try a different gauge
so why do you think when you put in a cam with more duration and overlap they recommend upping the static compression ratio??? its because low rpm cylinder filling isn't as effective.
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Lairy cams yes but fast road cams no
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any uprated cam will make a difference. with a long duration cam the inlet stays open longer as the piston rises on the compression stroke pushing back out some of the air it has just drawn it.
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As i said lairy cams yes fast road no
look at kr, abf & autotech cam profiles. One has more lift, the other more duration and the later more of both and neither effect compression ratio
what cam is sgt_lemon running? Itd need to be a seriously big cam to have that much effect on compression.
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kr and abf are 16v so you cant use them in a comparison between a standard 8v and a cammed 8v. not sure what cam the sergeant has but he reckons that once it was fitted his idle got very lumpy.
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his gadge dosent stay up tho, if it dosent have a valve init where it screws into the cylinder the colume of the pipe can be considerd to be part of the combustion chamber, that will lower the compression ratio shown LOTS.
145 is enough to run tho
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I have a classic mini running a very lairy cam my compression gauge figures are about 280 per cylinder the overlap doesn't really affect reading
Op needs to use a gauge that works and then put his results up and we wouldn't all be going on about low readings in the engine
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I have acquired another tester to settle it haha :grin: if the sun comes out later I will test it again.
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I have a classic mini running a very lairy cam my compression gauge figures are about 280 per cylinder the overlap doesn't really affect reading
Op needs to use a gauge that works and then put his results up and we wouldn't all be going on about low readings in the engine
ok now we are veering of in a completely different direction again with talk of mad mini engines. but just out of curiosity. what is the static compression ratio of said mini?
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shall we get back on track :wink:
Sarge, different compression Gauge required, then new readings please. :afro:
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I'm away today so will do the tests again with my second gauge.
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I'm away today so will do the tests again with my second gauge.
whats the story with this one sarge? :smiley:
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Lazyiness and other car things been sorted. Tomorrow morning haha, i will get it done.
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Zzzzzzzz
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:whistle:
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Bit annoyed my posts where deleted as they do have some relation to the topic!
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Bit annoyed my posts where deleted as they do have some relation to the topic!
there is 1 of your posts still on page 2. 1 of mine disappeared to :angry:
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Did you do more tests?
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Second sh!tty tester that wouldn't hold a figure but if you looked at it the results all came out around 180
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That's a bit more like it!