cu engine low compression

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stew0145
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cu engine low compression

Post by stew0145 »

hi, ive just bought at t25 with the 2.0 cu Aircooled engine.it had been stood for a year before i got it. it only seems to be running on cylinders 3 and 4. ive checked that ive got a spark (replaced coil + plugs anyway). i checked compression, found 1 + 2 low (75). im unsure how to go about checking the tappets as i think they are hydraulic? could it be these that arent working properly, holding the valves open? any help would be gratefully recieved

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BOXY
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Re: cu engine low compression

Post by BOXY »

Here's everything you could need to know about hydraulic tappets.

http://www.ratwell.com/technical/HydraulicLifters.html" onclick="window.open(this.href);return false;

You could always wind the adjusters completely out so the valves stay closed and check the compression again.
2ltr Aircooled CU with twin Solex's & originally a 009 dizzie, but now back to standard.

stew0145
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Re: cu engine low compression

Post by stew0145 »

thanks Boxy, much appreciated. Will check the compression again tomorrow with the adjusters wound out. fingers crossed its nothing too serious

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Paul Weeding
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Re: cu engine low compression

Post by Paul Weeding »

Did you check the compression with the throttle fully open?? :smile:
LVH Engines & Restos
Type 4 Aircooled specialist

stew0145
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Re: cu engine low compression

Post by stew0145 »

yeah Paul checked it with the throttle open, not had chance to have another look today. might have to wait till the weekend now. thanks

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Paul Weeding
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Re: cu engine low compression

Post by Paul Weeding »

Ok, well don't wind the tappets fully off then... One full turn puts them roughly at the untentioned buy the lifters stage...

Check the comp again, and if it's still low a squirt of oil in the bore to see if it's rings or the valves that are leaking the pressure :smile:
LVH Engines & Restos
Type 4 Aircooled specialist

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