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Model specific boards => Golf mk2 => Topic started by: jezza16v on 13 March 2009, 14:35

Title: Is the 8v an 'interference' design?
Post by: jezza16v on 13 March 2009, 14:35
Hi all, I'm hoping to pick up a 1990 8v this weekend, its got 'fsh' but no record anywhere of a cambelt change. Its done 110k so I'm a bit worried about driving it home. I've only had 16v before and I know they smash the valves if the belt breaks, if the 8v does not, I'll take a chance and drive it, otherwise I need to sort out a trailer.  :undecided:
Thanks in advance, J.
Title: Re: Is the 8v an 'interference' design?
Post by: Wayne on 13 March 2009, 15:39
Yes if the belt breaks you could or will damage valves
Title: Re: Is the 8v an 'interference' design?
Post by: rubjonny on 13 March 2009, 15:59
unles modified no, its only 16v that is interferance
Title: Re: Is the 8v an 'interference' design?
Post by: jezza16v on 13 March 2009, 16:23
Thanks RJ, bog standard 1 owner for 18 years from new.......I'll risk it then and RAC can pick me up if it breaks. I'm probably worrying too much but I bought a renault 11 a long while back & belt snapped on the long journey home & wrecked the head...ouch!
Title: Re: Is the 8v an 'interference' design?
Post by: Wayne on 13 March 2009, 16:28
If the revs are high enough and the belt breaks it will bend valves, I have seen it happen when I use to work on them.

Title: Re: Is the 8v an 'interference' design?
Post by: rubjonny on 13 March 2009, 17:09
i guess if enough death is been given its a risk, alsdo high lift cams will increase the risk. if sedate driving and all std head the risk is minimal.
Title: Re: Is the 8v an 'interference' design?
Post by: twistedblack69 on 13 March 2009, 17:39
Yea Ive got a high lift cam on mine (came with it, not thru choice) and the cambelt went the day after I bought it, wrecked half the valves. Was not happy, that was doing 70 on the motorway
Title: Re: Is the 8v an 'interference' design?
Post by: Chris-White on 13 March 2009, 18:19
over 4.5k seems to be a bit more risky according to internet lands.
Title: Re: Is the 8v an 'interference' design?
Post by: mattneck(Beavis) on 13 March 2009, 18:42
over 4.5k seems to be a bit more risky according to internet lands.

www.internetissh!t.org
Title: Re: Is the 8v an 'interference' design?
Post by: jezza16v on 13 March 2009, 18:58
OK, now I'm really confused........Either the pistons can hit the valves when they're fully open or not (with the belt snapped that is)? I don't see why the revs would make a difference, surely its the mechanical geometry that dictates..? Or am I missing something?  :undecided:
Title: Re: Is the 8v an 'interference' design?
Post by: Chris-White on 13 March 2009, 19:10
since this topic comes out quite often, and someone on here MUST have a digi engine in there shed,

disconnect the cambelt and rotate the engine to tdc. Then rotate the camshaft. If theres any resistance before it goes all the way round, we have our answer.
Title: Re: Is the 8v an 'interference' design?
Post by: Ben Lessani on 13 March 2009, 20:11
It is not interferance when standard. When I was changing the stem seals on mine I was happilly rotating the crank with cam in place (with valves full open).

The problem arises, as said, when your at high revs, its a bit different to turning an engine over by hand - the components are at the limit of their clearances. Combine this with an agressive cam and you'll certainly see engine damage.

Original specs say its Non-Interferance, but some people have bent valves - but they tend to never mention the conditions.
Title: Re: Is the 8v an 'interference' design?
Post by: danny_p on 13 March 2009, 20:50
i've had belt go while pulling silly revs,   no piston or valve damage,

on modifyed engines it is possible,  aftermarket cams and skimming head reduces clearance,             if a modifyed 8v dose do piston valve contact as the valves are square on to the piston a LOT of damage is done.   
Title: Re: Is the 8v an 'interference' design?
Post by: jezza16v on 13 March 2009, 23:51
Thanks all for your advice. It turns out the belt was changed at 52k in 1999.......? Now done 110k, probably perished now. I think I'll make it my first job as soon as I get it home.  :smiley:
Title: Re: Is the 8v an 'interference' design?
Post by: Gambit on 14 March 2009, 00:40
do you want me to change your name to jezza8v? ;)
Title: Re: Is the 8v an 'interference' design?
Post by: jezza16v on 14 March 2009, 09:24
 :laugh: :laugh: :laugh:
No thanks, it will serve to remind me to think ahead more, sort of like a tattoo of an old girlfriend or ex wife... :rolleyes:
Who knows, I might even find myself another 16v one day?  :smiley:
Title: Re: Is the 8v an 'interference' design?
Post by: sidecarphil on 14 March 2009, 11:30
why not change it anyway ???

for the cost of a new belt and a couple of hours work it is better for piece of mind !!!!

maybe i just like wasting money !!!!!
Title: Re: Is the 8v an 'interference' design?
Post by: Ben Lessani on 14 March 2009, 11:34
Couple hours? The timing belt can be swapped out in about 15 minutes on a MK2 - easy peasy
Title: Re: Is the 8v an 'interference' design?
Post by: danny_p on 14 March 2009, 11:43
15mins is about right,   unless the allen bolts round out on  the lower pully 
Title: Re: Is the 8v an 'interference' design?
Post by: jezza16v on 14 March 2009, 14:37
I've done a driver and couple of 16v before no probs, (16v is much easier imo as less to line up) especially when the old belt is still there, takes me more than 15min though as I like to clean everything up as I go. It will be my first job when I get it home and into the garage.......I don't really want to be doing it on someone else's drive.........I remember those allen bolts on the lower pulley, a real pig if they're rusted in or someone's chewed them up before...... :rolleyes:
Title: Re: Is the 8v an 'interference' design?
Post by: sidecarphil on 14 March 2009, 14:42
Couple hours? The timing belt can be swapped out in about 15 minutes on a MK2 - easy peasy

yeah but your well practiced at the job and i like coffee breaks  :grin: :grin: :grin:
Title: Re: Is the 8v an 'interference' design?
Post by: Ben Lessani on 14 March 2009, 16:06
well practiced

I know ... stupid tappets :angry:
Title: Re: Is the 8v an 'interference' design?
Post by: sidecarphil on 14 March 2009, 17:39
well practiced

I know ... stupid tappets :angry:

poor work man blames his tools  :grin: :grin: :grin: