cam chain snapped anyone got any tips

[Ginger_boy]

Hi my 2004 2lt GV snapped its upper timing chain just before Christmas, long story short the chain tensioner obviously wasn't working and the chain ripped the steal splash plate off and wrapped it round one of the cam sprockets. Now not having done a dohc engine before I was wondering if there are any pitfalls in getting the timing wrong. Or is it still a matter of lining all the marks up ensuring all the chain slack is on the tensioner sides and put it all together. Obviously its a J20a engine and the Suzuki manual seems straight forward.
Any advice welcome

[d_r_1989]

Are these non interference engines? No valve to piston contact. Shouldn't be too hard a job if so. Just make sure you change all parts of the timing chain kit, chains aren't as forgiving as belts.

[Ginger_boy]

Well according to the great internet they are a interference engine. So head has come off as there was no compression on 2 & 3, on inspection there are marks on No 1. The strange thing is I have taken all the valves out now and checked them for concentricity they all are 0.03mm-0.05mm. I'm wondering now that when I did the compression test I had removed the cams so in effect shutting the valve and therefore not allowing any air into the chambers to compress. Should have done a air leak test instead.

[d_r_1989]

Interference doesn't always mean it will damage, there's always that 1per cent in which your lucky to be. Check the cams for wear/cracks as cast doesn't like any force it's not designed for (a cracked cam has been seen before by myself)
Putting it back together should be fairly simple and as you describe above. If the chain kit doesn't include new sprockets be sure to check them to make sure they are true especially the teeth. Also note some aftermarket chains come with timing marks on them so be sure to align them too if that is the case.

How bad is the contact on no.1?

[Ginger_boy]

Good shout about the cams not had a close look at them. The piston had two 10mm crescent not very deep most of it polished out when I clean them. I has to get timing chain kit that had the sprockets. Where the splash plate had gone round with the chain it had chewed up one of the cam sprokets

[Ginger_boy]

Well after 11 hours from rebuilding the last bit of the head in the workshop to a running engine on the car. No timing issue all went back with out a hitch. Even changed oil/ oil filter, air filter plugs etc runs like a dream. The better half is most to pleased to get her car back. Now off for a few beers to dull my now crippled back.

[ScottieJ]

Glad to hear it matey

[d_r_1989]

Good glad you managed to do it relatively trouble free

[Ginger_boy]

Now I have done the 2lt, I had better do the rubber band on the 1.6lt.

[Anton]