timing chain too slack or not

disco-v8 · Post by **disco-v8** » Wed Nov 14, 2007 12:04 pm

ok about 9 months ago i changed my cam on my rover V8 3.9 which also included changing the timing gears and timing chain....

ive just looked at it 2day and there is abit of slack in it already but dont no if its too much????

how much play should there be between the cranck and the cam (in degrees)?????

another words my cranck can move slightly without moving the cam, is this ok???

ian.stewart · Post by **ian.stewart** » Wed Nov 14, 2007 12:53 pm

The answer is it shouldent make any real difference, as the chain is in tension when driving the cam, really excessive slack will indicate there is chain or sproket wear, this has to be addressed if you think its excessive, as I almost demolished my engine due to excessive chain and sproket wear,
With a bit of investigating we have made an educated guess as to what happened,---- The chain was worn enough to be able to climb a tooth on over run, enough to break off a tip o of a tooth, which just happend to be the tooth next to the keyway, this bit of tooth fell into the next tooth root above the keyway and was caught iin the chain and sprocket together cleaved thru the weakest place by the keyway and breaking the sprocket into pieces, and bending the crank nose in the process. stopping the oil pump and leaving a few valves in the open for the pistons to clatter against

mgbv8 · Post by **mgbv8** » Wed Nov 14, 2007 8:34 pm

I was racing my old 3500 with 90k and 30 years on the clock. She ran fine under load and took a 150 shot of gas. But I had trouble getting a smooth idle.
When she eventually made 13.2 seconds on the drag strip I decided to do a rebuild. When I pulled it apart I found the chain was so slack I could move the crank 10 degree's either way before the cam moved. A new Cloyes gear and chain set put her back on the right track.

I dont know what the acceptable limit of movement should be, but I know just how much you can get away with now.

Nick Moore · Post by **Nick Moore** » Wed Nov 14, 2007 9:20 pm

ian.stewart wrote:...I almost demolished my engine due to excessive chain and sproket wear,
With a bit of investigating we have made an educated guess as to what happened,---- The chain was worn enough to be able to climb a tooth on over run, enough to break off a tip o of a tooth, which just happend to be the tooth next to the keyway, this bit of tooth fell into the next tooth root above the keyway and was caught iin the chain and sprocket together cleaved thru the weakest place by the keyway and breaking the sprocket into pieces, and bending the crank nose in the process. stopping the oil pump and leaving a few valves in the open for the pistons to clatter against

Now that's a post-mortem

mgbv8 · Post by **mgbv8** » Wed Nov 14, 2007 9:30 pm

But that was while doing a 7000 rpm burnout Mr Stewartt????

Disco is looking more towards the daily driver thing really!!!

disco-v8 · Post by **disco-v8** » Thu Nov 15, 2007 12:59 am

mgbv8 wrote:But that was while doing a 7000 rpm burnout Mr Stewartt????

Disco is looking more towards the daily driver thing really!!!

guess again mgbv8.....

im into extreme offroading, and with the extra weight and larger wheels/tyres i need as much power as possible.... plus im a petrol head so just love V8's

its great having a car the weighs about 3tons but still pulls away from alot of fast road cars

ive already had her totaly rebuilt and a few power upgrade done aswell

RP4 cam
k&n filter
gems 4.0/4.6 air flow meter (much high air flower than the hotwire)
head ported and skimmed (higher CR)
ignition advanced
tin head gaskets (higher CR again)
FSE fuel pressure reg

and this week im going to be spending nearly £200 on my V8 goodies

kev_the_mole · Post by **kev_the_mole** » Thu Nov 15, 2007 10:30 am

Oooooh chain problems!

We make vernier sprockets at work and we also can check your old chain and sprockets for "acceptable" wear.

Chain and sprockets will never be backlash free, neither are gears or timing belts but they are better.

Recently sorted out V8 Forum member Simon Owen (sowen) with a new chain and checked his sprockets. His sprockets were good to go but his chain was shagged so sold him a nice new chain.

If there are enough of you (20 ish) that need or Santa could bring new drives to then we could do a group buy and make an attractive (hopefully) package of new vernier sprockets and a spanking Wippermann (OE Mercedes and BMW) chain.

If you just want your chain and sprockets checked then all it'll cost is the return carriage of about £8.

Tony - sorry if this is in the wrong section or is advertising

Cheers,

Ian

mgbv8 · Post by **mgbv8** » Thu Nov 15, 2007 6:11 pm

Mental Disco!!!

I'd love to go to one of these days out to watch that sort of stuff. I think there is a place near Bedford where folk do it.
Is it one of those things where you can come and spectate?

Post by **Coops** » Thu Nov 15, 2007 6:54 pm

Ian i maybe interested mate in a set.
got any pics?????
and once i have the shop up and running you can sell them in there if you want

disco-v8 · Post by **disco-v8** » Fri Nov 16, 2007 2:06 am

mgbv8 wrote:Mental Disco!!!

I'd love to go to one of these days out to watch that sort of stuff. I think there is a place near Bedford where folk do it.
Is it one of those things where you can come and spectate?

oh god yeah you can watch.....

some people charge abit like £2-£3 just as they usualy have to cover insurance reasons but i think there the best place on earth

scrap bit of land with loads of off roaders doing stuff that you wouldnt even be able to walk climb up on foot....

plus as alot of sites are usualy old quarys, theres all sorts of un-road legal cars there with uncilenced V8's

what asound that is..... an inclosed space with V8's everywhere