Jump to content

Cam timing, engine not going etc


cute wee gem

Recommended Posts

I'm having some problems with getting this engine to go. Its got quite a big cam so I think this could be half the problem.

So far with the ignition timing I've gone right across the range of static timing, extreme amounts of advance (low compression due to cam) and even retard.

When its set to quite a lot of advance it coughs and sends smoke back through the carb, I thought this may be a problem with the cam timing. Its currently set to around 3-4deg retarded (It was meant to be advanced, but the engine was upside down when I set it, so I think I buggered that up :rolleyes: )

I think Gaz got an adjustable cam gear at some stage, so hopefully you or anyone else who has had experience with it can shed some light.

I'm thinking that if the cam timing is retarded it makes it more usable up in the higher revs and may not help starting if the battery won't let it wind over fast enough. I also had a thought that if its retarded (even if its only 3-4deg) the inlet valves are closing a lot later and since the timing is so advanced its firing when the inlet is still slightly open? (smoke out carb) :?

I may be blowing things out of proportion though. :lol:

Link to comment
Share on other sites

you timed it to TDC on the correct cylinder? i.e, checking which valves are closed on pot 1 or 4?

adjustable camwheels will make a difference, or, get it centrelined to spec. hardcore cunts can shim the keyway to give advance/retardation on the stock gears.

tried moving the dizzy through the range whilst cranking?

Link to comment
Share on other sites

Yeah, we're gonna tow it tomorrow, prob get a few more revs than a crusty starter motor, may be enough to get her going

But yuh, theres spark, gaps etc all good, its timed right and there is gas, its just not going, but as I said before cam timing + not enough revs to crank it up is probably the problem

If towing doesn't work, or it does but it won't start off the starter motor I'll goto the cam timing.. only prob with mini's is its fucking shit to get to it being so crammed in :(

Link to comment
Share on other sites

had this problem too, still do really, lol

1st problem, plugs: did you gap them properly stz? also, when i started my engine up for the first time (well, tried) i did heaps of fucking round with timing/air/fuel etc, by which time the plugs had attracted a fuckload of carbon, maybe check them again...

my points where fucked

my condesor was fucked.

my carbs are way out of sync, fucken hard tog et right btw...

have you fixed that vaccum leak on the inlet manifold?

my tappets clearances are shit.

also, might sound NEWB as, but are you 100% certain you put the clutch/flywheel on the right way, ie, not 180 degrees to where it should be, last time i had my clutch apart i remember i was pretty close to putting it back together the wrong way, although im not sure weather the lock nut is keyed so you cant do that...

Link to comment
Share on other sites

Flywheel is actually on the wrong way, as I put it on when I had no head on, and didn't bother to look at the cam :rolleyes:

Doesn't matter though right? - I made sure the dizzy is in the right way by getting #1 at TDC on compression stroke

No marks on front pulley, I'll just do it by ear/trial and error

Plugs are gapped right, I've taken them out heaps as it got flooded a few times etc so they are fine, decent spark there too so condenser/points should be fine, they look brand new too

I've put the single carb back on thinking it may be a fuel prob with the twins, still got nothing untill I took out the rather large oil pressure sender, and put the stock one back in (had a oil gauge set up) because it was hitting the dizzy and couldn't get fuck all advance going, once I done this I got smoke out the carb on a few occasions, dad reckons he heard a bang out the exhaust at one stage also, with the timing in the same spot we couldn't get it again.. talk about confusing

Link to comment
Share on other sites

Flywheel is actually on the wrong way, as I put it on when I had no head on, and didn't bother to look at the cam :rolleyes:

Doesn't matter though right?

Depends on the balancing. It's ususally wise to keep flywheel/pressureplate aligned and depending on the engine keeping them reletive to the crank. It wont cause it not to star tho.

- I made sure the dizzy is in the right way by getting #1 at TDC on compression stroke

How did you confirm this?

I've put the single carb back on thinking it may be a fuel prob with the twins, still got nothing untill I took out the rather large oil pressure sender, and put the stock one back in (had a oil gauge set up) because it was hitting the dizzy and couldn't get fuck all advance going, once I done this I got smoke out the carb on a few occasions, dad reckons he heard a bang out the exhaust at one stage also, with the timing in the same spot we couldn't get it again.. talk about confusing

I can tell you from experiance that if you get the timing 180 out it will back fire. Advancing or retarding will move the back fire from out the carb to out the exhaust or vise versa.

For the few seconds it's going to take I'd move the leads 180 as it will either fix it or confirm that firing order isn't the problem.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...