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Vernier pulley jamming the engine!! HELP

725 views 19 replies 5 participants last post by  chip 
#1 ·
Currently I am timing my engine.

I made the camshafts and pulley on standard marks, I installed the timing belt and tightened everything.
Then I turn the engine from the pulley and it was perfect after one complete cycle.
Next I removed the standard inlet pulley and installed the vernier pulley, tightened everything again but when I turned the engine it turned about 45 degrees and then jammed!:(
Have been trying to move the pulley around for a few hours! hoping to get it right but it seems useless. As soon as I install the standard pulley everything works fine.

Can anyone suggest any type of help as I can't see how it will get to work.:doh:

Thanks:)
 
#2 ·
I assume by one complete cycle you mean 2 revolutions of the engine?

If not then this might be your problem.
 
#3 ·
You havent installed it correctly.

Take a look at the back of the pulley and see where the pin goes into it in the cam, make sure that is orientated the same as the standard pulley when you install it while its on the zero marks, then you can adjust the timing from there.
 
#5 ·
Yes I have been lokking closely for the pin and checking pulley one over the other. My father just gave me a call and told me that he managed to do it correctly everything marked and on the zero. I will check how he;s done it and repost what I was doing wrong.

Now I need to retard it 7deg.

Iirc i need a protrector for the crank and mark tdc in order the time it correctly?

thanks a lot
 
#6 ·
Just turn it half a tooth, no point getting all exact over the 7 degrees as it varies from engine to engine anyway.
Sometimes I regret doing that article, people take it too 100% as a guide.
 
#7 ·
Thanks chip, as my cylinder head needed to be welded and skimmed as it had some pitting, when it was skimmed the valves came level with the surface of the cylinder head and so it cannot be skimmed again as the valves would be partailly cut.

As they are very close to the piston would the 7 deg retard affect them to make them touch?? Although I will tun the engine by hand I would like to know if it will be affected before doing it.

thanks again
 
#8 ·
I doubt it, but I havent tried it with that much skimming to actually be sure.

Depends on the thickness of gasket too of course.

Head doesnt sound anywhere near ideal for a turbo, compression ratio will be right up after that much skimming.
 
#9 ·
I had to use standard gasket because the block has wire rings aroun the bores, the comp. ratio before skimming was 8:1 and now it is 8.2:1 which i think is still good.

Best way is to try it and turn the engine by hand to avoid damage.
 
#10 ·
So you arent on standard pistons anyway? If so its a bit of a waste of time expecting anyone to guess your valve clearance TBH.

Turning over wont tell you anything really, as the lifters wont be pumped up.
 
#15 ·
You can get an idea of clearance by trying to push down with a wooden dowel (or something softish that won't damage the surface) on the exhaust follower as it's approaching TDC. you should have a mm or two clearance, depending how much oil is in the follower, preventing it from collapsing and giving a false clearance.
Personally, I'd be inclined to leave it at the stock marks if there was any question of clearance issues.

BTW, if the pistons aren't stock, have they had the notches deepened or, if aftermarket, are they made deeper? May help if you can give the make/model of pistons used.
 
#18 ·
I have managed to retard it and the exhaust valve is closed (avoiding power loss) Also I turned the engine by hand and it didn't lock at least. Although before starting it up I will remove the spark plugs and turn on the battery to be sure.

Yes the pistons are deeper, they are mahle for sure custom designed in the US to bring compression down to 8:1

Thanks
 
#16 ·
A lot more messing around, but one of the SBC tricks was to use a solid lifter and a light/inner spring to check for valve to piston clearance - as above, checking the physical clearance by 'gently' depressing the valve
 
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