Cam Swap Problem

[squirrel_hunter]

'99 Model SV650 with Hayabusa Pistons. Doing the cam swap and have encountered a problem.

The front is installed and all is fine, the rear is the problem. Have put the K3+ Intake into the intake on the rear cylinder and this rotates freely. The original intake is now on the exhaust but once the cam holder is seated it stops the cam from rotating.

Have tried the same with different cam holders, the exhaust cam from the K3 and a different original intake cam. All present the same problem.

But if I remove the valve buckets the cam rotates freely...

I assume from this the cam is pressing on the valve even in the position where it should not. The timing has been checked and rechecked. So I'm thinking the shim in the bucket is to big, how can I confirm this and find the correct one assuming that this is the problem.

Also just thought that the original exhaust cam should go back in to test, but as I want to use a different cam than the original exhaust I would still see this as a problem though it may help finding the shim size required?

But your suggestions please...

[Sid Squid]

Are you sure the valve assemblies are correct? Your thoughts on too thick a shim would be the first place to look, certainly as removing the bucket allows the cam to spin.
Also do not mix up the camshaft bearing caps, they are line bored with the heads and fit correctly in one position and one way around only.

[squirrel_hunter]

Valve assemblies have not been disturbed we only cleaned the surface coke off of them before reassembly.

The camshaft bearing cap was only swapped over to see if that made a difference. Will ensure the correct one is in there for the final installation, thanks for the advice.

[squirrel_hunter]

Just tried it with an original exhaust cam in and with the valve buckets and shims in place and the cam rotates freely once the cam holder is in place. So with this in place we decided we could check the valve clearances starting with the front...

So rotating the engine round to the F mark for TDC at the front we encountered resistance and the engine locked. Lucky we were only testing by hand. The front cylinder is not at TDC in this position as we checked previously using a height marker. So the assumption now is that we do not have the timing quite right.

Thus we will retry using all original cams to get the timing right before trying the swap again. But with this in mind how can we ensure that we are at the correct TDC in an engine without any cams or would it not matter? Or any further advice on either problem?

[Sid Squid]

Ideally you'd use a dial gauge in the plug hole. There is a TDC mark on the flywheel which isn't perfect but at least it would tell you if you're anywhere near or miles off.

[squirrel_hunter]

We are using the F mark on the alternator (with the cover on) to get to TDC on the front cylinder. I assume without cams installed having the engine in this position will give TDC at the front regardless of which stroke it would be on once the cams are installed, if I've articulated that correctly. We don't have a dial guage but are using a long screwdriver that we have marked to get a picture of where the engine is.

[embee]

As an aside, if you want to do cam timing accurately you first need a timing disc, something like


which you attach to the crank and arrange a pointer somewhere (bent wire off a bolt typically)

To determine true(ish) TDC get the piston more or less at TDC by feel, fit a dial gauge in the plug hole (usually need a longish extension on the gauge).
Turn the crank to get, say, 5mm drop, note the timing disc degree reading. Turn crank to the other side of TDC and exactly the same piston drop, note the timing disc degree reading.

Halve the difference in the timing disc degree readings and turn the crank to that value, this should be TDC pretty accurately. With the crank set here, re-position the timing disc to read zero. Recheck measurements.

Cam positions are done similarly, usually the timings are expressed as maximum opening point or "MOP" (i.e. full lift), which you determine by putting the dial gauge onto the valve bucket, turn the crank to give more or less full valve lift, set the dial to zero, turn forwards to give, say, 2mm drop, note angle, turn backwards to give exactly the same lift, note angle, then MOP is halfway between.

I was told F is not TDC but a mark you use when installing the cams so they aren't under pressure when installing.

The info was from Zoran and he is the SV God.

See thread http://forums.sv650.org/showthread.php?t=160933

this is how i will be doing it.

set crank to F
pull front cylinder cam chain tight on exhaust side place cam in and a line the drawn on marks on the k2 intake cams (new exhaust) with the cylinder head then count 16 pins across the top from second marked point on k2 cams to number 3 on pointy intake cam,fit cam chain tensioner.

rotate crank 360o listen for grinding noises.

then do the rear... pull cam chain tight up the intake side, line up 1r on the pointy intake cam so it is inline with the cylinder head then put exhaust cam in (k2 intake) count from number 2 on k3 intake 16 pins and align with drawn on mark on k2 intake (new exhaust) fit tensioner

turn crank 360 listen for noises check timing on front, spin 360 and check timing on rear

hopefully job done

thats my understanding of it any way lol

[squirrel_hunter]

I hold my hands up. It would appear to be a RTFM problem on my part.

Set the front cams with the alternator on the F mark. Then rotated to the R mark as if we were checking the clearances, which is of course wrong. What I should have done, and what has now been done is after installing the front on the F mark the alternator should be rotated a full 360 to get to the F mark again and then install the rear cams.

But the good news is the front and rear cams have been installed, as in the swap has been completed. The valve clearances have been checked and all of the intakes are within the service limits however I need to drop down 1 shim size from 1.70 to 1.65 on all of the exhausts...