Peter T Cam For Xu10J4 Engines Tapping ?

[chris 417 mi 34 2 Cars]

Purchased a peter t stage 2 cam from a forum member and mate off here a few years ago now and only recently got round to fitting it, ever since the engine has been run for the first time its tapping qute loudly.

 

Are there any mods need to be performed to the head before fitting these cams or is it possible i have a blocked oil gallery (totally happy with the cam itself btw ), as ive been advised by the guy i bought it off he had modified the valve seats when it was in his engine but he couldnt remember if this was needed to sort it out ?

 

Engine is xu10j4 block & head with s16 pistons and 2.1 diesel crank

[James504 12]

I would remove the cam ASAP. Either fit the standard cams or get a new cam.

[welshpug 1,661]

how long has the engine been run since the cam was fitted? might just need a proper run to build up the pressure in the tappets.

[chris 417 mi 34 2 Cars]

its been run on the rolling road and mapped to a certain extent as far as the guy whos mapping it dared take it ( on my decision),

 

Are there any specifics though when fitting these cams ? or is it just a strait swap for standard ?

[petert 588]

Did you check valve to piston clearance? That cam has too much lift at TDC for a standard XU10J4, let alone one fitted with a diesel crank.

[chris 417 mi 34 2 Cars]

To be honest i hadnt even considered this, once the engine was built it was turned over by hand and seemed fine, can this be remedied in any way ? im guessing ill have bent a valve or two by now then (although it seems to be iding and running fine :S)

[welshpug 1,661]

you'd need to take it apart and get the valve reliefs in the pistons made deeper at the very least, as for ho many bent valves its hard to say.

 

The reason you may not have noticed anything turning over by hand is due to the hydraulic tappets, they wouldn't have had much if any pressure in them so the valves wouldn't have been opening very far, add the pressure of a few thousand RPM and they'll self adjust to the base circle of the cam and give full lift.

[chris 417 mi 34 2 Cars]

ahhh right , ill get the engine removed stripped and sort some new parts then, guessing noones used the diesel crank with the stage 2 cam ?

 

How do i measure how much will be needed to be removed from the piston valve reliefs ?

[petert 588]

 

How do i measure how much will be needed to be removed from the piston valve reliefs ?

 

There are several methods. I don't recommend using plasticine, as you could bend a valve just finding out! I recommend using the "drop method" for a 16V engine.

 

Remove head. Remove cams from head. Remove one exhaust valve and one inlet valve from cyl. #4. Position crank at TDC for 1 and 4. Put the head back on, with inlet only loose in guide (no spring, retainer, collets etc.). Do up head bolts to 50Nm only. Set up a dial indicator on the end of the loose inlet valve. Drop the valve on to the piston crown, measuring the TOTAL amount from the valve seat to the piston. Remove head and repeat for the exhaust valve.

 

Using the Data:

On a std. 1.9L Mi16, you would have got a distance of 0.205" in total drop distance. From this, you subtract the lift at TDC for the cam. For a #3 inlet pulley and standard inlet cam this would be 0.045".

 

Thus,

0.205 - 0.045 = 0.160"

 

So there is 0.160" of clearance at TDC on a std. 1.9L. It's actually slightly less than this as the valve gets closer to the piston after TDC, by approx. 0.010". Thus 0.150". The recommended clearance for a hydraulic lifter on an inlet valve is 0.080" (0.090"). So you can see PSA is very conservative. For an exhaust valve the clearance should be 0.100" (0.110") minimum.

 

The recommend lift @ TDC for your cam is 0.100"-105". So you can see that it's on the limit for 1.9L engine. I can't recall the exact numbers for a 2L but I do know it's worse.

 

 

I would do a compression test before pulling it apart. If it's buggered you may as well get the head serviced first before doing any measuring.

 

Good luck!