Camshaft Timings

[WIL35]

My 4.2 has just been diagnosed with having retarded cams! What is involved in getting them to be correct?

Apparently it feels like it is ok on a partial throttle but is feeling significantly underpowered. This could be a possibility as the top end has been rebuilt with the engine in situ after the chain broke.

[trackcar]

Well to diagnose that they would have had to measure the timing, so that was ten minutes less work time than setting it up for you correctly there and then .. so why didn't they? makes no sense at all.

[SXS]

Who did you go to?

[Mars]

Do you guys measure cam timing with a protractor or with couple (or three) dial gauges using the Lift on Overlap method?

[350Matt]

when I did mine I used a degree wheel attached to the front pulley and a pair of dial gauges to use the lift on overlap method


Certainly went a lot better afterwards as one bank was 8° and the other was 10° out....

Matt

[Mars]

I see. Thanks. The degree wheel got you to TDC then you measured the cam lift at TDC?

I used to stick a dial gauge through the plug hole to measure TDC but the Cerb isn't a 4-valve head, so with the plugs being on the side of the head, I'm not sure how easy that is.

What confidence do you have in the degree wheel accurately reflecting TDC?


A few other questions (if you don't mind):

1. I'm curious what figures you are measuring to for lift?

2. Unlike a twin cam (per head) engine you only need measure the inlet I guess..??

3. (Never having done a V8 before) Do you have to measure/adjust both banks at the same time... so requiring a dial gauge set up on both banks at the same time? Any pointers for technique?

4. (last one) I'm aware there is more than one type of cam for the 4.5... how can I tell which type I'll have and do you have lift on overlap figures for them all?


Thanks for your input and apologies for the interrogation. I'd rather ensure I'm prepared with all the required kit and techniques before learning from my own mistakes.

[trackcar]

Nigel, I'll explain what I do on Saturday .. involves no dial gauges at all and i don't think you'd argue too much with some of the cars i send out

[Mars]

Magic. Thanks.

[WIL35]

SXS said:

Who did you go to?

Not sure I'm allowed to say on here, anyway I've found someone nearer to me who is familiar with the procedure, so I'm quite happy to pay for it to be done properly.

I just think I was 'lucky' that the chain broke while the car was still under warranty!