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Thread: Brian Crower 7M cams and ignition timing issue

  1. #21
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Quote Originally Posted by IJ.
    There are a bunch of variables that will affect the Cam's true 0 point such as ANY machine work done on the block or head, Belt stretch, Pully wear, Head Gasket thickness and so on.

    This is why they give you the "220@50 thou" Spec so you can degree them in and when your degree wheel says 220@50 thou you look at the Cam pully and this will be YOUR motor's true 0.

    From memory 1mm difference is around 2>3 degrees.

    Thanks Ian

    My motor has had atleast 2 head shaves and one decking of the block when I rebuilt it earlier this year. These were all absolute minimum though at my request. Shaving head or block or gasket thickness does give cam retard.

    It also has just an oem style ACL head gasket with ARP studs for a bit of piece of mind.

    Just a little update. I tried retarding the inlet cam this morning about 5 degrees to reduce valve overlap since my adjustable wheel is on the inlet cam. And it started and idled no problems. Looks like this weekend will be spent accurately degreeing the cams.

    BTW Ian the front crank pulley on the cressida 7mge appears to be solid and not have any rubber damper. So as long as the drive key is healthy my TDC timing marks should be OK don't you think.

    Andrew.

  2. #22
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Andrew: The Cressida damper is still a damper it just has a big weight pressed into it so it's worth check for true TDC before you start on the Cams.

    You'll also need to verify ignition timing once the Cam timing is done.

  3. #23
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    Default Re: Brian Crower 7M cams and ignition timing issue

    OK will do.

    Unfortunately I must now go to work ARGGGGHHH.

    I will try and accuratley degree the cam over the weekend.

    BTW did you have a look at the little timing chart?? Does it give you any feeling for the cam timing. It seems to be pretty mild to me.

  4. #24
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Andrew: They're going to be a nice punchy midrange type of Cam

  5. #25
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    Default Re: Brian Crower 7M cams and ignition timing issue

    It looks like the BC's are close to the hard weld regrinds I have, 322 and 218. I don't have Adj. cam gears though, and was told that they wouldn't have to be degreed in. Was I misled? I just lined up the cam gears and it started right up.
    I agree with IJ as far as the "punchy midrange". They really made a difference 3k to 7k which is were I wanted the power.

  6. #26
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Just thinking out load here but I should be able to check the intake opening and exhaust closing events without a fancy degree wheel since they both occur so close to top dead centre on the non firing cycle. Atleast according to the little timing chart anyway.

    I have accurately set all the clearances and I have decent digital vernier caliper that I could use to determine the 50 thou lift points.

  7. #27
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Measure the circumference of the Damper divide by 360 then multiply this by 220.

    Take a tape measure using TDC as 0 then mark where 220 degrees is on the damper this needs to coincide with 50 thou lift

  8. #28
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    Default Re: Brian Crower 7M cams and ignition timing issue

    I was checking the BC website and the Stage 2 are suppose to be "plug and play"? Should you have to degree them in?

  9. #29
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Quote Originally Posted by AJ'S 88NA
    I was checking the BC website and the Stage 2 are suppose to be "plug and play"? Should you have to degree them in?

    Update

    I have checked my TDC mark on the front crank pulley and it appears to be correct. I have made a simple check of the valve timing events and they are also as per the little timing card.

    I have compared the BC exhaust cam with both a stock NA cam and a stock Turbo cam and the distributor drive gear is retarded on the BC cam by about 10-20 crank degrees.

    I am borrowing a mate's cam degreeing set up on the weekend to set the cams up properly. I will also put the cressida intake plenum back on since it makes access to the cams easier than the supra style Y pipe ACIS intake that I have been using for the last 6 months.

    I emailed Brian Crower with a few issues and asked if they have had any other feedback on these cams. Short version of the answer is they have sold around 400 pairs and not heard anything about ignition timing problems. They also reported a customer who fitted these cams to an NA engine and gained 20 hp.

    I will keep you posted.

  10. #30
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    Default Re: Brian Crower 7M cams and ignition timing issue

    Quote Originally Posted by AJ'S 88NA
    I was checking the BC website and the Stage 2 are suppose to be "plug and play"? Should you have to degree them in?
    Degreeing is only really making sure you have a known 0 point to start tuning due to the variables I listed a few posts back.

    In this case it will help verify that the Helical gear has been indexed incorrectly to the Pin holes in the Camshaft.

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