Brian Crower 7M cams and ignition timing issue
- Thread starter amichie
- Start date
I'm gonna pull mine out of the box tomorrow and compare. I took a quick glance to make sure they weren't broke when they came in the other day, but didn't inspect them fully yet. Just to busy...
Andrew
As you have been running the cams for a few weeks & are going to install another adjustable cam wheel it might be a good idea to take pictures of the #1 journals to see if there is any unusual wear & check how wide your grooves are.
I dont think mine are a one of, unfortunately.:nono:
Pity no one provided a close up of the cams before we bought them.:3d_frown:
As you have been running the cams for a few weeks & are going to install another adjustable cam wheel it might be a good idea to take pictures of the #1 journals to see if there is any unusual wear & check how wide your grooves are.
I dont think mine are a one of, unfortunately.:nono:
Pity no one provided a close up of the cams before we bought them.:3d_frown:
Damn, and according to BC it's ok/no problem?
blocked with what?, i can't see it in the pic
BLACKCAT said:
blocked with what?, i can't see it in the pic
Yup. Same oil groove. I compared it to a set of stock cams I have as well, and its a bit wider(maybe 2mm?), and the hole looks bigger as well. The blockage in the first hole is actually the bottom of the bolt hole for the cam gear. I looked in it(oil hole in the journal) with a flashlight. I blew compressed air through there, and got nice flow through the rest of the journals, so it might not be a big problem. I compared the oil groove to the cap as well. If you look carefully at a set of stock cams, the hole for that oil groove is chamfered all the way to the top of the first journal. The oil groove on the BC cam(which is chamfered as well) is(very close to) the same size as that chamfered hole. I think Crower was trying to improve oil flow through there, maybe? Might allow you to drill out the oil passage in the head a tiny bit to increase flow to the camshaft? Is the first journal where the cam receives oil from the pump? I think the main problem with this would be if the journal doesn't sit perfectly centered on the head and cap. I think as long as it's centered well, it shouldn't have any problems. Does anyone have a chart or blueprint of the head that would show direction of oil flow, and if maybe that oil passage could be opened up a little? I'm pretty sure that oil comes through that first journal, then on through the cam, but would like to be positive. I also noticed that none of the holes in the journals were chamfered, and seem to be pretty sharp. Before I install them, I'm gonna change that. I really don't like sharp edges there.
No problem. It'll be a while yet, I'm in need of a few more things(I changed my plans in the middle of the build. Hate it when I do that), and am gonna have to put it on hold until after Christmas, unfortunately.
For some reason kids(nephews) think they HAVE to get presents. It is very tempting to be selfish this year....
For some reason kids(nephews) think they HAVE to get presents. It is very tempting to be selfish this year....
BLACKCAT said:
How close are you to getting your cams in??
I have tried two settings over the weekend.
It is suprising how much smoother the engine revs out now. I was convinced before that the 7M engine didn't like high rpm, but now it revs strongly and smoothly with these cams. The kickdown is really nice when you just give it a blast when your cruising along.
ATM both my cams are set at +3 advance and as stated above with slightly increased valve lash over what the BC timing card recommends.
I think I will just drive around and enjoy it for a while.
I was also thinking that maybe you could trick the ECU into thinking the Air Con was on all the time and this would automatically set the idle speed higher. Might be the easiest way to get a silky smooth idle. Might also allow me to run a little more overlap and get even better top end.
http://cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=AC&P=6
Just for test purposes, I think you could unplug the clutch switch on the compressor, and jumper that and the dual pressure switch? Not really sure, I would have to test it to see if it would work. Looks like it works off of ground, so might be able to ground the "to EFI" wire to accomplish the same thing? Maybe one of our electrical experts can chime in with an easy way to temporarily accomplish this...
Just for test purposes, I think you could unplug the clutch switch on the compressor, and jumper that and the dual pressure switch? Not really sure, I would have to test it to see if it would work. Looks like it works off of ground, so might be able to ground the "to EFI" wire to accomplish the same thing? Maybe one of our electrical experts can chime in with an easy way to temporarily accomplish this...
BLACKCAT said:
My TODA 264s just dialed in at 114 lobe centers when set 0-0.
This is more of a forced induction lobe seperation.
I am going to dial in less seperation to start off.
Looking at about 2deg retard on the exhaust,
and 2deg advance on the intake.
This will give me 110deg on lobe centers.
After the engine is broke in (not blown up), I will play with it more.
By the way, a Toda 264 when checked at .010" lift, came out to 260deg.
Any less than 114 LSA and it won't idle, atleast with the air con off. Air con on and maybe 112 is acceptable.
At my current setting of +3 advance on both cams I get good performance throughout the rev range. Interesting thing is no sign of any pinging even with 15 deg static ignition advance. I think with these cams you could use a higher compression ratio than standard. Anybody building up a motor with these cams might want to keep this in mind.
At my current setting of +3 advance on both cams I get good performance throughout the rev range. Interesting thing is no sign of any pinging even with 15 deg static ignition advance. I think with these cams you could use a higher compression ratio than standard. Anybody building up a motor with these cams might want to keep this in mind.
amichie said:
I used to run 10-15 additioanl advance when the engine was stock.
I may not be able to do that now, because I have a set of 10.5:1 Wiseco pistons now.
But I think your right about the 114 lobe centers.
After thinking about it, I went and put them back.
Did you ever set a degree wheel on your crank, or are you going strait off the cam gear marks?
7M-fanatic said:
I did put the degree wheel on but I couldn't really see it very well without removing the radiator. In the end I checked the exhaust valve closing and inlet valve opening events at the 50 thou lobe lift points and they agreed exactly with the timing card and the straight up zero marks on the cam wheels. At this point I was satisfied that the cams were correctly degreed and I just decided to start tweaking from there.
As I said earlier they are now both advanced by +3 degrees. As far as ignition timing is concerned I have tried 12,15, and 18 deg static advance and it seems to go best at 12 deg. Strange though no pinging at any of these settings.
