Cam problem

1971 HOLDEN HQ
6 CYL • 2WD • MANUAL
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LORIPHILLIP7
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1971 Holden HQ 71 cam problem
sir; i have have a 71 hq holden that we have put a vk holden carby engine that has been going well, now my trouble is, after an engine freshen up and cam change [crow cam part no.35626,mechanical/solid type profile] the thing won't start. it turns over ok, tapet adjustments ok, fuel ok,carbys ok cam and crank timeing marks set right [dot to dot] but i feel its somthing to do with the ignition timeing. i've been setting no/1 cylinder on t.d.s and dropping in the dissy also set at no/1 spark plug yet it's a no go; i believe it is to do with the way im maybe setting the crank timeing marks wrong nothing else has changed, and nothing is hitting or binding.[more cam detiles; inlet opens....32 b.t.d.c closes....66 dur...278. exhaust opens....72 b.b.d.c b.b.d.s closes....30 dur....282. inlet lobe lift at t.d.c on overlap .085; what am i doing wrong please...hal

May 18, 2011 at 9:24 AM
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KHLOW2008
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Have you checked the compression pressure?

Did you check the static ignition timing and ensure it is correct?
May 18, 2011 at 1:13 PM
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LORIPHILLIP7
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Hi, Static Timing ok, compression all over the place, timing marks on cam and crank were correctly set (dot - dot) with #1 cylinder on TDC.
#6 exhaust valve is not not open, it is exactly 180 deg out, when I get my exhaust valve to open #1 cylinder is now on BDC
Looks like I have to disregard cam timing mark and work as follows: set #1 piston on TDC and install cam in such a way as #1 valves are shut and #6 valve is fully open...never struck this before!
What do you think?
May 24, 2011 at 4:18 AM
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KHLOW2008
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Yes, you should revert back to the basics.

Use the valve overlapping technique. With # 1 piston at TDC, get # 6 cylinder exhaust vale to almost fully closed with intake valve just starting to open.


May 24, 2011 at 11:37 AM
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LORIPHILLIP7
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Update: I found that the timing mark on the cam gear was 180 deg out, once that was done I set the timing visually, getting NO.6 Cylindor on the rock, engine is fine, never struck that before. Thank you all for your help, you do a great job there.
Cheers
Aug 17, 2011 at 4:43 AM
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KHLOW2008
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Glad to know you have fixed the problem.

Have a nice day.
Aug 17, 2011 at 12:51 PM