Cam timing? - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

laisu · 23rd July 2008, 07:16 PM

Hello, i fitted RB26dett stock cams to my rb25det engine, i now have a problem with compressions.(5.5-5.8bar in all cylinders) I also used rb26 cam gears. Would it be possible that the cam timing is wrong, the markings match.

hytech · 23rd July 2008, 07:52 PM

So you are using solid lift camshafts in a hydraulic lifter head, are you still using the hydraulic lifters as well? In my experience you can't swap camshafts.

laisu · 23rd July 2008, 09:35 PM

Yes, i am using stock rb25 hyd. lifters.

Why cant you swap camshafts?

laisu · 25th July 2008, 07:20 PM

i looked up, that rb26 and 26 cams have different timing, even different years of rb25 and 26 have different timing.

First, to prove my theory i lifted the intake cam 1 tooth later and exhaust cam 1 tooth earlier. It worked, compressions raised from 5.5 to 9.5-10bar. Then i fitted adjustable cams to fine tune and now the compressions are 11.5-12.0 all around.

Lookes like you can use rb26 cams in 25 head with hydraulic lifters.

Tomorrow i´m off to dyno and hoping for something around 600hp.

23rd July 2008, 07:16 PM	#1 (permalink)
laisu New Users Join Date: Jun 2008 Posts: 3	Cam timing? Hello, i fitted RB26dett stock cams to my rb25det engine, i now have a problem with compressions.(5.5-5.8bar in all cylinders) I also used rb26 cam gears. Would it be possible that the cam timing is wrong, the markings match.

23rd July 2008, 07:52 PM	#2 (permalink)
hytech GTR Register Member Join Date: Feb 2003 Location: Auckland NZ Posts: 90	So you are using solid lift camshafts in a hydraulic lifter head, are you still using the hydraulic lifters as well? In my experience you can't swap camshafts. __________________ GTR the badge all V8 boys fear!!! Hytech Engines Street R32 GTR - 10.86 @ 130mph (209kph) www.hytechengines.co.nz

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23rd July 2008, 09:35 PM	#3 (permalink)
laisu New Users Join Date: Jun 2008 Posts: 3	Yes, i am using stock rb25 hyd. lifters. Why cant you swap camshafts?

25th July 2008, 07:20 PM	#4 (permalink)
laisu New Users Join Date: Jun 2008 Posts: 3	i looked up, that rb26 and 26 cams have different timing, even different years of rb25 and 26 have different timing. First, to prove my theory i lifted the intake cam 1 tooth later and exhaust cam 1 tooth earlier. It worked, compressions raised from 5.5 to 9.5-10bar. Then i fitted adjustable cams to fine tune and now the compressions are 11.5-12.0 all around. Lookes like you can use rb26 cams in 25 head with hydraulic lifters. Tomorrow i´m off to dyno and hoping for something around 600hp.