Best springs for crane 1.8RRs
This is a discussion on Best springs for crane 1.8RRs within the Internal Engine forums, part of the LSx Technical Help Section category; For the crane 1.8RRs, whats the better spring? 918s 921s crane gold duals other? Im running 212-220 0.590-0.600 lift (at ...
02-18-2006, 05:07 AM #1
Best springs for crane 1.8RRs
For the crane 1.8RRs, whats the better spring?
crane gold duals
Im running 212-220 0.590-0.600 lift (at the valve) and dropping in excess of 30rwhp everywhere after the first dyno run.
My setup is:
comp 212-220 0.558-0.568
comp R lifters (the 75 series, not OEM replacement)
crane 7.250 pushrods
stock stem seals
Would it be worth going to hollow stem valves?
02-18-2006, 07:31 AM #2
Comp is recommending the 918's even with their biggest XE-R cam, at .605/.609 lift. I know you would be accelerating the valves faster with the 1.8 rockers, but not som much that you would have fatigued the springs in one dyno pull.
You said you've lost 30 hp across the board from one pull. Did anything unusual happen? Have you put a vacuum gauge on it to see if you have a valve sticking or anything? Wouldn't think that hollow stems would net you much at this level either.
What heads/how large are your valves? Stock?Hammer - hammertime.us
2001 Light Pewter Metallic Camaro SS, 6 speed
K&N, SLP Lid, SLP y-pipe, GMMG cat-back, Lou's Short Stick - more to come!
02-18-2006, 04:22 PM #3
Thanks for your time Hammer.
I use stock valves. Head have been shaved 20" raising compression from 10.1 to 10.4. Only other mod to the heads is a 5-axis valve seat job.
Ill check compression and fuel pressure this week. Will be upgrading the fuel pump to a Walbro intank unit shortly, as injectors are 85% at 6000RPM, 90% 6500RPM and shot at 7000RPM. Could be falling fuel pressure - but i would have thought that would be consistent for ALL dyno runs.
There was no difference to the tune between pulls. Same AFR, same spark.
Good to know te 918s are recommended even for their XE-R cams, as I reckon I have similar ramp rates, but on smaller lobes.
I will change springs as a last resort.
Is changing the rod bolts safe to do while engine is in car? It wont change the geometry at all?
02-19-2006, 04:46 AM #4
many people have had issues with the comp R lifters. what amount of preload do you have on them? regardless of the crane procedures for setting preload, the comp R lifters have to be set at .004"-.006". if you set them up using the crane preload procedures of 2 full turns, which nets about .100" preload, you may have just damaged the lifters themselves.
02-20-2006, 01:56 AM #5
Thats what Im thinking. I'll check the preload tomorrow and reset them. 0.006" sounds good. Thanks for the feedback. Ill update this thread with my results.
02-21-2006, 03:33 AM #6
Well I queried the setup used for the rockers. On base circle, no more than 1/2 to 3/4 a turn. I'll get them checked soon anyway - set them to 0.004" as per comp instructions - just worried about the chatter on startup - but we shall see.
As for the drop in power, its back. Changed the fuel pump for a Walbro unit (old one has plastic bits in the swirl pot ) and svo30 injectors. I'll never run out of fuel now NA. Was 95% at 6500 now 70%.
On another note my exhaust has reached its limits. The pipes glow red hot (almost white) past the cats. Too much restriction there - so my next mod is a bigger pipes. I currently run 1/5/8 shorties but am thinking 1/3/4 or 1/7/8 LTs. Hopefully, should gain me an additional 10rwhp+.
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