Some help needed

Some help needed

Joined: September 24th, 2007, 7:39 am

June 25th, 2012, 10:46 pm #1

My 351C suffers under the hood of my Mach1. I havent been able to drive it much except short tests around the block. It overheats and lacks power. I also having a ticking sound of either valve, lifter or detonation. I cant say which.

I got a Robert Shaw thermostat and restrictor is in block, headgaskets are checked and double-checked during assembly. New 24" radiator w pulling flexfan, and pushing 16" flex-a-lite electric cant keep it cool. I thought heating problems would go away when i got the new radiator and pushing fan. But not.

I then started thinking about detonation as a possibility, since it makes some kind of ticking noise under the valvecovers. Im running a XE274H on a 10.8:1 4V CC. Cranking pressure is 210 PSI, running on 98 European gas. Block is zero-decked, flattop kb177s, chambers measured in at 62.3 cc. Too much pressure?

I took timing down from 18 initial and are now at around 14-16 but same story and it idles worse. Next move was to loosen preload on the lifters but i got here before reading threads about high compression/detonation and wrote this thread.

What do you guys think. My setup a recipe for detonation and i need another cam or any other suggestions?
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Joined: June 12th, 2009, 1:31 pm

June 25th, 2012, 10:56 pm #2

i this a new build?
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Joined: February 13th, 2006, 4:59 am

June 25th, 2012, 11:20 pm #3

If that's the correct cranking compression you are definately detonating on pump gas. It should be closer to the 160 at most for safe running. I would recheck your comp. and see for sure. Then try some c12 race gas and see if it clears up. With zero decked 177's you will be in the 11's for comp.
Last edited by steve.k on June 26th, 2012, 1:17 am, edited 1 time in total.
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Joined: October 23rd, 2005, 1:22 am

June 26th, 2012, 1:29 am #4

Yes try a higher octane fuel first. 210cranking under light load shouldnt rattle anyway but eliminate one thing at a time.
What about Air Fuel Ratio and running Lean?
Try a different Carb or triple check Fuel supply! Check for air leaks that may lean the Carb out.
I know you said that you doubled checked the Head gaskets , did you take any photo's? Maybe its a faulty Gasket?
Goodluck
Last edited by GT-SCOTT on June 26th, 2012, 1:29 am, edited 1 time in total.
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Joined: September 24th, 2007, 7:39 am

June 26th, 2012, 8:15 am #5

Thanks for your help guys.

Dan: Yes, well engine was assembled during 2010. I had to rebuild the 9" 2011 so i just tried the car a few times on the street with same problems as today. Thought it was due to insufficient cooling so a bought a new rad for this season. I have it under the build section here:

http://www.network54.com/Forum/263038/t ... aiming+400

Pic of the gasket is below, had to use thicker SCE copper gaskets due to pistons out of the hole. Thickness is .042" with the pistons out.

I have checked compression on all cylinders twice after rebuild and last week with same result. ~210 on all.

Carb is a Holley 650 DP on a Torker, 67 primary jets and 76 sec. Nr. 28 boosters. Running a 4.5 powervalve (10" stable vacuum @ 900). Float level is ok. Have Autolite 24 plugs and they look somewhat black/brownish (mostly been idling). They are not pitted or damaged.

The car idles ok on the driveway, but once i start driving the problems appear. I'll try to get a hold on some race gas for test. I would really want it to run on 98 with some booster though, if it takes another cam for that i have no problem swapping.


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Joined: March 12th, 2002, 2:39 pm

June 26th, 2012, 12:29 pm #6

What water pump are you using and belt set up?
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Joined: February 13th, 2006, 4:59 am

June 26th, 2012, 12:47 pm #7

Does the engine seem to run on when shut it off?also what heat range of thermostat? I run nothing but 160 degree stats. I find the 195s get engine to hot in most conditions. We built a 460 one time that had 220 lbs comp. In my opinion 210 is to high for pump gas of any kind.
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Joined: September 24th, 2007, 7:39 am

June 26th, 2012, 1:01 pm #8

I have a 180 degree thermostat (#333-180). Waterpump is belt-driven original which i thought was in nice condition so i re-installed it.

The engine does have tendencies to run-on, and usually makes some puffs before shutting down.
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Joined: February 13th, 2006, 4:59 am

June 26th, 2012, 2:00 pm #9

Yes if they tend to want to run on fuel is to low octane. You may be a touch lean which adds to trouble. Try some good fuel and see if it helps. I like the Cooler stats as it gives the engine lots of room to get hot.
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Joined: December 13th, 2005, 6:39 am

June 26th, 2012, 3:03 pm #10

What is your inital timing set at? What is your total advance set at? Are you running vaccume advance on your distributor? I had to eliminate the vaccume advance on mine cause it would run like crap with it! Have you checked the springs in your distributor? Anything out of place in the ignition system will give you nightmares. P.S. my initial timing is at 18 degrees and I beleive is 38 degrees total. I run a duraspark distributor with lighter springs a MSD 6-AL with MSD blaster2 coil. I had similar problems as u did until i fixed ignition issues. If u want more engine specs of my build its in the Engine Build section under MY 362C NOW WITH VIDEOS.
Last edited by nova467spanker on June 26th, 2012, 3:06 pm, edited 1 time in total.
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