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| Engine still not running right |
| Author |
Message |
    
B-Man
Member
Username: belliswood
Post Number: 16
Registered: 06-2009
| | Posted on Thursday, November 12, 2009 - 08:28 am: | 
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Put in rebuilt engines and the starboard reverse rotation flatlines at 3000 rpm. changed everything on the outside we could (carb, ignition, fuel flow checked, timing,l etc.) and no change. begins loosing power at about 2500 rpm and then flat lines at 3000. mechanic thinks the cam is the culpret. The builder reused the cam and had it reground to manufactures specs but mechanic thinks the cam was not ground right. what do any of you think!!!!!!!!! |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1632
Registered: 11-2002
| | Posted on Thursday, November 12, 2009 - 08:53 am: |
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It's easy enough to check the lift on the cam.
How do you regrind something that's already worn? Don't tell me they welded it, then reground it. Seems like way too much work.
You don't mention the engine but if it's a late model 7.4 I have a new cam and gear for a CW rotation motor. PM me if you're interested.
Are you achieving full timing advance? |
B-Man
Member
Username: belliswood
Post Number: 17
Registered: 06-2009
| | Posted on Thursday, November 12, 2009 - 03:45 pm: |
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Dont know what they did to regrind it, the engines are 4.3L v-6's. |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 7125
Registered: 09-2003
| | Posted on Thursday, November 12, 2009 - 06:07 pm: |
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Time for a NEW cam and lifters, I suspect. I assume they are still available? (Maybe not.)
Jeff |
makomark
Senior Member
Username: makomark
Post Number: 1865
Registered: 09-2008
| | Posted on Thursday, November 12, 2009 - 06:47 pm: |
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Plenty of cams out there - just ask one of the cam houses. may take a couple days for reverse rotation as they usually don't stock them. The flat tappets are the samme as the SBC & BBC.
The timing advance check as recommended earlier is a good one. I'd verify the fuel pressure at 3000 rpm. Compression/leakdown test would be insightful, too.
As far as regrinding the cam, it should be adequate if the original one wasn't in too bad a shape. The ones I've seen result in smaller overall lobe diameters, with the lift being that specified. You can easily check the cam with a dial gauge and a degree wheel. A bit time consuming but not difficult. Removing the valve cover and running the engine will only let you see if the rockers are moving - it won't let you verify the lift or the duration.
It isn't clear from your post but I suspect the engine hasn't been correct since the rebuild. If that's the case, I'd be asking the rebuilder when he's comming down to verify all is correct if you are certain all the externals are correct. |
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