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| race engine https://slantsix.org/forum/viewtopic.php?t=23763 |
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| Author: | terrylittlejohn [ Mon Jun 25, 2007 6:48 pm ] |
| Post subject: | race engine |
think i have a spun cam bearing, racing this weekend bent 5 pushrod , i replaced them same result, rockers were sticking to shaft then bending pushrods. the only thing i see damaged are the vavle tip are scuffed,they will have to be filed before i can remove them to see if guides are hurt, only have the top end apart now, has anyone had this happen before its the first fo me. 
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| Author: | Ron Parker [ Mon Jun 25, 2007 7:02 pm ] |
| Post subject: | |
Wow that is a oil issue. I have never seen rocker arms seize on the shaft and bend push rods. I think you have a deeper problem than the damage you say. I have never seen a cam bearing spun but im not an engine builder. I have broke some push rods before but it was not from rocker arm seize up. Thanks Ron Parker  Jaggers Fabrication Slanted Attitude Dart |
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| Author: | slantzilla [ Mon Jun 25, 2007 8:12 pm ] |
| Post subject: | |
I have heard of spun cam bearings, but never on a Slant. You didn't have the head off recently and plug up the oil hole through the head gasket, did you? 
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| Author: | Dart270 [ Mon Jun 25, 2007 8:15 pm ] |
| Post subject: | |
I spun a cam bearing when I put a new tight cam in. Didn't see oil to the rockers so I shut it down. Had to drill a hole in the rear brg and it was fine after that. Also honed the rear brg with crocus cloth to loosen up the fit with that cam. Sorry to hear about the mess and hope it works out OK. Lou |
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| Author: | terrylittlejohn [ Tue Jun 26, 2007 3:29 pm ] |
| Post subject: | race engine |
going to pull the bottom end tonight, the engine has 55lbs oil pressure at idle not in gear,this engine has been together for last two years, trying to find the right tuneup with the 4-71 blower, i have had the head off to replace burnt gaskets several times but the trouble seems to be at the cam bearing, i will know for sure we i pull the cam. |
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| Author: | slantzilla [ Tue Jun 26, 2007 4:17 pm ] |
| Post subject: | |
Hope it's not hurt too bad for you Terry.
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| Author: | terrylittlejohn [ Tue Jun 26, 2007 7:13 pm ] |
| Post subject: | race engine |
thanks for the prayers, just pull the cam and lifters everything look good, the rear cam bearing moved just enough to block the oil passage. in all the years i have been racing this is a first, do you think the faster rise in rpms might have just found a weak bearing? with the 4-71 the rpms come up real quick. i am getting close to the right tuneup, the belt problem is fixed the head gasket didnt blow and all the plugs are not melting,the 60ft times are in the low 1.50et and 1/8mile are in the 7.40et only ran 12.06et in 1/4mile because i have to lift with all these little problem i have to work out but she getting close now. look like the rockers and shaft got the worst so far ,i will take the crank out tomorrow. 
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| Author: | Charrlie_S [ Tue Jun 26, 2007 7:21 pm ] |
| Post subject: | Re: race engine |
Quote: . look like the rockers and shaft got the worst so far ,
If you need them, KIWIJOHN on e-bay has NOS rockers, and new shafts are still available from Federal Mogoul
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| Author: | terrylittlejohn [ Tue Jun 26, 2007 7:32 pm ] |
| Post subject: | rockers |
charlie does federal mogoul sell rocker and shafts to customers so i can order from them my self? |
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| Author: | Charrlie_S [ Tue Jun 26, 2007 8:21 pm ] |
| Post subject: | |
I checked my local Car Quest ware house, about 2 months ago. They show the shaft as being available, someware arount $30-$35, but no rockers. Rockers here: http://tinyurl.com/3dozsk |
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| Author: | Doctor Dodge [ Wed Jun 27, 2007 6:34 am ] |
| Post subject: | |
Years ago I had a SL6 with a slightly oversize rear cam bearing bore and it would spin the rear cam bearing and block the oil feed to the top. I ended-up "dowel pinning" the rear bearing so it could not spin. I used a hollow roll pin with one end ground flat and square, then pressed the pin all the way into the oil feed passageway going to the head. Once the cam bearing was in position, I carefully tapped the hollow pin out of the passageway enough to stick thru the upper oil feed hole in the cam bearing. You can use a junk cam as a 'stop' if needed but be careful to not nick and then turn the dummy shaft, that can gouge the bearing surface when you pull it out. DD |
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| Author: | terrylittlejohn [ Wed Jun 27, 2007 8:48 am ] |
| Post subject: | race engine |
thanks, she all apart now,  bearings are good, the tips of the vavles needed to be filed to get them out but the seem fine ,guides look good to, just to make sure i am heading to machine shop to have cam bearing installed and the head checked. only problem is parts are slow get here unless you own a jet ha.let you know how it turn out.
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| Author: | terrylittlejohn [ Sat Jul 07, 2007 9:23 am ] |
| Post subject: | race engine |
doug you sad you had a engine that had spun a cam bearing, did you notice any marks on the back of the bearing that looked like it had spun, the reason i ask is when i dissmantled the engine i tried to fish a wire down the oil passage to the cam and couldnt find the oiling hole and when i pulled the cam the oil hole to the main bearing was solid not with debrie it seemed to be the block surface.when the new bearings were installed i can fish a wire both ways but the machine shop said the bearing showed no signs of spinning, what yours or anybody elses ideas. 
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| Author: | Doctor Dodge [ Sat Jul 07, 2007 9:55 am ] |
| Post subject: | |
If the bearing spins, you will see marks on the bearing bore and on the back of the beaing shell. It could be that the rear cam bearing was not installed correctly, I have seen (and corrected) that problem a few times. DD |
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