Hot Rod Forum banner

21 - 25 of 25 Posts

·
More for Less Racer
Joined
·
19,283 Posts
If the replacement piston was the same weight, or close, there would be no real need to re-balance the rotating assembly unless you asked for a race type balance job where they weigh and match everything to a finer tolerance than the factory balance.
Generally, a stock replacement style piston like you've got will be close to original weight.
 

·
Registered
Joined
·
64 Posts
Discussion Starter #22
Just an update here while I still linger in machine shop hell 4 months later. In hindsight it appears I was caught up in some kind internal machine shop dysfunction. They let a couple employees go due some pretty big %^&$ups and theft of parts. It is a real **** show. So I listened to Ericnova72's advice and basically told them to "keep the heads and suck it " So all told I'm out $1000 and some 243 head cores.

Thinking I escaped relatively unscathed I went ahead and assembled the engine. After spending a few days trying to figure out why the engine wouldn't start I bought a oscilloscope and found the cam and crank signals were out of sync. Out came the engine and yep sure enough the crank reluctor was installed 180 out. I had pictures of the parts before dropping them off and the reluctor was good. Turns out one of the former, currently unemployed employees removed the reluctor and installed it wrong.

Too many long cranks washed out the bearings so I hauled all the parts back to them. They agreed to fix the reluctor and replace all the bearings wash parts at no cost. They informed they cleaned house and the problem child is gone. Apparently he installed another reluctor wheel incorrectly on a high $$ race engine build as well.

So finally get the parts back. Initially everything looks good get the parts back home and on closer inspection of the cam bearings I see the #2 cam bearing is covering half the oil galley hole. Obliviously not cool and the block will be going back as I do not have a cam bearing tool.

Just out of curiosity how long would the cam bearing live if ran like this?
523904
 

·
More for Less Racer
Joined
·
19,283 Posts
That cam bearing is not off alignment enough to cause a problem....while it looks bad to the naked eye, you have to realize with the cam in the bearing the actual oil feed opening is the diameter of the hole BUT only about .002" thick, the oil clearance between the cam journal and the bearing.
You could block nearly 80% of the opening and not have a problem , it's not like it has to feed a steady stream the size of that hole to some other component.

There are some engines that the race modification is to thread the feed hole in the block and install restrictors with just an .030" to .040" hole in them on the feed to the cam bearings.
 

·
Registered
Joined
·
64 Posts
Discussion Starter #24
That cam bearing is not off alignment enough to cause a problem....while it looks bad to the naked eye, you have to realize with the cam in the bearing the actual oil feed opening is the diameter of the hole BUT only about .002" thick, the oil clearance between the cam journal and the bearing.
You could block nearly 80% of the opening and not have a problem , it's not like it has to feed a steady stream the size of that hole to some other component.

There are some engines that the race modification is to thread the feed hole in the block and install restrictors with just an .030" to .040" hole in them on the feed to the cam bearings.
Thanks man just paranoid after the cluster fu%k this engine build has been. It freaked me out when I saw half the oil feed hole covered but reading up on it the past couple hours counter intuitive as it seems some partial coverage is acceptable. I was just looking for a hard spec to go off. I'm just going to run it.
 

·
True Hotrodder
Joined
·
1,156 Posts
As mentioned you can run it like that without issue. Or you could open the cam bearing up a bit but then you have to deal with the debris cleanup.
 
21 - 25 of 25 Posts
Top