78 replies to this topic

[super6al]

Hi all

Great explanation by KTS & imack & a clever bit of engineering, something else learned. I took some photos last night that may be of use to PACINO to explain to his engine builder. Hope these help. The top 2 photos show the bearing correctly installed. The bottom 2 are the bearing installed 'backwards' . The bottom photos show the circumference groove in the cam in constant contact with both oil holes so oil will indeed be continuously fed to the rocker cover. As Lupus said, how much of a problem this is I can't answer. Perhaps the best way forward for PACINO is to request the engine builder be present (or video call) when he starts the engine . Regarding the Oil pump end bearing, I measured a bearing & its pretty much symmetrical so I can't see a problem with it installed either way - unless someone knows different.

Alan

 IMG_7143.jpeg   35.62K   2 downloads  IMG_7144.jpeg   34.76K   0 downloads  IMG_7145.jpeg   37.56K   1 downloads  IMG_7146.jpeg   35.37K   0 downloads 

Edited by super6al, 20 March 2024 - 06:50 PM.

[RooBoonix]

I think your front bearing (timing chain end) is fitted backwards. It's vitality important that the front bearing (timing chain end) is not fitted backwards. Even though the holes in the bearings align with drillings in the block the bearing could be fitted backwards. If fitted backwards, the rockers will be fed with a continuous supply of pressurised oil which will result in the rocker cover filling with oil.
When the bearings are fitted correctly, the rockers will be fed by a pulse of pressurised oil once every camshaft revolution via the groove and slot in the camshaft journal.
The oval hole in the bearing needs to align with the oil feed drilling from the crankshaft. The round hole in the bearing must align with the drilling that goes to the cylinder head and rockers.
Your engine builder 'appears' to have aligned the oval hole in the bearing with the oil feed drilling to the cylinder head which indicates that the bearing is fitted backwards.

Considering the size and convoluted shape of the oilway to the rocker shaft and the comparable size of the return holes to the sump via the pushrod holes and the holes in the tappet section of the block, that seems incredibly unlikely.

It's not unheard of. The feed would be a constant, pressurised, oil feed and the drain back to the sump relies on gravity ultimately. Best to get the bearing orientation correct.

[PACINO]

Hello kids! Thank you very much for your help. Those photos come to mind along with KTS and imack's explanation.
The guy who built the engine is coming tomorrow to the workshop where the engine is. His idea is;
-remove the distribution cover, remove the camshaft, and look at how the bearings are installed. I imagine he trusts that only the first bearing (distribution side) may be misplaced. Because if the one in the center is also bad, I understand that he'll not be able to replace it without opening the block.

This decision seem me a little ridiculous. I think that when in doubt if something is not ok, the right thing to do would be to take the engine and open it to check everything.

*By the way, the company that sells the ACL brand 'front cam bearings' has responded to me saying that: the bearing on the oil pump side DOES NOT have a 'notch' anywhere. So I understand that it does NOT have a specific sense of rotation. You just have to match the hole with the oil hole. Therefore, I think he placed it well. Correct me if I'm wrong.

Luis

[Earwax]

Just a shout out to the engine builder.  It seems to me that he is definitely trying to do the right thing here - coming around to double check that front cam bearing.  Also- in the series of photos he has taken along the way It does look like attention has been made in the build.  To PACINO - swapping out cams without splitting the motor etc is also fine to do ( eg testing a few cams on a dyno for power figures)  Google some videos of it in an A series mini if you are worried.

 

'

[PACINO]

Just a shout out to the engine builder.  It seems to me that he is definitely trying to do the right thing here - coming around to double check that front cam bearing.  Also- in the series of photos he has taken along the way It does look like attention has been made in the build.  To PACINO - swapping out cams without splitting the motor etc is also fine to do ( eg testing a few cams on a dyno for power figures)  Google some videos of it in an A series mini if you are worried.
 
'

Hello Earwax! I appreciate your response, although I don't understand the last part well... all that about doing tests on the power bank and so on. The camshaft is new (Sw5).
What this man has to do is check the engine, and fix what is wrong, such as correctly installing the distribution bearing, which is already certain to be wrong.
What I say that this should be done at his home, calmly, and not in a workshop that doesn't belong to him. I think this is the correct way.

Kind regards
Luis

[imack]

https://www.facebook...CHkT3ak3n5J9jX/

[PACINO]

Cheers imack. Yes, he sent me those photos a couple days ago. Plus this:

"The oil pump end is not the problem Luis. It really doesn't matter which way round that goes. The oil pump end is the REAR of the engine. It isd the FRONT bearing, the one at the camshaft drive end, that is specifically orientated. The biggest of the three bearings on the right of your photograph. THAT is the essential one. The long/oval hole aligns with the oil feed coming from the main bearing journal. The smaller round hole aligns with the oil fed that goes up vertically in the block to the rockers. So with the block sitting on the sump face, the long/oval hole is to the left, the small hole up at the top". K.c

[PACINO]

Hi everyone. After four days in his house, today the guy bring back the engine to the workshop. With the engine there, I tried to turn it, and I fill it so hard than before. He's sent me a photo and a short video. The bearing cam is another one, but I don't know if it was machined.



https://youtube.com/...-KapWbGSNZYp8V9

[Lplus]

Hi everyone. After four days in his house, today the guy bring back the engine to the workshop. With the engine there, I tried to turn it, and I fill it so hard than before. He's sent me a photo and a short video. The bearing cam is another one, but I don't know if it was machined.



https://youtube.com/...-KapWbGSNZYp8V9

It doesn't look as if it needs a lot of force to turn it.  To check the front bearing fit just insert the cam front end in the cam front bearing and see how tight it is.  At least it's the right way round now.

[PACINO]

Cheers Lplus! The engine looks so tigh than before. By hand, turns very hard. The workshop boss'll try to start the engine even if this is the case. Good idea? I don't know.
Luis

[PACINO]

https://youtube.com/...HadFHppnJlaLASk

[Lplus]

https://youtube.com/...HadFHppnJlaLASk

Not sure why you reposted this. It doesn't seem too much effort, perhaps you could put a spring balance on it and see how much torque is needed to turn it?  I wouldn't expect the cam to spin completely freely but others  on here may have a different view.

 

I have in the past lightly scraped a bearing or two to ease a tight camshaft which subsequently ran fine. You can check for the tight spots by looking for the polished areas of the bearing after rotating it for a while and removing a tiny amount of metal using the edge of a very sharp curved blade held perpendicular to the bearing face (never use abrasives as they may contaminate the white metal).  Whether you are prepared to do that is entirely up to you.

[PACINO]

Hello Lplus! I posted this video that the builder sent me so that I could see that after replacing the cam bearing distribution side, the camshaft rotates smothly. That doesn't worry me now. The problem arises when everything is assembled, that turning the engine requires a little bit too much effort.
I think the problem is in the crankshaft bearings. They are not machined correctly or to the right size, and for that reason it's so tight. That's why I'm afraid to turn it on.
Because it's true that the double valve springs exert a lot of pressure, and that the engine right now hasn't oil. But it doesn't spin dry. It still has the assembly grease when a new engine is made.

Kind regards
Luis

[sonscar]

Rule out the valves by slackening the rockers and remove the pushrods?Steve..

[Lplus]

Hello Lplus! I posted this video that the builder sent me so that I could see that after replacing the cam bearing distribution side, the camshaft rotates smothly. That doesn't worry me now. The problem arises when everything is assembled, that turning the engine requires a little bit too much effort.
I think the problem is in the crankshaft bearings. They are not machined correctly or to the right size, and for that reason it's so tight. That's why I'm afraid to turn it on.
Because it's true that the double valve springs exert a lot of pressure, and that the engine right now hasn't oil. But it doesn't spin dry. It still has the assembly grease when a new engine is made.

Kind regards
Luis

i find it hard to believe that an engine builder would fail to notice tight main bearings when assembling an engine, Those are the first to go in and the crank should turn easily without rods attached. I suppose the big ends could be oversize but any significant error would lock the whole lot up completely.   Having built a couple of engines of my own in the last year or so, I recall both needed a spanner to turn them over before inserting into the car.  By far the greatest resistance was the new rings in the newly bored and honed bores.  Both needed two batteries in parallel or the first start but once run for a short time they freed up nicely.