new bearings enquirey

[Murff93GTiR]

im doing a full engine build and ive kitted the bottom end out with a full set of acl race series bearings and i noticed on the conrods which are brand new std ones that there is the slightest bit of play in them is this just yo allow for oil to go between the bearing and crank for lubrication?

 

[gtirx2]

Plastigauge the bearings to find what clearences you have.

http://www.plastigauge.co.uk/

 

[Murff93GTiR]

Everything is brand new and thebcrank was all measured and micropolished the play is very minimal not even a mil i would say

 

[gtirx2]

I would still plastigauge all the big ends and mains just for peace of mind.

Its very cheap and easy to do and then you know for sure.

I dont think you should be able to feel any play in the actual rod bearings,maybe you mean the the con rod side clearence which you will feel play on,this needs to be measure with feeler gauges i think.


You need to get a manual and follow it to a T,you need to measure every clearence even if all the stuff you are using is new.

 

[jambo_gtir]

Everything is brand new and thebcrank was all measured and micropolished the play is very minimal not even a mil i would say

Even half a mm is too much mate, you shouldn't feel any play at all. The only play you should get is the little end where it can move side to side a little bit.... Go on ebay and get some plastigauge like he said ^ 8)

 

[jambo_gtir]

.....assuming you mean up and down play, rather than side to side?

 

[Murff93GTiR]

the play is only on the rod caps the crank has no play.like i said crank was check micropolished and confirmed at std size with std race series acle bearings fitted.the play may have been side to side as i cant quite remember how i moved them but it was ever so slight and i assumed this was to allow oil between the facings for lubrication as this is what i have experienced with other cars and it seems normal?

 

[mikeyp]

c;earamce is 0.030mm to 0.055mm on the standard size big end bearings. get some plastigauge and make sure that they are within that clearance. that's 3% to 5.5% of a mm of clearance, basicly very little.

get it measured or all your hard work could be for nothing mate. i'm just doing this to my engine today.

 

[Murff93GTiR]

Thanks mate ill do that.appreciate the help

 

[vss irvine]

make sure your rods arent ovaled

 

[mikeyp]

the actual rods, as in the seat for the bearing?

 

[MarkTurbo]

I rebuilt my bottom end recently after a big end failure. I caught it very early so got away with just a polish on the crank, std size acl bearings, all clearances were in tolerance and there was slight side to side movement on my rods as you've described after torquing up. Best get it checked to make sure though ;-)

I've done 2 hillclimbs and a sprint since with no problems.

 

[Murff93GTiR]

Rods are brand spankin new and have 0 miles on them.the bottom on was only just starting to go and wasnt making a knock but got the crank meaaured and checked by a precision engineer and it was reported to be in very good order so it was then micropolished.got the oil pump stripped and checked and it was reported in gwo also so just got it cleaned up and a slight recon and replaced the seal.