Just wondering what peoples thoughts are on the accuracy of plastigage?
Does the bearing tollerance change once the oil is in the system and pressurised, and do you take this into account when taking readings?
Cheers

it's great stuff i use it for bearing clearances in large ship gearbox's and also generators. Clearances should remain ok.
got loads of it all sizes saves so much hassle

Jeff, what do you mean by the clearance changing under pressure? The plastigauge will simply measure the clearance between the shaft and journal you measure. It is what the factory use to measure the clearances so you are as good as can be.
If you get some you will need the finer tolerance set for bikes and makesure it is a full set with the two different types of grease.
It is easy to use but is only as accurate as the user, by this i mean if you move anything on build up or break down it will be translated in to an incorrect clearance, usually a larger clearance than is actually there and you will put over size shells in closing the oil clearance up too tight.

Hi Chris,
Yer sorry not very well explained on my part. As you mention about the shells, once the engine is back together and the oil pressure is up, does this change the available clearence?
The reason i ask is someone in work suggested that the clearence will change once the oil pressure is applied, but i have used platigague a couple of times before and the engines are still going well.
The person in work also suggested that it was a bit of a hamfisted/ammature way of doing things, but when questioned he didn't give me any reasonable alternative way of measuring the tolerances, so i thought i would ask as it made me question if i was missing something.

Thought you were maybe using it for the first time. The guy at work prob means once the crank is running on the oil the clearance changes a there's oil above and below the crankshaft, but the clearance is measured as one large gap using plastigage if you get what i mean so is correct and all manufacturers specify this method of gauging the clearances so its the only way to go.

Variablevalves suck wrote:Thought you were maybe using it for the first time. The guy at work prob means once the crank is running on the oil the clearance changes a there's oil above and below the crankshaft, but the clearance is measured as one large gap using plastigage if you get what i mean so is correct and all manufacturers specify this method of gauging the clearances so its the only way to go.

Cheers for that, i think the guy was just trying to be smart and make out he was some kind of Jeremy Burgess.
And as you say if it's good for Mr Honda it must be good