I'm in the process of reassembling a block and measuring my bearing and rod clearances. So my very first attempt in doing this 1 of my main bearing clearances and 2 of my rod bearing clearances were out of spec. The project was on hold for about 1-2 months. So once I got new bearings and attempt to measure it the 2nd time around (this time with a different brand of plastiguage), I have 3 main bearing clearances that are our of spec now.

My main question to people that have use plastiguage in the past, could different brands have such a difference in results? What plastiguage brand is most reliable or consistent? The results on this threw me off entirely because I do not know what to trust at this point and have seriously considered micrometers for peace of mind.

This motor will have very little mileage for its life since it's going on a project car that won't be driven much. Regardless, I would like to do things the right way. So for all the plastiguage and micrometer gurus, please share your feedbacks.

 

Also to clarify things. On my second attempt of measuring my main bearings with plastiguage, I've only replace one new bearing in hopes fixing the one bearing that was out of spec the first time. I also had a second pair of eyes from a friend that has plastiguage several motors before. We were really surprise with the different results the 2nd time around.

 

i have always used the auto parts store plasti. ; the green one.
but using plasti is the last '' double check'' ; to be sure you should measure parts, a 0.0001 0-1 micro and a bore gauge at least

 

May I ask what kind of bearings your using??

Are you measuring 4 angles per journal or just taking 1 measurement?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">i have always used the auto parts store plasti. ; the green one.
but using plasti is the last '' double check'' ; to be sure you should measure parts, a 0.0001 0-1 micro and a bore gauge at least</TD></TR></TABLE>

Mmuller, the results of this has got me to really think about going with micrometer measurements instead. The plastiguage I pick up at the auto parts store brand was "PowerBuilder" and I forgot the name of the 2nd brand. The results were so drastic between the two that I'm baffle. Nothing has change except for re-measuring after 2 months and the addition of a new bearing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX T-Si &raquo;</TD></TR><TR><TD CLASS="quote">May I ask what kind of bearings your using??

Are you measuring 4 angles per journal or just taking 1 measurement?</TD></TR></TABLE>

CRX, yes I'm using stock honda bearings. I'm just taking 1 measurement, I wasn't aware of the 4 angles per journal process.

 

bump feedbacks anyone?

 

Sorry, being busy searching for stuff.

I measure the journals in 4 angles to ensure roundness. This is step which I like to take to give myself a piece of mind. People make mistakes but if I checked it and it breaks then it does not feel that bad cause you did it.

Just heard too many stories where machine shops mess this up and mess that up so why not take precautions. There is a better reason why but I just can't remember it.

I normally use the plastiguage from autozone or discount auto. The people there does not know what it is unless there is an actual car guy/gal there.

 

Measuring the crank should be done in several places.Bearing clearance should only be measured 90* from the parting line.This is the tightest point and the standard they use for listing clearances.Bearings are not the same thickness all the way around.The bearings are thinner the closer you get to the parting line.Different bearings can have a different profile.Plastigage is not consistent enough to be measuring the difference of a couple tenths.Good mics and a bore guage are the only way to measure accurately.Plastigage will get you in the ballpark.