Inliners International Forums General Discussion Engines 292 Bore & Crank Measurements

Good afternoon ;

I finally got back to my engine build project and have more numbers .

The old 1964 engine has a bad block .

The crank's main bearing measured out to 2.283" using a Japanese electronic device .

Previously I was told the rod journals @ 2.0875" are 0.010" undersize (I think) ? .

I was able to buy a 1977 American made 292 , it has a 3.873" bore .

The bore is perfect with NO ridge whatsoever .

Rod journals are 2.101"

Main journals , # 1 is 2.303" & # 2 is 2.284" , I ran out of daylight and didn't measure any more .

All the bearing shells have what I think are GM #'s on them , I'll post the shell #'s later if that's helpful .

Comments and suggestions please .

TIA , looking for ward to finally getting this engine overhaul done and back in my truck .

The size for standard mains and rods are as follows:

MAINS
STD. 2.2983"/2.2993"
.010 2.2883"/2.2893"
.020 2.2783"/2.2793"
.030 2.2683"/2.2693"

RODS
STD. 2.0992"/2.1000"
.010 2.0892"/2.0900"
.020 2.0792"/2.0800"
.030 2.0692"/2.0700"

Thank you ! .

And the bore is.......??

Oops ~

I just realized I forgot to post the bearing sizes and stamped in GM part numbers , maybe someone here knows how to decode them ? .

The # 1 main bearing mics out to 2.303" the bearing shell had # 1159857 stamped in it

#2 : 2.284 stamped 1159859

#'s 3 , 4 , 5 & 6 were all # 1159857 , I am hoping someone will be able to tell me what the journal sizes are .

The various bearing shells are date coded June or July 1977.

The cam's lobes look very nice (this whole engine is super clean and low mileage) but some moisture apparently got into it whilst in storage so two of the tappets has slight discoloration on their feet , I am thinking maybe a 1964 pre SMOG cam and tappets might be wise here .

This engine is going into my 1960 C/10 short bed light duty Shop Truck , it'll mostly just haul me and my lunch pail around , TH350-C slush box tranny so I want something nice and smooth , not Hot Roding as I'll be using the original 1969 Rochester MV (?) 292 carby .

Cam shaft suggestions ? .

Maybe a C-50 cam ? .

I want dead smooth idle and good off idle in traffic response , I keep the current old clapped out 250 CID in sharp tune and it has plenty of power , the 292 is just to make me smile.

Knowhutimean ? .

TIA , I think I fixed this so I'll get notified of any responses .

With the exception of the #1 main journal, your measurements show that the mains are about .004" below the size for .010" under, indicating extreme wear. The #1 main shows to be oversize by about .004" of what a standard crank should measure, indicating a mic that needs to be calibrated with a checking standard, as it is not possible for it to be oversize that much. Since your bearing shells have no indication of undersize on them, you can only assume they are intended for a standard journal size.

Thank you ! .

I was thinking the same thing , I was wondering if I didn't use the caliper correctly .

Will the GM #'s help ? .

The journals and shells look fine , the whole engine looks nearly new .

No comments on the bore size ? .

The pistons are GM and have nothing stamped in them anywhere .

Sorry, the stock bore size is 3.875". As for the bearings, the part # doesn't tell what undersize they are, this is only stamped seperately on the steel outer shell or ink stamped. Standard bearings aren't machine stamped as to their size, only undersizes have it on the bearings. So having no undersize on the bearings would indicate they are standard bearings. The pistons also don't have markings identifying them as standard bore, only if they are oversized.

THANK YOU ! .

No need to be ' sorry ' ! .

I am greatly appreciative of your help here , hopefully you'll be able to answer my other Q's a bit too .

I'm in the cleaning stage right now and want to get new parts inbound A.S.A.P. .

If I'm reading you correctly , I need to order up Std, bearings rod & main plus six new Std. pistons .

TIA ,

From the measurements you provided on the crank journals, it is in dire need of being reground, it is well under .010" undersize with standard bearings which is a disaster waiting to happen. Do not order any parts until the machine shop tells you what size it will cleanup grind at. The same for the block, the pistons may be standard but the bore could be oversize. Sounds like someone just threw the engine together without checking anything just to sell it.

The front cylinders are notorious for having huge ridges in them and requiring a .030" overbore at the very least even in a low mileage engine. This in itself is suspect of it being bored already beyond standard. You need to load it up and carry it to a shop and get it checked out thoroughly before you proceed.

O.K. ;

I'll do just that then .

My truck is in tiny pieces so I'll have difficulty moving that long crank but I'll manage it .

I have not been able to press the wrist pins out yet so I was going to haul the rods down there anyway as I want them re sized and balanced .

Cast pistons are difficult to remove when they are press fit, and many shops have a disclaimer about breakage when doing this, so just be prepared.

Thanx for the heads up ! .

I wonder why I am not getting notices of replies ? .

THANK YOU for pushing me to have the journals Miked ~ I took the crank to the Machine Shop last night and jotted down the sizes as he checked each one with a good quality micrometer ~ they're all spot on ! YAY ! .

Now I can go shopping with confidence .

He said he thinks the newfangled aluminum bearings are good .

Really ? .

Sure, no problem! Better safe than sorry, now your ready to order parts and have some fun.