Spare bolt identification

[Tea]

Evening all,

Would anyone be able to identify where this bolt is from? There are two of them lingering on the work bench and they definitely came from a Morris Minor at some point, but where in the Morris I’m not sure. The con rod is a possible contender.

[Tea]

The head of the bolt is a little blurry, but says NEWTON 17T in case that helps.

[philthehill]

Shouldered fitted bolts are fitted to the con-rod caps and main bearing caps on the 'A' Series.

Are you absolutely sure that the two bolts came from a Morris as I do not recognise the thread.

[Tea]

Almost certain. We had just finished putting everything back on to the restored car and found these two left over Although I can’t imagine that we missed anything, the only things put on the bench were from this saloon and a pick up that’s been put on hold. I’ve gone through suppliers websites to see if I can find a match but with no luck.

[philthehill]

What engines are fitted to the saloon and pickup? I can then physically check the con rod bolts and main cap bolts against the small block and large block engines I have.

[King Kenny]

Possibly gearbox to engine?

[philthehill]

All of the gearbox to engine bolts are straight (without top shoulder) 5/16" UNF bolts.

[oliver90owner]

Actual length, diameter and thread form may avoid a lot of guessing.

[RobThomas]

Main bearing cap bolts?

[Tea]

The engines are a 1098cc in the saloon and 803cc in the pick up.

I have a vague recollection of struggling with replacing the engine to gearbox bolts and so will check that when next on the farm - there’s a possibility it was a job that was ‘left for another day’. I’ll also get measurements of the bolt when I’m next (either next Tuesday or the one after) at the farm where we work on the cars.

Thanks for the help so far

[philthehill]

The two bolts as I mentioned above are not the bolts for holding the engine and gearbox together. Those bolts have a straight shank and do not have a fitted shoulder.

Those bolts are either main bearing cap bolts or big end cap bolts as they are the only bolts with a fitted shoulder under the bolt head listed in the BMC spare parts list.

Again the thread looks to be too coarse to be UNF which the main bearing cap and big end cap bolts should be.

When you do measure the bolts please specify the number of threads per inch (TPI). I would suggest that the TPI of the bolt in question is 18 TPI.

The surface condition of the bolts indicates that it has been disassembled from an engine for some considerable time.

Phil

[RobThomas]

Starter is 3/8 UNF x 1 3/4, I think. 7/16 UNF x 2.5 for the main caps.

[Tea]

And here’s where they’re from...

B26FF1E5-E1E8-4488-8070-CD12D50BA826.jpeg (656.73 KiB) Viewed 1339 times

I removed the cover off of one of the spare upturned engines to find that we’d pinched them from here to replace the ones left on the table as the threads had gone. Mystery solved and the main thing is that we didn’t have to pull the engine apart to check. Thanks for the help as always!