Search found 529 matches

by ndevans
Mon May 20, 2019 10:33 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Thanks Phil.

I'll probably go for the other clamp you posted, I think the one I have is an imitation of that. There's nothing worse than having a job to do and not having the right tool to hand! Quality tools are just as worthwhile as quality parts!

Cheers N
by ndevans
Mon May 20, 2019 9:40 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Who knows when I'll need it?
I may not buy one right away, but I will when I need it next.
by ndevans
Mon May 20, 2019 8:57 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Success! I was going to try a jubilee clip around the clamp, but haven't got one large enough, so I thought I'd try a G-clamp. Before I did that, I tried one more time by hand, this time squeezing the clamp as well as holding it down. After a bit of persuasion, I got the piston in! I think the clamp...
by ndevans
Mon May 20, 2019 11:26 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

It's a +0.04" rebore, from standard. Regarding the clamp, can't remember where I got it from, probably the local car parts shop, so it could well be a far east knock off. It did seem to work ok when new, on standard pistons, but maybe a bit of use has left the clamp a bit more pliable than when new?...
by ndevans
Sun May 19, 2019 10:54 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

The bore/piston next to that one looks ovalled, or is a figment of the camera? Is it possible the pistons aren't round, giving clearance issues? Do you have old, suitably sized pistons to attempt refitting ? No, it's a trick of the light, and the skewed perspective of the relatively wide angle lens...
by ndevans
Sun May 19, 2019 10:51 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

That clamp certainly does not look to be concentric around the piston/rings. You say that you had no problems when using the clamp previously so there is certainly something strange going on now.! Which is why I was wondering whether the clamp could become distorted sitting unwound on the shelf! I'...
by ndevans
Sun May 19, 2019 10:07 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Groove measured with a Vernier caliper at 3.82mm, piston ring at 3.2mm. Oil ring not measured, but visibly narrower than the ring depth. This is what the piston and clamp looks like from above, before tapping it in. Clamp not fully done up, but it'll only go about 1 more click, maybe 2. IMG_20190519...
by ndevans
Sun May 19, 2019 7:23 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Have you checked the ring groove depth cf the ring measurement? Doubtless there will be a specification for that, too. I doubt it is wrong, but one never knows, particularly if the components have been sourced from foreign parts... Like Phil, I have never had trouble with refitting pistons in bores...
by ndevans
Sun May 19, 2019 10:04 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Just a thought-what about the orientation of the oil ring gap wrt the clamp? Is that a consideration?
by ndevans
Sun May 19, 2019 10:00 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Thanks for your help Phil! I'll just keep trying, maybe a gentle approach will help!
If I don't have any joy I might try one of those motorcycle clamps, looks like it'll do the job. I did think about trying a jubilee clip, but I haven't got one large enough.
Cheers N
by ndevans
Sun May 19, 2019 8:52 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

I did wonder whether I was using it the right way up, but I've tried both ways to no effect. I'm using it with the ratchet at the lower end. I'll try tightening it up then backing off a notch. I didn't have this problem when I put the pistons back on last time-but they were standard pistons, althoug...
by ndevans
Sun May 19, 2019 12:41 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

No, it's pretty even all the way round. I'm making sure the compressor is flat against the block before holding it down, then tapping the piston home. It's like the compressor just can't hold the oil ring firmly enough. I've tried it in all 4cyls, so I don't think it's a problem with the block not b...
by ndevans
Sat May 18, 2019 11:45 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Well there was only one bottle I could crack open after today's struggles!
IMG_20190518_233931~2.jpg
IMG_20190518_233931~2.jpg (1.43 MiB) Viewed 146 times
by ndevans
Sat May 18, 2019 11:17 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Well, I followed Philthehill's advice, and somehow managed to get 2,3&4 in, but it took 2½ hours and umptynine attempts. Given up for now, beer needs to be drunk. Urgently. The problem seems to be that the compressor does not properly grip the oil ring. As soon as the piston slides down far enough f...
by ndevans
Sat May 18, 2019 4:50 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

All piston rings checked and gapped to 0.012" for the top, 0.008" for 2nd. All oil rings checked, not in need of adjustment as all at around 0.035". Still can't get the pistons in, it fouls on the oil ring every time. The compressor is done up as tight as I can get it, the rings, compressor and bore...
by ndevans
Fri May 17, 2019 10:42 pm
Forum: Off-Topic
Topic: Currently drinking.....
Replies: 37
Views: 1004

Re: Currently drinking.....

Tonight's lubrication:-
IMG_20190517_223633~2.jpg
IMG_20190517_223633~2.jpg (1.4 MiB) Viewed 20 times
From Box Steam Brewery, picked up last Sunday, after running the Two Tunnels Hilly Half Marathon. Doesn't really taste minty, but does have a slight mint aroma.
by ndevans
Fri May 17, 2019 9:37 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Ok, just checked ring gap in no. 1cyl. Both compression rings were undersize at 0.004-0.005". For a Marina 1275, allowing 0.003" per in cyl bore, that should be 0.008". Both now filed to 0.008". However, I then re-read the ring instructions, and it says "top moly ring must not be filed", see below p...
by ndevans
Fri May 17, 2019 9:14 am
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Have you checked the piston ring gaps? When fitted there must be a gap between the ends of the piston ring to allow for expansion. Details of ring gaps are in BMC wksp manual. No, I haven't. Do I need to check the oil ring gap as well? Here is a pic of my ring compressor-same as yours:- IMG_2019051...
by ndevans
Thu May 16, 2019 11:09 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Having a problem getting the pistons in. The piston ring compressor doesn't seem to compress the oil control ring enough, the piston gets stuck every time. I don't recall having this problem last time.
Is there a trick to it?

Cheers N
by ndevans
Wed May 15, 2019 11:39 pm
Forum: Mechanical
Topic: Engine in bits for a rebore-anything else worth doing?
Replies: 73
Views: 1591

Re: Engine in bits for a rebore-anything else worth doing?

Thanks gents. Crankshaft now back in, & turning freely, though not torqued down yet. 2 further questions if you don't mind! 1-How much endfloat should the crankshaft have? It's a 1275 engine, ex-Marina, not A+. Is the endfloat set by the centre thrust washers, or the thin washers in front of the fro...