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Rookie with IHC M

Dobbo56

Registered
Hi all
No good didn't anything but a small cough ( it might have that beer thingie). Took the head back off as I think that the compression valve is not opening to allow fuel in, to much tension on the spring so I threaded the stem for a nut to adjust tension. :unsure:
So in for a penny or in for a pound, decided to check out the piston ring, should have left things alone as this little M might become garden art. :cry: So what I have found is that someone has had a go before as the piston has a repair in the head, rings look like they are new, but broke no 4 ring when it came out but Bill's motor parts will have it. Babbit bearings have cracks and splits and both bearing bolts are bent, so any suggestion or confirmation could the crankshaft be bent???? :help: Will post more photos tomorrow
Cheers
Dobbo
 

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asw20

Registered
Is there any chance, if you just put it back together (after replacing the broken ring) and giving it a hone, that you could belt it up to something?
Assuming your exhaust timing is right, maybe it just needs the rings bedded a bit. Another option is a few squirts of oil in the plug hole and a few down the oiler pipe to up the compression. This will also up the vacuum to open the atmospheric inlet. The spring on that is only quite light.
Also is that a bit of corrosion in the bottom of the bore? Shouldn't really be a problem as the piston hardly gets up that far. I wouldn't worry about that repair, or the bearings. Just keep the lube up.

Jarrod.
 

rodneyt

Registered
if crankshaft is bent there should be a noticeable wobble at flywheel rim/s, also when conrod and piston off/out, the crankshaft should give a slightly sticky feel in at least 2 places as you turn it over very slowly... it would help if cam gear removed too, so there is no other things affecting the turning friction.
 

Dobbo56

Registered
Jarrod
Those were my thoughts exactly, put it back together, after I get the new ring and use my Buzacott to turn it to bed them in. Yes that is scoreing on the bottom of the bore, so am going to run the honer though.

Rodney
I did slowly turn the flywheel and didn't fell any binding, so I then sat a tape measure under the shaft extended the tape so it just touched the shaft and locked it, then turned the wheel again with no noticeable movement, so my untechnical approach makes me think it's straight, just a worry that the bolts are bent.

Cheers guys
Dobbo
 

cobbadog

Registered
I would let the bearing slide as they are and replace the broken ring. Spring tension on the inlet should be just enough to close and seal the valve.

Soemthing of interests was my conversation with Bill Redman of Bills Motor Sports on Saturday. He does repairs to pistons now or is about to add it to his many abilities as well as doing the babbit bearings and white metal shells as well.
 

asw20

Registered
I'm going to say that someone used a bit of 2" water pipe and a hammer to bash the piston out. (perhaps after hitting the big end bolts first?)
I still reckon it's fine.
There is a lip in the bore, but shouldn't be a problem so long as the rings are good and maybe just need some bedding in.
You have cleverly lit the shot to show the pitting at it's worst. While it may initially cause some loss of compression, you have more rings which won't come up that far. It will soon fill up with carbon once you get it going.
While you have it belted up (after assembly), I'd think have it all set up to run with oiler going, petrol on (can't remember, but it's only something like an 1/8th to a 1/4 of a turn open on the mixture screw) choke open so it doesn't flood and I would be surprised if it didn't just fire up after a while. It wouldn't be the first time an engine needed a bit of help until the rings bedded in a bit.
You could use a timing light on the ignition while doing this, too.

For good measure, have the camera phone going on a tripod while you indulge in a few beers / pot of tea / coffee, etc so we can enjoy it with you!

We're all here to keep you encouraged, Jarrod.
 

cobbadog

Registered
When your talking to him remind him that it was you that referred him to me, he thought that was very good of you but he didn't quiet remember you. He certainly sounds as if he knows his stuff and now I hope NZ op.

On the News tonight they are talking of opening factories again in NZ so hopefully a ring manufacturer will too.
 

Kynoch

Registered
Hi Dobbo If you can let me know what size the rings are I might be able to help as I over ordered on my last bye up on rings and have some spare ones that I can sell cheap if they fit
 

Dobbo56

Registered
Hi Dobbo If you can let me know what size the rings are I might be able to help as I over ordered on my last bye up on rings and have some spare ones that I can sell cheap if they fit
Hi Kynoch the bore is 4.127", piston is 4.10", ring width is .250" and depth is .137"
Cheers
Dobbo
 

cobbadog

Registered
Hi Kynoch, you dont have any rings to suit a bore of 3 1/2" and rings to be 3/16" wide?

Bill rang me today and said that he had some rings to suit the McDonald and he read back to me the sizes and I said that sounds not quite right. I went back to my email to him and found I suffered with fat fingers and stuffed up with one of the numbers so I rang him back and let him know of my mistake.
 

Dobbo56

Registered
I also spoke with him today about the ring I require and he said he would get back to me in a couple of days.
I also asked him about a set of rings for my BSA 420, he said to go to VACES, Steve Woods, but he doesn't have any and as Bill supplies him I went back to Bill for a price.
Also ordered the gaskets for BSA engine and carby, they should be here by Friday so it might get finished first, depends on the cousins other halve, if he can fit me in to paint the cowling and fuel tank
 

Kynoch

Registered
Hi Dobbo and cobbadog The rings I have left are
3.3/4 x 1/4 4 off
4.1/8 x 1/4 3 off
5.1/2 x 1/2 5 off
If they are any use please send me a message
 

Dobbo56

Registered
Well received a parcel in the post today from Kynoch (y) :giggle: , 3 piston rings. It was like Christmas again, couldn't wait to open it andfitand them to the piston.
The rest of the day the missus had me helping her down the back yard until she got a phone call so off I slinked and cylinder honed and piston, rings and cylinder well oiled, then in it all went, all bolted up finger tight but ran out of day light. I am learning that the more I do lately the easier the skin comes off, got pieces out of me everywhere. Tomorrow will reassemble the rest of the M when the missus allowed me some time off.
Thanks Kynoch :clap:
Cheers
Dobbo
 

Engineman87

Registered
Dobbo I have that cooling tank we spoke of and am picking up the fittings tomorrow for you to try, will drop them off in the next day or two.
 
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