If you don’t mind my comments. That’s quite common with the cylinder skirt more so with the 3mm extra rods. Your piston clearance will depend on your cams. With the larger oversize pistons you are correct the top outer edge of the piston will need to be relieved and the last thing check the size on your head gasket bore. Hope this helps.
Yes, thank you! I definitely need to look at the cams now you mention it as they were apparently reground. To what grind I don't know. I can measure the lift and should be able to calculate how much the valves move from that to get a rough idea. I do have pictures and descriptions of the process from someone who does this professionally so what I am doing is the normal way of doing all this. It's just tricky since all the people who do it are on the other side of the world so my approach is just do things slowly and methodically. All these comments are really helpful!
If you have a spare cylinder head, with your spare block you could use these as your mounts for the pistons, using the head would also mean that you have exactly the correct angle for the indentation. Is there scope to bore the cylinder head to oversize? Does make you wonder why the parts manufacturers cannot just make things to the original specifications... Nice work!
These rods are specifically to raise the compression ratio. I would have been OK with standard ones but I think they didn't have any when I ordered them (was a while ago so I can't remember!). I don't think you can bore the cylinder head so it's quite normal to slightly modify the pistons. The register does have a warning about not taking too much off though. The angle is known. It's exactly 45 degrees.
I was just wondering if the piston is that high out of the block will it raise the compression ration a lot or to much. Could it beyou may need to put a spacer to raise the head that amount which would save machining the pistons?
I’m sure this may well have been suggested, but have you thought about getting a chest or head mounted camera sling? This would allow you to take these videos with the use of two hands?
That sounds like getting into putting more effort into the filming than the car! I will try to keep the film more stable though. It's tricky with my phone holding it still. Maybe a gimbal type holder would help and it isn't too much. The truth is I think about filming after I have done whatever I am doing on the car usually. That's also why I tend to repeat myself. Nothing is really planned!
@@asciimation As a vintage Austin 7 enthusiast in the UK, I love watching your videos. I’m always worried you’re going to drop something valuable, or the phone! I only thought I’d suggest so it was easier for you, your videos are great, and any wobbles aren’t an issue at all.
I think I did that on the Austin engine from memory (spacer between crankcase and block) but on the Riley engine I want to increase the compression ratio. I think it's only 6.5:1 standard so it can definitely be increased. Of course you never know how much has already been skimmed off the head/block so the only way to know will be measure it! I did equalise the chamber volumes so should somewhere have the volume of the head recorded. I can check it by filling it with liquid (I really need to get a burette) and measuring how much it takes. You can measure the cylinder volume and head gasket volume too and calculate the ratio.
You might want to buy a endoscope attachment to your phone, this will let you see how much clearance you need grind out for the positions. It's also very useful tool and can be used to show and get advice.
I have one actually! It is USB so I can attach it to my laptop. Good idea! The other way is to use plasticine on top of the piston and check the indentation in that.
If you don’t mind my comments. That’s quite common with the cylinder skirt more so with the 3mm extra rods. Your piston clearance will depend on your cams. With the larger oversize pistons you are correct the top outer edge of the piston will need to be relieved and the last thing check the size on your head gasket bore. Hope this helps.
Yes, thank you! I definitely need to look at the cams now you mention it as they were apparently reground. To what grind I don't know. I can measure the lift and should be able to calculate how much the valves move from that to get a rough idea. I do have pictures and descriptions of the process from someone who does this professionally so what I am doing is the normal way of doing all this. It's just tricky since all the people who do it are on the other side of the world so my approach is just do things slowly and methodically. All these comments are really helpful!
The main point that the cams are a problem is on the overlap. So assembly is possibly your only option.
If you have a spare cylinder head, with your spare block you could use these as your mounts for the pistons, using the head would also mean that you have exactly the correct angle for the indentation. Is there scope to bore the cylinder head to oversize? Does make you wonder why the parts manufacturers cannot just make things to the original specifications... Nice work!
These rods are specifically to raise the compression ratio. I would have been OK with standard ones but I think they didn't have any when I ordered them (was a while ago so I can't remember!). I don't think you can bore the cylinder head so it's quite normal to slightly modify the pistons. The register does have a warning about not taking too much off though. The angle is known. It's exactly 45 degrees.
I was just wondering if the piston is that high out of the block will it raise the compression ration a lot or to much. Could it beyou may need to put a spacer to raise the head that amount which would save machining the pistons?
I’m sure this may well have been suggested, but have you thought about getting a chest or head mounted camera sling? This would allow you to take these videos with the use of two hands?
That sounds like getting into putting more effort into the filming than the car! I will try to keep the film more stable though. It's tricky with my phone holding it still. Maybe a gimbal type holder would help and it isn't too much. The truth is I think about filming after I have done whatever I am doing on the car usually. That's also why I tend to repeat myself. Nothing is really planned!
@@asciimation
As a vintage Austin 7 enthusiast in the UK, I love watching your videos. I’m always worried you’re going to drop something valuable, or the phone! I only thought I’d suggest so it was easier for you, your videos are great, and any wobbles aren’t an issue at all.
I would have thought a spacer plate or shim between the head and block would be an easier way to solve your problems.
I think I did that on the Austin engine from memory (spacer between crankcase and block) but on the Riley engine I want to increase the compression ratio. I think it's only 6.5:1 standard so it can definitely be increased. Of course you never know how much has already been skimmed off the head/block so the only way to know will be measure it! I did equalise the chamber volumes so should somewhere have the volume of the head recorded. I can check it by filling it with liquid (I really need to get a burette) and measuring how much it takes. You can measure the cylinder volume and head gasket volume too and calculate the ratio.
All you need to know about Riley Motor: ua-cam.com/video/-hkeel6xKvE/v-deo.html
You might want to buy a endoscope attachment to your phone, this will let you see how much clearance you need grind out for the positions. It's also very useful tool and can be used to show and get advice.
I have one actually! It is USB so I can attach it to my laptop. Good idea! The other way is to use plasticine on top of the piston and check the indentation in that.