10 replies to this topic

[ItsNotDads]

Hi all,

 

My son’s engine project is a 1380 block with good cylinders 1,2 & 3 but 4 is oval.

 

Trying to work out with the machine shop if the block can be used. I rang Omega and their pistons are 73.405mm. Providing 0.095mm bore clearance. We will end up with too big a gap after honing.

 

Daft question of the day, but are there decent pistons that are manufactured closer to 73.5mm actual size?

 

Many thanks,

Andy

[nicklouse]

Talk to MED about their liners.

 

 It I would be looking at starting again.

[ItsNotDads]

Thanks. Already spoken to MED. Was advised that if the block is already 1380 there wouldn’t be enough material to machine the step necessary to locate a liner. Their suggestion was a new block and start again. Trying to avoid that if possible.

[imack]

Thanks. Already spoken to MED. Was advised that if the block is already 1380 there wouldn’t be enough material to machine the step necessary to locate a liner. Their suggestion was a new block and start again. Trying to avoid that if possible.

This is what they told me too, yet in their latest project 63 video they are boring a Cooper S 1275 block to take liners that's already been bored (and not offset bored) to 73.5mm.

[Earwax]

Hi

 

IIRC  Honda and Mazda do 73.5 mm pistons - but not sure of gudgeon pin height  -- again from memory I think I have used 73 mm other brand ( non Mini) in a 1360 build??? - so the gudgeon pin height must have matched ( I was using standard rods

 

Here is a link to just an example ( not certain of all parameters) 

[Icey]

I was speaking to a machinist at Fiennes, he was saying that they don’t machine a lip for liners, so I don’t think it’s a hard-n-fast rule that you can’t sleave a 1380 if needed, but you’d want to confirm that.

Edited by Icey, 05 February 2023 - 10:40 AM.

[ItsNotDads]

 

Thanks. Already spoken to MED. Was advised that if the block is already 1380 there wouldn’t be enough material to machine the step necessary to locate a liner. Their suggestion was a new block and start again. Trying to avoid that if possible.

This is what they told me too, yet in their latest project 63 video they are boring a Cooper S 1275 block to take liners that's already been bored (and not offset bored) to 73.5mm.

 

Interesting, thanks. Just watched it. My sons block isn’t offset bored either.

[ItsNotDads]

When was speaking to a machinist at Fiennes, he was saying that they don’t machine a lip for liners, so I don’t think it’s a hard-n-fast rule that you can’t sleave a 1380 if needed, but you’d want to confirm that.

Thanks. I’ve swapped DMs with a machinist there too who thinks they can help. May have to let them take a look. Guess it also comes down to cost. The block is a good 76-79 1275GT block and otherwise seems ready to run. Liners vs start again

[ItsNotDads]

Talk to MED about their liners.

 

 It I would be looking at starting again.

Having spoken to Fiennes on the ‘phone (very good, lots of sensible advice freely given), I fear starting again, might be the best option. Hohum.

[imack]

Have you spoken to KAD about liners?

[bpirie1000]

Make it into a "modern @rt piece" make it into a coffee table wire in somemfancy cheap LED lights, chuck it on e.bay....

Recover some losses... someone gets a.series art....