Is my engine build nightm are coming to an end?

[Chris Wilson]

Won't bore you with all the details but my rebuild on my Mugen V8 race engine is perhaps coming to an end. I have had Omega Pistons commissioned to make a bespoke set of pistons for it, but, although the best piston makers in Europe, they are VERY slow and unreliable on delivery times, and they are so busy they are saying that "normal delivery times are subject to delay" which probably means about a 2 year wait... Anyway, a company in Japan have e-mailed me about the availability of pistons that will work, but require some con rod mods, and they aren't a bad price, either. These are the last item needed to complete this engine, to say it's been a nightmare is an understatement, bits have come from all corners of the world, or had to be made at vast cost. Maybe dyno time approaches at last?

 

Here is what they sent, a bit of fiddling, but seems a way to progress this:

 

"Dear Mr. Wilson,

 

We are happy to know that you could use the gear spindle for your engine.

I have attached here the invoice. It's including the postage of JPYen2,000.-.

 

In reference to the pistons, although I am not sure if accept this kind of a

method or not, we have a type of pistons which can be used by giving modifying work

on the small end of the original connecting rod.

 

Piston compression height: Original = 27mm / Tomei = 26.3 mm

The outer dia. of Piston Pin: Original = 21 mm / Tomei = 18 mm

Connecting rod length: Original = 126 mm needs to be increased to 127 mm by

offsetting work on the small end bushing.

The width of the small end of the connecting rod: Original = 24 mm needs to be

17 mm by machining.

 

The piston crown surface will be 0.3mm higher than the original, but there should still

be a distance of 0.6mm between the piston and the cylinder head. If you want to

have the distance greater, adjust it with offsetting work on the small end bushing.

 

Top Ring: 1.2 x 3.3

Oil Ring: 2.0 x 2.5

 

Those pistons were originally made to be used with Pankl's connecting rods, but we

were also using them with the original connecting rods by modifying the small end.

Up to now, there has been no trouble occurred on either the connecting rods or

the pistons used with this method.

 

For your reference, we also attached a photo capturing the original rod, the modified

rod being set in the piston, and the crown surface of the piston.

 

The price of the piston is JPYen ******/ per piece (including rings, pin & circlips).

And, we have them in stock."

 

 

"Have them in stock", not something I have heard often in relation to this damned thing, I can tell you

[HadeS]

Go for it?

[Scott]

Bloody hell those look light.

[Chris Wilson]

Bloody hell those look light.

 

One would hope so

[TTRickeh]

That's a cool looking piston

[Scott]

One would hope so

 

I know they are lightweight, clearly, but they look really really light. As above, very cool looking.

 

What is the rev limit you are aiming for?

[Chris Wilson]

In period the engines were limited to 9500. Tomei Engine in Japan (not the Tomei people who do the road car engine stuff, a different company, but similar name) have updated them and run them to about 11,500. That'll be one of the pistons from their updated units. I will stay at 9500 as that's where the cams I have are all done by. It's just a typical modern N/A 2 ring race piston, to be honest. But "In Stock"

[Swampy442]

This is gonna be probably the most moronic question but cant you approack Mugen to get pistons? Even ones youre looking at need 'work' Cant you get some made bespoke?

[Chris Wilson]

Mugen stopped supplying parts for these years ago, and the only people I would trust to make custom ones are Omega, and they are snowed under, and "unreliable" as to lead times even when they are quiet Judd will make billet ones, but we are talking serious money for a batch of just 8, or even 16.