2450 (78mm x 100mm) engine build

[Steve Arndt]

Knuf in Germany told me with my dry sump, to omit the tray.

[twodollardoug]

I omitted mine with the dry sump also.

[Eddie010]

This is one of those subjects you'll find a lot of different ideas and things to say about it..

Thanks Clatter,
I know, but just asking what people think or use.

In my own built I never used one, but I did not have them then.
(have bought a few 1.7 porsche engines with them in it).

Regards Edgar

[Eddie010]

Thanks guys.

[Eddie010]

I am going to try this here.
Does someone have a 1/2 inch longer headstuds laying around that they want to sell.

Let me know please.

[Passatman]

Edie how thick are these liners at the top.

[Eddie010]

Edie how thick are these liners at the top.

The 103 liners are mostly 115 at the top,
but i made this 100 113 at the top, so 6.5mm thick.

Regards

[Passatman]

That is thick it should seal well if prepared right.

[Eddie010]

That is thick it should seal well if prepared right.

I hope so, I lapped the cylinders in the head and in the case.
Hope that is enough.

Regards Edgar

[Eddie010]

exhaust head

[Passatman]

That is thick it should seal well if prepared right.

I hope so, I lapped the cylinders in the head and in the case.
Hope that is enough.

Regards Edgar

I have my oxyboxer to build and i am going to lap the cylinders into the head just to make sure i have a flat surface to put my copper head gasket.

[Eddie010]

A question for the guys who use big stroke engines,
I bought 1/2inch longer Head bolts, but they are a bit to long for my taste,
did you guys cut them on length or did you leave them as long as they are.

Regards edgar

[MegaRookie]

Hi Edgar, yes, I guess you or have to use shims or shorten them. With my 86 stroke engine and long barrels, they where more than long enough.

Mark

[Ol'fogasaurus]

A question for the guys who use big stroke engines,
I bought 1/2inch longer Head bolts, but they are a bit to long for my taste,
did you guys cut them on length or did you leave them as long as they are.

Regards edgar

Are you talking about bolts themselves or "double end" studs?

Usually it is not considered to be a good idea for either bolts or studs to be shortened but... it has been done before.

Head studs, often referred to as "double ended studs" are threaded on both ends of the stud with the center of the shank not being threaded. The unthreaded part of the shank is for stretching and any shear loading (for example) to take place; e.g., threads, in general, change the strength of the fastener). Threads and nuts don't allow the fastener to stretch especially in the area where the they have a grip on the threads. The design/shape of the stud in it's self tells a lot about it's designed use also.

If you cut the top threads off then you have to have the threaded distance leftover for the nut to fully use; usually it is considered that 3 full threads showing after torqueing are considering to be the minimum.

Nothing is easy is it.

I tried to find some tech data on threads and grain direction but it was something the sites did not talk about. Anyway, when forming the bolts there is a lot of work done to get the grain direction going from the head to the end of the fastener... in a straight line.

The cutting the threads (using a die or lathe for example) you cut the through grains weakening that area. Rolled threads compress the grains, again doing some weakening but not as much as cut threads. For high strength work rolled threads are generally preferred.

Lee

thread grain patterns copy.jpg

I found this which does give some idea of what happens.

The machined grain structure shows the grain pattern cut way from the joining thread (remember the threads are wrapped around the bolt) while the rolled threads show the grain pattern being bent over and compressed down to the rest of the grain pattern (no cutting the bolt for the threads they are pressed into the fastener during the high pressure rolling of the threader [think of rubbing your hands together with a piece of clay or something like that between them). While not the best of pix but it gives an idea.

Lee

[Eddie010]

Hi Edgar, yes, I guess you or have to use shims or shorten them. With my 86 stroke engine and long barrels, they where more than long enough.

Mark

Ok thanks for that info, does this configuration still fit in your engine bay when it is so wide.