1994 Turbo RF build

[ColinH]

5 hours ago, 94RF1146 said:

Busa block. Look how different is the head gasket marks. 

Shame these aren’t cast iron as would be straight forward to hand scrape that to perfect mating surface with no gasket at all.

[94RF1146]

On a custom billet block you can offset the cylinders (exemple : 2 & 3 moved forward a bit and 1 & 4 moved backward a bit).

M.

Edited October 4, 2025 by 94RF1146

[94RF1146]

4 hours ago, Duckndive said:

Good question i don't know how far they can bore a busa block EDIT =  + 3mm 

could a stroker crank gain 300cc ? 

but i know that most send the blocks to the USA for replating 

https://millennium-technologies.com/

The 84mm Busa overbore is prone to crack between cylinders. It's all over Psychobike.

M.

[94RF1146]

Inspected the bottom end...all good, just replacing bearing each side of cam chain. Gonna start grinding the new top case (stock bore) to clear the rod bolts (65mm stroke). New stock 1074 block and 2 x Devcon 10710 epoxy on the way.

Edited October 11, 2025 by 94RF1146

[94RF1146]

Good news today...

Received my temporary NHRA license, my 2 package of Devcon 10710 and got my Team Ape sponsoring back for 2026 season.

M.

[slayer61]

Congratulations Sir 

 

[94RF1146]

 

[94RF1146]

Received my cylinder head. Cleaned it and started porting it (clean 60 grit + blend the pocket bowls). Gonna have the cooling ports welded for max surface area and rididity.

[ColinH]

I am interested to see how deep they can fill the cavities with weld. I often thought of filling ports with molten aluminium to perhaps 5mm blow head level, then TIG welding the remaining height to tie it all in.

not sure if that’s of any benefit though as all you need is more face for gasket area. 

[Arttu]

1 hour ago, ColinH said:

I am interested to see how deep they can fill the cavities with weld. I often thought of filling ports with molten aluminium to perhaps 5mm blow head level, then TIG welding the remaining height to tie it all in.

One drag racer once told that he tried casting aluminium into a Busa head but the head warped too badly. 

For my friend's Busa we filled the head with tin-lead alloy. The idea was mainly to improve heat sinking capacity when running dry block. It worked quite ok but melting point was maybe slightly too low. After the engine was overheated once the alloy was started to melt on the exhaust side. 

[1260Pete1]

30 minutes ago, Arttu said:

One drag racer once told that he tried casting aluminium into a Busa head but the head warped too badly. 

For my friend's Busa we filled the head with tin-lead alloy. The idea was mainly to improve heat sinking capacity when running dry block. It worked quite ok but melting point was maybe slightly too low. After the engine was overheated once the alloy was started to melt on the exhaust side. 

There is a special concrete type material that we use in hayabusas that does the same thing.

[Arttu]

6 minutes ago, 1260Pete1 said:

There is a special concrete type material that we use in hayabusas that does the same thing.

Yeah, I guess that's pretty much best option in reality. Only problem is that it doesn't conduct heat very well, if I recall correctly.

[ColinH]

1 hour ago, Arttu said:

One drag racer once told that he tried casting aluminium into a Busa head but the head warped too badly. 

For my friend's Busa we filled the head with tin-lead alloy. The idea was mainly to improve heat sinking capacity when running dry block. It worked quite ok but melting point was maybe slightly too low. After the engine was overheated once the alloy was started to melt on the exhaust side. 

I’m thinking you would need the whole head very hot when poured so shrinkage is similar rates as like welding, it will pull like crazy when only small section shrinks.

i guess at serious levels of warP you not only affect mating surface but cam alignment etc. perhaps not one to try!

[ColinH]

1 hour ago, 1260Pete1 said:

There is a special concrete type material that we use in hayabusas that does the same thing.

I know in machine tools they use epoxy granite as seriously ridgid but assume on engines it may be more metal based? 

[Gixer1460]

I'm aware of filled blocks either epoxy granite / sand / cement but I believe its more of a rigidity thing - they barely run more than 30 seconds so overheating isn't of primary concern when your pushing 50lbs of boost ! Doing the head as well - maybe not so easy to do as any pockets of trapped air 'could' explode the filling pneumatically? Its all a bit ghetto - easier to get a solid billet of aluminium, bore 4 big sleeved holes and numerous stud holes with a slot in the end and bingo ultra solid, rigid block!

[94RF1146]

Welding the water ports  is just to reinforce the head's deck., not filling up the whole thing. I should get my  other block by the end of this week. Got my 0.041 wire to o-ring the block . I also got my JE custom pistons priced out from APE (4-6 weeks lead time)...

I do little by little every week.

M.

[94RF1146]

Got the wire. The block arrived at post office. Pick up tomorrow.

[94RF1146]

New to me block is in beautiful shape. Time to  clean and re-enforce it.

Edited November 13, 2025 by 94RF1146

[94RF1146]

My wallet got thicker!

 

Edited November 18, 2025 by 94RF1146

[94RF1146]

Look what guys are doing to the Ford 7.3 Godzilla.

I need to solve those "slit" issue too.

Talking to my local machinist tomorrow...

 

[Gixer1460]

A word of warning for you - non Suzuki and OSS content in particular is frowned upon around here! Whilst it maybe applicable to what you want to or are doing, it ain't motorcycle or OSS related so it could get pulled!

[94RF1146]

36 minutes ago, Gixer1460 said:

A word of warning for you - non Suzuki and OSS content in particular is frowned upon around here! Whilst it maybe applicable to what you want to or are doing, it ain't motorcycle or OSS related so it could get pulled!

You see the slits in my block between 1-2 & 3-4, well, I have to resolve this. That's a 94-98 boosted GSXR/RF problem ( high HP). The Godzilla motor has the same issue and it shows what the owner did. 

I'll fix my issue, finish my rebuild and post back or not.

I started a "Pamela Drag Bike " FB page.

M.

[94RF1146]

Left my block at Wally the machinist today. He's gonna make the slits perfectly strait and press fit a piece of steel with 1-2 thou interference. After that that, I'll fill the block with my DEVCON 10710 return to Wally's and get the block & cylinder head decked and o-ringed. Have to order the copper gasket, only comes in 78mm bore (C8479).

M.

[Maggotbreath]

What are your specs for the O ring... grove depth/width, wire size? I'm still debating copper or MLS. I did almost 60,000km with O ring and copper so little hesitant to change to MLS!

[94RF1146]

7 hours ago, Maggotbreath said:

What are your specs for the O ring... grove depth/width, wire size? I'm still debating copper or MLS. I did almost 60,000km with O ring and copper so little hesitant to change to MLS!

Hi Gord.

In my case I'm using a 0.032" copper head gasket from Cometic. Using the 0.041" wire, I want 8 thou protrusion. See pic below for the grooves.