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7K (Big Block!?)Build Suggestions

Featured Replies

Just bought myself a 7k, which will eventually replace the 5k currently in the ke30.

The 5k was making 87HP atw @6000rpm which was with the old camshaft ([email protected]') since then I have fitted a bigger [email protected]' cam so maybe up around 95hp? but will confirm this on Thu at the Dyno.

Pretty happy but as per usual I want a little more hence the 7k

Has anyone built a decent 7K? experience? power figures?

I will do the usual... up the compression ratio, bigger lift and duration cam, rev to 6500 i'm thinking due to the stroke length, porting, bigger valves, valve springs, side drafts, exhaust and rebuild the engine.

I'm aware I will have to mod the engine mounts and probably the sump to make it fit, any thing else? Ideas?

 

Cheers!

I'm really interested to see what you can get out of one, and at what revs.

 

Before I deviated to a 2TG conversion, I was looking to strap an SC14 onto one. And may yet do.

 

edit: will you keep a K series gearbox or go T or W?

Edited by Mechanical Sympathy

Efi or carb 7k? The 7K-e's had a much better cylinder head from factory. I have a geni toyota multi layer steel manifold gasket for a 7K-e(the carb ones are definitely different), i'd be happy to donate for the price of postage.

 

Why not supercharge the 5k? You've been in a boosted K haven't you? Haha

 

 

80.5mm bore and 87.5mm stroke is fairly undersquare, i would not recommend for revs where the small capacity motors make power...

Would have more torque of course so maybe forced induction by supercharger or turbo could be the go with this one...

I'm build a 7k I have used the following

7afe h beam rods spool make these

Acl race bearing through out

Acl race piston

Chrome moly rings

Chrome moly push rods

Balance everything

Three layer head gasket

I got a lj xu1 cam grind done

Used a k bigport head that's fully ported to about 36mm runners

Match ported manifold

A15 valves

5 angle race valve grind

Double valves springs

I run about 11.1 comp

I'm using twin 32/26 webers with electric fuel pump

Custom extractors and exhust

Recurved electric disturtor with msd box and coil

I'm making about 120kw at flywheel on engine dyno at 6700rpm

  • Author

Efi or carb 7k? The 7K-e's had a much better cylinder head from factory. I have a geni toyota multi layer steel manifold gasket for a 7K-e(the carb ones are definitely different), i'd be happy to donate for the price of postage.

 

Why not supercharge the 5k? You've been in a boosted K haven't you? Haha

 

It has EFI on the engine but I'm going to run carbs I think, as for supercharging I have been in contact with a few engineers about a VASS certificate and some suggest it will have to meet emissions test that could cost $3000 to have done! no thanks! Has anyone had their supercharged K series VASS certified? if so by whom and how? I would love a blower but would also like it to be legal.

  • Author

I'm build a 7k I have used the following

7afe h beam rods spool make these

Acl race bearing through out

Acl race piston

Chrome moly rings

Chrome moly push rods

Balance everything

Three layer head gasket

I got a lj xu1 cam grind done

Used a k bigport head that's fully ported to about 36mm runners

Match ported manifold

A15 valves

5 angle race valve grind

Double valves springs

I run about 11.1 comp

I'm using twin 32/26 webers with electric fuel pump

Custom extractors and exhust

Recurved electric disturtor with msd box and coil

I'm making about 120kw at flywheel on engine dyno at 6700rpm

 

That's a pretty impressive output! My 5k is only 83kw at the fly? an extra 40odd kw would be great!

I pushed it past 8000rpm but it didn't make any more power

Maybe if I go solid cam and custom roller rocker MIT get bit more

Only 1.2mm bigger

But there are 103.8 long

Comes down to ur head porter and the cc of the chamber

I'm build a 7k I have used the following

7afe h beam rods spool make these

Acl race bearing through out

Acl race piston

Chrome moly rings

Chrome moly push rods

Balance everything

Three layer head gasket

I got a lj xu1 cam grind done

Used a k bigport head that's fully ported to about 36mm runners

Match ported manifold

A15 valves

5 angle race valve grind

Double valves springs

I run about 11.1 comp

I'm using twin 32/26 webers with electric fuel pump

Custom extractors and exhust

Recurved electric disturtor with msd box and coil

I'm making about 120kw at flywheel on engine dyno at 6700rpm

 

Damn dude, that sounds like one crazy k motor. Pics/vids or it didnt happen :P

Could look into boring out the block towards 2000cc capacity. Maybe 85mm flat top pistons?

Options could be 85mm L18 Datsun pistons, or if the walls are too thin maybe 83mm L24 pistons:

 

http://forums.nicoclub.com/datsun-nissan-engine-specs-look-here-for-info-on-your-engine-t469974.html

 

7AFE conrods:

 

http://www.spoolimports.com/spool-conrods/toyota/7afe-conrods/toyota-7a-fe-conrods

 

Modifications for piston wrist pin diameter, and piston pin height. With the flat top pistons go with a 3K or 4K head.

Would need custom extractors. The genie or pacemaker extractors are more designed for the smaller capacity 3k/4k engines.

Personally i would go 4age or 3t. The k motors are awesome but its just dollars to chase minimal hp. All depends on what your looking for. Hands down your cheapest option would be a 7k-te for best power and drivebility. would imagine that it would pull hard

I work for a engine machine shop anything is possible with time and money

i when through 4 heads kept hitting water gallery

3 blocks due to core movement ended up putting sleave in the block to get to 82.5mm bore

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