Just Bought A 5K.. Now What The Hell Has Been Done To It?

[megamannz123]

Hi all,

I just picked up a 5K for my ke30 and have started to dismantle it for a rebuild, so now i'm trying to work out what I actually have here.

The push rods have been cut and joined together, why? maybe due to a high lift cam? still has the hydraulic lifters.

The cam has 298R stamped on the front, maybe this is the degrees duration? sounds like a lot if it is?

It has the D dish pistons in it so I thought it must have a 5K head on it but from what I hear the 5k head does not have much of a combustion chamber in it, mine seems to?

Any ideas?

[springersrolla]

it looks like a 5k head. does it have ally lugs under spark plug 1 & 4?? also whats goin on is that adjustable rocker gear and you said hydraulic lifters?? more photos would help. no idea bout the cam did you hear it run??. you could always cc the head

[megamannz123]

Nah never heard it run. Here are some more pics.

[megamannz123]

Shortened push rods.

[kickn5k]

Shortened push rods.

 

That is dead set, the dodgiest engine mod I've ever seen!!

 

What makes you say it's a hydro cam?

 

[megamannz123]

Yeah and ones broken too, dodgy as! also the little lug locator on the front of the cam is all cracked and bent.

Those lifters are Hydraulic aren't they I haven't pulled an engine down for 16years!

[springersrolla]

wow!! dodgey!!! wht the ʞ©$ɟ is all that dog shit?!?! not a 5k head don't know why its running hyrdaulic lifters and adjustable pushrods with cuts and the ʞ©$ɟ with welding?? looks like youve got a little challenge on your hands

[GJM85]

What you have is a dished piston 5k with a 4k or 5k flat top head.

I would call this someone's disaster.

There is a 6mm difference in head heights between the flat top or 'O' dish piston motors & the dished 'D' shaped piston motors. Large compression chamber for the flat tops and small chamber for the bit D dished motors

This results in a 6mm difference in pushrods length hence the chopped and welded pushrods.

Massive carbon build up indicates poor combustion due to very low compression or a rich fuel mixture. The original stuff you need to fix this isn't easy to find because nobody knows what they are looking at.

 

In your position the easiest and safest fix is as follows

Buy a rebuild kit with the flat or 'O' shaped pistons.

Find another camshaft, yours is cracked anyway. Have it reground to a new and solid lifter profile.

Do the chev/ Datsun solid conversion. Holden 202 solid lifters and Datsun A12 pushrods.

It's your only sure way to get that engine running in the near future

[megamannz123]

Yup it sure is a mess!

That sounds like a good plan, I have the a 3K-c I can strip down for the Cam and maybe even the head if it would work once I get the flat top or O dish pistons. Are 3,4,5k cams all interchangeable?

The 3k has a 75mm bore and the 5k is 80.5mm will this slight difference cause any issues in the combustion area? or is it just a bolt on and go, the 3k head I have has 10thou off it and is in good condition so maybe that's the best bet.

So the 202 solid lifters will slot straight in with the A12 push rods? Obviously I will get the lifters refaced too with the new Cam.

I appreciate your help, like I said I haven't worked on a K series for 16 years!

[josh247]

haha,

Shortened push rods.

 

thats pretty dodgey hahhaa

[altezzaclub]

I look at the cam and my fingers itch for the MIG welder... Just a little spot of weld and a file or lathe would do it!

 

Maybe the motor was planned to be turbo'd! Cartainly you will have to decide on either combustion in the piston dish with the D-shape, or in the head with that 4K head, so replace either the pistons or the head.

 

Should be a challenge!

[megamannz123]

Hey, does anyone know where to get some pistons? I tried Nason but they only have the D dish type. I am after the flat tops or O dish as I'm not using a 5K head.

[megamannz123]

So I have just some calculations and come up with a 7.25:1 compression ratio! this thing must have been a slug!

bore is 81mm, stroke 73mm, head gasket .5mm, dished piston 22.5cc, combustion chamber 35cc. I wonder how much I can take off the head without the valves hitting?

[luk3333]

Hey, after reading your monstrosity i thought you might be interested to know I have a 5K head, with correct rockers and pushrods for a hydro 5k and a reground hydro cam I'm looking to get rid of. If you are interested in buying the gear PM me :)

[KE25_rolla]

lol.

 

I did some dodgy stuff in my days but nothing compared to that!

 

Stick with what GJM85 says as this is what I did in the past and it has been tried and tested!

 

Good luck.