How Much Can Be Machined From 5K Head?

[megamannz123]

I have the bottom end complete but before putting the head on I'm having a three angle valve job and going to have a little more machined off the head. At the moment I have around 18cc combustion chamber which works out to about 9:1compression, I would like to take it up to about 10:1 so I figure a 13cc chamber will do it. Not sure how much that will work out to in machining off the head but I guess my engine guy will be able to work that out.

Has anyone had their 5K head machined, if so how much? and did it work? blow up? recommendations? Will it be limited by the rocker/pushrod set up, I'm keeping the original hydro lifters.

[altezzaclub]

Put a piece of graph paper on the combustion chamber and run your finger around it. You should get a dirty outline of the chamber, or use a felt-tip pen. Then count the number of mm squares on the graph paper to get the area of it.

 

Once you have the area it is easy to work out the amount to cut off to get your 5cc gone. My 4K chamber is 30sqcm, your 5K is smaller I think.

 

I'd say you could take 40thou off and not worry about the rocker on the valve, as that is more a factor of the cam. What cam lift are you aiming for?

 

We just measured Steve's 18RG, which was skimmed to death before he used it, and found it was 11:1. It's skimmed so much the valve seats have been touched by the cutter! No wonder it flew!

[megamannz123]

Thats a great idea! cheers

My cam is Camtech 529-110 261deg duration and .417" lift.

[altezzaclub]

That cam is fine, similar to mine at 265deg. It pushes the pushrod up an extra 1mm or so, and if you skim the head half a mm that is still only 1.5mm more pushrod movement. Some cams alone increase it over 2mm.

 

The bit of paper in the photo here is actually graph paper.

 

http://www.rollaclub.com/board/topic/42407-the-girls-ke70/

 

Are you porting the head too? Its a simple and free way to get extra flow if the ports are smaller than the gasket & manifold diameter.

[megamannz123]

Took the head in today, going to take 40thou off. After closer inspection the vavles have been de-shouded and the intake ports have been cleaned up. With the new vavles/seals, double springs and seat cut it will be like new.

The bottom end is a 5k 40 over with new pistons, rings, bushes, bearings, pushrods, lifters, seals etc. compression estimated at 10:1 and also putting a set of factory twins on it with the cam as mentioned earlier. Should be a bit of fun! 100hp? in a 900kg car.

[altezzaclub]

Sounds good! If you get a chance in the future swap the cam for something around 275-280deg, it will work better with the compression and twin carbs.

[B.L.Z.BUB]

I had a flat top 5K and dropped a dished piston 4k-U head on it. Put a massive cam in it. I never got it running but the guy who did said it was a bit of fun till it blew head gaskets and all the clearances went to shit haha. Must have been 11:1 or higher. Wish I had followed through and got it running.

[megamannz123]

Maybe I should put a different cam in it now, while its being built, something bigger.

Wade 169? 280 degrees, 0.405" lift

Camtech CT003 517 274deg, 0.442"lift

Crow cams suggested this grind 286deg, 0.465" lift

Thoughts?

[altezzaclub]

Depends what driving you do with it- All trips or night drags and you can use over 285deg, but driving around town and getting out of the gutter would be a pain. The 169 is good, it still uses stock springs. The theory is that lifts over 0.4" need the Holden 202 springs, which is what Richard just bought for his Tighe cam. I think its a 150A, and he does mainly long trips to Uni and back and lives in the country. Mr T himself said "Yeah, OK, I'll fix you up with something.." and it has one set of lobes at 311deg and the other at 290 odd...Not something listed in their catalogue!

 

Anyway, it always pays to chat to the guy who will cut it and explain what you want the car to do and what else you are doing to it. If you're up and down the Te Karaka Road, (one of my all-time favourites!) then get something 280-285deg. Compare the Aussie cams with what you can get locally in NZ, we can always mail you one from here...

 

http://www.tighecams.com.au/COROLLA3K.htm

[megamannz123]

thanks, that all makes sense. It's for a car I rarely drive and we live out of town so a big cam should be fine, I never go into town! I bought some Crows 4220 double springs today. That 150A does look tempting. I live in Gisborne Aus so I can get one here, I am from NZ though!

[altezzaclub]

Shame- I thought the Gisbourne was NZ's, some great driving arond there.

 

Yeah, build a racy little car if you're not stuck in Melbourne traffic, something that goes up hills without changing down and cruises at 100kph all day. What are you planning for the suspension?

[megamannz123]

Planning on leaving it stock looking, it's a one owner with 60k on it so very good condition, I just want it to go better! Probably just freshen it all up wih new shocks springs and bushes.

My next build will be a road racer RX2 once we have a bigger garage!

[altezzaclub]

fair enough- you can always fit anti-tramp rods to the rear if it walks about on its leaf springs, and some longer LCAs in the front will give it an unnoticable touch of negative camber that helps the handling a lot. Richo has his sacked to the ground, in fact I had to take the rear bump stops out to give it some travel, and while it looks cool in a JDM sort of way the ride is horrible!

[coln72]

Richo has his sacked to the ground, in fact I had to take the rear bump stops out to give it some travel, and while it looks cool in a JDM sort of way the ride is horrible!

Sounds like my old KE35 :)

 

Used a Wade 169 grind in my old 5k. it was a motorkhana/autocross car so I felt I could of gone bigger

[megamannz123]

The cam is done, went with a Crow cam.

280deg adv, 214deg @.050, .442" lift

This is what was suggested for my specs with a red line of 7000. I will let you know how it goes once its all up and running.