altezzaclub

Sadly, now is the time! Easy to get out seeing its half stripped, whip off the sump, have crank cleaned, check clutch, lighten flywheel, do bearings, check oil pump, clean rust out, put it back together. This is the time to decide if porting the head will help & take 20thou off to raise the compression.

How often are you going to adjust the ride height?? Nearly everyone (me included) picks a ride height that suits and leaves it there, so having the ability to change ride height is wasted... Different if you're racing it.

yep- Although I do have both coils firing at the same time. Interestingly, we checked plugs recently and the driver's side 4 were beautifully clean (the main ones) and the passenger's were black and crappy. So although they fire together the secondarys are not in a place where there is a good burn. (which is why the factory fitted them I suppose!) Since August its done two trips Orange to Armidale and back, and a trip up to the Queensland border... No problems at all, except a bolt came fractionally loose in the rear suspension and caused it to creak over bumps. ..and the UJ at the diff shat itself, but hey, it was free!

http://www.club-k.co.nz/Forums/viewthread.php?tid=7374 From blown 5k Super Moderator

Measure the 5K head combustion chamber with a sheet of plastic and a burette or pipette. You seal the valves with grease, seal the plastic onto the head with grease, and run turps in through a hole in the plastic from the pipette. That will measure the volume in the chamber. The two 5K pistons had quite different heads, so I don't know which you have. Philbey, I'll look it up again...

$70,000 for the motor.. how much for the head do you reckon?? The block/crank/pistons are common, so a lot fo that must be just for the head. Ask the Pinas we have on here, there are half a dozen members from up there I think. They can take a look for you, & I expect they already know of those motors.

When I measured my 4K head it had 31cc in the combustion chamber. The gasket occupied 7cc The shallow-dish pistons in a 5K have 6cc in the dish. The 5K cylinder contains 1/4 of the 1496cc, or 374cc. So your compression ratio will be (374+6+7+31) to (6+7+31)

Ignition timing can do that, give it 8-10deg advance and see if that makes a difference. Otherwise do a compression test to see if an exhaust valve is leaking. If it doesn't fire a cylinder it dumps that unburnt fuel out into the exhaust where the flame from the next cylinder fires it. So if a plug or lead or any part of the ignition circuit is missing a cylinder that might do it.

Heath, press "use full editor" at the bottom under this "fast reply" screen and it will load the photo using that. "click to attach files" button.

Make it matt black! Chop the springs to death, fit the biggest chromies you can find and a straight-through exhaust! Hang on... you can save yourself a lot of time by just setting fire to that much money...

haha! I had a Datsun 1200 wagon, bought it off the original owner, and dropped in an A15 & a 5speed. It needed to haul a higher diff but it was easier to go from 12" to 13" rims back in the 80's. Dropped it by 10%, so the same as a diff change of 4.3 to 3.9 Play with this- http://www.tyresave.co.uk/tyresize.html

Ouch! Throw-out you reckon? I suppose it can be welded if you can find the right guy. Are you going to pull the block out and flush all the rust flakes out of it?? When I did that to my 4K I was amazed at how much there was in the channels of the block. I replaced the bearings but never took the pistons out.

The 5K head might have the opposite effect and lower the compression. They had one shallow dished piston set (called "O"-dish) and one deep dished set called "D"-dish, depending on the motor you got. The D-dish had a smaller combustion chamber as the burn was in the piston dish, the O-dish had the combustion in the head. However both were for 1500cc running about the same compression ratio as a 1300, so they will be relatively bigger. Someone on here will probably know, but you should just measure the volume & area of the 5K head chamber and work out what ratio you will get.

hmm.. check a wrecker if they have one, unless an AE71 owner reads this. I wonder if that was the start of the overheating problems that blew the gasket.

Go up a rim diameter and keep tall profile tyres. That has the same effect..

Do a compression test and see if one of the inlet valves is leaking back into the carb. Is this a sharp explosion "BANG" back in the manifold, of more of a "cough" as it misfires? Our R31 Pintara does it just as you accelerate again after trailing the throttle, so changing gear is a common time. It just gives a little cough as the throttle opens. I don't want to look at it, the car is worth nothing really, but the cost of buying something else to replace it will be...

The next photo is the exciting one! The one showing the gasket and the head... So, valves ground too? The usual terrible list of things that "you might as well do this while you have it apart.." Cam sent off for a grind now its off the road, extractors bought before the manifold is needed, new timing belt...

If it has never worked well with that carb, check the size of the idle jet. That actually runs the motor up to about 2000rpm when it hands on to the main jet. The float level could be too high and be flooding it too. Check the timing at idle and 1500 & 2000rpm to make sure you are getting advance as it gets going. What have you changed since the motor was last running sweet??

How fast do you want to go? Its only a 1300cc and a very old design, it makes about 60bhp I think, and 130bhp would be a racing version of the motor. The usual mods are cam, carbs, extractors and exhaust. Have the flywheel lightened and get the who thing balanced. If the motor is worn out convert it to a 5K 1500cc, or drop a 5K in if you can find one. The 4AGE will make it go, but there is a lot of work to fit one and they are also getting to be old motors. Here's what we did. If you're happy enough with a down-draught Weber, use one of thoise, get your cam ground & get a new exhaust. http://www.rollaclub...the-girls-ke70/

Burnt inlet valve will backfire too. When does it backfire? Idling? Accelerating? Over-run/downhill only?

Well, its probably one of only three things- Cam timing.. is it a stock cam? Are you certain it is set correctly, which you can check by measuring in degrees when the valves open & shut. Carb- lean lowdown or rich lowdown. Does it idle OK and pull away without any flat spots?? Does altering the idle mixture change the idle speed?? Ignition timing- What is it set to at idle, and does it immediately advance when you open the throttle a little??

rob83ke70 is assembling one as we speak. Its to go into his Dyna. Email/PM him about it, I assume you might be up for a change in mounts, and I don't know what gearbox it runs. You're right, they're all basically the same motor.

Quite a range.. I took mine down to 6kg without any ill effects. Definately helps it rev quicker. What has everyone else used?

What's caused the gasket blowout? Have you had overheating somewhere along the way?

arrgh! You need a diagram of the vacuum/anti-pollution setup for that motor, and it would probably be a good idea to spend an hour at a wreckers with a camera and a notepad. The only obvious one is the missing screw, that looks like it is the throttle 'hold-open' to raise the idle speed when cold.