ozconnection

That situation sucks. Since you know that the power is down, can we also assume that the people who put the cam in know it's 10% down on power?? What is their explanation? Did they recommend the other cam? Maybe your new cam isn't well suited to your combo. Are they truely L specialists? Were they happy to give you back your engine knowing it was down on power? Are they genuinely interested in helping you or just money grabbers? Put the other cam back in and pick up 10% power, if you did it this way around you'd be happy, right? Good luck mate but I'd be asking the guys on the west coast some more questions.

That's a comment that's bound to stir up some 'interest' around here. How much does it generally cost to ship a complete L Series to Oz (and visa versa)?

...and very cool it is...... Have you worked out how much that motor would be to build for a customer? ....just wandering.......

I'm quite surprised that this missmatching is so obvious. I've never seen this with any of my gaskets here in Oz. Having said that, don't worry, those passages are designed to prevent steam pockets from forming and NOT for bulk coolant flow. Leave it as it is.

Oh gee, if only there was a simple answer to this.... In that other thread, I wanted to run small ports and a high quench head with a biggish cam and a dual plane manifold to get the torque that I needed. With plenty of static timing and longish runners I would have a stump puller, all done by 5000 rpm but strong from say 1.2K rpm. Tony suggested the P65 manifold and now I have one of those too. I have megasquirt but I now have another car that is going to be ET spec. So I have a whole bunch of parts waiting for another engine construction.....and an LD28 stroker crank. Vega, its the combination of parts that will give you what you want, or need. My 280C is a street cruiser and the thought of bulk torque appeals so a large capacity, high comp, small ported and appropriately timed engine with a P65 EFI manifold with a biggish cam to get the whole thing breathing. I think it's easier to swap cams than rip off heads all the time to try that illusive 'optimal' port size.

http://forums.hybridz.org/index.php/topic/72851-small-port-heads/page__view__findpost__p__692619__fromsearch__1

I'm working on a lead! I'll see how things pan out and report back.

OMG.... That's gotta hurt

Please report your findings with the 180 degree thermostat. Your scenario is strange and I'm curious how this change effects things.

How hot does it get with the 10 min warmup? Dunno, things don't seem right, with a 160 thermostat and you're seeing 210 in summer, that seems too high too me with that temp. thermostat. And now you struggle to get past 145 with colder weather. The two don't add up but..... Try putting in a new and tested 180 thermostat and report back.

You don't mention what intake manifold you've got the 390 on. That will make a big difference to how you set up your carb. You don't mention how big your cam is or how much vacuum you have at idle. Is the trans. auto or manual? You'll be very surprised at how much driving is done without using the main circuit in the carb. I was shocked when I did some testing a while ago. Changing from #54 to #52 jet size will do very little. What was your stock jet size on your primarys? Your idle air bleeds are possibly too small but if you make them larger you run the risk of going too far and leaning things out too much. Its hard (but not impossible)to put back in what the drill bit has taken out. Float level will make a difference. Do you have an electric pump? It's so easy to check for internal carb leaks with a few feet of hose connected remotely to your carb on a bench with leg supports where the mounting bolts go. Turn your pump on and watch what happens. Lightly bump and move your carb to see how easily fuel will spill into your manifold when you have your carb hooked up and the engine running. Raise or lower your needle and seats/float level accordingly. How is the float level in the secondaries and how far open are they at idle. They contribute to the idle as well, so check 'em. Let us know how you get on.

He hit the nail on the head when he said "far bigger cam". That's the deal with stock type cams, they're designed to work with low compression engines. It's all to do with valve overlap and dynamic compression. Run the E88 head but put in a cam that is designed to work well with the higher expected compression ratio otherwise your fears will come true. Good luck with it.

What else can I say.......

Great tip though...thanks mate.

Nothing came to Oz with an LD28 in it. The LD28 water pump's I have come from Japan.

I think this shows the differences a little better.

I have what you have...an idea of running just that! I think you'd agree that the most important part of this conversion is the carb and they are available but they're expensive...and who can tune 'em? I'm pretty good at tuning Holley's but the blow thru type will be challenging! I'll keep an eye on this thread to see if anyone anyone posts up anything.

I'm with Zmanco, strange symptoms indeed. The installed thermostat will act as a kind of restrictor in the block cooling system. It will allow block coolant pressure to build up to around 25-30 psi. When you remove the thermostat out of the system, coolant pressure will only be as much as the radiator cap will allow and is 13 psi in your case. That's your reason for your core plugs popping out when the thermostat is in. The core plugs can be either made from a brass type material or steel. Which ones do you have in your engine? I think you have to be careful with the softer brass ones when installing them. What I can see happening is that whilst you're driving them into place with a socket that is smaller than the lip of the plug, the central part of the core plug 'depresses' so that the lip diameter alters very slightly. The fit is therefore not as tight in the block. When I built my L28 recently, I used a piece of wood over the lip of the core plug to get it started and then drove it home 1mm below the machined hole in the block with a socket that matched the lip diameter of the core plug. The shape of the core plug was not changed by hammering, it only varies because of the fit into the block. On my L28, I have an external bypass line from the base of the thermostat housing to the intake side of the water return hose from the radiator. I know some engines don't have this external bypass line. Im my case I close up the bypass hole in the thermostat as it's not needed. Just some thoughts on the subject and I think your engine will be Ok. Good luck mate.

An Australian construct?.....hmmmmm, very nice. I guess I'll only ever be seeing the back of this one lol

Looks like a P90 Nigel, did you get that off ebay?

Yep, off with its head!!

I took an engine out of my car that was running ok, put it in the corner of my shed and left it there for 12 months. I knew it had a blown HG but I drained all the coolant out and thought I would be fine with that, I'd change the HG when it was time to put the engine back in. Unfortunately, some amount of coolant must have entered a cylinder and rusted the bore...I could NOT turn it over. As soon as I took off the head, I could see what had happened.

.....and design. I remember Saab used to run with a similar concept as you. They were only low boost engines at around 5 psi IIRC. I'm curious about your head and how much work has been done to the chambers. The N42 head is rather prone to detonation when more is asked of it than was originally intended. It's not very modern in its chamber design and there are some coolant issues to compound the situation. Some guys on here have done wonderful things to try and overcome the barriers, it is HybridZ after all, but I hope you have someone who can tune your management, with such a fine line between success and, well, you know what I mean. Failure is the wrong word. I/we don't wish you to fail, at all. I would be the first guy to wish you luck with this or any project but like the other boys who have chipped in so far, you may have some trouble tuning the beast. 'ave a go' and let us know how you get on mate. Cheers.