I am working on restoring my Magnum GT replica with a 13B NA engine with Holley 600. Today I test ran the engine, but due to improper throttle position the engine ran at high revs for about 10 sec during which it also misfired couple of times. I finally stopped it and when I looked at it I saw a hole on top of the block (see attached pictures) and I could see moving parts inside when I spin it by hand. It looks as there was some sort of a covering plate on top of this, because there are threaded holes on both sides, but I don't recall what it was. Did I blow the engine and what is it that is missing? thanks

 

Dont worry, I drive with that hole open everyday

 

no worries. it's one of two access plates between engine and transmission. it has no bearing on whether or not the engine is now damaged internally.

 

Thanks for the info, will run it again tomorrow, but I will make a plate to cover this hole.

 

Hello again, I ran the engine again today and it fired up right away. It sounded a bit loud so I turned it off and looked at the muffler underneath. It was blown wide open yesterday (see attached picture) when I had it running at very high revs. Today I disconnected the throttle cable and again it ran at very high idle. I took the carburetor off and saw that the manifold gasket is torn in two places (see picture 2). I read that such a high idle is mostly likely a sign of vacuum leak (too much air getting into the carburetor). I see 2 vacuum inlets on the Holley one up (facing the engine front) and one down (on the right side) and they are both currently blocked. There are several vacuum lines currently disconnected (don't know where to connect them) one coming from the top of the engine block and another coming from the oil filler neck. There are two thin vacuum lines coming from each dizzys and they are also disconnected. Also there is a thick vacuum hose going to the Racing Beat intake manifold that is disconnected (see picture 3). Racing Beat site says this is for connecting to power brake. What on Earth is power brake?

I would like to fix air leaks first before I try adjusting the carburetor. I bought a complete carb repair kit ($45) and will replace all the gaskets after I figure out connecting the vacuum lines. Any advise on how to connect minimum vacuum lines between 13B and Holley 600, preferably with photos, would be greatly appreciated. I searched this forum but couldn't find a good reading that would apply to my setup.

 

the way you stated this is kinda funny. you don't really have a choice. you're going to have to deal with all the vacuum leaks before you do anything in terms of tuning it.

i guess the main question is do you still have the rat's nest or not? look for threads that walk you through rat's nest removal and you should see what to do with vacuum lines and what-not.

power brakes = power-assisted brakes. look for a tube coming off the brake booster body that runs across the firewall. it gets vacuum from the engine when it's running so you don't have to stand on the brakes when you want the car to stop.

also, is that a spacer between the carb and manifold? in one photo it looks like there is an open spacer with the gasket on top of it. if my eyes were not messing me, then it shouldn't go there. if i am mistaken, then carry on.


EDIT: actually, scratch the comment on the rat's nest. i just remembered this isn't in an Rx-7 and there isn't one in your earlier photos.

 

Keep vacuum ports on dizzy open. Block any unused ports on the carb. If you currently have the brake booster hose open this is a major vacuum leak so you need to plug it into the brake booster assuming you have power brakes. If not plug it. The two outlets near the oil fill port, plug the one at the base and keep the one on top open. Make sure your idle set screw isn't keeping your butterflys open on the carb too. Back it all the way off, then give it a quarter turn or so

 

Yes there is a spacer between the carburetor and the Racing Beat intake manifold with gaskets on both side of the spacer, one has a big square hole and one has 4 holes.

Are you saying that I shouldn't use the spacer?

 

I will plug the power brake outlet on the manifold. As far as those 2 outlets on the carb body, the top one was plugged the bottom R one was open. It doesn't mean this was right at all, but you said opposite, so I'll do what you said, plug the bottom right one and open the top one. Tiny OMP hoses are there but are not connected to the carb. I mixed some 2 cyl oil with the gas in the tank. I'll leave two dizzy holes open and remove the hoses, like you said. What about the filler neck outlet and the top of the engine block outlet? I think one of those goes to the air filter that is missing. Not sure which one? What about the other one? Now there is a spacer between the Holley and the intake manifold. Should I keep it or remove it? I will check the idle set screw, but when the car ran at very high idle, the big butterfly was open perhaps 1/4", even though the throttle was all the way back ( there is a return spring there ). The big butterfly should have been closed at idle, no? I killed the engine by closing the butterfly all the way by hand. thanks for your help

 

I didn't say to leave anything open on the carb, plug any opening that isn't being used. If you don't have the OMP hooked up, plug the holes.

I also said to plug the hole at the base of the oil fill port on the block. Keep the top hole of the oil fill port open or like you said connect it to your air filter.

Your biggest problem is that your butterfly's are 1/4 of the way open. THIS is causing your high idle.

The spacer should be used. The butterfly's probably won't open all the way without it and it may also increase your torque a bit.

 

No that an inspection cover. Clutch and flywheel is what u see spinning

 

Sorry I should have read entire thread. Everyone is pretty much spot on. Vacuum leak = high idle. Can't tune correctly unless All vacuum leaks are fixed. Probably got too much unburied fuel in your muffler then hot exhaust ignited it. That was most likely your BANG. No big problem. A non boosted rotary can rev real high for a while Not saying you should purposely do it tho. But yes fix all vacuum leaks first. Then go from there

 

OK I'll take care of ALL the vacuum lines like you suggested, before I adjust the carburetor. That WILL be the minimum vacuum line setup for Holley 600 ( for everyone's benefit ). Question, should the big butterfly be open at all at idle, or should it be closed?

 

OK here are the pictures of my Holley as I got it, all vacuum inlets are left the way they were. The big one is plugged and 2 smaller ones facing the engine front were connected back to back. The other small one (the one with the blue plug) is plugged and the other small one at the bottom of the body (angled under 45 deg), was and still is left open. Does this seem ok? The big vacuum port on the manifold left side has a 90 deg adapter and a thick hose coming from it is now plugged with a screw.

That is the setup at the moment. Now I looked at the butterflies, primaries are closed with only about 1/4" of transition slots open. The secondaries are closed all the way and they don't open at all with a full throttle movement. They only suppose to open from a vacuum pump and they do even though they seem a bit stiff. I am still unsure whether there is anything obviously wrong with this setup?

 

The oil filler neck vacuum outlets, the bottom one is plugged, the top one (air filter) is open.

 

You will have lung butter! You need that bottom one hooked up to some fresh air, as it acts as the crankcases fresh air intake. Then the top one should be hooked to some light vacuum source preferably with a PCV valve inline.


Lung butter is bad. Dont do it.

Also, that 600 holley appears to be a super early (nigh 20 years old) 0-1850C 600. They dont produce that one anymore, and its a basic 4160 vac secondary carb. rebuild kits are 30$ Note the "tuned" internal (external) vac source for the secondary linkage.

Those early castings were probably the best produced platform for modification. If its run well all this time, id just rebuild it after a nice carb dip and compressed air blast to the main body and metering block.

 

no. i'm not saying not to use a spacer. in one of the photos, it looked to me like the gasket with the 4 holes was being used above (as opposed to below) the spacer and i was questioning that to see if what i saw was correct. that's all. i know some photos occasionally deceive the actual situation, so i didn't want to make any statements out of turn.

 

Thats an old as crap holley "shear plate" and it was designed to not let any of the screws fall into the intake on an open plenum set up. It came with all holley carbs from 1972-1998.

Nowadays its a special item for extra $$$ seeing as most people just chucked them anyways. You wont need that on the 4 hole RB manifold, OP.

 

Yes when I took the spacer off, the four holes gasket was placed on top, between the carb and the spacer and the bottom one had a big square hole and it was placed on top of the manifold. Are you sure this is incorrect?

 

well, with that whole center section of the gasket just hanging there, unsupported and definitely NOT sealing anything, then yes, it's incorrect. whoever originally put it together should have put it below the spacer at the very least, but honestly, you should probably use two of the open gaskets when put it back together since there is nothing to seal the individual runners.

 

until now, i had never even heard of one of this. live and learn, i guess. thanks, man.

 

You have a funny way to compare things - lung butter, I gave up smoking long time ago.

Thanks for the info on the Holley model and approx. year. Is there a good reading you could recommend on how to rebuild a 4150 with photos?

The plan:
Open the vacuum port at the bottom of the filler neck on the block.
Repair the muffler and put it back on.
Remove the spacer, put a new 4 hole gasket on.
Rebuild the carb basics - need some reading on what to replace.
Mount the carb on the manifold, leave throttle cable unplugged for now.
Close all vacuum ports on the carburetor. I read if something is not connected, plug it.
Test run the engine again.

Stay tuned. thanks

 

Order a Holley Trick Kit for it. Should be cheap. Do me a favor, and look on the choke horn for a number that reads something like R1850-2 or something like that.

It would be on the back side of the choke horn, towards the primary float bowl adjustment nut.

 

Bottom one at an angle needs to be plugged/capped.

 

You can put fuel line with a small cone breather filter on there if u want to be fancy