So I have a mild streetport engine and we were putting on my racing beat holley setup on it when we noticed the intake holes on the gasket are a lot smaller than the ones on the intake. I knew you wern't suposed to make them bigger on a stock engine but since it's a street port engine i thought what the heck and we cut them larger to fit the intake holes. Is this a bad thing?
The reason i ask is becuase sometimes when I wind it out in the higher rpm's (5-7k) it starts making this funny noise that doesn't sound like a smooth rotary reving. It sounds kinda choppy and looses acceleration.... But sometimes i can catch it and it winds straight to redline easy.
So heres some clues that may help. The intake setup is for a stock port engine but from what I've seen it's the same kit for street port. I have a stock pump on it but a larger one ready for installing. And this used to be a turbo car, could it be the dizzy is locked? And another thing is it's been using A LOT of fuel.

 

It sounds kind of like a miss on top end, but I couldn't tell you why off the top of my head.

 

I changed my intake gasket a couple weekse ago and the port holes on my gasket didn't matche either, so I cut them to match. I don't think it really gave me any gain, but it also didn't cause any issues, so I don't think that's what's causing your problem.

 

Alright, good info guys! So maybe it's my dizzy??? Could it be off by one tooth?

 

The random cutting out at higher RPM's is what my old RB Holley setup did alot. I finally traced the problem to low vacuum signal not allowing the vacuum actuated secondaries to activate. There were numerous other problems that I didn't figure out until I blew the engine up, but that was from the PO installing it incorrectly, and I had no idea that it was done incorrectly until I got the installation procedures from RB to install the setup on my new FB. I ended up selling the entire system because I want to go a different route.

I would cut the gasket to fit your port size. If you don't, you'll choke off your engine and there is a possibility of the gasket getting soft with fuel and oil over time, and eventually disinigrating (sp?), possibly causing engine damage. Good luck.

EDIT: what gears is it cutting out in? Is it all of the gears or just certain ones. My old setup would fall on it's face after about 5.5k in 1 and 2, 3 was normally good, and 4 it would make funny noises (knocking).

 

It's pretty much any gear at higher rpm or under load like up a hill. But it's good if I punch it and the 4 barrels open. But I haven't ben able to tell if their opening.

 

its cause its a holly, cutting the gasket to match the ports should impede flow, infact leaving it there probably would.

 

What?!?! lol

 

You can't tell if they're opening at high rpm by revving it in your garage because they're vacuum actuated. I posted a video at one point, but it seems that Putfile is down for maintenance. Here is a link to the thread.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/what-sound-461869/

 

......... I know, I can't tell if they're opening when driving it.........The reason I can't tell is because it starts acting up and sputtering so I'm not sure if they're open. and I don't have a garage at my house. lol
It's not like I'm just testing it standing still!

 

You mentioned you were running a stock fuel pump. Holley carbs want 6 PSI of pressure. Stock pump can't do that.

Are you checking your timing with a timing light per factory specs? If you can get it to line up to the marks, your timing should be OK. One thing to look for, my car was running like **** when I timed it according to the timing marks. Found out the PO had the crank pulley 90 degrees off. I lined the crank pulley correctly, then re-timed it. She ran good then.

 

Good call on the fuel pump. If you're running the stock fuel pump, get yourself a Holley Red pump or Carter equivalent. No need for FPR, because they max out at 6psi.

If you want to know that this is your problem, search out the "screw trick" for holley carbs. It's a poor-man's mechanical secondary setup that will eliminate the guess work on whether your secondaries are working. I did this at the end of my first FB's life (rusted out, motor shot after 180k miles) and WOW, what a difference. I had my room mate who is a 60's muscle fanatic giggling like a little girl every time the secondaries would open.

 

I already have an after market pump good for 115 GPH and 7 psi. I just need to find the time to get it on there. And I don't think the car would be running this good if it was off 90 degrees, I can drive it fine other than the high reving part. Do you guys think it could also be the four barrels aren't opening at all due to they're stuck? I had this setup on my previous car and the four barrels once stuck open! I was out a 1/4 tank of gas before I knew what was wrong.... lol So since they stuck open once they could be stuck shut??????

 

I had one that was actually 90 degrees off. Hard to start, would not idle hardly and poor power. Fell on it's face above 4000 RPM.

Only in a rotary can you be off that much and it actually runs!!!

 

Thats funny, but mine starts fine and has good power to redline only if you can catch it right...... it's wierd.........

 

Dude, totally sounds fuel related. When you put that other fuel pump in, let us know. I feel that is the issue.

JC

 

I agree with 80's old school. it sounds like the fuel pump.

 

i'm still saying that you should check out the Screw Trick. It sounds like your secondaries aren't opening all the time.

 

has anyone ever tied port matching the RB holley intake to the ports? I know RB said it is done the way it is for a reason but what is it?

 

Well I got the after market pump on it yesterday and it still does it, I actually almost got stranded today cause of it. I pulled pretty hard coming out of a driveway and as soon as I hit 4th it completely bogged and stalled. I coasted a good 25 seconds before it would start back up. Heres a thought, I usually use klots 2 stroke racing oil (techniplate) which I was just informed by a friend this week that this specific oil is made strictly for racing engine cause it does really well at protecting....... BUT in the mean time it leaves a lot of sludge and crap in your engine and such. The reason this is no big deal for the racing quads nd such is because they'll need to rebuild their engine frequently and don't mind the sludge.
What I'm thinking is that it's clogged up my carb and stickied it up. I used klots ALL summer on my other car with this exact carb so I'm thinking it needs cleaned up! If this is my prob it shouldn't be too much of a problem.
So heres another question........ I have another froend who has a good working holley 600cfm......... is that too big for my street port? I've seen 650's on 12a's before so I was thinking a 600 on mine should be ok???? Thanks guys!

 

i have used a 600 vacuum on a 12a streetport and works fairly well after modifacations.
as stated before use the screw trick on the secondary linkage see if what happens.
also need to verify you have proper fuel press during high load via fuel press gauge
fuel bowl level maybe low meaning inlet needle valve needs adjustment
bogging/hesitations are indications of the lack of fuel flow especially on the top end
checking spark plugs for color will help tune the fuel mixture; black=rich,white=lean,brown=.
personally you should use a dbl pumper mechanical secondary carb it's easier to tune
vacuum secondays you need to purchase different metering plates,springs etc.. & also lacks the secondary squiter that helps the transition from cruise to power.
check these out and lmk what your results are.

 

I don't think the carb is outta tune cause it ran GREAT last year under full throttle. But now I gotta go to a dinner so I'll check that stuff when I get back. Thanks!

 

So I think it's getting worse...... I added some carb cleaner into the fuel and sprayed some other cleaner on and around the carb too and nothing better, just worse..... And it almost seems like it's not as worse when it's cold...... Hmmmmm I think it might be internal..... possibly a cracked apex seal??? I'm gonna check the plugs tomorrow to see if it's too lean, rich or just right and possibly test the compression.

And I tried finding the "screw trick" but I couldn't find anything but people talking about the screw trick..... help???

 

you take a small screw and nut and fasten it too your secondary linkage on the carb. Without going out and looking at mine, it's basically a half moon that the secondary linkage slides in until it reaches the end and then begins to pull open the secondarys. By installing the screw somewhere in that half moon, you can somewhat control how soon your secondarys will open and not rely so much on the vacuum pressure building up to do so!! I would first change that fuel pump though!!!!

 

I already have changed it..... post #20......... A pic of the trick would be dandy! lol