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Lacking performence after installing new 531 head

shoestring said:
We may be talking about a case of over-camming here. Combining that with reduced compression ratio from the larger chamber of the 531 head and it's a double-whammy. If you've checked all the obvious stuff and it's ok, put the T cam back in and see what happens.

Many years ago I had an '80 Malibu with a 283, way too much cam, and nowhere near enough compression. It was TERRIBLE up to about 3000 rpm, then it came on like crazy (in a relative sense). Dicked with it for a few years trying to make it work before I finally took cam out of it and swapped on a set of stock 283 heads (much smaller chambers). Idle vacuum went from 11 in to 17, and it was way more tractable, even with less gearing.

I don't know why these cam/compression mismatches tend to come on at about 3000. Maybe somebody around here does.
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That's where the flow goes from reversion to a more constant flow in one direction. You can't install a cam with a lot of duration and expect it to produce low end. That's why modern engines have variable cam timing systems. My 1970 Boss 302 Ford had very little low end. The power would hit hard at about 4,000 RPM and pull hard up to 7,500 RPM. If I had the pedal down it would start spinning the rear tires and wouldn't stop until about 70 MPH with a Power lock differential. Boss 302 heads were designed for Trans AM racing. They would flow to 9,800 RPM. The 531 is somewhat like the Ford Cleveland head. Larger factory cast ports for higher flow. That means they are going to get stagnant flow at low RPM/velocity. So, as mocambique amazon said, what did you expect?
 
2manyturbos said:
That's where the flow goes from reversion to a more constant flow in one direction. You can't install a cam with a lot of duration and expect it to produce low end. That's why modern engines have variable cam timing systems. My 1970 Boss 302 Ford had very little low end. The power would hit hard at about 4,000 RPM and pull hard up to 7,500 RPM. If I had the pedal down it would start spinning the rear tires and wouldn't stop until about 70 MPH with a Power lock differential. Boss 302 heads were designed for Trans AM racing. They would flow to 9,800 RPM. The 531 is somewhat like the Ford Cleveland head. Larger factory cast ports for higher flow. That means they are going to get stagnant flow at low RPM/velocity. So, as mocambique amazon said, what did you expect?
Click to expand...

I don't know. I guess I expected it to work. It was a crappy lesson but I learned it. Went from that to a 406 with AFR heads and started stomping the locals...
 
mocambique-amazone said:
The 531 isn't good for low grunge.
This head perfomance is at high revs.

The better choose below 3500 is a 530.

The combustion volume of a 531 is more than of a 530.
VX3 cam is a screamer one.
Your combination: 2.0 + 531 + VX3 is only made for high boost AND high revs.


Good luck, Kay
Click to expand...

junge, junge, junge...Why you write such fake news..
531 is a mainly a fantasy thing giving 2-3 more cfm MAX flow as an un-touched head....2 or 3 cfm flow max out of 150-165 is how many %

You do the math yourself so you can see with your own fingertips just what a small nearly unmeasureble, but more important un-feelable difference it makes in all but 1 situation: Use in racing class where the head must remain un-modified.:oops:

Head volue same applies....1-2 or 3cc...a couple of tenths maybe in compression.
You think the difference from 9.25 to 9.38 is going to be felt..:oops:

See if you and dozen of others didn't write this "its a high Are Pea EM head" stuff, this poor bastid wouldn't be in the position now..

Basta mit diese 531 scheisse.:-P
 
Many mickles makes a mackle John

I did expecting this kind of post from you.

Have a nice day old grummling bear.

Good to know you know nothing about my experience and knowledge.

I don't care of the Trump-style of post you do for this reason.

The Internet is full of tur-turs.


And you know by your own:

A lot of very small steps will bring you forward, or in the wrong direction.


Best regards, Kay
 
mocambique-amazone said:
Many mickles makes a mackle John

I did expecting this kind of post from you.

Have a nice day old grummling bear.

Good to know you know nothing about my experience and knowledge.

I don't care of the Trump-style of post you do for this reason.

The Internet is full of tur-turs.


And you know by your own:

A lot of very small steps will bring you forward, or in the wrong direction.


Best regards, Kay
Click to expand...

Projecting a bit there?
I asked a few simple questions..That's not trump-style...he never asks anything...
What he does do is he dodges and deflects and turns areound and attacks people asking even simple questions...

Look at your above post...not even an attempt to address the simple questions.
 
When i still had my 940lpt i dropped a K-cam into the 530 head. I even used an adjustable cam pulley to advance the cam timing as much as possible, i believe 6degr. And still it would not pull as well from low revs as the OEM T-cam. It would only start pulling from 2700rpm upward. This was specially annoying because at motorway speeds in 5th gear it wouldn't accelerate for s***. i had to drop a gear each time. Not cool.
I ended up putting the T-cam back in. (engine starts pulling hard from 2250rpm)
So i would advice the OP to do the same. The T-cam is perfectly fine for daily driving.

The VX3-cam was designed as a kinda revy clean emissions cam for a european market NA B230FB (130HP)
The A-cam would have been a better choice. Volvo used it in the B23FT (760turbo, 185hp)

If you are on a quest for more power you can do other easier things first like opening up the airfilter box for free-er air intake, installing a free-er flowing exhaust (2.5"-3.0" ), use a boostcontroler to up the boost to about 13-14psi, install remapped chips for injection(LH2.x) and ignition(EZK)

PS is the OP aware that the crank pulleys is a 2piece with vulcanised rubber in between? This rubber has been known to let go resulting in the 2 halves of the pulley shifting in relation to each other resulting in wrong TDC indication. Which in turn could lead to wrong cam timing if you follow the TDC mark as is when installing the cam belt.
 
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As I said, I'm not talking about a normal loss of low end grunt due to the head/cam changes.
When I just start the car it almost stalls when pressing the gas pedal, and if not stalling it just won't accelerate at al, and my vacuum is really low. After 2-3 minutes of warming up it gets better.
I'll try to post a video of this ASAP
Thanks for the help!
 
531 comes stock with Vx3, B230. +1 on checking shims/valve lash when getting head back from shop. Have you checked hall sensor, does your dizzy have one?
 
That's very similar to what mine does. Low vacuum, rough idle. On a cold start, it breaks up REALLY bad when I rev it. It's horrible until it warms up a little, then it's smoother. Now today it started misfiring under light throttle, but heavy throttle it's fine. This started after I pulled the cat, so it's currently running open downpipe. The cat is definitely backed up and falling apart, so I'm gonna try to make a pipe to put in its place. It sounds like a straight piped diesel... can't keep it like that lol.
 
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