360 no power on acceleration

[Dartfreak75]

Compression tester is the one tool I don't have, but should get.

Sorry I missed this!

 

[Dartfreak75]

That is a good cam!!

Oh crap that is not a good cam I thought that was the summit 454 lift cam! To much cam for that setup!!

 

[barog]

Some serious mis-matched components, that cam and factory manifolds. And, the factory manifold on the passenger side has a flap that can rust shut, plugging that side of the exhaust.

• Your dots on the timing chain: Is it a 3 key way timing chain (+/- 4* and straight up) ? Did they line up the dot on the key hole of the crank? or the dot by the tooth?

I had headers they did not fit, I didn't want to pay $800 for ones that fit.
JB Welded the flap open on the outside lever.

The cam and crank and crank are lined up dot to dot, it is not the adjustable type.

 

[barog]

Oh crap that is not a good cam I thought that was the summit 454 lift cam! To much cam for that setup!!

I think that is the cam, I can't find the card, but I had it bookmarked.
Found the card, that's the right cam.

 

[nm9stheham]

Thanks for the photo of the timing chain.... looks correct, as best as can be seen from a photo. Just wanting to be sure.

The cam may indeed be too large, especially if the stock type pistons have been used in the rebuild. The compression testing would tell us the while story in that regard. If you can get one and do that, it would be very worthwhile to have that info. It can be done with the timing cover off.

If the cam was indeed too large, then at some higher RPM, like maybe 3000 RPM or more, the engine would start to feel like it was taking off better.... This also has to do with the rear axle ratio.

The suggestions about the plugged exhaust are good.

 

[Dartfreak75]

My next question would be how does the engine run at higher rpm? And what gears do you have and what converter? That cam doesn't start to make power until 2500rpm so if you have 2.76 gears cruising at 55mph your somewhere around 1500-2000 rpm if you floor it your not in your power range! I would say that is your problem.
That cam recommends a 2500 stall with 9:1 cr! If you have a stock converter and 8:1 compression no wonder you have no power.

 

[318willrun]

I had headers they did not fit, I didn't want to pay $800 for ones that fit.
JB Welded the flap open on the outside lever.

The cam and crank and crank are lined up dot to dot, it is not the adjustable type.
View attachment 1715241012

your doing the right things. I would certainly do a compression test next, but a cam swap may be in your future

 

[AJ/FormS]

You have not specified all 4 things we need
1) the cam/compression
2) the TC stall, real stall not rated stall
3) the rear gear/tire roll-out
4) the vehicle weight

The first thing if you have the factory compression, is to pull that cam outta there and break it in half. It is pushing your cylinder pressure so far down as to make a slanty feel strong; I'm not kidding. I'd be surprised if that 360 topped much over 110psi. That cam desperately wants headers, and with 54 or more degrees before the valve even gets to .050, your manifolds are backing everything up into the intake thru the overlap period of 61* or more degrees.If you gotta run manifolds put the stock cam back in there. Wait forget that; get a stock-spec cam with faster ramps, or a solid lifter cam with fast ramps, on a 108LSA, and tight hot-lash; that will wake her up.
In an A-body
That Summit cam@8/1 Scr needs a 2800TC(probably more) and 3.73s (minimum).
That Summit cam needs ~10.5Scr and it will still be lazy out of the gate, still wanting a 2600 and 3.55s
It's just a slooooow-ramp cam

Without 2,3, and 4 the rest is anybody's guess. There may be nothing at all wrong with your engine other than the cylinder pressure.
EDIT
Hang on, I may have been a lil harsh in condemning that cam. Summit does not specify where the advertised is measured from. I made the erroneous assumption that it was .008 or .006, in which case I would still throw it away. But if they measured it from .004 or heaven forbid from .002, then it could still be a great cam for an engine with more compression than yours,lol. And still that cam is specifically not for you, because it has no bottom-end at 8/1 Scr, and the only ways around that are higher TC and racier rear gears, which are not the greatest ideas for a streeter.
For a dual purpose streeter 3.55s are about the max recommended because 65 will be 2800 to 3000rpm, so not that great for touring with.
Streeters need bottom end because the greatest majority of the time they are stuck at low rpm. There is no point in having a 6000 or better race cam in an engine that spends 80/90 something percent of it's life below 4000. That high-rpm cam just steals you low-rpm power. The factory cam will make waaay more take off power, when saddled with the factory TC, Scr, and hiway gears.
That doesn't mean you have to be stuck with a lo-powered factory cam. You just need a faster-rate of lift cam than the factory one and a similar advertised seat to seat size when measured from the same starting point. Then you can punch up the biggest .050 timing on there that the grinder will permit. And that .050 is what the engine makes power with,mostly, cam-wise speaking.

 

[crackedback]

You will HAVE to open the distributor and shorten the mechanical advance. That cam will require 18+ initial timing. More likely in the 20-22 range.

Two pieces to advance, initial and mechanical to hit your total number. Initial is more important than total.

You also have no idea were the cam is timed. Lining up the dots is not a good method to install a performance cam. It needs to be degreed to verify install. If it was mine, I'd advance the cam 4 degrees, maybe more.

Not a great cam unless you have more converter with no rear gear.

 

[AJ/FormS]

Post 33 edited

 

[barog]

If changing the cam will fix the problem I am fine with that, it's not a drag car, I just want to drive it.
Everything else will cost more money and work.
I did not choose the cam so I will try to find something better.
After I check the compression.

 

[AJ/FormS]

If changing the cam will fix the problem I am fine with that, it's not a drag car, I just want to drive it.
Everything else will cost more money and work.
I did not choose the cam so I will try to find something better.
After I check the compression.

Ok, great. Just make sure the tool you use is known to tell the truth, because part of a cam recommendation will be based on your results. If the tool overstates the facts then you will get a bad recommendation.
The real measured stall of your TC will also be needed,(altho in this case it might not be that useful), and your rear gear if you intend to keep it. And I'm guessing it's an A-body, which with an SBM/904,only vary from about 2800 to 3400 pounds,lol.

 

[Dartfreak75]

If you are sticking with the manifolds I would recommend this cam. That is assuming you have stock stall and highway gears.

 

[nm9stheham]

And one final question OP... which may be dumb to ask, but just making sure. When you stomp on the gas, while cruising at, say, 40-45 mph, does the trans downshift from 3rd to 2nd? Just making sure your downshift linkage is in place and setup somewhere close to correct.

While you are about this, it would be good to see/find out what rear gear ratio you have. It will be on a tag under a rear axle pumpkin, and read something like '2.76' or 3.55'. If the tag is gone, then there are a number of videos on YouTube showing how to do it. (The results get interpreted differently for a limited slip versus 'open' (non-limited-slip) rear gear.)

The 'something better' for a cam will depend on several factors, as AJ pointed out. He missed one: how you want to use the car/engine. But I think we can say now that you want a good cruiser/driver, not a drag car.

BTW, do you have any further info on the new torque converter? Is it just s stock replacement tans/TC?

And, if this is a cam issue, and you want to time the existing or new cam (as properly suggested), and which may be good to install advanced a few degrees, then you will need:

• A timing gear set with an settable crank sprocket, like this; see the 3 key slots on the crank sprocket for adjusting cam timing: Mancini Racing Double Roller Timing Set
• And then a degree wheel, which can be bought, or printed and pasted on foam poster board from the following link; the center hole has to be cut as accurately centered as you can if you do the 'paste-on' one here: The Machinery Cleanery Universal Timing Disc, Degree Wheel, Downloadable - Goniometro per Messa in Fase dei Motori a 4 Tempi -
• And a borrowed/bought dial indicator to measure the .050" lift angles of the lifter

 

[BrianT]

A compression tester can be rented at most auto parts stores at least around here. I would find out what your cranking psi is before making any cam changes. Not saying that a cam change isn't necessary, but you need to know where you're starting from before buying a new one.

 

[barog]

You will HAVE to open the distributor and shorten the mechanical advance. That cam will require 18+ initial timing. More likely in the 20-22 range.

Two pieces to advance, initial and mechanical to hit your total number. Initial is more important than total.

You also have no idea were the cam is timed. Lining up the dots is not a good method to install a performance cam. It needs to be degreed to verify install. If it was mine, I'd advance the cam 4 degrees, maybe more.

Not a great cam unless you have more converter with no rear gear.

A question about this, when I have advanced the timing just by hand a small amount, I did get more performance out of the engine at 5-10 mph.
It would spin the tires from a stop. But I would also get pinging.
If I added advance to the cam would it give me the power without the pinging?

 

[barog]

And one final question OP... which may be dumb to ask, but just making sure. When you stomp on the gas, while cruising at, say, 40-45 mph, does the trans downshift from 3rd to 2nd? Just making sure your downshift linkage is in place and setup somewhere close to correct.

While you are about this, it would be good to see/find out what rear gear ratio you have. It will be on a tag under a rear axle pumpkin, and read something like '2.76' or 3.55'. If the tag is gone, then there are a number of videos on YouTube showing how to do it. (The results get interpreted differently for a limited slip versus 'open' (non-limited-slip) rear gear.)

The 'something better' for a cam will depend on several factors, as AJ pointed out. He missed one: how you want to use the car/engine. But I think we can say now that you want a good cruiser/driver, not a drag car.

BTW, do you have any further info on the new torque converter? Is it just s stock replacement tans/TC?

And, if this is a cam issue, and you want to time the existing or new cam (as properly suggested), and which may be good to install advanced a few degrees, then you will need:

• A timing gear set with an settable crank sprocket, like this; see the 3 key slots on the crank sprocket for adjusting cam timing: Mancini Racing Double Roller Timing Set
• And then a degree wheel, which can be bought, or printed and pasted on foam poster board from the following link; the center hole has to be cut as accurately centered as you can if you do the 'paste-on' one here: The Machinery Cleanery Universal Timing Disc, Degree Wheel, Downloadable - Goniometro per Messa in Fase dei Motori a 4 Tempi -
• And a borrowed/bought dial indicator to measure the .050" lift angles of the lifter

I am a quite an amateur at this, and at first I did not have the linkage connected after the engine went in.
Then I found out what it does and connected it. I don't know if I have it adjusted correctly, I followed the instruction I found online from an old service video.
Mostly my testing has been around the neighborhood at low speeds. I figured that would take the down shifting out of the equation.

 

[318willrun]

how long has this motor been assembled and running?? Are ya sure a cam lobe or two isn't flat ?

 

[barog]

how long has this motor been assembled and running?? Are ya sure a cam lobe or two isn't flat ?

I followed break in procedures, I thought this could be an issue and took off the manifold last time, everything looked OK to me, when compared to pictures of other peoples cams I saw that were asking the same question.
I don't think I have a photo.

 

[318willrun]

I followed break in procedures, I thought this could be an issue and took off the manifold last time, everything looked OK to me, when compared to pictures of other peoples cams I saw that were asking the same question.
I don't think I have a photo.

ok. Just trying to tie it all together.... the "pinging and no power" I mean

 

[nm9stheham]

Yes. Changing cam timing is independent of ignition timing. Advancing cam timing could be a small contributor to pinging, but this does not sound like a situation where it will be the 'cause'. I suspect you got the total ignition timing up into the 40's when it pinged.

Advancing the cam gives more low RPM torque....which is what is lacking here. It also reduces top end RPM's to a degree. But, from your description, a simple cam advance of 4 degrees will not make a big enough difference. It will be noticeable, but not like reducing the cam by several 'steps' in size.... which sounds like is the need.

The point in post #34 is that sometimes parts get machined in error and throws the cam timing waaay off. It would most likely be in the crank sprocket or in the cam indexing to the cam sprocket. Cam timing being off would also show up in the compression readings. BTW, the position of the crank sprocket versus crank key looks right in your pix.

I am a quite an amateur at this, and at first I did not have the linkage connected after the engine went in.
Then I found out what it does and connected it. I don't know if I have it adjusted correctly, I followed the instruction I found online from an old service video.
Mostly my testing has been around the neighborhood at low speeds. I figured that would take the down shifting out of the equation.

OK, at least that issue is likely out of the equation, as you say. Just needed to be sure. Sounds like this 'no torque' situation is happening in 1st or 2nd gear, so is indeed a real issue.

 

[nm9stheham]

ok. Just trying to tie it all together.... the "pinging and no power" I mean

You can get get pinging with ANY SCR/DCR. Just advance the timing enough ... Example: I had that high 5's DCR rally engine knock when the distributor got whacked and moved waaay advanced in ignition timing. And I over-advanced the ignition timing on a worn out Vega engine and got it to knock too LOL

 

[barog]

I just found some notes from when I got this engine.
The guy said it was bored 30 over and had flat top pistons installed.
596 heads
The torque converter is rated 1700.
I will have to figure out the gears, but I would assume stock.
The engine and car did not come together, the stock engine was a 318

 

[318willrun]

You can get get pinging with ANY SCR/DCR. Just advance the timing enough ... Example: I had that high 5's DCR rally engine knock when the distributor got whacked and moved waaay advanced in ignition timing. And I over-advanced the ignition timing on a worn out Vega engine and got it to knock too LOL

yeah, I know. But it seems he has moved his distributor in many positions of timing. He's verified the timing chain is on dot to dot. Just look'n for any possibilities...

 

[j par]

Post 33 edited

no worries I didn't read the first time past the first couple sentences it's too much sometimes...