Cadco pro street heads and cam choice I FIND THE PROBLEM!

The Mad Cadder

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Re: Cadco pro street heads and cam choice

Ted in Olympia said:
it does not look like a good piston design to prevent detonation and does not create any quench. Kind of reminds me of the 1980's type pistons that would ping at 8 to one compression.

The picture is the forged piston that MTS sells (or at least when I purchased them). The flat are matches the head and help prevents detonation.

Ted

Yea and all else equal walker told me those mts pistons add 35 hp too
I still have the txt

His piston looks like a generic aftermarket replacement for 120 heads..
With eyebrows added.. I had the exact same in my Skylark.. Silvolites
Racetec does not list anything for Cadillac.

Now that iam thinkin about it the soapdish must have been a really bad design
too ..its quench was no where near the combustion chamber shape
 

Ted in Olympia

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Re: Cadco pro street heads and cam choice

Your English is great!

Due to your location and intended use I would want to make an engine with maximum reliability and be willing to forgo some hp. That being said I would buy a set of stock 71-73 cast pistons and use those to complete your build. With those pistons you will loose about 35hp but will be able to run regular gas.

The cam card you have in incomplete; I know there are some here that like the Cad Company but this is a perfect example of what they give you. Other than that with the lower compression that cam is more than likely to be okay with the new build.

Ted
 

8ad-f85

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Re: Cadco pro street heads and cam choice

Are those .990" pins or 1.000" ?
 

dave brode

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Re: Cadco pro street heads and cam choice

Caddy123 said:
These are 2032 racetec pistons.
Special made for my bore.

What is the bore size?

What is the rod length?

Is it a 472 or 500 crankshaft?

Dave
 

Caddy123

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Re: Cadco pro street heads and cam choice

Combo first stock 500 crank 6.750 forgEd I beam rods Kb 382 block zero deck.
Idle rough shaking no detonation .
Engine dissambled cranking to much for set lash cam bearings gone..
And kb pis ton shrink to .005 .....piston to wall.....
Ordered pistons racetec so I have not bore only hone.
Send a Kb 382 as example he say have made this piston for other caddy cliënt is perfect.
Is say ok.
But other cliënt can not have 120 cc heads.
With -28 cc cr way to low I think.
Have mail racetec for a solution.
With New pistons from mts I much go to 4.380 bore
 

Caddy123

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Re: Cadco pro street heads and cam choice

This say the custom piston dealer about the pistons.
Can any it translatie so I can understand...
Gr Danny

The round dish design will NOT cause a rough idle. There were similar scratches in the sample you sent to me. You may be sing too much timing if you are hearing it “ping” . If you are going by “original” specifications as far as timing , that was for 100 octane LEADED gasoline and is TOO much timing for current fuels. We have used this dish for local customers with great results and long life
 

8ad-f85

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Re: Cadco pro street heads and cam choice

The round dish design will NOT cause a rough idle. There were similar scratches in the sample you sent to me. You may be sing too much timing if you are hearing it “ping” . If you are going by “original” specifications as far as timing , that was for 100 octane LEADED gasoline and is TOO much timing for current fuels. We have used this dish for local customers with great results and long life

Agreed on the dish subject, but leaving out the quench leaves a strong challenge to overcome with chamber temperature.
Cam timing different from stock changes the initial timing and the rate of curve, but not so much the overall. That has more to do with how the chamber itself works.
The timing curve shouldn't be changed to cope with lack of knock resistance, that's more of a reactive measure to poor engineering or guess work.
The basic concept of dynamic compression and factoring a potential VE curve to come up with a cylinder pressure curve should be planned into any non-stock build.
 

Ted in Olympia

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Re: Cadco pro street heads and cam choice

This is the answer I would expect from them. You need to retard the timing so that you do not hear any ping but this may not be possible if compression is too high for the fuel available.

They say they have used this dish with great results but I have not seen a piston like this used for Cadillac application. Looks to me they took the flat top piston used for the 120 head and modified it to use with the 76cc head. Not really a custom design piston with the engine best interest in mind.

But I do not think piston design would cause rough idle, and this is the first time I see you mention this?

Not really sure where you are asking us to go with this topic? I already gave my opinion so use stock 8.5 cast pistons if the pin is stock size and the rod is stock length. If you got .030 pistons than I think your current block can be honed to fit (assuming there is not something I do not know).

I do not think the dish in your current piston is a good design regardless of what the manufacturer says.

Ted
 

8ad-f85

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Re: Cadco pro street heads and cam choice

Retarded timing to compensate for too much compression (cylinder pressure and temp) would contribute to poor idle.
It would also be somewhat poor advice in an attempt to make a bad parts choice work better.
 

Caddy123

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Re: Cadco pro street heads and cam choice I FIND THE PROBLEM

Ok im STUPID !
I found it 1 3 5 7 detonate I hear it and rough idle and now responsive idle mixture screws.
The valve spring hit the rockers so the stick and move not free.
..............
Thanks for al your help gr Danny
 

8ad-f85

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Re: Cadco pro street heads and cam choice I FIND THE PROBLEM

So, you put this engine back together and ran it?
 

Caddy123

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Re: Cadco pro street heads and cam choice I FIND THE PROBLEM

Clean the engine.
Al New bearings (sealed power stock ok)?
Polished the crank.
Rods check up engeneer overhere.
Hone New rings same pistons cadco says also ok!
MTS 15 cam with springs.
Edel 2115 ported polished dual plane (or single plane better )?
2000 stall convertor.
Quadrajet Carb.
Cr 10.05
If it good run with this set up I dance and you hear from me....
 

8ad-f85

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Re: Cadco pro street heads and cam choice I FIND THE PROBLEM

If not?

Wishing the best for you.
Hope it turns out OK.
 

Caddy123

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Re: Cadco pro street heads and cam choice I FIND THE PROBLEM

Ok ok im learning im going for the cadco 540 H.
I have read the forum that is best for my cr.
Any body a clue best rear gear ratio and stall speed.conv
Engine Comes not above 5000 rpm.
Will figure out best cruise rpm.
Gr Danny
 

Magnus Rochester

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Thoughts on running EFI carb on Cadillac with a 500?
 

Darius

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For what it’s worth:

One of the first electronic throttle-body fuel injection systems
was made by AirSensors, and I was an installing dealer for them. From first hand experience that unit worked well with the Cadillac 500 CID engine - and also with smaller engines both NA and boosted.

i have NO experience with any of the current offerings though I’ve reviewed the specs on most of them.

Also For what it’s worth: I’m using NOS hardware and electronics along with newer (greater flow) injectors in my twin turbo Caddy powered Studebaker.

bro. d
 

48Austin

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This is a reply to a 5 year old thread. Some thing phishy.
 

Magnus Rochester

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For what it’s worth:

One of the first electronic throttle-body fuel injection systems
was made by AirSensors, and I was an installing dealer for them. From first hand experience that unit worked well with the Cadillac 500 CID engine - and also with smaller engines both NA and boosted.

i have NO experience with any of the current offerings though I’ve reviewed the specs on most of them.

Also For what it’s worth: I’m using NOS hardware and electronics along with newer (greater flow) injectors in my twin turbo Caddy powered Studebaker.

bro. d
Thanks
 
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