[jimang]

Hello, i am new here and been reading a lot, thank you for all the info everyone puts on here.

To start i been trying to build my 79 vet and could use a little help.
It's a chevy 350, Crank i believe is stock # 3832442 seen its out of 78 to 88 heavy duty 4 bolt 2 piece rear seal. Heads are World Products s/r 1-052, Rocker arms are comp steel 1.52 ratio, i know pistons are .60 over cant remember what they are, torque converter is 1,700 to 2,100 stall, flex plate 168 tooth internal balance, stock distributor, headers, elelbrock 1406 600 cfm, nothing has been done to automatic tran, stock rear end. i have tried couple cams.********* first cam was a summit cam Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,400-6,000
Intake Duration at 050 inch Lift 224
Exhaust Duration at 050 inch Lift 234
Duration at 050 inch Lift 224 int./234 exh.
Advertised Intake Duration 282
Advertised Exhaust Duration 292
Advertised Duration 282 int./292 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.465 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.488 in.
Valve Lift with Factory Rocker Arm Ratio 0.465 int./0.488 exh.
Lobe Separation (degrees) 114

************2nd cam was Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,500-6,400
Intake Duration at 050 inch Lift 243
Exhaust Duration at 050 inch Lift 257
Duration at 050 inch Lift 243 int./257 exh.
Advertised Intake Duration 295
Advertised Exhaust Duration 313
Advertised Duration 295 int./313 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.500 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.486 in.
Valve Lift with Factory Rocker Arm Ratio 0.500 int./0.486 exh.
Lobe Separation (degrees) 107
Computer-Controlled Compatible No
Grind Number 295TH7

nether was good choose, the thumper cam sound good ran baaaadddddddd!!!!!!!

i removed the valve covers an seen that the number 5 and 6 cyllinder compression side rocker arms where barely moving and there was a popping noise from exhaust, ran good at idle and ran bad in gear.

now i am lost picking new cam. like i said i am new but reading alot. I would like it to sound health and run good. i want to keep adding to this car little at a time. i know i really need to know the compression ratio.but dont understand it all yet still reading, i have the cam out at this point. where do i start to do this right. i know a got a lot to go. i dont drive this car to work or on long trips. want to burn out and move when i want to. please any help. thank you for your time

[Landshark928]

How are you breaking in those cams? How are you setting valve lash? It's odd for 3 cams to have issues.

Two rockers not moving could be either lash setting or you really wiped a lobe on break in.

[techinspector1]

Originally Posted by jimang

where do i start to do this right.

Disassemble the motor and clean it thoroughly, just like you were doing a new build. The shrapnel from the roached cam will begin chewing away at new parts as soon as you fire the motor again. While you have it all down, you can do some measuring and we can determine your static compression ratio and the best cam to use.

We can also help to eliminate any more roached cams by following these tips and tricks upon assembly....
http://www.crankshaftcoalition.com/w...ips_and_tricks

[jimang]

hello, sorry the summit cam just didn't do anything for the car and the comp cam just sound good looked bad when taking off. is there a place i can find a easy understandable way to do this sat. compression ratio. i got cam out can i figure it out at this point or will i need a compression for plug with motor running. this is the whole part i am not getting. as for setting lash did by the book turning over setting one at a time, just had to of messed up some where. will learn one way or other. i tried to set the ones the was not moving that much and nothing, lifters are ok little wear on bottom of the not much,when i took valve cover off i put finger in oil in lower bottom corner of heads and under the oil looked like sliver fine fine sparkle metal. just need to know how to do first step, again thank you for your help

[techinspector1]

Originally Posted by jimang

just need to know how to do first step

First step would be removal of all exhaust fasteners, then all cylinder head bolts, followed by removal of heads from block. Then all accessories and timing cover off the front of the motor. Then taking the 4 nuts loose on the torque converter and sliding it back. Then remove the bellhousing bolts and winch the motor out of the vehicle. Continue tear-down until you have no bolts or nuts left tight. Clean everything, using engine-cleaning rifle brushes in the oil galleys and in the oiling passages of the crankshaft. When you get to that point, post your progress on this thread and we will help you figure it out from there.
http://www.summitracing.com/parts/MRG-5192/

[jimang]

again thank you for the help, i understand to tearing down part and going to do now , i have done this in 2009 putting everthing new in. i just dont know how to tell what i got from there. to figure static compression ratio,will be done tearing down today and posting soon, thank you

[Richiehd]

If you are running a flat tappet cam with lots of spring pressure, you need to use off road racing oil such as Bradd Penn or the Joe gibbs stuff. These oils have the zinc additive you need to make that cam live.

[454C10]

You are trying to run too much cam for the stock gearing. I would bet a 79 vette has a 2.73 or a 3.08 gear.

I would run no more than a compcam 260H cam with your stall and gear and compression. Plus the 260H is less likely to go flat due to slower ramps.

pull the engine and completely disassemble and clean it. I bet at least one of the engine bearings are chewed up after your cam when flat.

use an oil additive. www.zddplus.com

[cobalt327]

Originally Posted by jimang

again thank you for the help, i understand to tearing down part and going to do now , i have done this in 2009 putting everthing new in. i just dont know how to tell what i got from there. to figure static compression ratio,will be done tearing down today and posting soon, thank you

When you get the heads off, put the engine on TDC and measure that cylinder's piston depth from the block deck to the piston deck. This can be done w/a depth micrometer, the depth measurement of a caliper or a straight edge and feeler gauges.

Then flip the heads upside down and the leveled head's chambers are filled with a 50% rubbing alcohol/50% water mix (to lower the surface tension, or water alone can be used) w/some food coloring added.

The head's combustion chamber is covered w/a clear piece of plexiglass w/a small fill and vent hole so the bubbles can be seen and 'chased' out the vent (or use a CD w/the plating removed by scraping the plated side 'backwards' w/a razor blade to pop the plating off). You use the cover over the chamber to keep the surface tension from fouling the measurement. A thin layer of grease or vaseline seals the cover to the deck. The valves are left in w/springs to hold them shut and a spark plug is installed as well, so the chamber will be watertight.

The piston voulme will almost always be published by the manufacturer, so with all that info and the head gasket compressed thickness, that will give you the static compression ratio.

Once you know the CR, you can then go about deciding on a cam or on what mods need to be made to run a cam you might have already chosen.

[ap72]

Originally Posted by cobalt327

When you get the heads off, put the engine on TDC and measure that cylinder's piston depth from the block deck to the piston deck. This can be done w/a depth micrometer, the depth measurement of a caliper or a straight edge and feeler gauges.

Then flip the heads upside down and the leveled head's chambers are filled with a 50% rubbing alcohol/50% water mix (to lower the surface tension, or water alone can be used) w/some food coloring added.

The head's combustion chamber is covered w/a clear piece of plexiglass w/a small fill and vent hole so the bubbles can be seen and 'chased' out the vent (or use a CD w/the plating removed by scraping the plated side 'backwards' w/a razor blade to pop the plating off). You use the cover over the chamber to keep the surface tension from fouling the measurement. A thin layer of grease or vaseline seals the cover to the deck. The valves are left in w/springs to hold them shut and a spark plug is installed as well, so the chamber will be watertight.

The piston voulme will almost always be published by the manufacturer, so with all that info and the head gasket compressed thickness, that will give you the static compression ratio.

Once you know the CR, you can then go about deciding on a cam or on what mods need to be made to run a cam you might have already chosen.

That fluid Cobalt is referring to as the 50/50 mix is often sold as the blue windshield washer fluid, you prob have some in the garage.

You need to tear the short block down too and probably need to check the bearings and surfaces for wear. Also the lifter bores should be checked if you're loosing cams as they can cause that problem.

Just to let you know ahead of time you're probably looking at a $500-$1,500 expense, between any necessary cleanup machining, new bearings and gaskets, new cam kit, cleaning etc.