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Ivan
Ivan, ASE Certified Master Technician
Category: Car
Satisfied Customers: 4871
Experience:  ASE Master Tech w/ 20+ years in the field. Self employed for 9 years. Member of AUTOLAB radio show.
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82 caprice classic: kit..rpm..top speed of 55 -60 mph..plugged exhaust

Customer Question

I Have a 82 caprice clasic with a 305 engine I just put a crank kit in, the timing gear set is a double roller and the crank gear has 3 positions, 0*   +4*    -4* I used the o* mark to set the cam gear timing..it runs poorly and pops through the carb on a heavy rpm has a top speed of 55 -60 mph them pops through carb, acts like a plugged exhaust but I have checked this. any ideas
Submitted: 8 years ago.
Category: Car
Expert:  Ivan replied 8 years ago.

Hello,Customer Did you install the gears dot to dot? Also, If the gears were installed dot to dot, I believe that position is #6 not #1, so maybe the dist. is off by a little bit. Just a thought.

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Ivan

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Customer: replied 8 years ago.
Reply to Ivan's Post: As my name indicates I am a retired mechanic so my son and I did this together so every step was double checked, yes dot to dot,It is on top dead center #1 on chevy.I checked that when we installed the crank.
Expert:  Frank replied 8 years ago.

The early 80's v engines wher good for eating cam lobes.Can you get it to sound like popcorn when you nail the gas pedal in park?That also has teh first year scan data capibility to see parametrs so you can see if its lean.A pluged convertor and late ignition timing run about the same.You really need to get a voltmeter or scanner on it to see the O2 voltage to know if your rich or lean.

Customer: replied 8 years ago.
DVOM indicates colsed loop operation, cycling <.5v > .5 v: nas no converter, I have dropped the exhaust, cam was replaced 35000 ago, advancing the timing raises the rpm SLIGHTLY where this happens, also my son reoprts it was fine before we noticed a rod knock which turned out to be # XXXXX rod bearing washed out, we pulled the engine and dropped a crank in w/o pulling the top end, this is why i was trying to find out info on the ofset of 4 deg listed on the crank gear.
Expert:  Frank replied 8 years ago.
The factory chains have only one mark-when useing a after market chain set put it at 0-( the factory actually retards the cam for emmisions and advancing it to zero will give it slighlt more compression and torque.If it runs like a stuffed convertor-double check to see if the balance has spun.Bring #1 to tdc and check the balance markes.You know that there where 2 diffent timing markers used aon the small block-the early models wher low about 3 o'clock on the timing cover and the newer ones are more like stright up.Double check the piston at tdc to balance marks.You also did a lot more work to that then just putting a timing chain on.
Customer: replied 8 years ago.
already done this, also attempted to advance timimg manually to overcome the possibibity of retarded timing, we did bring it to compression TDC by testing for compression on #1 when inserting dist at #1 position.
Expert:  Frank replied 8 years ago.

Did you change the crank?

Customer: replied 8 years ago.
Yes , NAPA reman crank, I have double checked the crank # XXXXX me, not the Physical # XXXXX on the crank though.
Expert:  Frank replied 8 years ago.

Do did not degree it in and I wonder if the tdc marks are different.Pull #1 plug and rotate by hand the crank with a coat hanger in the cylinder as a gauge and get the piston up to tdc and see what the marks on the balancer show-after that your going to have to dgree the cam to make sure the cam is in time.A chain off 2 teeth will run like a stuffed convertor.

Customer: replied 8 years ago.
as I stated I already brought it to Physical TDC and checked the vibration dampner marks, also we double checked the cam to crank timing marks, do you know what the +4deg marks on the crank gear are for.
Expert:  Ivan replied 8 years ago.
Wow, you guys have made some progress. Have you loosened the rockers a little to see if maybe the valves are overadjusted?
Customer: replied 8 years ago.
yes this is one of the first steps taken, but remember I never had the heads off and it worked before.
Expert:  Frank replied 8 years ago.

Beside the obvios valves-valve adjust-intake gasket-carb and ignition timing(you did disconnect the set timing connector?) your left with valve timing off of the timing chain

 

Expert:  Ivan replied 8 years ago.

I think you should perform a compression test if you haven't done one and recheck where you stand. Maybe the crank had too much lift and maybe a valve got kissed by a piston. At this point anything is possible.

Ivan