11.5 car whats it take

big reazon said:
Guess I have to do a rebuild pulled all spark plugs and did a compression test the results were as followed 1-100,3-100,5-110,2-120,4-80,6-100. What mods should I do while it is apart are their preferred cheaper pistons? Do I need rods and crank upgrades for my goal other than arp bolts? Will porting and polishing the heads make since if I leave the intake stock other than an rjc plate? Dont have the money to spend on a roller cam right now what would people recommend this kinda bums me out because I payed for a good running motor or atleast it was advertised that way. Would it be worthwhile looking for a 4.1 block?
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Well if it's on the engine stand already, might as well take it apart and see what you have to work with. Then go from there, maybe a cam lobe is wiped or a head gasket is blown.

Chuck
 
Found nothing really cylinders still have crosshatches on them but there is a slight bulge at the top of the cylinder where there i usually a carbon ring but it is the actual cylinder the pistons are pretty clean and the valves seam a little dirty so I guess Ima have the heads checked and go from there. No sludge in the motor. No flat lobes. No head gasket problem. So off to the machine shop with the heads to see if there is a problem with them.
 
It wasn't worth pulling the heads. That leakage isn't too bad considering the engine was cold and probably sat for a while. Should have left the heads on and ran it out. Probably some leakage at the valves and a little past the rings. Correcting it will net zero power. I've ran with bent valves and a lot of leakdown where it was noticeable at idle and cranking but it picked up nothing fixing it.
 
"there is a slight bulge at the top of the cylinder where there is usually a carbon ring but it is the actual cylinder"
Depending on your budget/situation, I wouldn't put it back together like that myself, you may be able to see the cross hatches but your cylinders are worn, the top of the cylinders are the original bore size. The others may tell you to just run it like it is, me, nah, make it right, then put it back together....
Right now you are only out a set of headgaskets and a set of ARP head studs or bolts, which ever you prefer. The stock bolts are stretch to yield, so technically your supposed to scrap them and buy a new set.
The compression reading should be within 10% of each other, after a rebuild 150 psi seems to be typical, sometimes higher/lower.


Chuck
 
Well might just go get the heads ported now that their off at the very least and whats the best was of sealing this thing back up head gasket wise. Also Are the factory pistons forged or hyper-eutectic?
 
As Bison said, you should have gotten the car running and got your feet wet before you rebuilt the motor.

I just ran an 11:57 on a beater $600 stock long block with factory valve springs. One cyl tested @ 65...



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Yeah will you live you learn I made the mistake of pulling the heads off already So do you guys feel that porting the heads on a completely stock car is worth it since they are off the car and all. And what would you guys do for sealing them up now that the factory gaskets are gone.
 
big reazon said:
Well might just go get the heads ported now that their off at the very least and whats the best was of sealing this thing back up head gasket wise. Also Are the factory pistons forged or hyper-eutectic?
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The factory pistons are neither. They are eutectic. Clean up the bowls and get a valve job done.
 
big reazon said:
I have a 81 chevy malibu that I am currently building and have bought a grand national motor and trans complete for 1500 bucks. Now I know these motor combos were 14 second combos back in the day. But being that my last sbc in my other malibu ran 11.6s to 11.8s I would like to beat that or at least match that...
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Should have just threw a turbo on the SBC then, problem solved... :tongue:

There are guys here running close to nines with just a cam, turbo, stall and injector swap, they didn't even touch the heads. Your goal shouldn't be a problem for you, especially if you do decide to touch the heads...
 
big reazon said:
I have a 81 chevy malibu that I am currently building and have bought a grand national motor and trans complete for 1500 bucks. Now I know these motor combos were 14 second combos back in the day. But being that my last sbc in my other malibu ran 11.6s to 11.8s I would like to beat that or at least match that or I feel that the swap would be a waste. I feel the gm high tech performance is very discouraging because they make it seem like you have to spend 7 to to 10 grand to get there. Now what do you guys say. Im real mechanical so labor isn't really a problem it is what parts do I grab and install I have George at Turbo Tech to tune it if he can even tune these older computers. I want to run at least an 11.5 maybe high 10s one day But I dont want to do things twice and I dont want to have to take a loan out on the house so what are the necessities currently the motor is all stock.
Click to expand...

get in touch with one of the cars that ran TSA at Bowling Green this year---------all ran low 11's with totally stock looking cars right down to the factory air box
 
Had a couple dead exhaust valves. Knew it was the heads the cylinders looked too symmetrical to be that far different. Gotta talk to the machinist on the bowl job and a valve job.
 
Well the heads are off getting ported should I do a bigger flat tappet cam while I have the motor down since roller isn't in the budget unless I find a used set up.
 
How much are you spending on a port job?

The engine that you bought, less trans/converter, stock turbo-intercooler-injectors had a very good chance of breaking into the 10's in that light car.
The only thing it needed was the timming chain and valve springs replaced and it would have run 11:30's all day...

Stock cam has run deep in the 10's in a heavy GN and your goal is 11:50's...

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timming chain and valve springs. Whose parts would you recommend for that they are sitting in the shop scheduled to be dropped off at dg machine since no one at my machine shop wants to port cast iron.
 
Remember what bison said, you don't need a full race port job, just clean up the bowls. You can do that yourself.

I think the common springs are LT1 and are cheap. Search this site for timming chains. I would go with a stock replacement but look it up.
Also, vendors with this site carry alot of what you would need.
look up Fullthrottle and see what they sell...


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