LYN-TMR

Hi Guys,

I was wondering if anyone has experienced the same propblem or may even shed some light on my problem.

Iv got an xy with a 393 stroker in it still running 2v heads. its got a holley 750 hp dp, f246 crane cam, 10.6comp, weiand manifold, pacemaker 4 into 1 extractors.

This set up I was told it should make 260-280 rwkw but its only pupming out 211rwkw.....

Iv put on 2 different dynos and Iv tested it with and without pipes and still only makes 215rwkw with no pipes.

Does anyone know wat could be holding it back????

xdclevo

Make sure your cam is ok and survived run in, as i wipe all the the lobes on a previous motor with that cam and make low power. Ended up running 240rwkw with 351 cubes which was still a tad low but ran in the 11's in a full weight XD.

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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.

LYN-TMR

Thanks for the reply...Ill get the mechanic to check it all out for me.

I was told it could be my valve springs or even the dergrees for the cam.

Do u think that could be it or are you thinking more towards the lobes have been chewed??

It pretty much dies after 5000rpm where as its meant to be making power all the way to 6000 - 6500rpm.

xdclevo

Mine fell flat after about 5500rpm, where it used to rev free to 7000 and a bit more.
The cam is definatly somewhere to start, and fairly easy to check, and i found out by pulling out a few lifters and seen them worn bad.
Or another easy way to check cam is with a magnetic base/dial indicator and check what lift you see at the valvespring retainer.

Just remember to subtract off the lash you gave the rollers and if 26 thou, you should see approx 540 ish on the inlet and approx 560 at the exaust.
Check all 16 valves.

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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.

geos sho

have you all discussed pusrod lenght and geometry of the drive train. cam degrees on this engine will basically change your peak HP and torque rpm ranges and not truely change hp. by the way i hate Crane wipe one of there cams to. i run a split lift and duration crower 4 degrees advanced it rocks!!!!
if you are'nt getting float valve springs should be fine make sure open and seat pressures are set to the cam specs. the crower is 552 298 intake 562 308 exhaust.100 over pushrods

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my need is speed

LYN-TMR

Thanks for the replies guys.

Im just now waiting for my mechanic to come back from overseas to be able to rip it open and check it all up for me.

If you have any other ideas or suggestions keep them coming as this is doing my head in.

xbgt74

I guess you have upgraded the fuel lines to 1/2'' and fitted an electric fuelpump?I know someone who's 351 xy picked up another 40hp just by changing the standard fuel lines to 1/2'' and a holley blue fuel pump....just a thought...

LYN-TMR

No actually I havnt.

Iv upraded the fuel pump to the biggest mecahnical I can find for a cleveland but teh fuel line is still standard.

xbgt74

you will pick up more HP if you run a new line from the tank to the carby...fitting an electric pump bolted to the chassis rail near the tank...you will need to fit a modified sender unit with the 1/2'' suction line.....the mechanical pumps are'nt good enough...been there ...done that...

LYN-TMR

Hey guys,

I thought Id just update use.

I finally got around to taking the car down to the workshop and we got the motor stripped and check it all out...

Basically the guy that built it for me the first time ripped me off and he was a just a sh!t c*nt of an engine builder. Use might have heard of him O'Brien AMS in Swan Hill.

Whe the motor was stripped we realised that he has put in a a crane f238 instead of an f246, the head work was poor and it flowed 430hp when I was told and I paid for the heads to flow 500+hp, he put smaller valves than what we agreed on, the lifters were damaged as the lifter bores werent machined 100% and still had metal on them.

So I ended up changing the cam, redoing the heads, put a bigger stall in, changed the whole ignition system and a couple of little things that came up along the line.....

The cam has been run in on an engine stand but Im now driving the car around to run it in for about 1000kms then itll be back at the shop for a nice tune then off to the track.