253 rebuild not starting.

[Lex]

Pretty much 65psi across the board except number one which is about 10psi.

If that is the compression of motor, that is crap.

 

[chrisp]

If that is the compression of motor, that is crap.

... or the cam timing is way out.

 

[figjam]

Does it have the valves seats modified for unleaded petrol ? If not, and has been run on unleaded, you could have valve recession, which will result in low compression.

 

[chance23]

Yep, I know the comp is crap. Just wasn’t sure if it was just because it’s a cold, fresh motor.
Cam timing isn’t out. I’ve properly degreed it.
Could be a carb issue as it’ll fire in the SYB but won’t carry on. I’ve adjusted the Quad down lean and also rich. No love.
Unsure about unleaded. It had been sitting in a shed for years before I picked it up cheap. Could be a possibility.

 

[Smitty]

.................: OIL PUMP WILL NOT PRIME THROUGH SENDER HOLE. ..............

I call BS on that comment... for 40 years I have been doing that, prime the pump via the sender ( via 1/2 litre in the oil plunger)
instant oil pressure every time

 

[figjam]

If it has been sitting for years, how is the fuel pump diaphragm ? Does it pump fuel when the inlet line ( to carby) is disconnected ?

A long forgotten thought from way back, have you used the correct head gaskets ?.
Something about using 308 gaskets lowering the compression ………….. dunno, too far back, old farts memory, imagination ?

 

[EYY]

I call BS on that comment... for 40 years I have been doing that, prime the pump via the sender ( via 1/2 litre in the oil plunger)
instant oil pressure every time

It's a gamble you shouldn't be willing to take. If you force it in hard enough it'll work - just not a good work practise. No BS there.

Prime it properly and it minimises the risk of wiping a lobe or doing more serious bottom end damage when you start it.

Another thing, don't crank it over trying to get oil pressure - most holden v8's won't have enough pressure to turn the light off with cranking alone. And cranking it over wipes all the lube off the cam too.

 

[vc commodore]

. Compression is there, but low. I’d expect that on a cold motor though. Pretty much 65psi across the board except number one which is about 10psi.
.

Was the compression test done wet or dry with those figures? If that's the wet figures, you have cam or head issues....If that's dry. do a wet test and report back.

Oh and finally, if that motor is rebuilt, I'd be rebuilding it again....You can push more compression from your butt.....Compression figures should be 130+PSI....

 

[Deuce]

I call BS on that comment... for 40 years I have been doing that, prime the pump via the sender ( via 1/2 litre in the oil plunger)
instant oil pressure every time

It may have worked for you. I tried it once and it was hopeless - never again will I try it this way.
So quick to whip pump off, sneak a little vaso in while spinning by hand to get that suction noise, then reassemble.

 

[Bigfella237]

I agree, those compression figures indicate a serious problem (I reckon you could install a piston with no rings whatsoever and still get 10 pound).

Everything I've read above points to valve timing being way out. With those compression figures I'd be pulling that engine apart again, something is very wrong internally.

Andrew

P.S. Just a silly thought... I don't suppose you have a VN-style camshaft somehow (with the different valve layout)?