Engine fails to start after rebuild.

General Chat About Engine Build

Moderator: phpBB2 - Administrators

paul c
Getting There
Getting There
Posts: 265
Joined: Tue Mar 11, 2008 7:41 am
Location: Takaka New Zealand

Re: Engine fails to start after rebuild.

Post by paul c »

That's the next job on my 4.6. I bought a degree wheel now just need to make a piston stop and find the cam specs, I'm using a 4.2 cam. Always like to check as often the cam can be a few degrees off from the keyway.



DaveEFI
Gold Member
Gold Member
Posts: 4603
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Engine fails to start after rebuild.

Post by DaveEFI »

Must admit I've never understood this. They can machine a cam so all the valve timings are correct for each cylinder - but get the keyway position wrong?
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

GDCobra
Knows His Stuff
Knows His Stuff
Posts: 377
Joined: Sat Feb 04, 2017 9:21 am
Location: North West

Re: Engine fails to start after rebuild.

Post by GDCobra »

DaveEFI wrote:
Wed Nov 03, 2021 9:38 am
Must admit I've never understood this. They can machine a cam so all the valve timings are correct for each cylinder - but get the keyway position wrong?
I guess the answer would be that all the lobes are ground in one operation so maintining the relationship is reletively straightforward but the keyslot is produced at a separate op' hence the relationship between this and the cam profiles depends on the setup accuracey.

It is a pretty poor excuse though?

Mind you 12 degrees is probably a whole tooth out on the cam gear rather than inaccuracy of the grind

DaveEFI
Gold Member
Gold Member
Posts: 4603
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Engine fails to start after rebuild.

Post by DaveEFI »

What we need is the cam driven by a servo motor, so MegaSquirt can adjust the timing. :lol:
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

Post Reply

Return to “Engines Area”