1256 Engine Rebuild

[77vette]

I have a 1256 here with the head off if you want it. sell for like $30

[dunc]

Thanks for the offer. Where are you based? Im near chch so if youre a long way away would you be prepared to just send me the camshaft? Cheers dunc

[gordo]

Better option would be to send the camshaft and the followers, marked for which lobe they are for, to minimise any wear that may occur from a mismatch.

[77vette]

im in Auckland. not ken to dismantle it etc. I could put it on a pallet tho and post with mainfright. should cost roughly $80 to send to chch

[dunc]

Need some technical advice on this ongoing saga of my dead engine. Got the engine out and sump off today. As suspected, the oil pump drive gear is chewed to bits, and there is bits of the gear left in the bottom of the sump. Not good. The cam shaft gear that drives the oil pump has broken off the leading edge of a couple of gear teeth.

How important is the endfloat on the oil pump? I had the pump rebuilt with a new kit when i had the engine rebuilt. THe haynes book says 7 to 10 thou. My oil pump is 33 thou. Its over a millimetre out - so the oil pump gear possibly sits slightly too high in relation to the cam when the pump is installed. It looks like the oil pump drive pinion may not have been pressed on properly?

Could be a likely cause for the gear to chew out? Its an offset drive distributor model. I figure if Haynes manual make a big point of it then its fairly important.

If so ill be going back to the guy that did the engine. Im now worried about where else the metal filings could have gone. My brand new engine is no longer brand new! The guy that worked on it has to come to the party either way.

Also - do you need a gasket where the oil pump bolts up to the block? There was a thin one on it.
Any advice appreciated.

[dunc]

And to Gordo - nowe that i have it off it certainly looks like that new pump should fit straight in - its actually a bit smaller since the relief valve is all internal. thanks for that. Hope to have the beast back on the raod soon - subject to getting a camshaft.

[gordo]

I hope it was the old oil pump that was 33 thou (that's 0.84mm) and not the new one!
The end float is set by the gear in the housing, ie, it's the end clearance of the gear(s) and if it's excessive it's almost always due to wear (a new one would have to be incorrectly mnachined and I just can't see that happening) - under the circumstances I suspect it was incorrect assembly.
There is a gasket between the pump and the block, it should be in the gasket set and must be used.

The filter 'should' have taken all the material out of the oil as, IIRC, it is a full filter system. However, I would still be giving everything a damned good cleanout with plenty of detergent and hot, high pressure water - if you have one of the commercial wash bays in your part of the world, they work well - just make sure you dry it out ASAP afterwards.

[dunc]

Gordo - yes the old pump is the one thats at 33 thou. The new one I just bought off you is within tolerance.
So could the incorrect endfloat on the old pump (the one i had rebuilt) be the cause for the gears chewing out?

I spoke to the guy that rebuilt it and he doesnt want to know about the issue, since i had supplied him with the brand new oil pump overhaul kit.
So apparently its something wrong with the kit I supplied - like the gear wasnt hardened properly. I dont buy that explanation.

Sounds to me it wasnt assembled correctly. But just wondered if that endfloat issue is enough to cause the gears to chew out like they did.

[gordo]

If you supplied the rebuild kit, it was his responsability to assemble it correctly - part of that is checking the end clearance, si, IMO, that's BS On that topic, IIRC, you thought the drive gear, driven off the camshaft, was incorrectly assembled - upside down? - and that may have resulted in excessively high thrust loading on the gears and that may have caused excessive wear to occur - how did it compare to the new pump drive gear?
Regardless of that, it should make SFA difference at the drive if it was as much as a mm out of the nominal height as, IIRC, the driven gear is constant pitch and doesn't have a specific meshing height.
The 'hardness' is also, IMO, plain BS as there is a oil film separating the various parts of the pump and wear should certainly not be an issue. I've strripped a LOT of pumps, over the years, from different manufacturors and makes, and as a general rule there will be, at most, some light scuffing, period, even on engines with well over 100k miles. Even then, that's usually from fine debris being passed through the pump before being captured by the filter. Sometimnes there will be evidence of wear between the gear faces, as they also have fine debris get caught get between them as they rotate.

To get back to the wear of the gears, my first suspicion is that the gear was incorrectly fittle to the oil pump shaft and that caused very high loads on the meshing contact point - which chewed out the gears - and the gear on the pump body - with the resulting high end clearance/float.

If you strip the pump, I expect there will be a badly worn drive gear (the one on the shaft) and where it contacts the cover plate and the other, driven, gear will show a lot less wear.

They are very easy, basic engine work on and, with a manual and basic tools, you should be fine doing it yourself. most important things, IMO, are CLEANLINESS, making sure everything is correctly torqued down and using the dummy bolts to align the head gasket and head, as mentioned elsewhere.

My persoanl opinion is your builder fornicated up the rebuild and now is hoping you'll just go away - name and shame time, perhaps?

[dunc]

Anyone know if a camshaft from an 1159cc engine is the same as and interchangable with the one from a 1256cc? cheers. also if anyone got one lying around id be keen to take it off your hands....

[gordo]

It's important to have had the friction plate centred on the flywheel, otherwise there is a very good chance the spline and the spigot in the rear of the crank will never line up.
I usually lifted the engine (short block) in by hand and there can be a bit of rocking involved, but usually only took a couple of minutes. Making sure the gearbox was raised on a floor jack (but not too high) certainly helped the alignment process.

[caine]

I got one u can have it if u can get it out

[dunc]

Chevettes been back on the road now for about 6 weeks. Reassembled the motor with secondhand camshaft from local good bloke Nick who is a Vauxhall collector and sold me an old engine to cannibalise. Nick is brother of Chris on this forum I think. Thanks to Gordo too for the oil pump I bought off you about a year back - it works good. so if you see a red hatch crusing round Canterbury its probably me. Still on the hunt for bits for my other car for conversion to 2.3 slant. Gearbox and bellhousing tricky to find...

[cul8r]

Step brother yea, he's into his Vauxhall's big time!

Ill keep a eye out, not very often I see a chevette cruising around

[dunc]

Hi - Been some time since I posted on the forum. Hope everyones still enjoying their cars.
My original chevette with the now recon motor is still going strong - draws a bit of attention when driving round north Canterbury.

My other project chevette has now finally been shifted to my new garage so my HS copy project is finally underway. Was sitting rusting in my dads paddock for about 3 years and has really suffered. But amazingly it drove under its own steam to my new place. Been searching pretty much every day for the last few years for parts for the conversion to singlecam slant 4 and haven't made much progress yet. So far ive managed to get a 2.3 Bedford motor (low compression type) and extractors and a couple of other random bits, and heaps of info. Really need to find the rest - especially engine mounts, gearbox, bellhousing, axle etc etc. Everything is getting hard to find. Im hoping to get some twin Stromberg carbs from out of the uk soon. It wont be a powerhouse but I want it to be a fun road car that one day I might be able to take on the odd have a go track day or gymkhana and maybe rally sprint in future when im rich. Main thing is to get bodywork, paint and basic suspension repairs, and basic motor transplant done first, and work from there, eventually getting to tuning, brakes etc when money and time permits. So far have got it mostly stripped out interior ready to do some rust repairs and maybe seam welding and convert to upright rear shocks. Will get the progress photos uploaded soon. Might start a build thread depending on how progress goes in the net few months. Was originally going to build as a nice tidied road car (has been my plan since teenage years!) but now going to look at keeping the inside pretty sparse and maybe fit a rollcage at some stage depending on how it goes.

Meantime - if anyone has any advice or bits for sale - im all ears.
Main things now looking for are back axle (keen to go for piazza), sedan turrets, any bellhousing and gearbox that will fit (pref 5 speed - probably have to go Toyota W series). Start getting stuff fitted up and go from there with all the other surrounding bits and add-ons.
Gonna be a big project.

A lot of people (including mechanics) trying to convince me to ditch the slant 4 and instead work with the 8 valve 2 litre Opel/Commodore motor and box ive got already sitting here - but I cant help but lean toward the 2.3 to keep it more similar to the original HS chevettes. G200 was tempting for a while initially - seems that some guys on this thread have done it and found it most straightforward swap.

Anyone see the completely rusted out original HS on ebay recently? I was going to try to buy it cheap and import it, till the guy told me he wanted minimum 7 thousand pounds for what was essentially a pile of bits (but very hard to find bits!). One day...

Cheers