Engine rebuild

GroovyCarrot · Post by **GroovyCarrot** » Thu Jul 29, 2004 8:09 pm

Apparently the genesis is currently being held by the police, and it seems that it'll be going straight to the scrappy from there

Still, I'll be working on getting it, it was in beautiful condition, and I'm planning on doing a 350 mile drive to pembroke next sunday and it'd make it quite a lot more comfortable.. although, if my engine's still in pieces by then I'll have to take the corsa anyway. On the plus side it's relatively new and has a 5 speed box.. on the downside it's a corsa. Anyway, we shall see...

GroovyCarrot · Post by **GroovyCarrot** » Sun Aug 01, 2004 10:05 pm

Progress report: Hoisted engine out this morning, spent the afternoon seperating the component parts.. I've got all of the various parts off it, and the engine is split into the head, block and sump now, so pretty much ready to get the con rods and pistons out tomorrow and start fitting the new bits

I'm quite happy with that progress really, thought it'd take much longer to split up than that.. just have to see how easy it is to put together again now

Tahrey1043 · Post by **Tahrey1043** » Mon Aug 02, 2004 2:33 pm

grab a camera and give us a full, haynes-eclipsing (destroying?) step by step?

it'll help you with putting it back together as well

GroovyCarrot · Post by **GroovyCarrot** » Mon Aug 02, 2004 6:41 pm

I only wish I'd thought of that sooner, it would have been helpful.. thing is, I'm pretty much finished now, it should be ready to go back together tomorrow

I'll give it a good couple of days to reassemble, because this is the part where things start going wrong.. but with luck I'll still be on track for sunday

That way I can do the 600 mile wearing in period in two trips down the length of the M4

Tahrey1043 · Post by **Tahrey1043** » Tue Aug 03, 2004 2:39 pm

yknow it takes longer if you hardly touch the lower gears mate

GroovyCarrot · Post by **GroovyCarrot** » Wed Aug 04, 2004 10:11 pm

Would have thought that it would be irrelevant which gears I was using, more to do with amount of strain on the engine and amount of revs? Although, I guess strain on the engine tends to go more with accelleration than 70 mph cruising..
Anyway, it seems I'll be taking the corsa to wales

My parents pointed out that it might be a silly idea to take a completely untested engine that I'd only just fitted right across the country, which is a good point, but it does mean being stuck with a vauxhall for two 7 hour trips..

bstardchild · Post by **bstardchild** » Wed Aug 04, 2004 11:32 pm

GroovyCarrot wrote:Would have thought that it would be irrelevant which gears I was using, more to do with amount of strain on the engine and amount of revs? Although, I guess strain on the engine tends to go more with accelleration than 70 mph cruising..
Anyway, it seems I'll be taking the corsa to wales My parents pointed out that it might be a silly idea to take a completely untested engine that I'd only just fitted right across the country, which is a good point, but it does mean being stuck with a vauxhall for two 7 hour trips..

But....... I built a car engine once before a 6 hr trip to France - in fact the previous evening I was still putting it back together. Take the polo - it will be fine if it runs when it starts why should it be a problem?

Tahrey1043 · Post by **Tahrey1043** » Thu Aug 05, 2004 4:45 am

eh i was just thinking in terms of total number of revs

i dunno............... clueless on the whole running-in thing (what difference does it make whether it's been run for 600 miles or 6 miles?)

it may run when you first start it, but there could be all kinds of things you've forgotten about or messed up that will cause it to sputter out 5 miles up the road... or after the first couple hundred, just in time to blindside you as you settle into a comfortable sense of security with a job well done!

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Thu Aug 05, 2004 7:32 am

It makes sense what tahrey is saying (for a change

) IF you drive about at 30 in third youll do more revs than in 4th but still be below 3000rpm (the unwritten rule limit when it comes to wearing in an engine) then in theory youll wear your engine in quicker. As for taking the trip youll have to do it rather slowly wont you if u go on the mway cos of ur gearing yes?

Tahrey1043 · Post by **Tahrey1043** » Thu Aug 05, 2004 4:29 pm

why thanks......

yeah im thinking to go along with your rule there, it's a 50mph cruise, though might be able to slowly open it out to 55, 60, just to keep in with the left-lane traffic. and 3rd around town just to speed the process up

GroovyCarrot · Post by **GroovyCarrot** » Thu Aug 05, 2004 10:30 pm

Hmm.. surely 3000 only a rough guide as an unwritten rule.. accellerating up to 3000 rpm would put far more strain on the engine than cruising at 70 at 4,500 rpm, surely?

I'd consider taking the polo, but I'm not entirely sure it'll be finished by then, given that I've only just got the head in and all the time I have is until 5:00 tomorrow afternoon before I have to do a solid couple of days at work. Plus, I've just got myself insured on the corsa for another couple of weeks, so it seems a bit silly to waste that.

One thing I've been wondering slightly.. having replaced piston rings, big end bearings and main bearings, should everything be quite so tight that I can't actually turn the engine anymore? It's a bit of an issue from the angle of getting the timing set up, apart from anything else.. I checked, and I haven't left anything lying in the cylinder block, everything's torqued correctly, but the pistons are very stiff in the cylinders... Just slightly wondering quite how tight they should be at first. I'm hoping they'll loosen off when it starts turning over and gets a good bit of oil in there

bstardchild · Post by **bstardchild** » Thu Aug 05, 2004 11:27 pm

GroovyCarrot wrote:Hmm.. surely 3000 only a rough guide as an unwritten rule.. accellerating up to 3000 rpm would put far more strain on the engine than cruising at 70 at 4,500 rpm, surely?

My guide for running in has nothing to do with revs

Don't let it labour under load - in 5th and 800 rpm up a steep hill

Don't let it rev excessively - you can use quite a lot of the rev range without harming it - like bouncing it off the red line

Keep the revs and load constantly varying - avoid M-ways and dual cabbageways - stick to variable A's and B's

GroovyCarrot wrote:I'd consider taking the polo, but I'm not entirely sure it'll be finished by then, given that I've only just got the head in and all the time I have is until 5:00 tomorrow afternoon before I have to do a solid couple of days at work. Plus, I've just got myself insured on the corsa for another couple of weeks, so it seems a bit silly to waste that.

Fair point...

GroovyCarrot wrote:One thing I've been wondering slightly.. having replaced piston rings, big end bearings and main bearings, should everything be quite so tight that I can't actually turn the engine anymore? It's a bit of an issue from the angle of getting the timing set up, apart from anything else.. I checked, and I haven't left anything lying in the cylinder block, everything's torqued correctly, but the pistons are very stiff in the cylinders... Just slightly wondering quite how tight they should be at first. I'm hoping they'll loosen off when it starts turning over and gets a good bit of oil in there

oooops - you have a problem here when you build up an engine at every stage you should be able to turn the crank with out too much effort - as you add more friction to it the amount of effort to turn it will increase but it's only very slight (or should be) obviously this should all be done before you put the head back on - valve trains and cam shafts greatly increase the ammount of effort need to turn and engine over

Whenever you build an engine copius quantities of fresh clean engine oil on items being assembled are preferable to grease but if you are building an engine to store for a while then grease (or an engine builders paste) is prefrable to oil..

I'm just finishing the 24V lump - honed bores new rings and a set of big end shells and I can turn the engine over by easily with the front flywheel loosely mounted on the crank

Tahrey1043 · Post by **Tahrey1043** » Fri Aug 06, 2004 6:48 am

when that motorbike guy on the telly was slapping the fatboy V-twin engine together in an hour and a half, you could see where he got to the point you're at, and could still "pump" the cylinders reasonably well with a couple fingers each... at idle it's putting out hardly more power than a couple of guys pushing it would, so resistance to the point where you cant turn it doesnt seem healthy.

if you whack a load of oil in there, does it improve?

4500 at 70?

oiya i knew mk2 gearing was a little frantic, but DAMN

(3900 for me, it looks like so far.. til i get the calibration sorted anyway! which will probably involve one of those bike speedos, and having a laptop in the car with a sound-frequency grapher and a microphone attached (yes, i have access to all four of those

))

the manual says something like not using more than 2/3rds of the maximum engine speed while running in, and as yours is supposedly 6300rpm... so that makes it around 4200 revs for starters... not so bad... by your reckoning on revology, a nice thrum along 60-limit roads without breaking the law often/by much should do the job nicely. Say, keeping it between 1800 and 4000?
(which covers most everyday driving situations anyway - for comforts sake you wouldnt want the engine speed staying much out of that range for long - either a lot of noise and thirstiness, or a complete lack of oomph and labouring)

GroovyCarrot · Post by **GroovyCarrot** » Fri Aug 06, 2004 10:45 pm

It might be a bit closer to 4000 rpm actually, I haven't done 70 in it for a fair while so I forget

It was above the 4,000 mark, I'm pretty sure of that. Doesn't feel too uncomfortable though, it's strangely civilised.. only gets a bit raucous as you go over 80-ish.

I do indeed have a problem, as my local friendly mechanic pointed out to me when he serviced my dad's car earlier, just as I finished refitting everything into the engine bay. I took the sump off, released the big ends and tested the pistons, stiff but moveable, so I took a couple of the main bearings that I changed out and it now turns.. grudgingly, but it turns. Looks like I was sold the wrong set of bearings

Luckily though, I had a stroke of bad luck which prevented me changing all the main bearings (completely stripped an allen bolt that held the oil pump in place, so I couldn't remove the crankshaft), so I had only changed the ones that it was possible to get to without taking everything apart. Still doesn't look like it'll be done before I leave for wales, but at least they're relatively easy to replace. With luck, that'll sort it... fingers crossed, touch wood etc

I've just got to hope that my sister doesn't mind me putting 800 miles or so on her car

GroovyCarrot · Post by **GroovyCarrot** » Fri Aug 06, 2004 10:54 pm

4500 at 70? oiya i knew mk2 gearing was a little frantic, but DAMN (3900 for me, it looks like so far.. til i get the calibration sorted anyway! which will probably involve one of those bike speedos, and having a laptop in the car with a sound-frequency grapher and a microphone attached (yes, i have access to all four of those ))

Please, please don't say you're actually going to attempt to calibrate your rpm counter by connecting a bike computer and a microphone to your laptop and comparing the two inputs? Even I wouldn't go that far