Ello chaps.

Bottom end is all built up, and as follows:-

Block rebored to 0.5mm oversize.
New AE 0.5mm oversize pistons and rings.
Polished crank with new standard bearings.
The old conrods with new bolts and shells etc...

My question is, when the cranks turned to the point were all the pistons are level within the block it gets very stiff.

Its pretty free until that point. But takes a bit of elbow grease to get it past that point. Is this normal on a freshly built engine? Obviously it isn't run in yet.

My thoughts were that it was because it wasn't run in yet and that the conrods are at there most extreme opposite angles, requiring a greater turning force on the crank?

Any advice would be great

 

hi mine done that on my cossie a 100 miles ago and i asumed the samething but a hundred mile later and it still stiff at that point hmmm

 

thats where the block heas least wear as towards the top it has more wear due to engine firing at the top of the block and forcing the piston against the block at the the top, it`ll be fine once ran in!
put no.1/4 pistons right down the bottom and dip you hand in oil and rub it round the bores, same again on 2/3 and it`ll be free`er promise!

Sean (never gave bad advice yet lol)

 

Sorry Sean but the lad states that this is a rebored engine so that shouldnt be the case at all.....

Oval conrod caps are common as are bent cranks.. were these all checked?

 

this happened to me on the first xflow engine I did when I was fifteen, got the conrod caps mixed up meant the bearings were slightly oval.
also when you put the pistons in did they go in easily or did you have to hit 1 harder than the others?
if so remove the pistons and refit using plenty of oil as 1 of the rings may be slightly out of place
hth

 

Right. Basically we pulled the engine apart and found that the cylinder bores were fucked and needed that it needed new shells etc...

Took it to a local engineering place and got them to rebore it to 0.5+ oversize and check the crank and polish/grind it if need be and supply shells etc (would they have noticed a bent crank while doing this?).

Picked it up, lubed everything that was needed to be lubed, in oil and put it back together (once with the main caps the wrong way round so the crank didn't even turn LOL). And this is the result so far.

Crank turned free as owt before we attched conrods pistons etc...And it even turns free until the point i have described.

Stu mate, the engine was running without much problem before the rebuild (i.e no knocks and bangs) just wasnt producing any real power. So i just thought that a bent crank wouldn't have been a possability or oval conrod caps. Thats my inexperience showing through now innit!

As for the conrods caps being mixed up...would this cause the crank to not turn at all? Like when the main caps were mixed up? Or just stop it turning where i am describing?

Are there any marking on the caps so i can wip the sump off and make sure they are on the right way?

Will still do what Sean said and see if it makes a difference.

Sick a cunt here

 

the caps will make make a difference, they are numbered 1 to 4 on the rod & the cap

 

Hi,
Best way to proceded here is to remove all four rod caps.

Now rotate cranka nd ensue it turns easily..

Then ONE at a time, refit a rod cap, and check the crank still rotates fine.

If so, REMOVE AND MOVE TO NEXT ONE.... so you only have one rod and piston connected to teh crank at any one time.

When you find one that sticks where you suggest, you can deal with it as necessary.

 

Cheers for the help fellas, much appreciated.

I'll not beable to attempt this till tomorrow sometime, but i'll be sure to let u know how i get on.

Stupid question but, will the new conrod bolts that i have fitted be ok to use again with the engine not even being started? Not being a cheap skate, but no point buying new bolts if i dont have to is there

 

UPDATE.

Finally got round to taking out and checking the pistons and guess what...the crank gets stiff even without any of the pistons in.

This has me slightly confused as the crank from memory turned just fine before everything was put back in.

If the weather picks up, i'm gonna go and crack the main caps off and have a look...but don't really know what am looking for

Any help would be appreciated

 

Top man for taking her apart again and not just leaving it...
Will be worth it in the long run

 

Stu - Cheers for that mate, made me feel all warm inside

Been out again and cracked the main caps off...and the bloody thing is STILL sticking at a certain point!!!

There's nowt holding the crank apart from the oil pump and shit on one side and the main oil seal on the other.

What the hell could it be??? I'm sooo bloody confused now its unreal.

Daft question, but i havn't primed the oil pump yet...was just gonna do that once everything else was sorted/fitted up prior to starting it up. Could that have anything to do with it?

 

Luckily the 1.6 CVH parts are cheap as chips and common as hell. Nothing different in the RST compared to the N/A versions.

 

I would remove the oil pump and the rear main seal carrier, just leave the crank in its 5 main bearings, try it then. If it still sticks try loosening each main bearing cap off one at a time and turning the crank, if it still sticks try the next cap and so on.

Also dont try to lign up the oil pump with the block flange, try to get it centralised on the crank.

 

hello everybody have you not checked the oil pump if you fit it in the incorrect place on the crank this is what can happen as for oiling the bore you should have done that any way to help the pistons get moveing until the engine can get its own oil there thereif im wrong let me know

 

Moonie - It defo dosn't stick when its just the crank in there. I'm thinking oil pump now aswell mate.

When we fitted it, we tried to make sure that the flat edge of the block was inline with the oil pumps, so they were both flat togther. The idea being that it'd make a better seal for the sump gasket

B13nde - All the bores were oiled up! Come on i know its my first time but i aint that daft

I was wondering if it was something to do with not priming the oil pump up yet, as i was going to do this once everything was built up before we tried to start it

 

to tell you the truth ive never oiled the pump up just left the king lead off and cranked her over for 15 secs but in your case it mite be worth a try hope all this helps

 

When you fitted the oil pump did you get it centrel on the crank you didnt make it line up with the bottom of the block did you? remove pump and try the crank then, most people try to make the oil pump line up with the block fluch at the sump side it may look right but the pump will be offset on the crank and have a tight spot ive seen pumps shatter this way read the haynes manual its there about this point.
All i can think of unless the caps are distortin the block when there tightened up ?
Best of luck,its best to bore the block with the main caps torqued up also,so im told anyways lol.

 

This is VERY good advice and may well be your problem by the sound of things... fingers crossed

 

Here:
http://www.pumaracing.co.uk/cvh.htm
scroll down a page or two and there's a whole chapter about lining up the oil pump.