250 engine rebuild thread

Discussion in 'Megane Projects' started by ianplymouth, Nov 8, 2017.

  1. I will weigh them for you tomorrow :laughing:
     
  2. Have you checked the difference in weights of the cranks?

    I know the 197 crank is lighter than the 1*2 one, was wondering if the 250 one may be similar?
     
  3. The cranks in the 250 and 225 look identical, the only difference i have found is the bolt that holds the pulley on is a bigger diameter in the 250.
    don't know about the 197 crank, would it even fit ???
     
  4. Yep, it should drop straight in, just a suggestion mind, I’m just trying to think of the best ways to lower the rotational mass
     
  5. I think i have done that already by fitting a single mass flywheel, that was some difference in weight :openmouth:
     
  6. I thought similar when fitting mine! DMF is heavy!

    Have you decided on cams for the build?
     
  7. Very heavy, quite surprised

    Yes i have decided, the standard cams are staying, the benefits of the cams don't really add up, £1500 and no one can say what i will gain.
     
  8. Cave you thought about Clio 1*2 cams? Similar spec to cat cams and can be picked up for penny’s.
     
  9. The 250 pistons are all within 6 grams apart from the one the valve hit that has lost 10 grams.
     
    Big Uno likes this.
  10. I have had a look for a pair of 197 cams but nothing that i can find, they need machining apparently, would consider if i could find some.
     
  11. Pulled the crank and a piston out of the wife's DCi 175 today, did go and buy an engine stand from Machine Mart thinking it would make it easier and safer to work on the engine, opened the box pulled all the parts out to find that both legs didn't have any holes to bolt it together, so it will be going back tomorrow and getting my money back.

    Anyway pic bellow is, on the right a 250 piston and rod and the left the DCi 175, nice and chunky con rod as standard.

    [​IMG]

    also these con rods are a snapped cap type, so they are a really strong, wonder how much torque these would take

    [​IMG]
     
    Big Uno likes this.
  12. Forget about 197 cams, they are way too lairy. You’d want 172 cams at most and even they are really hot for a turbo engine. Tbh, i’d just keep the standard cams in if i where you!
     
    ianplymouth likes this.
  13. Really appreciate your input mate, but i had already made my mind up that the standard cams were staying, will get that other sorted this week and i will let you know. :sunglasses:
     
    tutuur likes this.
  14. Big Uno

    Big Uno RSM Trader

    Cheers mate :laughing: im not so worried about my new ones now being within a gram.

    Ive been looking at cams too, but struggling to find decent results from 172 cams in the 225 engine. Or any others for that matter.
     
  15. I am not bothering, standard ones will do for me, don't want to make it "peaky"( like an old 2 stroke motorbike) a nice spread of torque across the rev range and i will be happy.

    It just seems a lot of money for say the Cat cams, the tool for setting them up is £225 +vat and delivery :confused: i think it was going to work out around £1600 + toooooooo much, that money would be better spent on say, a custom turbo and would get better results.
     
  16. Big Uno

    Big Uno RSM Trader

    Agreed on the price, been looking at the catcams, also got the springs to consider, and extra load on the cambelt? Never used catcams products before so no experience, have a friend running some fairly hot ones in an evolution 8 and it is litterally all or nothing with his set up :smiley:

    Trying to find more on the 172 cams but dont know whats needed to fit them correctly and delete anything vvt ralted oil ways etc?

    Anyway I think if all round power is what you are aiming for you have made the right choice sticking with the stock cams.
     
    ianplymouth likes this.
  17. Just a quick update
    The Dci engine is nearly ready to go back in, needed to get a rear crankshaft oil seal as the old one looks like it might be weeping, that turned up today, so fit that and the flywheel/clutch and then the gearbox (with short shift mod) and should be fitting this weekend.

    I also had a call about my cylinder head yesterday, ready to pick up tomorrow (today) so drove down and the guy is still fitting the valves, the guy putting it all together said the 250 valve stem seals won't fit under the Supertec valve springs, he has managed to find some seals that fit but he needed to check with the boss to see if they were okay to use, he also noticed that two of the hydraulic lifter seats were broken out, so there was a real possibility that the hydraulic lifter would drop and give no valve lift, so i don't know when i will get a call to say it's all fixed, they said it would be sometime next week but i can wait.
    From what i have seen already they have done an absolutely fantastic job, will get some pics up when it's in my possession again.
     
    Big Uno likes this.
  18. Big Uno

    Big Uno RSM Trader

    Looking forward to seeing the head complete :smile:
    Did you get a photo of the lifter seats damage? Wonder what they will do to fix that.
     
  19. I am looking forward to getting it back" done", i didn't get a photo but i think i can show you on a head i have what the problem is, i also know how they are going to resolve it, when he explained, i was a bit taken back, but this is what they do so i am going to trust them, he also showed me another head with the same sort of problem and it looked good.
     
  20. I'll just leave this here. 172 head (and cams) on a forged 225 bottom end! Note, this is hp at the wheels. fa044a1206ff1505390686cc8187cb78.jpg

    Sent from my SM-G955F using Tapatalk
     
    Big Uno likes this.
  21. Big Uno

    Big Uno RSM Trader

    Thanks thats useful!

    Guessing thats yours? Are the two graphs before and after only the head change?

    Decent power! What turbo / fuel system is it running?
     
  22. Yep, won't clog the OP's thread up with my car (it's on Cliosport if interested - same username) but the graphs are just different boost levels. You can see the torque tapers at higher boost, which is because boost is tapering. Something I am trying to work out as there should be another 50hp there up top. I don't have a before/after - engine was built with the Clio head as I'd been advised it'd flow better (it's also in a Clio btw). Worth noting it was not a straight bolt on - had to move the tensioner.

    Running a twin scroll efr 7163. Fuel is handled by a Walbro 460 in tank lift to a 4.5l surge and to the rail via a deatschwerks 350il - running E85. As mentioned, jump on Cliosport if you're interested to know more.

    Look forward to seeing this build progress.

    Sent from my SM-G955F using Tapatalk
     
    Big Uno likes this.
  23. Sorry, username on Cliosport is Camsmyth - https://www.cliosport.net/threads/the-missile.807467/

    Sent from my SM-G955F using Tapatalk
     
    Big Uno likes this.
  24. It is a design fault in this twin scrool exhaust housings.Wastgate flaper is directly afected by exhaust flow and it is like a big sail.not eaven a very stiff spring can hold it close.
     
    Campbell_Smyth likes this.
  25. A quick update

    My wife's Megane Dci is now up and running, just got to sort the drivers window motor out and then she can have it back, then i can get my 225 back into the workshop and get on with the rebuild :sunglasses:
     
    Big Uno likes this.
  26. Okay not posted for a while as i am still waiting for my cylinder head to be finished, it been 14 weeks now, running out of time.

    So after speaking to a very knowledgeable on here i have today taken delivery of another cylinder head, so at least i can at least start planning to get things moving again :sunglasses:

    [​IMG]
     
    Big Uno and Paul21 like this.
  27. Big Uno

    Big Uno RSM Trader

    Nice to see your back on track again, would be interested to see what differences there are between the 250/265 head and the 197, stems and valve sizes?
     
  28. Well i will be collecting the other head tomorrow, so i can get my big valves out and fit them to this head, so until i get the other valves out i can then let you know the difference.
     
    Big Uno likes this.
  29. Big Uno

    Big Uno RSM Trader

    Cheers mate would good for reference! Should have yours finished long before me now!
     
    ianplymouth likes this.
  30. Ha ha with any luck yes
     
    Big Uno likes this.
  31. Big Uno

    Big Uno RSM Trader

    not if you send the head to the same place again :tearsofjoy:
     
  32. Can't see that happening, i will more than likely have to wait till Christmas at the earliest
     
    Big Uno likes this.
  33. I took the valves out of the 197 head and the exhaust valves are 5.5mm in diameter, the exhaust vales in the 250 head are 6mm diameter, so i took it to a local engineering company (i have used them before for other stuff) they pushed out the valve guides on the exhaust side, then reamed them out to 6mm, then reinserted them in the head, dropped the head off at 10am and then told i could collect at 3pm.

    They also have had a look at the 250 head and they say they can sort it out for me, told them i am not in a rush as i have the 197 head.

    I have now fitted the Supertec valves and springs to the 197 head.

    The head has now been fitted to the block, torqued down, followers and cams fitted, new cam belt, manifolds fitted, new hybrid turbo fitted, now ready to be put back in the car.

    Had a couple of hours on the car tonight, engine is in and suspended on it's mounts, i have completed a few other jobs but not quite ready to run it up, will be later this week :sunglasses:
     
  34. Big Uno

    Big Uno RSM Trader

    Great stuff Ian! Cant wait to see how your build performs!
     
  35. Great work Ian.

    Be a monster when it's done :sunglasses:
     
  36. Cheers mate
    can't wait till i start running it in, it's been such a long time now
     
    Big Uno likes this.
  37. Well i put the drive shafts in, started to put the suspension back together on the drivers side, all going well until i put the disc on and found that the wheel bearing is knackered :rage:,don't remember anything the last time i drove it :dizzy:, so had to pull the hub back off again, so will have to pick up a bearing tomorrow, carried on with the passenger side and that is all back together, also fixed a very very small coolant leak, the rubber bung just behind the thermostat that is on the stub had a hole but was so small that even when pressurised it would just form a drop on top of it, so drained the coolant a bit, removed it and filled it with some sealer.

    Back down tomorrow to do the wheel bearing and then maybe a fire up :sunglasses:
     
    Cazper and Big Uno like this.
  38. matt e

    matt e South East RSM Area Rep

  39. matt e likes this.
  40. Picked up a wheel bearing kit this morning, got the hub out with not much problem, the bearing out of the casting well that was a different matter, big old socket and a 4lb lump hammer, didn't budge one bit, so plan B, i have a 10ton puller for boat props, so jury rigged that, wound it as far as it would go and still not budged, left the full pressure on it and out with the blow torch, 10 minutes later still not budged, so finally out with the lump hammer again and bingo it started moving.
    Cleaned it up in with the new sensor ring and pushed the new bearing in with the vise, well that was 2 hours gone.
    Fitted the frame around the hub, checked the bearing all okay, so greased it all up and put it all back together, fitted the whole unit back onto the car.
    Connected the battery, disconnected the fuel pump power lead, doubled checked oil, coolant etc and hit the start button to build up the oil pressure, one full start sequence and then connect the up the fuel pump, pushed the start button again and away it went, a couple of quick checks around to check for leaks of oil, coolant all looking good, hydraulic tappets were ticking a bit.

    Switch it off, checked and i think i had an air lock in the coolant system, think i got most of the air out now, ran it up again and the tappets quietened right down, left it running to get the temp up everything looks and sounds great.

    Started to put the front end back on but ran out of time, hope to finish it tomorrow and then take it out for a drive over the weekend.
     

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