No way u broke yours too. Cant believe it. Im getting scared to go to scoffs now. Lmao. Hope you get it sorted soon. Looking forward to seeing your car in the flesh.
No way u broke yours too. Cant believe it. Im getting scared to go to scoffs now. Lmao. Hope you get it sorted soon. Looking forward to seeing your car in the flesh.
What makes u say that Phil? Mine was very low comp 7.2:1 if I remember correctly..Originally Posted by GTphil
My original plan for the low comp was because of the nos and to build in some safety for the shocking ign map and crap carblol.
If I knew I was eventually going efi then I would of raised the comp a little..
I just think i could have made the same power for a lot less boost, after all I'm only in need of an honest 220hp and a good launch with slicks for a 12 second pass.
The only reason i went low comp was that's how my engine was before i built it, and it always seemed to perform well all be it at much lower boost. I really need to invest in a set of calipers as that's the only reason i didn't work out the ratio, it must be fairly low comp to tolerate 4 degrees of advance at 22lb boost with no knock.
True, but it's not a massive problem.. I certainly wouldn't go far as to say its where you went wrong with the build and let's face it everyone used to go low comp back in the day (and I'm not just talking about renaults).
Be interesting to see exactly what's failed.. Perhaps u wasn't getting away with 4degress lol
Maybe so, Scoff has good ears thowhilst i was on my way to scoffs i blew a boost hose, stopped to sort it and after that the first time i gave it some stick i noticed the boost went upwards of 27psi for a split second, i was off the gas instantly then when i arrived i closed the bleed valve and went and did some testing an made sure the boost was holding 22lb and it was. Who knows maybe i caused some damage then although i was never at full throttle.
Either way I'm coming out of sulk mode now and the curiosity is starting to bite and i can't wait to also find out what's gone wrong
either way I'm coming out of sulk mode now and the curiosity is starting to bite and i can't wait to also find out what's gone wrongwe've all been in that mood with these cars once or twice, get her cracked open and share the mess with us
Well...........it's been a late one, I have taken the head off and discovered my issue, it appears a bit of a random one
Firstly i was greeted by this
Then this
So it would appear and going along with the small shards of metal i found in the combustion chamber that something has been bouncing around in there
Couldn'd figure out at first where the metal had come from, then found this
Doesnt appear to be any piston to valve contact so i'm gussing that for whatever reason the valve guide just gave way
Wow that's a really odd failing
So what's the plan now strip it all done and check everything over or you going to risk it for a biscuit and chuck a new head on and see how it runs?
The head was completely standard, I have a bran new liner and a low comp piston spare, so I'm going to change that and a new set of big end bearings and put a new head on and see how it gets on. Will give the sump a good cleaning out and maybe run it for a few 100 miles with no turbo to try and catch any swarfe.
I can't get my head around what's actually caused it, i had that valve guide replaced a few years ago after dropping a valve. From the picture it looks a little like its come out of the head and slid down the valve stem and been smashed. I will have to compare it to the others but i don't think they stick out that much normally.
On a positive note all the cam followers are in a1 condition and the engine appears to have had a good tune and the plugs are good and no signs of det at all.
That's not too bad to put right then.
I guess the hardest part will be finding the time.
what is it with these cars every time you make a leap forward something pops up and you have to take a step back again.
When i first saw the damage that's exactly what i thought, the lumps only done 3k since a full re-build and i was just starting to get the tune good for decent power and i get a nice random failure like this!That's not too bad to put right then.
I guess the hardest part will be finding the time.
what is it with these cars every time you make a leap forward something pops up and you have to take a step back again.
I can see why people ditch the c1j, the thought has crossed my mind, but then i have to remind myself why I'm doing what I'm doing.
When i joined this club my mech knowledge was worse than poor, and 12 second c1j's were the benchmark, so the goal was to do the same on a self built lump, on a tight budget, to kind of show what i have learnt/picked up over the years.
Until the above has been achieved it will be a c1j under the bonnet, i might consider and engine conversion after that.
When i first saw the damage that's exactly what i thought, the lumps only done 3k since a full re-build and i was just starting to get the tune good for decent power and i get a nice random failure like this!
I can see why people ditch the c1j, the thought has crossed my mind, but then i have to remind myself why I'm doing what I'm doing.
When i joined this club my mech knowledge was worse than poor, and 12 second c1j's were the benchmark, so the goal was to do the same on a self built lump, on a tight budget, to kind of show what i have learnt/picked up over the years.
Until the above has been achieved it will be a c1j under the bonnet, i might consider and engine conversion after that.
That's inspirational right there
Great stuff Phil
Haha Phil used to think the carb top was the turbo. True story
I have even admitted it in the very first post on this thread
Wow definitely unlucky with a valve guide failing! New head/piston and it will be reet
Chin up bro we will both be in the 12s soon. No doubt!!
Done some more stripping down this evening, took the sump off (what a ****ty job that was) pulled out the damaged piston and liner, i also found plenty of valve stem oil seals in the sump including the metal parts that go around the plastic, wish i had just not bothered with them in the first place now
So I was shocked to find the big end shell had a little more scoring marks on it than i had excpected.
However they weren't deep scoring marks and the crank appears to be fine
I also took apart the oil pump to see how my new internals have faired to some of the more experienced eyes on here.
Again although it has a few marks i think it will be fine. I did however notice that with regards to my oil pressure when the lump was running was that it wouls sit at 45psi then when i floored it the oil pressure would drop to 40/41psi then rise a little to 42/43psi and after a few pulls it would sometimes drop below 40psi for a few seconds before rising again. This is with a genuine filter and 10-60 fully synth oil using the standard oil cooler.
So the plan is to take my new head (when i get it) along with the piston i'm going replace the damaged one with and my oil pump to the machine shop for a pressure test and flatness check, to get the conrod bearing faces cleaned up and any work i can have done on the oil pump.
Stick the new piston and liner in along with a full set of big ends, new liner and rings for the piston also. wang it all back toghether with the new head then modify the timing sensor to i can maybe advance the ignition a little more than 4 degrees and try to get the boost upto 24psi again and see how it fairs on scoffs rollers power wise.
10-60 fully synthic oil might be the problem its to tin for c1j 10/40 part synthic is what you want really. oil temp would be lower and oil pressure would be higher with 10/40 oil
I remember reading a thread on here about oil grades and it was mentioned that 10-60 probably wasn't the best oil for a freshly built lump, due to the tighter tolerances i did use 10-40 for the first 400 miles in that time it was changed twice, since that it's had two oil changes both with 10-60 fully synth the lump has only done 3k.
once it's back up and running i will give 10-40 part synth a try and see how it gets on, it's also cheaper than the 10-60.
just a note i run 10/40 semi synth in mine and oil pressure is bang on, always seems fine temp wise etc, i just change it every 1k or so to keep it nice and fresh, probably overkill but nothing wrong with being safe
Ok, done some more investigating and it seems the valve guide has definitely come out of the head slid down the valve towards the head then been smashed as the valve has gone back up.
I had this guide replaced after cracking the original one a few years ago due to a dropped valve.
So answers on a postcard, has the guide not been fitted properly or is something like valve bounce to blame?
Obviously I have the piper valve springs fitted and when they are fully compressed the coils are quite close together but not touching. Just wondering with 7500rpm plus could they be going coilbound?
Here are a few pictures from the strip down
This is the offending valve guide
And here are some marks I have noticed on the cylinder head, something tells me this isnt exactly ideal
It appears the spring seat has made the marks you can see above
Ok guys, my donated previously un skimmed 73.5mm cylinder head is currently getting some love in the form of bead blasting, pressure testing, re-facing, and the valves and seats re-cut.
I also took my oil pump in to the engineers shop to see if there was anything they could do with it with regards to the scoring marks.
He quickly replied that they can get hold of a full bran new pump for £75 plus vat, great I thought, then I remember reading on here about how campus pumps were confused with gtt pumps.
I have spoken to them today and they said the "new" pump looks slightly different to the original one, but the rotor and all the other dimensions are the same.
I'm after as much info about these campus pumps so I can try and decide if I should use it or not. I have read the oil pump article but the pictures don't work so I know why a campus pump won't work but still can't spot the difference.
Campus oil pump here
http://www.renault4.co.uk/gordini-en...wear-large.jpg
Totally diferent to gt turbo ones. If I remember rightly less oil pressure in them as they don't need to feed an oil cooler and turbo.
That's great, so that pump is quite a bit different to the GT pump.
As I thought, do any other campus's run a pump that's similar to the gt one, or were all campus pumps the same?
Last edited by GTphil; 16-05-2013 at 21:45.
As far as I'm aware campus pumps are all the same.
Did you fill pump with oil before refitting and check it flowed out of oil feed pipe to turbo before starting engine.
Cheers, on my initial engine build I gained the oil pressure using an old dizzy drive and a drill...
I'm also concerned that cgb has new oil pumps on e-bay for £40 or so the picture looks like a gtt one, then the add says not for use on modified or race engines
Those are campus ones by the look of the pic.
Can see the two circles in the casing for the two viens.
Gt turbo ones have one big circle.
Cheers for your help
A few updates,
The oil pump was a campus pump they got hold of, so decided against it
My cylinder head looks the muts nuts it was previously un-skimmed and they took 4 thou off to face it up
From this (the one on the left)
To this
No cracks at all between the valve seats
The head was bead blasted, pressure tested, faced, and the valves/seats cut.
So this leaves me with the issue that my compression once I’m done putting it all back together will actually be lower than it was before so looks like I'm going to have to be brave with the ignition timing and boost to get 230hp
Either that or some nitrous, would like to get a 12 without gas then lump some gas on and go for a low 12........looking way ahead into the future here tho.
Currently its finances that are holding me back, my budget is quite frankly depressing, being a stay at home dad and working part time really doesn’t go to well with owning a gtt
What about water inj ???
I like the idea of water injection but would be concerned tuning it to run with the WI and then having to change it to run without. As the kits can be expensive and unreliable and if your water runs out
Only way to tune the ignition with any degree of safety is on the rollers with the knock box rigged up.
i could go mappable ignition but the budget just won't allow
If lower, skim the head to raise the c/r.
If higher, that's not a bad thing, if you can keep under the det' threshold. If you prefer to play safe though, either fit a thicker headgasket and/or open up the squish area; both of which will lower the c/r.
My last head was 72.9 and i managed to run 24lb manifold, with 4degrees of advance right up to 7.5k in fourth. This was the run just before the valve guide failure.
I think i may use a std headgasket or even a campus one just to raise the cr a little, don't want to skim the head as it's a good un. I should really get a set of standard comp pistons but again for now just can't justify it. I know a few other c1j's that have got away with a fair bit more than 4 degrees.
Get wmi with a low level sensor and spare 2 litres in the boot.
o.e headgasket is perfectly fine to use.
I have a bladder like a camel so i could perhaps not bother with the 2liters in the boot, and just hold on for a few hours before going for a drive......
might look a little strange pulled up at the side of the road filling up my WI tank.
I just think that for what i want i could spend the money for WI elsewhere and see better improvements, maybe a billet comp wheel for the blower
I'm currently hunting around for the final few parts I require to start bolting the engine back together.
I'm after a standard headgasket set, what's the best brand to buy? I have had a few issues with the corteco sets and their quality recently.
Need some boost back in my life
the payen 1.9mm matey is a good one
also make sure you torque head to 80nm boss
The payen headgasket is nigh on identical to the mellior phil
O.e for win
Come on Phil, chop chop!
Longest project in history!
Moderator - please change the title to 'Project 12 years'Longest project in history!
Moderator - please change the title to 'Project 12 years'
I have been putting to much time effort and money into catching these
Look at that disgusting stinking slimy thing.
But enough about Phil - that's a monster of a fish. Good work fella.
That's a big old carp Phil, what was the weight ?.
Not overly into fishing myself but you might know of my brother Dr Paul Garner as he's pretty well known in fishing circles.
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