Engine build, the money pit opens...

[Chesney84]

Hi guys, so the block is fully stripped and at the acid dippers for a while and now cleaning and prepping the internals. The aim is to achieve around 250bhp mark so would appreciate any advice as you guys have a lot more knowledge of what will and won’t work.

The plan was to keep the Standard crank and rods (was going to get them inspected at work, then lighten the crank and have them all balanced and shot peened). Was thinking of having a small hole spark-eroded into the rod through to the bearing to act as under crown oil spray as well. My question, for the 250bhp mark are these parts capable of of this power? My experience says that stock rods and crank don’t tend to fail as long as you are sensible to the machining done?

Also turbo? Was looking at a T28 (to go with a 285 cam), much modification to get this to fit? Not interested in the plumbing as I can sort that easily, but heard peope saying new manifolds required but I was of the understanding that the T28 flange will mate to the existing manifold (which I’m having bored, ported and ceramic coated).

Any advice or potential pitfalls you know of would help greatly as not got much knowledge of the C1J’s strengths and weaknesses!

Cheers guys!

[Ian S]

Standard crank and rods (lighten the crank and have them all balanced and shot peened).

I'm told the rods are forged. Most people seems to use them even at much more torque. Maybe even those 500bhp nitrous drag C1J engines.

Was thinking of having a small hole spark-eroded into the rod through to the bearing to act as under crown oil spray as well.

I've not heard of this one.

I used a T2 turbine / T25 body / T28 compressor. I don't know the size of a T28 flange. I thought T2, T28, etc., referred only to the shaft diameter.

(which I’m having bored, ported and ceramic coated).

I'm told by people who have used it on the C1J manifolds that ceramic coating a pointless waste of time and money. It lasts approx no time before it comes off. On the inside of an engine, when it comes off it acts as grinding paste. They can crack, or bend if wrapped, is boring it going to make it weaker then normal?

Any advice or potential pitfalls you know of would help greatly as not got much knowledge of the C1J’s strengths and weaknesses!

The block can crack. The flywheel end crankshaft seal can leak. The coolant flow at the rear of the water pump end maybe poor. That piston tends to expand and rub the bore before the others do. You might have excessive crank case pressure and an extra vent might help. You might need an oil catch tank to prevent oil spraying from your dump valve. Even with one, over 12,000 miles, with the fast moving air mass pressing into it each time it closed on full boost, 24psi, my throttle shaft gradually bent and started sticking. With that heavy turbo, the gearbox end exhaust manifold nuts seem to undo themselves and the gasket become damaged.

C1J, 250bhp, T28, you're not going to have a nice drivable engine. Serious lag, nothing off boost. Hard work off boost, then hard work on it. Clutch slip, wheel spin, bouncing front wheels. A lightened engine that stalls with just a little clutch. Having to rev high and dump it and wheel spin out of each junction if you want to merge briskly. In the wet, playing with the clutch but still not being able to find the wheel spin point so as to make good traction.

It stopped being fun to drive around town and I wouldn't do it again with a 1.4 litre C1J after all that. After the last one capitulated due, for the 2nd time, to collets coming off, or valve breakage, not sure, I'd use a low boost 2 litre and done with, 250bhp and 230ft lbs at only 6 psi. I nearly bought such an engine off a pal maybe 12 years ago and I expect I regretted not doing so ever since.

[Chesney84]

Thanks for the reply Ian,

Ok, so the standard rods and crank should be more than man enough to cope with the increase in power and torque. I'll get them NDT'd and inspected at work and then just get them lightened and matched to some forged pistons then balanced.

The squirt jet/ under crown oil cooling is just an idea at the moment and I need to see how the oil journal holes line up etc. The idea being that the oil flow through the crank to feed the big ends will in theory when the holes line up squirt under the piston crown to dissipate some of the heat from the piston. Not going to give any extra power but should help with reliability etc. by keeping engine temps down. This needs quite a bit of thought as to how big the hole will need to be so as to actually work but not adversely affect oil pressure, and the angle of the hole as to which direction it sprays in too! There is a spark eroding firm nearby that are quite helpful so shouldn't be much of a drama or expensive and spark eroding shouldn't overly compromise the structural integrity of the rod either. Seems feasible so far and doesn't require fabrication or machning of oil rails to do the same job.

Another idea is to radially machine vertical "gas ports" into the piston crown through the top land and into the upper most ring groove. The theory being that combustion will force the ring out and seal and seat it more effectively against the bore. This isn't a new idea and drag/ race engines have had this for many years. My colleague has had quite a bit of success with this on his own engines (road) without any issues in excessive wear or reliability.

Turbo, I'm still weighing up all the options but fully take on board all your advice, I think I'm going to hold out for a T2 flanged Holset turbo. These, if you pick the right spec, can be incredibly fast spooling and minimise lag, as well as having the ability to produce power levels that I'm wanting to achieve. This would require modifications to the downpipe and turbo inlet and outlet as Holsets tend to utilise V-Bands.

I'm starting from scratch and in no rush to build as this is a second engine whilst the one in the car will remain standard. The car will only be driven a maximum of 5000 miles a year so the strain put on it will be kept to a minimum. I want to stick with C1J and Carb set-up, just want to see what we can get out of it and have a bit of fun trying things out.

Will start a thread on the Projects section for people to read if interested.

Thanks again for the input and advice, really is appreciated, as you are the guys with the knowledge and experience with these cars and lumps!

Andy

[Chesney84]

Oh and the manifold, was going to get if dipped then crack checked to make sure I've got a solid unit to start with, then get the inside reworked best I can but without taking too much material away so not to decrease its strength, then ceramic coat the outside only. I've never heard of people ceramic coating the inside of exhaust primary's? I certainly would never do that or suggest it. The risk as you say is way too much for stray debris to fall off and into the intake, via the turbo and cylinder head!

[youngscottie]

Thanks for the reply Ian,

Ok, so the standard rods and crank should be more than man enough to cope with the increase in power and torque. I'll get them NDT'd and inspected at work and then just get them lightened and matched to some forged pistons then balanced.

The squirt jet/ under crown oil cooling is just an idea at the moment and I need to see how the oil journal holes line up etc. The idea being that the oil flow through the crank to feed the big ends will in theory when the holes line up squirt under the piston crown to dissipate some of the heat from the piston. Not going to give any extra power but should help with reliability etc. by keeping engine temps down. This needs quite a bit of thought as to how big the hole will need to be so as to actually work but not adversely affect oil pressure, and the angle of the hole as to which direction it sprays in too! There is a spark eroding firm nearby that are quite helpful so shouldn't be much of a drama or expensive and spark eroding shouldn't overly compromise the structural integrity of the rod either. Seems feasible so far and doesn't require fabrication or machning of oil rails to do the same job.

Another idea is to radially machine vertical "gas ports" into the piston crown through the top land and into the upper most ring groove. The theory being that combustion will force the ring out and seal and seat it more effectively against the bore. This isn't a new idea and drag/ race engines have had this for many years. My colleague has had quite a bit of success with this on his own engines (road) without any issues in excessive wear or reliability.

Turbo, I'm still weighing up all the options but fully take on board all your advice, I think I'm going to hold out for a T2 flanged Holset turbo. These, if you pick the right spec, can be incredibly fast spooling and minimise lag, as well as having the ability to produce power levels that I'm wanting to achieve. This would require modifications to the downpipe and turbo inlet and outlet as Holsets tend to utilise V-Bands.

I'm starting from scratch and in no rush to build as this is a second engine whilst the one in the car will remain standard. The car will only be driven a maximum of 5000 miles a year so the strain put on it will be kept to a minimum. I want to stick with C1J and Carb set-up, just want to see what we can get out of it and have a bit of fun trying things out.

Will start a thread on the Projects section for people to read if interested.

Thanks again for the input and advice, really is appreciated, as you are the guys with the knowledge and experience with these cars and lumps!

Andy

Would think very carefully before modding the block for piston oil jets
The gt oil pump is in the poor to useless category and I don't think it's up to the job

[Chesney84]

Would think very carefully before modding the block for piston oil jets
The gt oil pump is in the poor to useless category and I don't think it's up to the job

Is there any mods to the oil pump that improve its capability or upgrades? I was thinking about one small hole (1-1.5mm) per con-rod, no mods to the block. Was going to fully refurbish the pump before putting it in but any way to improve it?

[Ian S]

I don't really recall, but seem to have a partial notion that their may have been a taller oil pump from a seller in France. Bit more capacity maybe.

I was told that people would ceramic coat the piston tops. Some vendors wanted to sell and coat, a much as possible.

There is an earlier and later standard exhaust manifold, one is a lot large bore, seem to recall that may be the later one.

VNT turbos provided the least lag on the bigger boost 5's I drove. A pal had a carb'd C1J with a VNT making 244BHP and it drove like a normally aspirated engine. Would not have guessed it was turbo'd.

Piper 285 @ 110° camshaft seemed to be the favourite back then. Re-pro's sometimes wore in a few months, they were blaming porous metal. One I knew also ruined a new set of followers in the process.

Most of them used the standard pistons. The tops are 13mm thick. We machined a 'dish' into them to try and increase the swirl and reduce the det. Det is the main limiting factor in how much boost you can run. My head was skimmed to bring the compression ratio back up to about standard. The block often does not have a flat top so it was becemming normal to skim the block. My next engine was skimmed a bit further so the pistons protruded a bit, into the gasket area. The combustion chamber in the head was partially welded up and re-shaped, similar to racing mini's, to further increase the swirl, the mix, and reduce the det'ing further.

[tubbyG]

For what its worth, there are not many people around who have a genuine 250 brake c1j on carb. As Ian has said its more cost effective to go down a 1.8/2.0 turbo conversion route. I am sceptical of the figures branded about of past built cars as dyno's are .....well dyno's. I bet if the past big power cars went down the 1/4 then their trap speed would indicate a lesser power, on a carb then I think 220-240 is more realistic without gas however there are those who have gone to 250 and beyond.

For that level of power though I would go forged rods also - Mark Davis (member on here) has/had done a great EFI build to achieve a touch over 250bhp, im unsure of the torque exactly, but unfortunatley he bent a rod at that level of power. This was on efi, standalone management and all the usual bolt on upgrades and a heap of boost on a new garrett gtx. He is hoping to push closer to 300 this year but with forged components.

To get to the power you want you will needs lots of boost, and atleast standard compression. If sticking with carb, then my own advise would be to get away from the standard ignition unit as this (although works well) is a limiting factor when changing cam/turbo spec, not just for power but overall driveablity but will allow you to get the most out of your setup.

A holset turbo would be great addition and is miles ahead of the old T28 units that are used by many.

The oil pump can be shimmed to increase oil pressure but unfortunatley flow remains the same.

[Ian S]

Also, you'd need to change the liners in the block around the pistons.

Away from the OE cast ones to some 'steel' liners.

The OE crack at the narrow sides.

Big Jim Racing, at CTM, now retired from car engines, found a way to hold the liners down in the block so he could skim them at the same time as the block.

One of his engines, in a red car owned by Phil from Surrey, philr5t, https://www.rtoc.org/boards/member.php?1075-philr5t , was making about 310bhp on Scoffs rollers. But they seemed to have difficulty keeping the head down and lost the gasket a couple of times.

He's what he had to get that.

And something extra to think about, you might need a LSD in the gearbox, I certainly would have benefited at my 220bhp, or whatever it was, but couldn't afford. Overtaking at, say 30mph, meant doing it with the steering wheel turned 90° with one or other wheel spinning all the way past! No boost , then barking mad boost and wheel spin.

You need to control that torque, hence the seam welded subframe and new poly bushes. And the OE shocks probably won't do, and tyres certainly won't do. Strut brace, needed, easy to feel the difference. Same was said for the welded subframe, but again I could not afford. Nor could I afford the VNT or I'd have had one. Also, mappable electronic ignition was necessary as my setup was under performing and det'ing at a certain point, the map needed taking down a few points there and up a few elsewhere, alas, I could not afford.

Engine:
full re build BIG JIM RACING
full efi c1j
custom efi manifold
comp ratio 7.7-1
custom rocker shaft to remove valve bounce
block red
l/b bottom end
woosner forged rods
woosner forged pistons
steel liners
new gtt oil pump
new water pump
all gaskets
new timing chain/tensioner
new push rods
new cam followers
piper 285 cam
10mm magnecor leads
h/l springs
major head work and shaping
block skimmed
ported and polished head and manifold matched
bigger valves
ap paddle clutch
new starter motor
4 in to 1, four branch manifold
vnt turbo t3 custom fit
3" one off downpipe
3" sidey
full samco hoses
13 row mocal oil cooler
oil catch tank
alloy rad
12" davis craig fan
low temp thermostat
low temp fan switch
custom pace charge cooler
high capacity dual intercooler
k&n big air filter

Turbo type:
VNT

Boost Pressure (@ manifold):
26psi

Transmission:
short shifter gear stick
standard box re built with a quaiffe lsd

Wheels:
15" by 8's schmidt ml's with 185/45/15" tyres on strethched look

Suspension Details:
gaz coilovers
new subframe seam welded and powdercoated
complete set of poly bushes
new wishbones

[Matty]

Personally I would avoid drilling/EdMing the rods for oil squirters, it's a big risk starving the little end of oil. I have converted my A series engine to under crown cooling using BMW oil jets, which only open above a certain oil pressure, they are fairly simple to machine and fit, and should be fairly simple on the C1J too.

If you want to reduce engine drag, then putting oil drains in the followers work well, along with a small groove down the side to reduce the suction effect of the oil. And wasting the side or the followers also reduces friction. You'll need to do this on a cylindrical grinder, but you only need a thou a side.

I've done all sorts in the past, gun drilled cam shafts out, evacusumps, reduced cam lobe widths etc...required mods to followers too.

Also have a look into Nikasil coating of engine components.

[Matt Cole]

445bhp C1J 😉

https://www.rtoc.org/boards/showthrea...highlight=Glen




https://www.rtoc.org/boards/album.php...pictureid=4620

[Ian S]

Here we have my flywheel, or same as mine, 3.7kg, by Big Jim. It's so long ago now that I don't clearly remember. I haven't thought about any of this for a lot of years.




A VNT:


A car making 250bhp. Surprising how much space seems to be in there.


That might be my crank, by Big Jim.

And a VNT turbo, that apparently also made 250bhp or so in the above sprint car. It seems to have a wastegate as well as the VNT.

[Chesney84]

Thanks for all the responses and sharing your experiences chaps, only just got round to logging in to the forum and read up. Certainly given me a lot to think about! I think from reading this that the C1J lump, if built properly, can cope with the power. However, I feel like in most cases, the cost will be a limiting factor rather than what's possible. Although it would be miles easier and more reliable to stick a big lump in I want to retain some of its originality. I know it seems somewhat ironic saying that as I'm likely to be replacing pretty much all of it bar the block, head and carb. Genuinely though guys, thanks very much for all the help

[Chesney84]

Has anyone got any experience with the Holset HX27 turbo? I believe it is matched quite closely to the Garrett GT28R?

I believe the specs are as follows:
Turbine 53mm Inducer, 46mm Exducer
Comp. 45mm inducer, 60mm Exducer

They seem very highly spec'd and apparently spool up incredibly quickly/ early?