504 Ti (XN2) rebuild and carb conversion

P

Pee Dubs

Member
Fellow Frogger
Joined
Jan 9, 2015
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Location
New Zealand
Has anyone had experience of rebuilding 504 engines and/or converting to carbs?
Engine is a well worn XN2 that I plan to convert to dual 40 DHLAs. Sorry to all the purists out there but I'm not confident that the KF injection system on it can be resurrected so I'm going for simplicity of a carb setup. The engine is destined for a GL body that I acquired with the head removed so I have some parts from that carb engine to convert it.
 
Hi

NO experience of this but was working in a similar direction with my 404, for which I had found an injected head. I am now doing it with the KF injection, but had initially had the same plan as you.

Despite extensive research and searching was unable to find suitable manifold. There are some out there, but I couldn't find any.

If you manage to find or fabricate a solution to this issue I would be interested in hearing any news/designs/contacts

a) May need to revert in future, although do have faith in current set-up
b) I have a second 4 port 404 head and am looking for a car to suit it.

Good luck

Andrew
 
Thanks Andrew, I'm going to fabricate the manifold- a little bit more effort but hopefully I'll achieve the desired result.
The ti heads themselves aren't a bad design but the manufacturing to achieve smooth airflow through the ports leaves something to be desired. Not sure how changing the ports would affect injection but I'm modifying them for carb setup, and the manifold will be made to match ports as far as is possible.
I assume that you also got timing gear incl. cam, and injection timing casing to convert the other way? Carb conversion seems simple in comparison, so good luck to you also!
 
It is quite simple if you have the manifold, but it can be quite thirsty depending on the state of tune. You will also need to reprofile the cam, the KF cam does not work well with dcoe's. Even if you have the carbies, it may be better to convert to EFI, Graham Wallis of this forum can guide you. If your heart is set on the carbies, let me know what power you are after and I can give you conversion parameters. We have done many, from mild streetable to full group 4.
 
Hi Thanos, you've been very quiet lately? Scott and I will be in touch shortly as we intend to build an EFI motor for the Classic car.

Does "Motorman" still do manifolds for XN2s?

Thanks

Cheers

Jim
 
Hi there,
I've successfully converted my Peugeot 504 Ti engine to run on carburettors. For my conversion, I used four Mikuni CV carburettors off a Yamaha R1. This required a custom manifold to be made, which was fabricated by Bogg Brothers in the UK. Unfortunately, the conversion requires a custom electronic ignition to be run because of the factory placement of the distributor. Of course, for my conversion, electronic ignition was necessary to get the correct advance curves boost conditions.

You'll need to get a timing cover off of a carburettor 504 motor and remove the injection pump assembly. Which is easily done. I don't agree with the need to reprofile or replace the cam, as I'm successfully running a Ti camshaft with my setup, and the engine has plenty of power and is smooth.

I'm sure if you go the route of using DCOE/DHLA carbs, you'll be able to find a manifold that fits around the distributor. However, from my reading on these forums, you'll need some sort of extension to raise the distributor to clear the manifold, regardless.

Let me know if you have any questions about my setup.
 
callipygous said:
I don't agree with the need to reprofile or replace the cam, as I'm successfully running a Ti camshaft with my setup, and the engine has plenty of power and is smooth.
Click to expand...

This is what I have heard. In fact, I was told (years ago) by 2 knowledgeable people that if I wanted more power out of my carby 504, to fit a cam from an injected model.
 
pug303 said:
Hi Thanos, you've been very quiet lately? Scott and I will be in touch shortly as we intend to build an EFI motor for the Classic car.

Does "Motorman" still do manifolds for XN2s?

Thanks

Cheers

Jim
Click to expand...

Hi Jim

There was nothing much to report, hence the silence. We are in the middle of swapping the 2 liter of the latest rally coupe with a works V6 on steroids, I will let you know how it goes. The EFI motor with QTB's sounds like a great idea. I will ask Motorman if he has any intake manifolds left over.

Thanos
 
Beano said:
This is what I have heard. In fact, I was told (years ago) by 2 knowledgeable people that if I wanted more power out of my carby 504, to fit a cam from an injected model.
Click to expand...

This is a different situation altogether: The XN2 cam is slightly bigger than the XN1 cam, so putting an XN2 cam in an XN1 motor will give more power at higher revs. But the post deals with the replacement of the KF injection in XN2 engines with DCOE's. Here are some hard facts on XN2 engines:
1. Replacing the "awesome" XN2 cam with a Wade 112 increases the power of the KF engine by 6 bhp ATW. Even the tame 112 is "more awesome".
2. Replacing the KF injection with DCOE's and keeping the XN2 cam results in power drops of around 4 bhp ATW while at the same time increasing fuel consumption by 30%.
3. Replacing the KF injection with DCOE's and replacing the XN2 cam with much bigger cams increases power anywhere from 12 bhp to 60 bhp ATW.

Reprofiling the cam will cost under $100, it is silly to go through the conversion and miss out on the power gains to save this kind of money.
 
ThanosK said:
This is a different situation altogether: The XN2 cam is slightly bigger than the XN1 cam, so putting an XN2 cam in an XN1 motor will give more power at higher revs. But the post deals with the replacement of the KF injection in XN2 engines with DCOE's. Here are some hard facts on XN2 engines:
1. Replacing the "awesome" XN2 cam with a Wade 112 increases the power of the KF engine by 6 bhp ATW. Even the tame 112 is "more awesome".
2. Replacing the KF injection with DCOE's and keeping the XN2 cam results in power drops of around 4 bhp ATW while at the same time increasing fuel consumption by 30%.
3. Replacing the KF injection with DCOE's and replacing the XN2 cam with much bigger cams increases power anywhere from 12 bhp to 60 bhp ATW.

Reprofiling the cam will cost under $100, it is silly to go through the conversion and miss out on the power gains to save this kind of money.
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Thanks Thanos I agree with what you're saying here- cams have profiles optimised for the application so I wouldn't expect the timing of an injection cam to work well with dcoes (or dhla's in my case). I'm having a cam workshop take a look to see if a grind would work, but I'm not too hopeful that it is possible to get what I want (140-150hp) without a custom cam. If you have some suggestions on how to set it up I'd be all ears, just send me a PM if you're not comfortable posting details here. Btw fuel consumption isn't a major factor here - this will be a weekend car so extra gas is just the price of a good weekend experience!
 
Pee Dubs said:
Thanks Thanos I agree with what you're saying here- cams have profiles optimised for the application so I wouldn't expect the timing of an injection cam to work well with dcoes (or dhla's in my case). I'm having a cam workshop take a look to see if a grind would work, but I'm not too hopeful that it is possible to get what I want (140-150hp) without a custom cam. If you have some suggestions on how to set it up I'd be all ears, just send me a PM if you're not comfortable posting details here. Btw fuel consumption isn't a major factor here - this will be a weekend car so extra gas is just the price of a good weekend experience!
Click to expand...

Regrinds will work fine. The cheapest way is to get a Wade 140, 8.8 CR pistons, 1.5 mm head skim, 4-2-1 extractors (42 mm primaries, 45 mm secondaries, 60 mm exhaust pipe)
with a single muffler. If you can live with the exhaust coming out the side (under the right rear door), the engine will rev out a lot faster. This will get you to the power you are seeking; to go bigger you will have to go to forged pistons (Wiseco has made a number of custom CR versions for US$600, let me know if you need specifics) bigger valves and expensive cam grinds.
 
Have had a look at Wade 140 but think that it might be getting a bit rorty- I want an engine that behaves nicely on the street, so going for something a bit milder that I can hopefully do with a grind. Just going for standard pistons too, otherwise I start throwing too much $ at this rebuild. The laws of ever diminishing returns apply!
 
Well sorry for the lack of updates everyone, I've spent this year working away from home and so 'shed time' is minimal. Nonetheless the project has been ticking along thanks to the very generous help of a local old-school mechanic friend who tinkers in between his paying workshop jobs. Unfortunately this means a very slow rate of progress, but on the upside means that I get a wealth of experience in old tech and setup for the price of a few rums when I do manage to get home once in a while and visit him. It also means a lack of progress photos sorry.

As an aside, would it be possible for an administrator to move this thread into projects please?

Ok so firstly I should probably mention what engine setup I've decided upon:
XN2 Ti engine bottom end rebuilt with new mains, standard pistons & liners.
Ti head ported and matched with custom manifold with straight runners to twin 40 dhla's.
Ti camshaft reprofiled to suit fast road tune, adjustable crank pulley to enable adjustment of advance.
NODIZ electronic ignition with coilpack running off trigger wheel.

I considered a 123 distributor but really want a clean looking manifold without bending runners around the dizzy. Will retain dizzy drive suitably capped to ensure correct function of oil pump. Initially planning to run a base ignition map for pinto, but if someone has a carb XN specific map to start things off a bit more optimised I'd be all ears.

I've just recently had a closer look at the body that I intend to use, it is a 1974 GL auto in white, thankfully looking pretty rust free except for a few spots of surface rust all over and couple of minor holes on the rear guards. I'm planning to get this rust sorted and respray in white fairly soon, and considering flaring the rear guards while I'm at it to allow scope for some mild lowering and wider rear / rear rims.

I also picked up a donor car, a 1982 505 STI, that will contribute it's 5speed gearbox (with new bearings), and hopefully later all the running gear if it will fit.

So that's about where I am for the moment, still a lot of work to do before it moves under its own power (and goes to for recompliance as it's been off the road and unregistered). Having time to complete things is my major obstacle so apologies if future updates don't show much happening for a little while.
 
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A few piccys of the car from the yard where I picked it up for scrap price.
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Towed the car home and proceeded to tuck it away in the corner of the back lawn, much to my girlfriend's disgust. Seen here halfway through manoeuvring it through the gap between house and garage. Blue 504 is a one owner, all original '71 GL - too good to modify I thought, though it gave me a good taster for how good the standard car is, and what I want to improve on. Sold it just yesterday, hope I don't regret that!
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The Ti engine in pieces. Note the wear of pistons/liners - not sure if this was due to some issue or just the years of operation? Anyway it was obvious once apart that new ones were needed. Luckily the crank was in really good nick, - no machining needed, and head wasn't too bad either, just a light valve seat grind and skim.
DSC01416.jpgDSC01404.JPGDSC01405.jpgDSC01408.jpgDSC01409.jpgDSC01411.jpgDSC01414.jpgDSC01415.jpg

I now have a surplus of injection bits, condition unknown, if someone wants to make me an offer for them. Otherwise I'll sell them back to guy I got the engine off as he has a stash of all sorts of stuff for old pugs.
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Use the best fan blade you have.
One of our members bought a car from a friend of mine...I knew the car well, and it was very well-kept, original and driven carefully.
Not too long after he bought it, the fan disintegrated and ruined the radiator. He is a young guy so I guess he revved it a bit. Point is : I guess they get brittle with age.

Nice car. REAL door handles ! :banana: And a good idea to put a carby on it. Much more reliable.

(The later...flush with door.... ones are weak and break regularly).
 
Beano said:
Use the best fan blade you have.
One of our members bought a car from a friend of mine...I knew the car well, and it was very well-kept, original and driven carefully.
Not too long after he bought it, the fan disintegrated and ruined the radiator. He is a young guy so I guess he revved it a bit. Point is : I guess they get brittle with age.

Nice car. REAL door handles ! :banana: And a good idea to put a carby on it. Much more reliable.

(The later...flush with door.... ones are weak and break regularly).
Click to expand...

Good advice as they definately do become brittle with age. The fan blades should be fairly flexible.
 
Beano said:
Use the best fan blade you have.
One of our members bought a car from a friend of mine...I knew the car well, and it was very well-kept, original and driven carefully.
Not too long after he bought it, the fan disintegrated and ruined the radiator. He is a young guy so I guess he revved it a bit. Point is : I guess they get brittle with age.

Nice car. REAL door handles ! :banana: And a good idea to put a carby on it. Much more reliable.

(The later...flush with door.... ones are weak and break regularly).
Click to expand...
What I'm hearing here is that a modern electric fan may be the way to go, so when the time comes I'll have a look at what may fit nicely.

I'm a fan of the older door handles too, the button latch and feel of them is just so much more satisfying!

Carbs are a known quantity and just have that authentic period sound and operation that I'm looking for from this engine. A bit more power would be nice but without spending big $$$ that points towards a more modern engine with throttle bodies or a turbo perhaps, so I'm not sure that would suit the car for how I intend to use it.
 
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