Redtop sprint

[iandollysprint]

Maybe with some factor X petrol in the oil the lubrication quality decreases more than the viscosity so maybe even before an oilpressure loss is noticable the lubrication is very bad.

I have no experience with bike carbs on a car but how is the fuel supply? Is it on the original bike just a line from the tank and now you have a petrol pump? If this is the case your floatneedles are not designed for a pump pressure and the mixture is while driving way too rich by little flooding.

Jeroen

Thanks for the note. This is well worth exploring given the lack of a conclusive root cause to the original failure!

The bike carb set up is as follows

Original feed from tank remains into constant pressure pump delivering 3 psi fuel pressure to rail and bowls. This pump is from the bike set up so should be fine.
Carbs have had the main jets drilled to 1.8mm from 1.6mm I think. This is following various recommedations on other furms when using a C20xe engine on r1 bike carbs. It's the "thing" to do and is backed up by Bogg Brothers who also set bike carbs up as well as making and selling bespoke inlet manifolds to suit.

So I should be in the right "ball park" here. My engine spec is slightly different than standard as it has 276 degree high lift cams.

I have previously done a lambda check on my M635CSI where we shoved a lambda probe up the exhaust and took it for a full load run in 3rd gear to the redline.

So I think I should repeat this on the XE sprint which will at least tell me if things are a miss. Should be able to determine idle conditions as well. I think it was about £30 to do last time.

Obviously a full set up is needed at some point but I would only do this after the engine has been run in allowing me to run the full rpm range AND after the exhaust manifold has been sorted. I might be able to do this test end of this week which will take me forward.

I'll post results.

Ian

[iandollysprint]

Ian,

Jeroens explanation is spot on.

Essentially, the fuel condensates and literally "washes" the oil off of the bearing. You may be overfuelling on all cylinders but because, on these engines, pot 1 gets the least oil supply pressure it is that bearing that spun. On the ohv Triumph four cylinder it is pot 4 that gives way under the same conditions, for the same reasons.

I had to scroll back in the thread, but see you are using bike carbs. You can therefore set the fuelling fairly accurately for each cylinder. The more I think about it, the more I would suspect this as the cause of your original failure.

Thanks for the note see post above re my new plan

[iandollysprint]

ps
A full set up will also allow me to set the ignition timing for full power as it currently has a conservative map installed in the megajolt ecu.
Ian

[ponchoj]

Chances of fuel contamination in the oil being the cause of his problem are tiny. I would get it set up if it has only been guessed, but I wouldn't consider it a probable cause of failure.

Petrol doesn't condense when it's mixed with oil anyway. It may failr to vapourise in cold bores and can condense further there, but once it's been churned around with oil and goes from sump to big ends, it won't condense into petrol again when it reaches bearings. Besides, if it thinned the oil out enough to cause this kind of damage, he would have had plenty of noise at idle and the oil light would have come on.

You can see that the problem wasn't a slow heating and it wasn't even rapidly increased wear, it was complete lack of lubrication and a very sudden failure. Your problem was either oil surge, a problem with the pickup or something that blocked the oilways. I'd put money on it. It could also have been some crap in the oil pressure relief valve, though that doesn't usually present itself at high revs, more when the revs drop afterwards, so you can probably rule that out too.
A very common cause is people using too much sealant during reassembly which ends up in the pickup. I presume you'd be more careful than that though so we can probably rule that out?
Otherwise, you've got a modified sump (with questionable baffling?) a modified pickup, a recent rebuild and some fairly hard acceleration....

You're right to fit an oil gauge and you're right to monitor the situation closely. You're also right to have the fuelling and timing set up. With that in mind, you can probably completely ignore all that I've written above.

[iandollysprint]

Chances of fuel contamination in the oil being the cause of his problem are tiny. I would get it set up if it has only been guessed, but I wouldn't consider it a probable cause of failure.

Petrol doesn't condense when it's mixed with oil anyway. It may failr to vapourise in cold bores and can condense further there, but once it's been churned around with oil and goes from sump to big ends, it won't condense into petrol again when it reaches bearings. Besides, if it thinned the oil out enough to cause this kind of damage, he would have had plenty of noise at idle and the oil light would have come on.

You can see that the problem wasn't a slow heating and it wasn't even rapidly increased wear, it was complete lack of lubrication and a very sudden failure. Your problem was either oil surge, a problem with the pickup or something that blocked the oilways. I'd put money on it. It could also have been some crap in the oil pressure relief valve, though that doesn't usually present itself at high revs, more when the revs drop afterwards, so you can probably rule that out too.
A very common cause is people using too much sealant during reassembly which ends up in the pickup. I presume you'd be more careful than that though so we can probably rule that out?
Otherwise, you've got a modified sump (with questionable baffling?) a modified pickup, a recent rebuild and some fairly hard acceleration....

You're right to fit an oil gauge and you're right to monitor the situation closely. You're also right to have the fuelling and timing set up. With that in mind, you can probably completely ignore all that I've written above.

Thanks for your thoughts.
Things have moved on today. I have finally found someone to make a decent exhaust manifold for it. £650 plus VAT - JP Exhausts in Macclesfield. Their work is mighty impressive so I have booked it in for mid June. It will be an equal length primary and secondary manifold with a 2.25 inch outlet.

Also spoke to a tuning guy local to me who is renowned for his work on carbs. He will set up the car, fuel and ignition for about £250 and will need the car for a whole day.

So plan now is to get the manifold sorted, change sump gasket which has a bad leak on it, change timing belt idler which is whinning, get the car set up and THEN put some miles on it

Hard on the wallet but these things need to be done right to make the car...

[iandollysprint]

Now fitted bespoke exhaust manifold.

This was manufactured by JP Exhausts in Macclesfield. They had the car for a whole week. £650.

It's an equal length header for primaries and secondaries, primaries are 1 5/8ths, secondaries 1 7/8ths, outlet is 2 1/4. Plan is to convert the original sprint sports exhaust system to 2 1/4 inch later on. No funds at present to get this done. Hopefully it will flow 200bhp anyway.

Made a noticeable difference when fitted!

Unfortunately I had fuel pump failure last weekend so I haven't been out in it much. New R1 fuel pump fitted today. Now got to get it to the carb man for final set up. Seems to running quite sweet at the moment.

Ian







Off the car



and the old one...

[Carledo]

WOW! That is a proper work of art! I just got (for peanuts) a Redtop stainless 4 branch (FWD variety) but I can see you won't be needing it! Looking at where your engine mounts are I think it would have been a right bugger to adapt anyway.
Glad to hear there is an improvement from fitting the 4 branch and that its going well. Hope to see it in the tin at Cholmondely in September perhaps? Oddly enough I also suffered failure of the (brand new) fuel pump soon after building.....

Steve

[iandollysprint]

WOW! That is a proper work of art! I just got (for peanuts) a Redtop stainless 4 branch (FWD variety) but I can see you won't be needing it! Looking at where your engine mounts are I think it would have been a right bugger to adapt anyway.
Glad to hear there is an improvement from fitting the 4 branch and that its going well. Hope to see it in the tin at Cholmondely in September perhaps? Oddly enough I also suffered failure of the (brand new) fuel pump soon after building.....

Steve

Yep those engine mounts made it difficult to cut and shut anything to fit properly. If I was to do it again i'd probably go for a different mount arrangement and sit the engine at 0 degrees instead of the 7 degree tilt currently used. This would give much better access to use a choped down front wheel drive manifold. heho - live and learn.

[Carledo]

Yeah I used the Carlton mounts (what else?) and then fabbed up some brackets for them off the subframe. As you can see they are quite a bit further forward but I still cant use the Redtop manifold as a base cos the plugs are in the way!



Plenty of room for a 4 branch though, especially since I moved the battery to the boot!

Steve

PS BTW I saw my ally fabbing mate recently and mentioned your airbox requirement to him, he's happy to give it a go. Let me know when you're ready and i'll give you an intro!

[geeksteve]

That manifold looks fantastic.

[iandollysprint]

Rolling road results.

Only mapped to 6000 rpm as the engine isn't fully run in yet. Dialled the cams in the week before to make sure all was well.

Very pleased with the results. 190 bhp at ony 6000rpm and still pulling, it's easily a 200 bhp engine as I still have at least 750-1000 rpm before peak power is reached. 169 lbft of torque which the rolling road man said was very impressive. The flatness of the torque curve above 3800rpm will make it a very driveable car. (Flywheel figures). It was underfuelling so all needles have been raised to their top notch and the ignition was out causing pinking, now sorted!

Engine spec. Autosprint 12.5:1 high compression 86.5mm pistons, Autospint 276 degree sports cams, vernier cam spockets, inlet and exhaust set to 110 degree peak opening, JP exhaust 4 branch equal length header, R1 carbs and fuel pump with raised needles and 180 jets, megajolt ignition.

Unfortunately had an issue with the gearbox on the last power run run down and it got stuck in 5th gear! Looks like the selector fork has broken which is dissapointing given the box was fully rebuilt. Gearbox is now out of the car and on it's way to my gearbox man to sort out. Wife thinks I make these things up just to spend some time in the garage, i wish...

Ian

[mbellinger]

Good outputs Ian - they are a great engine.

Pleased that it is running right for you now. I cannot remember without scrolling back what gearbox you have in it. If it is Manta, they are a bit weak with much over 150bhp going through them. I rebuilt mine twice, and it had been rebuilt just before I bought it as well!

[iandollysprint]

It is a manta 5 speed getrag gearbox, just like you used, fully rebuilt with new bearings etc. I wouldn't have expected failure after 250 miles though! I think there is some other issue with the box as it started to jump out of 3rd whilst coasting and then ended up sticking in 5th. Both don't appear to be "too much torque" through the box issues. I suspect I have a worn/damaged sync ring and an internal broken selector. I'll know more next week when it gets stripped.

Doing some research suggest the boxes are weak if you use an old unit that hasn't been rebuilt...there are many examples of this box being ok even with turbo applications, it's also a very light box which adds to the attraction. I'll persevere unless it goes bang again after 250 miles!

[Carledo]

I think the Manta box is quite closely related to the Omega box (and the Carlton box which is identical save for the clutch operating mechanism) The gearbox I used from a 2 litre car is essentially the same as that used on the 3 litre V6 cars which push out nearly 220bhp and don't seem to have problems. A similar box with slightly different ratios and a different bellhousing area to the casing is also used in the Omega 2.5TD with its extremely torquey BMW diesel. Its not a Getrag box but it looks very similar and I think it's just a Vauxhall (or Opel) built version much like the Redtop itself where early heads were made by Cosworth (and carry the Coscast logo which makes them particularly sought after) and later ones are all Vauxhall/Opel made.
So, A) I don't see why the manta box should be particularly weak anyway, perhaps another urban myth? and B) if it IS, maybe its time to consider the Omega box! The only reason I didn't use a 3 litre one was because I wasn't sure the integral bellhousing would fit the 4 cylinder engine but I have since been assured that it will!

Steve

PS I've been told by my gearbox man that the Carlton/Omega box is a rather difficult and unpleasant box to work on, perhaps this fact could have some bearing on the quality of rebuilds generally? I've never built one myself but I did have a very unpleasant experience with a Getrag dogleg box in a 2ltr petrol (CIH) Bedford CF Van!

[iandollysprint]

Triumph Dolomite Sprint conversion to Redtop XE power. Write up
Ok so the conversion is now finished so I thought I would do a write up of the experience.

First of all the reason for doing it! Well my reason was simple, having rebuilt the original sprint engine with Newman Cam, 2 inch SU’s etc it had about 150 bhp but felt it was going to explode at higher revs! 70’s technology. Having read about 2 other XE conversions I was looking for something to do that was different and would need a degree of engineering thought, so I went for the conversion on my Sprint.

The car itself is in overall excellent condition having been owned by a Doctor for 26 years prior to 3 others having it as a semi-show car prior to my purchase 6 years ago. Body wise it’s excellent, this was the main reason I bought it. Mechanically it was tired so before the conversion the following upgrades were done.

Sierra disk brake conversion
Toledo steering rack (3.25 turns ratio vs. 3.75 for dolly)
AVO suspension with 250 lbs front springs and 150 lbs rear springs
Poly bushed everywhere
BMW E30 sports recaro cloth seats - very comfy and supportive.
Motolita wooden steering wheel.
So the starting point for a 200bhp conversion had already been completed I.e. sort out the other stuff first!

Next was to buy an XE engine. I ended up with a non-coscast engine for £200. I later found out that the head had been modified to prevent the porous oil/water jacket problem with the fitment of a metal tube in the central oil gallery.

Also purchased a ford Type 9 gearbox and adaptor plate but later changed to a Manta 5 speed Getrag as they were much lighter and I came across 2 of them for very reasonable money. I had a hydraulic clutch conversion which I have retained in the conversion.

The plan was to build a circa 200bhp engine so I completely rebuilt the XE engine with the following mods.

I used Autosprint 86.5mm high compression (11.5:1) deep pocket pistons which were well priced at £248 for a set. This allowed me to use Autosprint 276 degree high lift cams and retain the hydraulic lifters. This should create a 200bhp engine with suitable fuelling and ignition.

I also installed vernier cam sprockets to get the cam timing spot on.

The rest of the engine is fairly standard. Doing research on the net revealed that the heads flow well anyway so I did not mess with the head, just cleaned all the ports up. Valves were re-used and lapped in. The distributor was removed from the head and a QED blanking plate fitted in it’s place to fill the whole. This is a must do job as there is no room for a distributor when fitting in a sprint.

Next was the sump. I first purchased a manta big winged sump but later found out that this doesn’t really fit especially if you want the engine to be installed as far back as possible so sold this one for a daft profit. The search continued until I found a rather obscure sump for a 1800 Omega rwd application only sold in Germany. This had the all important front bowl which I needed. I paid about £25 for the sump in the end from a UK supplier who had ordered the wrong part. I later found out that omega sumps on 2.0 UK cars may well do the job as well.

The sump pick up pipe was modified to relocate the pick up central to the front bowl.

A meaty fast road clutch was then purchased. This was a hybrid of a Calibra turbo friction plate and is the biggest that would fit.

Gearbox was completely rebuilt by All Gears in worksop. Gearbox and engine mated together and then it was dropped into the car.

The engine is chassis mounted using SBD mounts and provides a firm location with little give in the bushes! The gearbox is mounted via a simple 90 degree bracket that allows the use of the original sprint gearbox mounting plate and rubber bush. The mounting plate is simply fitted backwards which gives perfect alignment to the gearbox. Mounting holes to the chassis were elongated to suit.

The engine is installed with a 7 degree tilt as originally designed for the Manta Getrag 5 speed gearbox. The oil sump is also designed with a 7 degree tilt.

The engine is a tight fit in the bay. There is about 10mm clearance to the bonnet when closed, 5 mm clearance of sump to steering rack and about 25mm clearance to the bulk head for the distributor blanking plate. This is without any ancillaries on the engine!

Pretty much everything else is now bespoke as follows.

Fuelling - Yamaha R1 carbs, rebuilt with simple rebuild kits, fitted to a Bogg Brothers inlet manifold. This was expensive but is very well made and actually provides short inlet runs which you need to avoid the air filtration system hitting the bonnet. Bike K&N style filters on each individual carb with cylinder 1 air filter slightly modified to allow clearance with the bonnet. This was just to get me going but they actually work very well. R1 fuel pump mounted to inner wing within engine bay. Ford cut-off switch fitted for safety reasons. Fuel tank and lines remain standard.

Ignition - Megajolt 3d mappable ignition with toothed crank wheel. The wheel is bolted to the crank sprocket. Bespoke bracket off side of engine to hold speed sensor in place. Ford EDIS module and new coil pack, new leads.

Cooling - SAAB 9000 aluminium radiator which when you cut off all the unnecessary brackets is actually a really good fit in the engine bay. I re-used the Kenlowe fan originally fitted to the sprint engine. Volvo 240 header tank again a really good fit in the bay. Totally bespoke hosing arrangement to reuse the sprint heater matrix and plumb in the header tank. This turned out to be very expensive but I am pleased with the result.

Sensors. The engine has a Vauxhall oil pressure sender fitted and oil pressure gauge. I fitted an oil temp sender in the sump plug which feeds an oil tem gauge. The water temp sender is actually a turned down sprint sender fitted to the original XE temp sender position. Works well. The rev counter is fed from the Megajolt unit and works fine. Speedometer comes off manta box via a Speedy Cables conversion to mate the two together.

Alternator - XE alternator used via a BMW 5 series (E28 vintage) adjustable bracket to allow proper location and connection to the Bogg bros manifold. Again works fine.

Propshaft - Bespoke item using a manta front end and the rest is a Sprint item. It’s a two piece prop and cost £105 I think to convert by Congleton Propshafts. Again works fine.

Gearstick - modified manta unit, converted to a quick shift with raised fulcrum pointed and shortened end piece. Original sprint stick welded onto the unit and new sprint wooden gear knob fitted. Rattles a bit so I need a bush/damping solution here.

Transmission tunnel - unmodified, fits like a glove.

Exhaust - manifold is a £650 jobby from JP exhaust in Macclesfield. It took 4.5 days to make but fits and works a treat. This mates to an original 2 inch sprint stainless steel system. Again works fine and does not restrict power.

Think that’s about it in terms of what you have to do.

Things I would do differentlyPerhaps go for conventional mounting of engine via modified brackets, this would reduce the inevitable increase you get in vibration you get from chassis mounting the engine with competition bushes but it might compromise the accurate fitting of the engine.

Use Motor bike throttle bodies with Megasquirt ECU. Cost about £500-600 extra but you get a fully mappable system for firing and fuelling.

Not use a 7 degree tilt on the engine to give more clearance of the R1 carbs. It’s tight in there and tricky to fit the air filters.

Things left to do Make up bespoke air filter box, this would mean relocating the brake master cylinder reservoir to the bulkhead for added space.

Increase rpm beyond 6000 as I run the engine in!

That’s about it.

What have I ended up with
Well I don’t suppose many people would have been in a 200bhp sprint! It’s a rather delightful car to drive, sounds nothing like a Sprint, drives nothing like a Sprint. The torque curve gives it away for me. Flat from 3800 and just keeps pulling. Docile at low rpm and even a little stumbly at very low rpm, but when you get it in the power band it just fly’s. It’s now a very quick car. Sounds mental when going for it yet also able to potter around town.

I set out to get a 200bhp engine and that’s what I have ended up with. The combination of the pistons/ cams/exhaust manifold and verniers works. My research prior to going down this route has been proven. Autosprint talked about 200 bhp plus easily with my plans and that’s what I have got.

I’m really pleased with the result, the engine has been rolling roaded at 190 bhp (flywheel) but only up to 6000rpm, peak power is expected to be at 6750 rpm with a rev limit of 7500. Interpolation of the power curve indicates a peak power around the 218-222 bhp range which will be might impressive. I don’t think I will be needing 7500rpm though!

And finally thanks…
2+ years it took to do with me living 170 miles away from the car in the week as I now work in London but live in Cheshire. So thanks to the Mrs for her patience (she did get some extra holidays out of it though)

I have found a lot of the suppliers very helpful.

Autosprint were clearly knowledgeable about there products and what would work well with them, like carbs ect
SBD Developments were exceptional for customer service and advice, parts supply was quick, always helpful on the phone.
Congleton Propshafts - cheap and professional service
Forum members - for ongoing support and advice - like swapping the gearbox mount the other way round - priceless.
Mike at Mikanics in Congleton for setting up the fuelling and ignition on the rolling road.
All Gears in Worksop for the gearbox rebuild (twice due to dicky 5th gear selector)

And the cost of it all.God only knows…but the car has an agreed value of £7500

Cheers for now

Ian