Fitting a Roller Cam to a 1250cc TF

Some time ago I fitted a Roller Cam from Len Fanelli to my TD after it had eaten 3 camshafts and two sets of tappets, admittedly over a period of 40 years. After having discovered my TF had eaten a cam lobe after only 3000 miles, I decided to fit it with a roller cam. Following a lot of consideration, I went with the same performance cam as in the TD, even though the TF is more of a concours car, it keeps everything the same.

I decided to go the whole hog with a new set of roller rockers, 6 blade water pump and plastic fan while I was at it.

While communicating with John on his steel tappet gaskets he asked me to do some photos and write the installation up for TTT 2.

The kit ready to go.

I know some people out there manage to change springs using special tools and rope or air in the cylinders, but because these are 350lb open pressure springs, I went old school and removed the head.

This is the first time I have had to do any engine work since the car was restored so I am now finding out what an absolute pain it is to work on a TF compared to a TD.

Why MG didn’t leave the bonnet sides attached to the top as Morgan did, I don’t know. Off with front bumper, radiator and shell, giving access to the timing cover. Drop the sump. remove the distributor and generator, and off with its head.

Swapping out valve springs was not too difficult on the bench taking care not to damage seals, which had to be removed to get bottom steel cup on.

Removing the timing gears was not hard, but would have been easier if (1) chain had split link, or (2) I had two pullers. Constantly moving between the two gears, pulling a bit at a time on each one was very time consuming. there is not a lot of room to get leavers in.

Next, out with the old and in with the new camshaft. It was the usual pain to get the centre bearing in, fortunately I have a 4-post hoist which made life easier. I would not recommend doing it on axle stands but it could be done. Remember it has to go in one particular way, so it gets its oil feed.

Now for the cam followers, there are two ways to fit these. Link outwards or link inwards. To fit link inwards, you need to grind a bit of metal off the block to get them in, this I did with the TD.

If you fit them outwards there is a slim chance that, as the cork gasket gets saggy, they will cut a hole in it. I ordered a John James Metal Tappet Cover gasket, so it has the plenty of clearance and of course will not sag.

Now head is back on and followers in, so I can measure the length of the push rods and have them machined to size. When I did the TD a friend had a lathe, but he has sold that, so now I have to get a machine shop to do it, so more running around. Job keeps getting delayed, and finally took 3 weeks.

First mistake here – more later!

Warning – length of pushrods is quite critical so as not to get interference with rocker on full open. You will need 2 turns below the body of the rocker, in my case that was 4-5 turns from bottom of recess.

I already had a set of roller rockers but if you buy a set, bear in mind there are 4 different ones, just as there are 4 different original rockers. The only thing with the rollers is they are a bit harder to tell the difference, but you must get them right.

Refitted the side plate, timing gear cover, distributor, generator sump, put in fresh oil.

What to do with the exhaust manifold was another problem. For years I have had a 4 branch manifold, which I paid a lot of money for, but it will not fit with a Laystall Head due to it being 12.5mm wider. This pushes the manifold out and interferes with the steering shaft. It was no problem on the TD as that is left hand drive. I am trying to modify it, but in the mean time I have sent the original manifold and down pipe off for ceramic coating, which will be another month.

I managed to get the 4 branch modified so it would fit, but am having problems with pin hole leaks on my welding. I re-fitted the original, now it is back from coating.

Engine all back together, fresh fuel in the tank, set the CSI distributor and selected curve 11 and fired it up, ran OK, will get to tuning when I have connected up the radiator and everything else.

Heard a crack, didn’t think too much at the time so went ahead and refitted radiator and surround along with front bumper. Fired her up again and heard another crack. Pulled off the rocker cover and saw two rocker pillars had cracked between the bolts in line with the shaft. Between puling the valve gear apart and measuring and refitting several times, I managed to break another 6 pillars before I noticed the marks on the bottom of the rockers. It looked like the cup of the push rod had been making contact with the rocker when the valve was fully open.

The instructions that came from Harland Sharp (the manufacturer of the roller rockers) said to set the adjusting nut two threads down, I set it 2-3, but that was forgetting about the recess; it should have been 2 turns from the surface of the rocker, not from within the recess. This is to give clearance at full open for the pushrod cup. Until I get a new set of pillars I cannot prove this, but it looks the likely suspect. I have had the same set-up in the TD for about 8 years and never had a problem with pillar breakage.

I don’t have the tools to remove the cups from the push rods. They were quite a firm fit and required a hydraulic press to get them in. So, as I did not wish to damage them, I took the alternate route.

I drilled/ground out the recess until I could get full angle without interference at 3 turns. Probably a bit over the top but I only wanted to do it once

Now the wait for the new pillars.

John had wanted some information on driving with this set up, but after what happened I put him off, forgetting about the TD. So, after downloading an app I did some quick runs. Unfortunately, the only quiet 100km/h road near me is not level or straight, also I was starting on a gravel hard shoulder, so I could probably do better. But I think the times shown (see Note 1) are good for a road car in this day and age.

I have always liked the roller cam in my TD, but I will say, it feels better with the CSI distributor. Thanks to the supplier* and one of his clients who put a similar spec motor on the Dyno and found the optimum curve (see Note 2). No pinking or missing and even the gear stick rattle at 3000rpm seems to have gone.

Bernard W Wood (New Zealand)

Ed’s note:      *Roller/Lifter camshaft kits are supplied by Len Fanelli of Abingdon Performance: laf48′ ‘at’

I am aware that there has been much debate about these kits on T Series sites and there are some who say they would not entertain fitting them.

The last thing I want is to get caught up in any controversy regarding this. I am not advocating fitting the kit; my sole objective in publishing Bernard’s article is to provide a technical article which readers might find interesting. Bernard had previously mentioned to me when I sent him the steel tappet chest gasket kit, that he was just about to fit one of Len Fanelli’s roller/lifter camshaft kits to his TF. Always keen to gather in articles, I asked him if he would write one for me. Although he would have preferred to have waited until he had overcome the difficulty mentioned in the article, he agreed to my request because I was short of copy at the time.

The performance figures from his TD with the Fanelli roller/lifter camshaft kit are set out below, after Note 1 (the engine spec). Note 2 shows an advance curve using different CSI distributor settings. The optimum curve is setting 11.

These should be possible with Bernard’s TF, once he has sorted it (to be reported in a future issue).

Note 1 Bernard’s TD’s XPAG is 1250cc +80 thou Laystall Aluminium head with 32cc chambers – about 9.8:1 CR, Fanelli performance roller cam and roller rockers, 1½” Carbs, 4 branch manifold, CSI electronic distributor curve 11. Uses 95 octane fuel and has a 4.55 diff.

Performance figures (100km/h road not level or straight, and starting on a gravel hard shoulder

0-60 km/hr                               5.0 sec

0-100 km/hr                             15.0 sec

0-60 mph                                 14.0 sec

¼                                             14.0 sec

1/8 mile                                   7.0 sec

Note 2 Bernard says that curve 11 is very close to the original curve if you set the static timing at 10 deg. BTDC instead of 0 deg.

2 thoughts on “Fitting a Roller Cam to a 1250cc TF

  1. Bill Chasser says:

    I have run Len’s 286/286 race roller cam in my TD for about 6 -7 years now.

    I have a few comments and don’t want to get in an heated discussion over my observations as well. I am also running HS roller rockers , custom chromoly push rods from an outside source and originally had a Laystall head with an 1971 casting date installed.

    Regarding exhaust extractor clearance on a RHD using a Laystall head. It was noted that my Laystall head had been milled off on the port side surface eliminating all but the very top of the lettering. This was likely done for steering box clearance as the head had been a spare destined for use on a TC race car by its previous owner. Unfortunately, cracks develop in several of the spring pockets and porosity issues ensued with the vintage head. It is now a large and very expensive paperweight on my Wall of Speed until I can get it repaired. I had contacted XPAG Engineering at that time and they DO NOT recommend the high spring pressures with their modern heads. That was 6 years ago and that advice may have changed, but I thought it to be worth mentioning. I found that using stock Chevy Z/28 springs are sufficient to keep valve float from occurring for normal street driving. I run my XPAG s hard frequently sustaining 6500rpm using the Z/28 springs and run the engine between 3500-5500 all day long. In talking with Len back when I bought the kit I was told his engineer said 350Lb springs were absolutely necessary. Unless one is expecting to be WOT above 6500rpm I don’t believe this is necessary. I’ve had no ill effects with my own setup. No disrespect to Len and his product line. Just my own empirical findings.

    The cam I am using again is the 286/286 duration, is a full race cam for naturally aspirated engines with a lot of valve overlap and is the most radical cam that Len offers. I’m hoping to discuss a more radical custom cam with him later. . I also found that the cam worked better at 102° vs the 106° cam timing spec that was provided to me by Len. There are a great deal of variables to be considered when selecting a cam profile. At 106° of cam timing with my 286/286 the amount of valve overlap and the crankshaft’s relative position, I was getting excess fuel load reverberation exiting the carbs even with the idle set at 1500-1700rpm. This would cause the fuel load to become excessively rich as the engine would try to pull in the fuel that it just spit out of the carbs. The engine would then sputter and cough then clean itself out and resume with more fuel reverberation or die unless I racked throttle. Maybe the cam works better for all out 7500rpm banzai runs at the track but it wasn’t tame enough for fast road use off track. I elected to use a vernier timing gear I sourced from Manley Ford to properly degree in my cam. I will say that my experience has come by multiple cam timing changes to find my sweet spot.

    Overall I can say I am very happy with the performance I’ve received from my various mods. I had to switch my Laystall out for a modified MKII ironhead. Along with the 286/286 cam and kit sans the springs Len provided, a Baker extractor w/ integrated intake MK II carbs jetted with GJ needles , Arias forged pop up pistons of my own spec, Saenz connecting rods, Phoenix Billet crankshaft and ARP fasteners … I have a reliable engine that can outrun freeway traffic with 4.55:1 final CW&P with the stock 4 spd. With no worries whatsoever. The engine is happiest above 3500rpm were the cam profile really begins to wake up. My cam selection and mods aren’t for someone who just wants to drive their car in a normally sedate manner. That was never my intention when I restored TD-4834. For me I want to have to fill in sports car experience. To drive the car as it was designed to do. (These engines were designed to run at 5000rpm all day long when they were stock). This was going to be my competition car for vintage racing and to give my father a taste of his racing past when he was a young man. With all my mods I can push out ~105HP on Sunoco race fuel that is available at the pump in my area. I very fortunate in that respect. There’s nothing like the aroma of race fuel on a Saturday morning LOL.

    The plus side to running any type of roller cam vs a comparable flat tappet cam is better torque, nearly no cam failures, no need for constant valve lash corrections due to lobe and lifter wear, no need to use ZDDP additives in the vain attempt to prevent flat tappet failures and frequent cam and lifter inspections and changes. I still use VR1 20w-50 that has ZDDP in their formulation. Though the purchase cost of roller cams can be daunting to some, it pays dividends in the long run with decreased operating costs long term. A satisfied customer.

  2. Len says:

    I found that the GJ needles were always slightly too lean, however after I installed my custom Stainless-steel swirl polished 37.5 & 35.5 MM valves the engine was much too lean. I found the best needle was a GS, with the jet below the bridge set @ .06250″ and the needle dropped .015″. & 3 in1 dashpot oil.The .0625″ setting results in a MUCH improved part throttle or tip in throttle response.The best fuel atomization is at .0625″ ( thanks to the racers) and never touch the mixture nut again. Fuel level set @ .220″ below the bridge.

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