4 cylinder TR race engine, 92mm

[marvmul]

Some racers have tried the alloy cylinderhead that is available for the 4 cyl. TR engine.

They soon abandoned it because of endless trouble, mostly with the headgasket.

I know of someone who has made an engine with welded liners, in fact he welded steel tubes solid with the engineblock (at the top) .

Steel is not a good bearing surface for the piston rings, so he did press cast iron liners within these tubes. This engine is running without problems, but it has

an iron cylinder head. Fitting an alloy cyl. head would make an engine like a lot of cars have : cast iron block and alloy cylinderhead. These engines cope well with the different expansion rate of iron and light alloy. Perhaps this would work for the TR engine?

I asked the chap who build this engine if he could make a welded block with 92mm bore. He answered that 88,5 mm is about the maximum bore if he has to fit iron liners inside the

steel tubes. After a while, he came with the idea of omitting the iron liners, reaming the welded steel tubes to size (in casu 92mm) and then cover the steel tubes with a Nikasil layer, by means of electroforese. Amongst others, Honda and Porsche had Nikasil liners at some time. I think I'll give it a go if there is chance of succes.

Does someone know of the characteristics of Nikasil? And of welded liners in a 4 cyl TR engine?

[Rhodri]

Nikasil had a bad reputation as something in the fuel corroded the nikasil causing blowback on the rings. Type in "nikasil Rover" to Google. BMW had the same problem and switched to Alusil, our recent Jaguars sufferred from nikasil bores.

[stuart]

Nikasil had a bad reputation as something in the fuel corroded the nikasil causing blowback on the rings. Type in "nikasil Rover" to Google. BMW had the same problem and switched to Alusil, our recent Jaguars sufferred from nikasil bores.

Definitely dont want anything to do with Nickasil. I believe it is the make up of unleaded fuel that caused the problem and it cost BMW a fortune in warranty claims with their engines and Jaguar had similar problems but they discovered it quicker and changed the material quicker.

Stuart.

[marvmul]

I did what Rhodri suggested (typing 'Nikasil Rover' in Google) and found that the problem Nikasil cars from BMW and other makes, occured in the early nineties (i.e. :530i and 540i cars) and by '94-'95 they replaced the Nikasil with 'Alusil'. BMW concluded that the corrosion was caused by the high sulfur fuels of that time. Nowadays the fuels contain much less

sulfur and in some sites it is suggested that Nikasil engines wouldn't suffer from corrosion in these days and even that a car with a Nikasil engine with good compression can be a good buy (mentioning the fuel price and the Nikasil problem will buy you a Range Rover V8 4.4 litres for small money I wonder?).

BMW says that, at the onset of the sulfur corrosion, only the top of the cylinder bore (the 2 or 3mm above the ring ridge) will be affected, but the corrosion would creep downwards to the surface the rings ride on, hence compression loss/blow by. According to BMW, first symptom will be rough idling : good to know when you would want to buy a

'Nikasil engine'. A cylinder leak test will make a sure diagnosis.

So I think that corrosion of Nikasil isn't a problem any more. Perhaps applying this stuff is? I thought is was applied by electrophoresis, on a website someone was convinced it

was sprayed on, perhaps the two methodes are used? I wonder how it is finished? No honing? Of course the dimensions of the bores should be right before the nikasil is put on.

[jellison]

Marv - you have my bonker tuned (newly cast, offset valved mega race head). Still facinated by the thought of going Alloy?

 

Really to do it right would cost the price of the head casting (alot!), all the machining, all the really good quality valves and then all the trick bits that fix the problem (yep you are right everyone including me tried and failed with the alloy head, until I went back to it with the final tweeks). To have a copy of the new iron one you have in alloy with the parts needed to fix the gasket issue (only an issue for racing) could cost 3 - 4000 UK pounds;).

 

My engine is having what should be its last rebuild with 92mm piston (special short ones) down from 92.5+, and super light billet rods, new liners, and that head.

 

Will be running it a few time this year in amongst most races in the 6 then likley it will be for sale at the end of the year at a very sensible price.

 

Use the iron one it is the dogs nuts (that is the head I had on the car when it broke the Thruxton TR outright lap record it still has (in 04).

 

Incidentally - Do you fancy my special long rods? (can easily get a set of short pistons made for them from our supplier). Lighter than a std rod and (about 8mm longer - would have to check exact extra length , but about that). Extra length stops too much rock at the top of the piston due to the shorter piston with higher gudgeon pin position.

 

PM or mail me (you should have my mail address still) if you need to discuss the above.

 

How about coming and doing the Big MG festival meeting at the Silvertone International this summer.

 

Cheers

Jon

[MadMarx]

My Porsche has nikasil coated liners. I don't have any corrosion from unleaded fuel so far. No measureable oil consumption.

[marvmul]

Marv - you have my bonker tuned (newly cast, offset valved mega race head). Still facinated by the thought of going Alloy?

 

Really to do it right would cost the price of the head casting (alot!), all the machining, all the really good quality valves and then all the trick bits that fix the problem (yep you are right everyone including me tried and failed with the alloy head, until I went back to it with the final tweeks). To have a copy of the new iron one you have in alloy with the parts needed to fix the gasket issue (only an issue for racing) could cost 3 - 4000 UK pounds;).

 

My engine is having what should be its last rebuild with 92mm piston (special short ones) down from 92.5+, and super light billet rods, new liners, and that head.

 

Will be running it a few time this year in amongst most races in the 6 then likley it will be for sale at the end of the year at a very sensible price.

 

Use the iron one it is the dogs nuts (that is the head I had on the car when it broke the Thruxton TR outright lap record it still has (in 04).

 

Incidentally - Do you fancy my special long rods? (can easily get a set of short pistons made for them from our supplier). Lighter than a std rod and (about 8mm longer - would have to check exact extra length , but about that). Extra length stops too much rock at the top of the piston due to the shorter piston with higher gudgeon pin position.

 

PM or mail me (you should have my mail address still) if you need to discuss the above.

 

How about coming and doing the Big MG festival meeting at the Silvertone International this summer.

 

Cheers

Jon

J.

It's because I bought a race prepared alloy head 1.5 years ago anyway (complete with valves), that I like to try this head first on my new engine. I think I have a chance

because the top of the engine is welded and then milled flat. When this will work, I have 2 complete engines and I can keep one of them as a spare. The cast iron head I bought from you is indeed very good : some months ago, my engine was tested back to back(one after the other on the same rolling road) to a very good engine build by a famous specialist : I had 8 bhp more and also more torque over the 4200 - 6500 rpm range!

[Rhodri]

Marvmul have you also welded the bottom of the liners and discarded the figure of 8 gaskets? Otherwise how are you going to renew these gaskets should they fail? I like the idea of what you are doing as I have a worked head that is going to have difficulty sealing on the liners even with a steel head gasket, as the chambers have been opened up a bit far.

[jellison]

J.

It's because I bought a race prepared alloy head 1.5 years ago anyway (complete with valves), that I like to try this head first on my new engine. I think I have a chance

because the top of the engine is welded and then milled flat. When this will work, I have 2 complete engines and I can keep one of them as a spare. The cast iron head I bought from you is indeed very good : some months ago, my engine was tested back to back(one after the other on the same rolling road) to a very good engine build by a famous specialist : I had 8 bhp more and also more torque over the 4200 - 6500 rpm range!

Marv - only one way to sort the alloy head gasket issue. Issue you have with you one is not sealing but that it is I believe not machined from a blank and had all the valves mo0ved as per the iron one (the first new iron one - even though they have advertsied them for years - they never made them!). Mail me if you want to kow how to fix it - I'll tell you as you bought the trick iron one and are a racer.

 

No point telling everyone, as these tweeks are not needed for the road.

 

Welding in liners - sounds well dodgy and what it it going to solve at the top of the block!!

 

Can't wait to start racing mine again in April at Brands. (2nd race of the season).

 

http://video.google.com/videoplay?docid=1469841583459902993 Last time out Late 06;) Pity about the Bug as the Rocket Griff200 comes by (Building mine this year;)).

[marvmul]

To Rhodri : I don't do the welding myself. The welding is done by a Mr C.Nuyts, who is specialised in new billet steel crankshafts.

He has made a special crankshaft for my new engine (in fact two cranks : one with 96mm stroke and one with 92mm stroke : the 96mm stroke is not allowed in the german TR Competition, so I may sell the 96mm crank) : these cranks have dummy mains and 8 counter weights and the crank pins for the conrod bearings are narrower by 5mm and also the diameter is smaller than standard.

I told already that, to accept 92mm bore pistons, there was no room to press cast iron liners inside welded steel tubes. Instead he has omitted the cast iron liners and only fitted steel tubes : the bores in the block that accept the liners are widened by about 5mm (diameter) to about 97mm. The outer diameter of the steel tubes/liners is 0.1mm wider and is pressed in the bores of the block : the interference of the liners with the bores in the block is the only provision to make the seal between the bottom end of the liners and the block.No figure of 8 seals and no chemical sealing product. At the top, everything is welded up, except the 10 holes for the head studs, then 10 new holes of about 10 mm are drilled for the coolant. I'm going to make 8 alu plugs with holes drilled in it, going from about 3mm to 8mm diameter : the 2 pluggs with 3mm holes are for the coolant drillings at the front of the engine, the rearmost drillings will get no plugs of course. The top of the block is milled flat now and the steel liners are reamed to size and also the nikasil coating is done and surface finished, ready to accept 92mm pistons : the engine block is a really nice piece of specialist work.

C. Nuyts is going to make the conrods for me also : in this way standard forged pistons with 31mm compression height can be used. The engine will not be ready before the end of the 2008 race season, I will report of the progress.

[Rhodri]

It sounds very interesting. If it all works it will eliminate the sealing problems at the top and bottom of the liners, especially at the top where the combustion chamber, in the head, has been opened up around the inlet valve. We await the road tests!!