Engine and Transmission Tech

A friend of mine bought a TR8 that supposedly has a TVR built 5.0 liter Rover V8. The engine number is S46D#####A. I'd list the numbers, but I didn't write them down. Looking at the on line engine numbers for Rovers, it shows that engines starting with 46D are 9.35CR 4.6Liter engines. No mention of the S. Is that the designation that makes it a 5.0 TVR built motor? The story behind the motor is pretty interesting. Supposedly the engine was bought by Mercury Marine to test as a replacement for the GM derived inboard motors they were selling. It never was used and was going to be scrapped. An employee put it into his TR8, and then sold the car to my friend. Same friend also has a TR8 that supposedly sports a 340 crank in a 3.9 block yielding something like 5.7 liters of displacement. But that's another long story. Does anybody know what the S stands for, or if there are different numbers for the actual TVR engines? It would be nice to know a little about the engine without having to tear it apart. It came with a crank driven oil pump, but the timing cover also has a hole for the distributor with a stud for the hold down. TVR claims 340HP for these. Maybe at the flywheel with sophisticated FI, but I drove the car, and it sure doesn't feel like that much.

Well maybe. Stick a soft stick down the spark plug hole with "large" piston at bottom," mark stick". Crank to top, "mark stick", subtract difference. Factor approx. angle of stick and = pretty close ? 340 hp, at the nitrous injected flywheel ? Stap it on a chassis dyno, would haft to be over 280, out back. Sounds like they rated the hp at a "sales meeting" ?Good Luck,roveman.

Good to hear from you, Todd. No luck here on the "S" either. I'm looking forward to reading about your project though. I sure would like to talk to your buddy about the 3.85" stroke motor though since I'm about to start down that road.

Anybody know how TVR made 5.0L? Was it offset ground 4.6 crank?

Nic, overbored 4.6 and uses the Australian P76 crank?

Seems like diminishing returns.

Edit: D'oh! The stock P76 rod journal is 2.0", so an overbore might get you to a scant 5.0L.



Edited 3 time(s). Last edit at 02/05/2010 03:55PM by pcmenten.

Just found something that said TVR Griffith 500 94mmX90mm. Early cars were rated at 340. Later ones detuned to 320 for driveability. Not a lot is known by my buddy about the 340 crank motor either. He bought the car in Ct. several years ago. Please excuse me if I don't get the following story perfect. Anybody who wants to talk to my buddy, PM me and I'll send you his phone number. He bought the car off of ebay several years ago before ebay became what it is today. The car was described as having a stroker motor. It was cheap, somewhere south of $5K for the car. The owner is or was a new car dealer. He wanted to build a big engine for the TR8, so he took the engine to a local machine shop in Ct. They build the engine based around a book on high performance Buick 215 motors. The owner told my buddy that the engine cost him $18K to build in 1991. It used a Buick 340 crank. There was a ton of block and crankshaft material that needed to be removed in order for the crank to spin. My buddy got the name of the machine shop and called to verify the story. The machinist remembered the build but couldn't remember specific details other than the 340 crank, the clearance issues, and the Kenne Bell roller rockers. The machinist invited my budyy down to look thru boxes of old records to see if he could find the actual multi page build sheets for the motor, but that hasn't happened yet. Right now, he is having a bitch of a time finding a starter for the car. Something about having to make a custom nose cone for it. He is pretty sure the tranny has to come out in order to figure it out. I've also driven this car, and this one is a beast. It makes staggering torque. My buddy had it on a dyno once, but the dyno operator shut it down at around 5000 RPM because it was lean. It made 258HP. Dyno operator said if the carb was right he had no doubt it would go to 300. To put that into comparison, I was there when Woody's car did 282 at the wheels, and another one of his stroker motors only did 252. I'm sure both are putting out better numbers now, but that's what I saw.

Todd, that sounds about right. The 340 crank has the right spacing on the mains, so it will fit there. It was the problem of the piston clearing the counterweights and the piston coming out the bottom of the block that we couldn't quite figure out.

Nic is all over that configuration. At this point he was looking at using Honda rod bearings to destroke it enough to resolve the piston coming out the bottom problem. The other way to do it was to re-sleeve the block and put in slightly longer and slightly larger cylinder liners. Have to have a good block.

There might have been a difference between the Olds blocks and the Buick blocks and the way the liners were fitted to the casting. I've heard that the Buick liners were ribbed on the outside and were cast into the block, but that the Olds liners were a press-fit. That would lend the Olds blocks to easier modification. Of course, core shift would limit what you could do with a particular block. But I'm not completely certain of all that information.

Can't believe "everything" you read in a British pub., bout US. built engines. Factually, Buick and Olds 215's "both" used ribed liners, integral cast, and were pretty thin. Never dropped and no cracking behind the liner. Other than head bolt pattern, were identical, excepting Jet-fire with thicker main caps, longer 12 point main bolts and thick-domed pistons. If your going to re-sleeve a 215,(waste of $), the "ridges" halft to go anyway. I don't see how the Olds had a "better" chamber,(wedge). Even with valves more centered in bore, both designs were very close in power, stock and modded. Many early teams chose the Buick. roverman.



Edited 1 time(s). Last edit at 02/05/2010 08:37PM by roverman.

From the www.v8forum.co.uk site that engine number was for a Morgan+8.

It will be a Morgan 4.6 engine then and probably standard unless it has had work.

TVR were notorious for over stating engine power, in reality most 5.0 engines produce in the region of 280 BHP but many have been improved to around 300-320 BHP with a new Mark Adams chip and bored out plenums, trumpet bases and manifolds.

Here's the link

[www.v8forum.co.uk]

Kevin.



Edited 1 time(s). Last edit at 02/06/2010 07:46AM by castlesid.

Definitely looks like it's a Morgan engine code. If it is really only a 4.0, that would be a big reason it doesn't feel all that quick. Whatever the engine turns out to be, it's still a nice driving car. I don't think he has any plans to modify the car beyond where it is. When he bought the car, there was a Ford rear end, Compomotive wheels, suspension mods, and all of the normal bolt on engine goodies. He still has the one with the 340 crank, and a third TR8 that still has the stock 3.5 with a cam and 4 barrel. All three cars are gold, but all three are completely different interpretations of a modified TR8.

Todd,

It will be a 4.6 so in standard spec 220 BHP and loads of torque.

Kevin.

Todd

I also bought 4 Rover V8 engines and some TVR parts from Mercury Marine a few years ago. One of the blocks was supposedly a 5.0 liter. But it actually was three 4.6s and a 4.0 with 8.1/CR. I was just happy to have 2000 pounds of cool stuff to work with. Here is an example:

Randall

Where and when did you get these engines? I am the guy with the proported 5.0 TVR motored TR8. I am attempting to decern what motor my car has only to satisfy my own curiousity.
I had a conversation with a bloke in GB some two years ago who worked for a company who supposedly made, or more aptly remade, 4.6-4.9 Rover motors to TVR specs. Although at present I can not put my hand on the correspondence he did say the TVR spec motors they built were 304.??? C/I and he remembered sending at least one to Mercury. This was back in the early to mid 90's. I will pick the brain of the P/O for more detailed information as to dates and any info he may still have and post any results.. He no longer is employed by Mercury Marine.

Todd is correct in his assesment of the car. It pulls well , however does not feel as strong as the other TR8.

At present I have 2 TR8's with mystery motors that feel quite satisfying when one gets into the loud pedal. One has been dyno tested and came up with 258 RWHP and lots of preignition. Time constraints did not allow any further runs after a timing reset. It does feel stronger than it did.

I can not determine with any certainty what motor the TVR motored car actually has as the S46D motor prefix indicates a 4.6 Morgan. ???????????

Any ideas ??

Charles

When the original Rover engine plant shut down, Mercury Marine abandoned the idea of using the RV8. They put everything they had in pallet boxes, and I bought four of them. This was a liquidation. Supposedly one of the pallets contained a 5.0, but maybe they where lairs or mistaken. I just checked one of the 4.6s; and the serial # starts with 60D.

The only way to tell for sure what size engine you have is measure the diameter of the bore and length of the stroke. You can do this with a pair of calipers and the cyl head removed.

This is the info that I have on the TVR5.0litre. But certainly there were variations. I recall that the 5.0 was just a stop-gap engine while TVR sorted out some newer, more modern drive trains:
bore 94 x 90 stroke
9.6/1 CR
325HP@5500, 350ftlbs
TVR crank, rods and pistons
18lb ribbed flywheel
TVR 435R/M camshaft
Ported cyl heads with 42.8mm intake and 36.8 exhaust, double valve springs
Modified intake manifold/plenum

Randall

Randall

Thanx for the comeback. I will just drive the cars for now. I do not want to pull it down just yet as I have a couple of other projects, one being installing a 3.5 in a TR7 coupe. That will happen while I try to finish the landscaping on the garage and try to get some kind of order in the chaos that is now my underhouse garage.

I am going to at least attempt to get a look at the stroke and perhaps remove the hedder and check the port sizing. I have also requested any info the p/o has or wants to give.

How did you find out about this mechanical bonanza ? Are there any parts or motors left and where are they ?

Charles

Randall

Received the following info from the P/O regards the motor in question.

Was "built" by Power Train Projects in GB from a 4.6 Rover/Morgan base motor. At the time there were only 2 motors built and both were 5.0. These were apparently followed by 4 or 5 others in various displacements. The two motors, one of which I have, were built to "marine calibration" specs from the Griffith motor base. The EFI plenum had the number 500 on its top. The second motor went to the VP engineering for MM. Use unknown.
He also said the intake ports and exhaust ports were quite restricted by the intake and hedders now on the motor and advised larger hedders and a rework on the intake to port match both.

Sounds like I have next years project. ??????????

Charles

Randall

Meant to ask before. Is the car in the pix a TR8 ?

Charles