Engine Rebuild Advice

[Matthew Poxon]

Afternoon Gents,

I am after some advice on an engine rebuild. I have posted in the Chimaera section as I know there is a wealth of experience in here and many of you I have met have some great builds.

The car is a Griffith 500 with the TVR short stroke 5.0 V8 94mm bore and 90mm stroke. The car already has a number of upgrades such as big injectors, ACT Carbon Fibre plenum, Clive ford crossover manifolds etc. The engine is a small journal non cross-bolted block. I very much like the flat torque curve the car currently has and I do not want to loose this.


Figures at the wheels

What I would ideally like to achieve is the following:

• Same torque curve but rev to 6.5k or 7k
• A modest increase in torque and BHP (360BHP and 400ftlb would be great)
• Ideally keep hydraulic lifters for
• Engine bottom end build using strong proven components to ensure reliability and to provide scope for future upgrades to the top end.
• Maintain originality with existing block the car came with so the engine / chassis numbers match.
• Bore block out to 96mm and fit top hat liners
• Crossbolt the block

My two lines of thought at the moment are:

5.2

• Bore out block to 96mm, cross-bolt, keep original small journal
• 90mm billet crank
• 96mm forged pistons
• Forged H beam rods
• H324 Camshaft (6.5RPM while keeping benefits of hydraulic lifters)
• Roller Rockers
• Minor cylinder head reworking
• inlet manifold porting / matching

5.3

• Bore out block to 96mm, cross-bolt, line bore block for large journal
• Doug kiddy 91.5mm large journal cast crank (I have this part already)
• Bore out block to 96mm, cross-bolt, keep original small journal
• 96mm forged pistons
• Forged H beam rods
• H324 Camshaft (6.5RPM while keeping benefits of hydraulic lifters)
• Roller Rockers
• Minor cylinder head reworking
• inlet manifold porting / matching

Any pearls of wisdom that may help me with my decision?

Matthew

[Boosted LS1]

Billet cranks are incredibly heavy and costly. Your engine doesn't need one of those imo. You could save a decent amount of money.

[Matthew Poxon]

Boosted LS1 said:

Billet cranks are incredibly heavy and costly. Your engine doesn't need one of those imo. You could save a decent amount of money.

I have seen that the are quite expensive! I do hear of cranks snapping and not just the weaker 500 ones, 4.6 as well. I was wondering whether it is worth swallowing the cost for that assurance.

What is the disadvantage to the weight of the billet crank aside from the obvious more weight to lug around, does the weight mean less efficiency / power?

[phazed]

Talking to JE a while ago, he stated that the 4.6 cranks don't snap.

As we know, the 5.0 cranks do snap and that isn't through hard use.

I know of at least one that has snapped when turning over to start!

Personally, I wouldn't worry about matching engine numbers, most of these cars have been. "messed with" in some way. Keep all the paperwork to show and have the number changed on the reg doc.

Go for the cross bolted 4.6 block, (big journal) and have it bored to what you want, probably giving you 5.2 litres?

All your other suggestions seem good although I don't know specifically of that cam.

Have the heads ported to the best that they can achieve as it is the heads on a NA engine that will release the power.

[citizen smith]

Probably best to have a chat with John Eales @ John Eales Engineering Ltd about your requirements. He is the V8 guru, Paris Dakar engine builder amongst other things.

[spitfire4v8]

For value for money I always say Rob at V8D .. but if you really are chasing numbers the best engine I've ever seen on my dyno is a John Eales 5.2 at a smidge under 400hp.

Torque of 400lb.ft is 80lb.ft/litre .. you won't get that from a rover using rover heads anyway (best I've seen is 74lb.ft/litre on a V8D 5 litre) so a capacity increase is your best friend if that's the sort of numbers you're chasing.

exciting project.

[Podie]

I've previously been a very happy V8D customer and wouldn't hesitate to go back.

I'm of the view that you phone up V8D or JE, state the characteristics you want and let them spec if for you. What's the point in going to experts if you don't listen to their view.

[Boosted LS1]

Matthew Poxon said:

I have seen that the are quite expensive! I do hear of cranks snapping and not just the weaker 500 ones, 4.6 as well. I was wondering whether it is worth swallowing the cost for that assurance.

What is the disadvantage to the weight of the billet crank aside from the obvious more weight to lug around, does the weight mean less efficiency / power?

It's mass may slow down accelleration. It will also have had no factory development or testing conducted on it by Rover or anybody else for that matter.

[MisterT]

Whether you'll want to keep the original block may depend on what has failed in yours. I know what a good RV8 sounds like but I'm not expert enough to tell what has failed on yours from your sound clip.

My engine failed after an overheated Donington track session and 6 liners had shifted

I chose to go for a 'new' top hat cross bolted large journal block from V8D. Sure I've lost a little bit of originality but this engine revs and feels so strong I wouldn't swap back. The crank is a shorter stroke than the TVR 5.0 with a small overbore to get back to 5.0 so it seems to spin more eagerly than my old engine.

If I've understood correctly there is a greater overlap of the crank journals on the large journal crank which I guess makes it a stronger unit and less likely to snap, hope so anyway.

If I had to do the process again i wouldn't hesitate to use V8D again.

[MisterT]

Just dug out the build sheet and it has an 86mm stroke and 96mm bore.

[motul1974]

Another one for the value of V8D.

I've just got 4.6 back out of my 450 as part of its gems conversion from him and gotta say his approach to upgrades was really very grounded with me with no apparent bias, quite the opposie in fact, he dissuaded me of a number of things.

I enquired about capacity upgrades with him and I was very close to his 5ltr engine, but decided to stick to original. At the time he didnt sound as if he was going to continue with the 5.4 option due to difficulties in getting a new crank made up. That was only a few months ago so things may of changed by now.

[Boosted LS1]

I produce those 5.5L cranks and as V8D have said, it's flipping hard to get a machinist to machine them. The reason seems to be that the crank grinders are tied in with John Eales, not to copy his machining specs. In reality my crank is totally different to his so there shouldn't be any conflict. His cranks won't make a 5.5 and don't have the 2.500" mains I can provide. Neither do they take chevy rods. Hopefully things may change soon and V8D can get back to making big engines :-)

Offset ground 4.6 cranks are cheap as chips and can offer reasonable stroke increases but the rod journal does get smaller. So there is a compromise as always.

Edited by Boosted LS1 on Thursday 13th September 20:17

[Belle427]

Cracking dilemma to have!
If money were no object John Eales would seem to be your man.
It’s hard to look past V8D for value though, their 5.4 Dominator engine looks reasonable value and an awesome package.

[phazed]

Out of interest, what crank does the V8D 5.4 use?

[900T-R]

I'd go for whatever John Eales will specify. He's old school and quite conservative/stubborn in some respects but you will know exactly what you have and the process is so much more painless and transparent than with any other engine builder I've worked with. Call him up, discuss and agree on spec, get a detailed Excel sheet with everything specced and priced up separately, three weeks later the engine is sitting on a pallet and you get an engine dyno report, you pay the balance and the lot is sent your way.

To be bluntly honest, trying to get specific information before ordering and during the build process from any of the others has been like trying to draw blood from a stone, the general attitude seems to be 'give me your money and I'll build you something, whenever I feel like it' - which won't do at all. As long as the others won't up their game regarding to communication and commitment to price/spec/deliveries I will decline to handle engine builds for customers except JED Rover V8s.

Edited by 900T-R on Friday 14th September 08:45

[ray von]

900T-R said:

I'd go for whatever John Eales will specify. He's old school and quite conservative/stubborn in some respects but you will know exactly what you have and the process is so much more painless and transparent than with any other engine builder I've worked with. Call him up, discuss and agree on spec, get a detailed Excel sheet with everything specced and priced up separately, three weeks later the engine is sitting on a pallet and you get an engine dyno report, you pay the balance and the lot is sent your way.

To be bluntly honest, trying to get specific information before ordering and during the build process form any of the others has been like trying to draw blood from a stone, the general attitude seems to be 'give me your money and I'll build you something, whenever I feel like it' - which won't do at all. As long as the others won't up their game regarding to communication and commitment to price/spec/deliveries I will decline to handle engine builds for customers except JED Rover V8s.

This is exactly what I got when dealing with one of the companies mentioned above. You'll be spending a load of money with someone so you need to choose carefully

[Chuggaboom]

You cannot rev an already overstroked old RV8 to 6.5-7k, and expect it to hold together, reliably !

TVR tried it in the TC cars before the AJP was around and they went pop frequently @4500cc....and you wanner go try 5.2 or more....hope you have deep pockets !!!

You'll need roller rockers, billet crank and H beam rods, and then keep it to 4.6 for a nice pokey revvy fun ride.

Or leave as is more or less, maybe 5.2, and waft along with the torque.

NOT BOTH.

MTPW

PS when I ever get the car back together, I shall be going 4.6 as above with other toy bits too.

[trev4]

Looks like powers perfromance are now doing a 5.2

[macdeb]

V8D? not for me.

Edited by macdeb on Thursday 27th September 17:15

[Podie]

macdeb said:

V8D? not for me.

Edited by macdeb on Thursday 27th September 17:15

I think we have all had a bad experience with at least one tuner / TVR specialist in our time.

I regularly see people recommending people who, based on my experiences, I wouldn’t trust to mop a floor - let alone touch my car.