3.9 rv8 rebuild

Hi guys!

Starting this thread as id like to keep engine related things separate from the rest of the build.

Anyways im going to rebuild a 3.9 efi engine that i bought at the weekend (thanks bencorkill)
main reason behind the rebuild is the motor has covered 130k miles and plus i want to fit megasquirt once it rebuilt.

Just so you know ive only ever rebuilt a 2 stroke engine before so i may be asking for lots of help and advice as this is all new to me. So prepare for silly questions etc

Heres what im starting with.





It is absolutely filthy so will need a bloody good clean and a paint when it goes back together.

Today i did actually start taking bits off. Only had about an hour before work but managed to remove the power steering pump, the alternator bracket, the radiator, and couldn't resist taking the plenum chamber top off.



Although this is what i found upon removal of the plenum chamber top



Is it completely ####ed or is this fixable?

A couple of loose trumpets is no great shakes, 'tis a common enough thing. I glued one of mine back in with RTF silicone and as far as I know all is still dandy.

If you are doing a rebuild then definitely replace cam shaft and followers and timing chain. New water pump would probably be a good idea too. Replace bottom end shells. Check bores for wear, leak test heads but make sure you clean the heads and valves then lap the valves and seats.

If you going megasquirt then Mr Noisy is your man.

HTH

Cheers kev just the sort of advice im after!

At least the trumpets are repairable!

I was going to replace the cam anyway with a H180 one from turner engineering. And they recommend replacing the followers when changing the cam

If im doing the timing chain would it also be worth changing the sprockets also?

Water pump will be replaced then as will the bottom end shells.


Thanks again.

just watch out as I think the performance cam from turners is just over the 0.43 max lift for the standard valve springs. that was the case for the 3.5 (common with my 4.4) set up I was looking at.

And another 3.9 rebuild, at the same time as Ben corkill!

If you are placing higher lift cam then I would remove all the trumpets and trim 10mm off them, don't be tempted for more as you will lose more low end but it will be just enough to help that cam breathe better.

Fett is the man for camshaft specs at the moment so heed that!

As Kev says I have the MS knowledge so between us you will get this build nailed.

Cheers , sam

Yup another 3.9 rebuild

Fett once ive got it all stripped down and start ordering parts i shall give turner's a ring and find out as they dont say how much lift it has on there website.
Saying that if its going to be too much hassle to fit that cam i may just stick a standard one in. Unless theres another you would recommend?

Sam i will heed the advice im given as i really dont wanna bugger this up

So 10mm off the trumpets if i do for the high lift cam. Sounds easy enough.


As for the megasquirt i most probably will end up asking for your help and advice. Read you install thread on lr4x4 and it looks complicated to say the least! But reading it has given me a good understanding of the work involved.

Cheers
Robb

lol, if you talk to turners they will get you in to lifter pre-load setting with shim kits too lol, they seem very keen on that atm although I think they are the best place to buy rocker gear like arms and shafts as they pay a bloke to measure and match pair it all as getting quality parts is hard nowadays as its all made in the third world. if you see my 4.4 re-build thread I am just about to put my discovery about followers after much re-search lol.

I can recommended a good performance cam and followers but it will have to come from Australia. With the seamail 4-6 weeks shipping and the £25 charge from you bank for the transfer it will cost you near as damn it £350 to your door. I have just ordered one lol

Thats dedication there John

lol, thats nothing, time and money on that 4.4- ouch!

Would it make me feel poorly?

considering what else you could buy with the time and money probably but I always wanted to re-build a v8 and hopefully I will save on the fact its a drop in fit as opposed to a chevy or the like

This post will give you an idea of what I replaced. http://www.landyzone.co.uk/lz/2218069-post12.html
cam+bearings, followers, chain + gears are a must.
Where you go from there is up to you, I'de recommend piston rings, all shells, maybe a reihone and a regrind on your crank depending on condition, head skim if warped at all.
The rocker reassembly is not cheap at all to replace, just hope there is only minimal to no play on the rockers. Grinding the valves is highly recommended while the heads are off. and I think that's about it.

Awesome cheers guys! I think i will stick with the standard cam for now as once its back together it will mostly be off road so going at a snails pace.

Mark cheers for that link gives me a really good idea of what i need.
So cam and bearings, followers and chain and gears shall definitely be replaced.

As for the rest i guess we wont know about until it starts coming to pieces.

you might need to get the deck flatted too, depends on how they are. I am having mine done.

I am going a bit further than mark in terms of machining and replacing bits with upgrades like cam, jp chainset and arp stud kits etc but I am probably more the fool for doing it lol

Yah I mean its a trade off.

Standard is MUCH cheaper but also then when it's all back together you wish you'd spent more

My bodge rebuild had a hone and ridge dodger rings fitted, ground crank and shells, cam and steel timing gear, gasket set and lapped valves.

Gave a shagged engine a new lease of life without breaking the bank.

She now runs smooth, cool and with acceptable amounts of go, not much torque but enough top end to pick the feet up. Oh and it doesn't smoke!

It's stock 3.5 and was 500 quid basically, that includes a £250 crank which frankly you could manage without if on a budget!

No point throwing massive money at it if you want it to run good for a few years, we don't do big mileage so rings, valves and cam/followers would actually see you right, get squirt on it and be happy.

You can always upgrade in future.

thing is standard stuff would be fine if it was built to the standard of the day your engine was made, but now its made on a mud floor in Afghanistan you have to buy performance bits just to get something that will last and is made to specs in the western world.

Noisy's injection system was a bit pricey, you could just get a carb or two

Noisy, your engine was from a car and spec re-built for a car by the last owner wasnt it? testing my memory now lol- the car spec cam will explain the lack of low end tourqe mate

That's true fett, the branded stuff at least is made in a decent factory!

And yes indeed Megasquirt is super dear but it does solve many woes. And waterproofing is something that pays for itself oh so quickly just in tears and face palming.

Yes John you are correct this was an SD1 10A motor, basically same as my 24D motor but without EFi cutouts in the heads, and it was fitted with a new standard cam from real steel.

I was told that standard rv8 cam off the shelf is now universally a 3.9 cam which is deemed to be the best all rounder over the years.

I think it's mainly due to the weight of my car vs. stock 3.5

Unless you are about to tell me different regards the cams.

I do have the real steel invoice at work for the parts inside the engine

lol yes , something different lol.

The cam real steel sell is the only std cam for the 3.5 or 3.9 still about, made in mexico by fedral mogul. reason it is still about is because its the old buik 215 cam which the yanks still use in said motor. its pre emissions and efi and was used on p5 at 10.5:1 comp.

However because it is a car cam (buiks,and rover p5) its power comes higher up the rev range, but it does produce slightly more power. lower low end torque which you are feeling though.

Case closed then, thanks fett

So really I should have fitted a torquey cam which would have produced similar too end but better torques for my LR fitment.

Not that I knew any of this of course at the time and was still limited by my budget also.

It's not that it's a problem as such, it's just that the motor is somewhat lacking below 2500rpm, then it comes on at around 3000 and is then considerably more spritely than the diesel competition, but really I need to be a gear lower than the diesels to be able to keep the pace at low road speeds, due to my rpm requirements.

Thanks for your help fett, that certainly helps my understanding of the issue!

yeah I think considering all your off roading that may have been better. the one I chose delivers the power from 1600 rpm , the std one is 1200 i think