High compression on V6 OHV

[The Gravedigger]

Good evening gentlemen,

I'm from Brazil and I'm restoring a Studebaker 1952.

I've purchased a Ford OHV 1997 4,0 liter and a rear axle 8,8" from the Ranger sold here from 96 to 2001.

As here we don't have many V8's and they are sky high priced I went for much cheaper V6. Diesels are 3 times more costly than gas engines, in average as well.

As for the eletronics, I'll go for a SA EFI, the local and known in the USA FuelTech, simpler and problem free with less parts.

But to give the pushrod a little bit more energy I could go for the turbo charger or a NA preparation.

Turbochargers here are easy to get but to make them street legal is a very difficult (and most of the times costly) process.

So the NA's "look normal" to the law and most of the times no need for extra documents with the law as they are visually camouflaged.

I've gone through many books and tried to research a lot about the pushrod type mod's and could get some ideas.

The best would be open up the engine and measure up everything so I could see what works or not. But if I can gather what works or definetely doesn't work it'd be a great help.

My main idea for a NA:

Comp cams 422 or a copy of it made by local company;

Free flowing exhaust with just one muffler and one pipe. The diameter is still to be defined depending on what point of power I might get to. I think 3" or 3 1/4"should be fine;

The valve size should grow (as per what I could find the intakes are quite small, 46mm I can't recall the exhaust now). I'd take them up at least 2mm on each side, maybe stainless steel so more resistant and a bit thinner at least ons the lowset part to help flow. I'll also port the intakes and exhaust a little bit as I have some experience on that.

The exhaust has to defined after the motor and acessories are in place so that I can see what space I have available. But it shouldn't be a problem.

The intake is still a mistery.... I've got two options either retaining the stock parts and simply putting a little bit bigger (75mm maybe) butterfly valve or making two independent units with 55 - 60mm twin throttles. On this case plenums have to be a bit big to avoid low and unstable vacuum.

And also many other small mods as ignition, electrical fan, etc.

Now the most critical part:

Compression ratio. I'd like to get it up to 10:1 or 10,5:1 so I can keep running on pump gas (here we have E25 as pump gas).

Or as a second thought I could get it as high as 12 or 13:1 and use E100 which we have fully available in every petrol station. The FFV's here run 12 or 13 ratios without big issues.

To go from the stock 9 to 10 I thought aboud using the 2001 onwards pistons and mill the heads 0,5 or 0,75mm.


On the other hand Chevy 4" pistons with a much higher compression height, (aproximately 3mm more) which will boost the CR quite a lot.

The advantadges of the 4"?

Cost is ridiculous (85 dollars the 8 at Summit, compared to a stock set from the Ranger here which is 650 dollars);

A bit more cm³ to the engine.

They are hypereuthetic which are slightly more resistant the stock cast ones, all of the books and researches indicate like 15% for NA engines. For SC or TC, they'll crack the same way because of temperatures.

Piston pins are smaller (0,5mm) so no big deal, even I can push the pistons up or down by that amount and use stock Chevy pins and compensate by making slighlty thicker "buchings" for the con rods.


Disadvantages are that block will the on the limit and pistons might run over valves (still couldn't find precise info on these limits).

I'd push the revs up to 5500 or 5750 rpm max, with reinforced rod bolts.

Two basic questions would be, would the Chevy pistons hit the valves?

Can the stock con rods withstand this mod? By what i could research the piston speed is not so high on the Cologne and then they might withstand.

Is there any other reasonable cost pistons and con rods to be used on th OHV?

To give you and idea here in Brazil, for forged pistons I'd have to pay US 1700 or a bit more for the forged pistons and US 1800 more for the forged rods.

Then it's cheaper to get them from the US and pay the import taxes (50% to 60% over the price on the bill).

I'm not willing a rocket, just to make the V6 perform a bit better than the 40 cv/l up to 60 or 65 cv/l.

I might consider the TC, but I'm really afraid of going to 0,8 bar (around 11 psi) with stock internals.


Sorry for the long writing, thanks a lot in advance.

 

[Tee Rev]

I've got a nicely built OHV in my 91 with minimal work.
If I were you, I'd go the 13:1 route & run the E100.
Flat top pistons from a SOHC 4.0L will do the job, no need for a 4" bore.
A mild port job on the heads & a 422 cam will do nicely.
No need for bigger valves. Stock is small, but work fine to 5500 rpm with the 422 cam.
Connecting rods are already forged so they'll be fine.
Piston to valve clearance won't be an issue either.


Trev

 

[The Gravedigger]

Hello

Good evening! Thanks a lot for your reply! I'll look forward doing that way! It seems much easier and safer for the engine.

Have you had any experience with Iridium spark plugs? I was really considering them as to help a the spark side. Together with some better plugs and a better coil. But I don't know whether they are really cost worth.

Can you recommend any suitable coil and spark plugs for the OHV?

Thanks a lot in advance.

Enviado de meu GT-P6210 usando Tapatalk

 

[Tee Rev]

I'm running the factory coil box & NGK TR5GP's. Never had a problem, so I haven't bothered to experiment.
I am also running a standalone ECU(SDS EFI), but never had a problem with the factory EEC-IV. I just wanted to be able to tune in case of future modifications.

 

[The Gravedigger]

Do you run basic maps for the moment? I mean, close to the original ignition timing?

Most probablly I'll have to change the stock coil and keep the old one as spare.... just in case... as the motor is from a caryard I'm not sure what can be good there.

I found the Screaming Demon coil at Summit and it seems a step over the original, and the cost is quite similar. Have you ever heard about them?

The cost, even with import taxes would fine, as a "generic" brand coil for the Ranger here costs about 60 dollars.

Have you found too many problems until you got the best tune up? I'll have wide band meter on the junction of the two exhaust manifolds to make adjustments and also control a bit the combustion quality.

On the present configuration you have what is the mileage you can get?

On E100, after fine tunning I expect I can get some 10 / 11 MPG on city and some 17 MPG on the road... of course that as "strolling" mode. Not a daily driven, so no big issues here.

Thanks in advance,

 

[Tee Rev]

I did try to have the factory ECU maps read as I was initially going to get a TWEECER. But for some reason the files ended up being corrupt?! or so they said!

I pretty much had to start from scratch with the SDS. It didn't matter, it only took a couple minutes to get it running & set the initial timing. & it only took a couple hours of cruising around & adjusting to get everything almost perfect. This was using a narrow band O2 sensor!
I did take it to a dyno for fine tuning & found that my timing was a little aggressive. Total advance was best at only 26 deg.

My fuel economy is surprising, I get 22 IMPG city & 28 IMPG highway. This is with 4.10 gears.

You'll be venturing into new territory with high compression & E100 for sure.

I know about the Screaming demon coil pack, but have heard that it's about as good as the stock coil pack.

 

[The Gravedigger]

Great!

Mine as per what I could find is a 3,08 rear axle.... but only when driving or when I open it up to double check.

Most probably I'll stick to the original coil or only if I can get an accel or something alike.... I'd like to have something more powerful (maybe three coils) because of the high CR and also to be able to run a little bit leaner on the cruise situation.

It's been a bit tough to find the SOHC here in Br, but I dod find them at the e-bay, at 180 dollars with pins and rings. I can't recall the brand now..... but I'd like to go for some Keith Black or Speed Pro..... if possible the hypereuthethic ones which are named to be a bit more resistant (like 10% as per what I could read).

I'm not so experient on push rod type engines, so the push rods, rocker arms and the lifters must be changed when using the 422 cam ? Shaall I use the stock ones or is there any special attention I should give to this?

I read in many places the spring should be changed to withstand the 422....

Also, with the original valvetrain the total lift of the camshaft is the adverised 0.500" ?

As I'm going to open up the engine in March I'd like to start preparing on tha spares I'll need....only the bearings and pistons I have to wait until I open up to get the correct dimensions.

But gaskets, fuel pump, oil pump, water pump and so on I can start already looking for and start slowly buying them.....

Do you have any recommendation of a good and reasonable price shop in the US (which makes international shipping if possible...) ?

Thanks a lot in advance,