v8 engine component interchangeability (blocks and heads)

I'm looking at new engine options for the 101. I have found a lot of incomplete engines for sale and this could work out cheaper than buying a complete one. What are the differences between the bits of the various capacity v8's

- so to what extent are bits the same and what could i use together?

What changed on them to give the varying capacities? was it different bore/stroke for them all or was any of the changes done with the heads?

i.e. - 4.6's with knackered blocks and bottom ends seem common - (there is one waiting for the scrap man nearby but it has good heads on). Are the heads off the 4.6 the same as on the smaller engines? There are a couple of 3.9 short blocks on ebay.. Could heads off a 4.6 or even my current 3.5 be used on a 3.9 block?

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Reply to
Tom Woods
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How have you buggered the 3.5 ??? ;-)

Steve

Reply to
Steve Taylor

Knowing Tom I guess it's the need for Speed --- I've seen him driving the IIa ;-)

Reply to
Lee_D

It is indeed the quest for more beans! Its just too slow! plus somebody (Martin at eastnor) told me that with a 4.6 in his 101 he gets better mpg while cruising and doesnt have to wear his foot out pushing it against the bulkhead!

The 3.5 aint buggered - needs the new cam fitting but even with that i dont think i'll be happy. Ive got the thing running dead on stichometric and still it gets 10mpg and 70 is but a dream! I've got an overdrive waiting but there just isnt enough possible speed there to justify fitting it!

I've got 4 weeks off this summer and i'm putting aside a week to put new engines in both my yellow car and the 101..

There is a 3.9efi that has swallowed some water on ebay for under £50 at the moment. What damage do you reckon it will have suffered?...

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Reply to
Tom Woods

Tom Woods uttered summat worrerz funny about:

Well I wouldn't touch it personally, sounds like alot of work and expense. Have you considered dropping car transplants a line to see what they want for a 4.6?

Lee

Reply to
Lee_D

A bent conrod or two at the very least.

Reply to
EMB

Is it likely to have buggered the block too ? Tom says he can pick up engines with cracked blocks, maybe for the rest of the parts ?

Steve

Reply to
Steve Taylor

3.5 and 3.9 - same crank and rods, different block (bore) and pistons. 4.2, different crank and pistons in a 3.9 block, same rods. 4.0 and 4.6, larger crank bearings than previous engines, common block for both, different crank, pistons and rods. If using a late crank in an early configuration (early style oil pump and a distributor), you need a spacer to go on in front of the front pulley as the nose of the crank is longer (by around 14mm??).

In a word, yes. All heads from around 1976 (ish) onwards are all the same apart from a couple of minor details. All EFI engines have a small chamfer machined into the top face of the inlet port, this is to allow clearance for the petrol injector spray pattern. All heads for steel head gaskets have

36cc chambers, all heads for composite head gaskets have 28cc chambers. The change happened at roughly the same time as they deleted the outer row of 4 bolts from each head, what are referred to as "10-bolt heads", but there are some 14-bolt heads with the smaller chambers, clue is the use of stretch bolts holding them down, and full top-hat stem seals on every valve instead of the early type rubber washers on the inlets only. Fit 4.6 heads with tin head gaskets for an increase in compression of roughly 0.6, or skim early heads by 0.035" to use composite gaskets. Don't worry about losing the outer 4 bolts per head, I don't fit them anyway, as they actually cause premature head gasket failures! 3.5 SD1 vitesse heads are about the best of the early style, they have slightly better finishing to the ports from the factory and slightly improved swirl due to the valves being cut deeper into the heads by approx. 0.040". 10-bolt heads have slightly better porting, exhaust flow is up around 5%. Badger.
Reply to
Badger

Thanks again for the mighty useful info! I will have to keep referring back to this! :)

Sorry i havent got the budget for one of yours! Having looked at the old accounts i'm nowhere close to it :(

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Reply to
Tom Woods

Why not look at the alternative route like I did when I was trying to source an autobox to stick into burrt. I found that autoboxes were upwards of £200, but that I could pick up rangies as MOT failures for silly money. That way you do get to try the goods before you plonk it in, and can offset the cost by breaking the rangie for spares to sell on.

I managed to pick up a 3.9efi auto rangie for £350, so will fit the engine and box complete into burrt, but still undecided to stick with carbs or efi when I install it.

Given that axles change hands for £100, and body panels can go for silly money in the right condition and place, it does help offset the cost somewhat if you have the space.

-- To reply direct rot13 me

bURRt the 101 Camper

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200TDi Disco with rotten floor 200 TDi DIsco, "the offroader" 1976 S3 Lightweight
Reply to
Simon Isaacs

There are issues that require some linkage ingenuity regards getting the pull correct on the kickdown cable in relation to throttle position if going for carbs. A rising-rate linkage is required, but one that has lost-motion for the first 1/2" of linear motion of the throttle cable, if memory serves me right. Any other linkage is a compromise between too much pull at low revs/loads or too little pull at high revs/loads. Badger.

Reply to
Badger

did suspect that the kickdown would be one of the problems, which is why I was toying with efi, especially as there will be no silly 101 gear lever any more. efi may also reduce further the number of times I need to lift the enigne cover, as there will be no dashpots!

-- To reply direct rot13 me

bURRt the 101 Camper

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200TDi Disco with rotten floor 200 TDi DIsco, "the offroader" 1976 S3 Lightweight
Reply to
Simon Isaacs

lost-motion

Not to mention the need to synchronise carbs regularly and the constant churning to start due to vapour-locking of the fuel lines!!! Fit a small petrol tank to act as a swirl-pot (about 4" diameter and 8-10" tall), feed this near the top with the supply from the existing pump, take a return from a second connection at the top of this new tank back to the top of the original tank (via a restrictor, it's only an air-bleed return, NOT full-flow, and you want to maintain a slight pressure in the swirl-pot tank, say 2.5psi?) - this gives a guaranteed supply for the efi pump, which you then feed from the bottom of this new secondary tank. The efi return goes back to the original tank which acts as a heat-sink to remove the heat from the re-circulated fuel returning from the (very!) hot engine fuel rails. A lot easier than cutting into the original tank to fit a swirl-pot! Badger.

Reply to
Badger

an auto gear lever would also make the engine cover a lot easier to lift as you wouldnt have to thread it over the big long stick of the manual box..

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Reply to
Tom Woods

i was gonna post and ask what the going rate for an old rangie was. I have been looking but most of the stuff on ebay at the mo is £500 ish and too nice to break or £100 and has no mot so i coulnt get it home. I need 1 months MOT really so i can drive it back!

I have justabout got the space to do it quickly.. (or Steve T - I noticed there was a bit of space in your yard next to that disco carcass...! I'l help put your 101 axle back on in approx 5 weeks in return!)

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Reply to
Tom Woods

and also means that the engine cover can become a decent sized bed for Harry, which the current gear lever prevents!

-- To reply direct rot13 me

bURRt the 101 Camper

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200TDi Disco with rotten floor 200 TDi DIsco, "the offroader" 1976 S3 Lightweight
Reply to
Simon Isaacs

WHAT Disco carcass....

;-) - it went to the breakers in Bury a month or two back. Now there's room for another 2....

Steve

Reply to
Steve Taylor

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