Mr Noisy said:

So I read on the Mez website that as I expected I can do the head mod in situ, with rags and a vacuum cleaner. This won't be much trouble but its work I don't want if I don't need!

Is the best course of action to pull the injectors out and look in the hole for obstruction?

Or just take the opportunity to fit improved heads?

Do 4.6 heads have the cutout for an EFi manifold though?????

Would have been so easy when the engine was out

Cheers!

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it can be done in situ and clearance varies with different heads and manifolds ,all the later heads are cut for efi

Thanks James.

So really its a case of looking in the hole to see what's what.

OR is it just best to accept the fact that it needs a cutout, so then it's a toss up between:

Strip down and mod my existing 3.5 carb sd1 heads which have been recently stripped and valves lapped, and appear to be working fine, or:

Strip down and remove my existing heads and fit either a stage 1 3.5 head (on eBay at the moment, have asked if they have cutouts but not yet answered) or 4.6 10 bolt heads which are plentiful and hopefully cheap enough.

What's the general feeling on the best option??

Just looked again at my old heads, they have much more cutout on bank 2 than bank 1, maybe they were ground in position?

Hmmm, needs looking at this I suspect

yes youd need to look ,head thickness /gaskets alter exactly where manifold sits ,how much are the 4.6 heads (would be my choice) ,as with a lot of things we are looking at some effect not massive ,but it is nice to know you have things near as good as can be and now you know it will niggle ,

ensuring theres no step where manifold fits head so smooth flow is worth spending some time with

4.6 heads are on eBay at less than 100 quid used, but I suppose something reconditioned is not a bad idea.

There's a set of big valve 3.5 heads on eBay that I'm in talks with the seller with, fully recon with hd springs etc, as new ready to go, but they'll be more than the 4.6 heads though of course they are as new.

Hmmm.

Yeah I appreciate its not making much difference, my main incentive is that just having bought Megasquirt I might aswell get it as right as possible before I start tuning it to the engine!

Port matching to the gasket would get around the cutout issue anyway!

you would want to check used head for flatness and do valve seats either lap in or new valves and a seat cut ,so would need possible costs factoring in ,removing metal at edge of port is a lot safer than further in where water jaket wall can be thin

Mr Noisy said:

Yeah I appreciate its not making much difference, my main incentive is that just having bought Megasquirt I might aswell get it as right as possible before I start tuning it to the engine!

Port matching to the gasket would get around the cutout issue anyway!

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your old gasket would be good to use for that as is in fitted condition

These 3.5 heads appear to have been machined aswell as they are 10 bolt fitment now and evidently brand new, still got blue paste round valves etc.

Gonna ring a little later for another chat and talk about price, will then decide whether to buy these or do mine. 4.6 heads are good but as you say then could end up warped/cracked.

Here's these 3.5 heads:





Cheers

Hi there,

If you can achieve the same levels of acceleration and make the same amount of progress on the new engine with less throttle input then it must be more efficient than the previous engine.

If you've got 4.6 heads sat there on the shelf with nothing to do they need putting on the car ASAP in my opinion!
All 4.6 heads will have a relief machined in to the castings for the injectors as before these were introduced Rover had already completely switched over to EFi anyway. The only exception might be if you've started with a brand new casting? However that's a very very slim chance and its 99% certain they will have the reliefs milled in anyway. Even if you are unlucky and they don't then it's no trouble to "have at it" with a dremmel or a die grinder for a few minutes.
The fact that they are 10 bolt heads as opposed to the 14 bolt heads you have on now doesnt matter - they will still bolt on just fine and the 14 bolt heads clamp the gasket in an odd way in any case. It's a poor design feature really.

You *can* play around with rags and a vacuum on the old setup if you like. However, if you're anything like me suddenly the workshop environment becomes an operating theatre environment when an engine gets built up so the idea of risking ally swarf entering the heads doesn't really appeal to me. Personally I'd take the heads off, strip off the valves, blast the casting with compressed air, bath the casting in petrol and break out the compressed air again to dry.

4.6 heads have a smaller 28cc combustion chamber to allow for the difference in thickness of composite head gaskets.
Making the assumption that the block has not been decked and you are using standard pistons then you will be able to fit 10 bolt heads just fine without any fear of valve contact. If you have been using the SD1 heads on comp gaskets then you will have dropped the compression ratio a bit so there may well be further power improvements to be made.

The only downside is of course you will need to re-set the rocker clearances which can be a faff. I've never liked the half-arsed system Rover used of "a few tight, a few slack and a few just right". It's obvious why they used it - to appease the bean counters in the office! I think it's worth investing in a set of chrome moly adjustable pushrods and get the whole lot set up perfectly.

The fact that there is a known problem re: the distributor is a clear elephant in the room and wants attending to really. I would suggest you either source a new Mallory unit or source a refurbished standard unit from somewhere like the distributor doctor. Of course there's always the stand alone wasted spark systems if you want to upgrade and are happy to play with laptops, but then we're talking about a considerably bigger investment!

*edit* need to type quicker... a whole page of posts between starting and clicking "submit". Perhaps this man flu that I'm suffering from is worse than I thought!

ive allways checked valve seats dry obviously we all have our own methods ,does he say how much has been removed as that can effect tappets and manofold fit

Going to find out more about these modified 3.5 heads this afternoon.

At the moment I have only my standard heads on my engine and want to decide what to do.

I think some information is getting confused here!

I have already ordered Megasquirt, so the distributor is going anyway.

The point is that i am getting wasted spark, laptops, lambda sensors etc, but there's no point if the engine isn't right!

I see the difference now with the 4.6 head combustion chamber, thankyou for that info.

These 3.5 heads pictured are still if interest to me because they are recon and tuned. 41.4mm inlet valves I believe.

If they have been port matched then they shouldn't need any grinding either. They are not 10 bolt heads but they look like they have been machined to remove the outer bolt holes.

Hope this isn't as confusing for you as it is for me!!

I've since discovered your engine build thread! So, I think (hope) I'm up to speed?
What is the casting number on those heads?
If you have any friends with a known good distributor then it wouldn't hurt to pop that in before you start the EDIS conversion.

It would be well worth your while giving Peter Burgess a call in Alfreton re heads. His workshop is about 3 miles from me and it really is an education talking to him. He has written several books on the subject, mind...

But if he's getting mega squirt there's no need for a dizzy test. ?

Hi guys

Im afraid that I'm now discounting any work on EFi or ignition because its all going Megasquirt regardless. Dizzy testing would be thorough but it really is irrelevant aswell!

I am going to call the guy at 2pm when he is at his garage then I want to find out casting number, port sizes, valve sizes and then we can try to get an idea of what they are all about!

After speaking to the seller I will try to get hold of Peter burgess, see if he can share some pearls of wisdom!

Dr_evil said:

But if he's getting mega squirt there's no need for a dizzy test. ?

Click to expand...

I suggested it because it would prove one way or another if the current distributor fault was sufficient to cause the symptoms mentioned. If there are no local garage buddies with a known good unit then the test can't happen since the whole point of the exercise was that it would be free.
Free diagnostics is always a good thing in my book!

Hello

Yeah I see what you were getting at regards eliminating the dizzy.

To be honest, I think it drives very well, perhaps as good as a standard rover v8 can do??

The ONLY real difference in running I have noticed between this and the old engine is that on tickover you can hear the crackling in the exhaust manifolds (thin wall tubular remember) which I assume is down to the fact that this engine has compression and therefore actually makes a bang, and it is generally a bit more lumpy v8 sounding than the old one. The old one just used to tickover like broooooooom whereas this does the proper brump brump brump thing.

It does not hunt or anything, just feels like you can feel each cylinder fire kinda thing, but again I put this down to it actually having a good compression!

It is just as jerky, hesitant, poor and undecided at mid throttle as th old one was, although looking at the cutouts in my old heads I can see that there must be serious spray interruption going on here most likely.

Trying to get hold of the eBay seller to ask him about the specs on these heads!

Ok now this is confusing.

The heads I have on now are ERC0216 carb.

The heads on my old engine are HRC2210, ground for EFi as standard.

The heads I am looking at on eBay do not have any of these numbers on, but they do have CFD1358.

Anyone recognise?

Have another look at the pics!





Are these even rover heads??

Hmm. Interesting stuff! How much have u seen the mega squirt for.... do the offer much benefit