Should the head gasket block/cover waterways?

[juncopartner]

Scotties right about the valves being the same, apart from the SC100 which are larger. That probably doesn't have any relavance now as you'll be lucky to find one.

[ScottieJ]

Scotties right about the valves being the same, apart from the SC100 which are larger. That probably doesn't have any relavance now as you'll be lucky to find one.

Or are they? after doing a bit of digging there's the tiniest of differences apparently

lj parts cat lists an inlet valve o.d of 31.6mm and exhaust o.d. of 27.6mm

From what I can find f10a valves sizes from Trechii ltd. are inlet o.d. 31.7mm and exhaust o.d. 27.65mm

[dcallaghan2011]

Ok, so I got the gaskets this evening and have been cleaning the block and have noticed small amounts of damage to the blocks face, so what I'm going to do is put the 410 back together (it's the later one piece type) as I stripped it down to decoke it and replace the valve stem oil seals, then I'll put it on the lj block and check it turns over ok, if it turns over ok I'll try to give it a run, if it wont run well then I will have a look at the 410 block I have got and consider using that.

Scotties right there are two types of head the earlier one has a seperate housing at the front of the head that unbolts off the head and holds an oil seal, wheras the later ones have a head cast in one piece. If you swap these around you will need to change the rear timing cover as well as the later one has a deeper pressing to fill up the space created by not having the extra housing. I should have plenty of the different type of covers, I kept them for this reason.

I've always used the F10 gaskets whenever I've had different engine/cylinder head combinations and never experienced any problems. Usually F8 heads to F10 blocks though. As I said before I don't use F8 blocks. You really should just just throw it away!!!!

Sorry what do you mean by rear timing cover? Do you mean the distributor housing?

[ScottieJ]

The rear part of the cambelt cover is what he means

I was doing a bit of investigation today with the heads that I had lying around, I haven't really got a clue what they are all off but anyway it looks like there are quite a few casting variations in the heads, there was one 1 piece head that interestingly had 800 cast into it and the other two are the earlier two piece heads didn't have 800 cast into them, I always thought it was the earlier heads that had 800 cast into them? I'm going to dig out the other 3 engines I have next and look at those, I have 2 f8a and 1 f10a.

The 1 and 2 piece heads do have different cams so they cannot be swapped between the two different style heads by the look of it, also there seems to be differences on the combustion chambers, some seem to be around 1.5-2mm deeper than others?? Once I strip the other engines I'm going to measure the combustion chamber volume on all 6 heads to see if there is much of a difference.

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Top head is 1 piece, notice the 800 casting on the side

Middle head is two piece and has what looks like the smallest combustion chamber. On the other two there is a small lip on section of the combustion chamber that points in, both are different depths but the middle one is flush with the rest of the head?

The bottom head is also a 2 piece.

Note the top and middle heads have different dizzy housings, 1 points the opposite way, I think the top is an sj head and the middle is an Lj head maybe? If that's the case it could explain why I've read that fitting an f8 head raises compression as that's the one that looks like it has the smalles combustion chambers?

[juncopartner]

Well I must admit I've only compared the valves be eyesite so if theres only 0.1mm difference I wouldn't have noticed!!! But the SC100 are definatly larger by eyesite.

The distributor/fuel pump housings are different between the SJ and LJ but you just need to unbolt them and swap them around and refit/retime fuel pump and distributor. The housing is also different on the Whizz kid SC100 and the helical drive to the distributors are cut in the opposite direction, but all you need to do is drift out the cotter pins to the drives and swap them round. I was told years ago that you could not do this by someone in the LJ register, but I did it on 3 SC100 engines with no problems. Everbody else seemed to leave them in place so the distributor was pointing downwards and made setting the points a bugger to do. Can't remember which head I've seen with the wrong housing in place and a hole cut in the bonnet cos the fuel pump or the distributor was poking through it, nice!!!!

The rascal/suppercarry head can be used but doesn't have a cam drive for the fuel pump so you'll need to fit an electric pump. The old Subaru pumps were the ones I used to use cos they were under the bonnet and designed to pull rather than push. It also meant that they were clean and easy to get to!!!

The ST90 head also fits and has a mechanical pump unlike the rascal. But they are probably rarer than the SC100.

Just as a matter of interest the ST90 also has a similar gearbox to the LJ80, I was going to build an LJ gearbox with ST90 gears many years ago as it has higher gearing which would have been better with the 970 engine, but decided not to bother as I like to go off road. Got as far as stripping them down and comparing the parts and it looked possible, think it was roughly 10% higher.

[dcallaghan2011]

Just a bit of an update, I cleaned the block up some more and it seems a bit too damaged just to put another head so for the time being I'm going to get hold of a 410 engine and put that in it. Also just for reference, the spare f10 engine I have taken the head off has 800 cast on the head, so it must either be some of the 410 heads are actually identical to f8 heads or the f10 engine has an f8 head on it (and it is definitely a 1.0L engine), or could even be that Suzuki just decided to randomly put 800 on some of the heads (they've done weirder things)

[juncopartner]

It could be the are using the old casting moulds from the 800???

[dcallaghan2011]

It could be the are using the old casting moulds from the 800???

Could be that as a 410 head gasket fits perfectly so it cant be an 800cc head

[juncopartner]

What I meant was they may have used the original casting moulds and machined it to suit the 1 litre and just left the 800 in place cos it was already there!!! But I have my doubts about that particular theory.

Its a question though, that has puzzled me for 25years would you believe!!!

Speaking of heads, I have a rocker cover with "Made in Japan" on the top of the casting that came of a very early LJ, but I have never yet to see another one though. Might polish it up and fit to my LJ when I rebuild it, thought it would be a nice touch. Its been sitting on a shelf for over 20 years with the intention of using it one day.