One step forward and two steps back

[Binny]

Hi Alec.

Unfortunately I now don’t have a running engine.

Closer inspection regarding the coolant leak revealed that the two inner core plugs behind the exhaust manifold have rotted and are leaking along with evidence of a major coolant leak from the head gasket.

When checking the cylinder head nuts it seemed as though the exposed ones were still extremely tight whilst those under the rocker cover were much looser in comparison. Whether this is the cause of the leaks I don’t know but I’m going to have new valve guides put in and at the same time the head will be skimmed.

It’s another £500 plus I’ll have to spend but hopefully it will then be set up for a good few years to come.

Are Payen head gasket’s preferable and is it possible to replace the valve seats if necessary?

[Alec]

Hello Binny,

sory to hear about that.
I would replace all the core plugs as they may well be corroded also.

There are originally no replaceable valve seats on the Triumph head, although it is possible that they may have been fitted by a previous owner.
If there are valve seat inserts probably all that will be necessary is to recut them. If there are not any you may wish to consider having them fitted, a bit more expensive but not overly so. (Exhaust seats only are needed)
Payen gaskets are known as high quality but I have used others without problem. If and when I had engine maching work done I would use whatever gaskets the machinist obtains.

Alec

[Binny]

Thanks Alec, I’ll let you know how I get on.

[Binny]

So the cylinder head is now off the engine and to be fair it was a straightforward job

However, I now have a bit of a conundrum. Long before my ownership the car was converted to carbs from pi and clearly this process was fairly involved as it seems that the cylinder head was also changed.

The head that is now on, or off, is a 219016 which I understand is from a later model. The valves are all in good condition and it has single valve springs. I have new 58923 and 111869 valve guides which according to the receipt still in the bag I bought from T C Harrison in Hull on 21st July, 1988 for the princely sum of £21.60.

I’m going to have the valve guides replaced and the head skimmed but before doing that it would be great if anyone could confirm that it will work well with the engine back on fuel injection. Chris Witor mentions that 219016 heads have better flow characteristics but they have smaller exhaust valves than a standard earlier pi head. Also which valve springs should I use - single or double?

Thanks.

[Alec]

Hello Binny,

the 219016 is what I have. P.I. engine heads were thinnner than others for a higher compression ratio. They were 3.3" thickness. If you are having any work done it's worth having it measured and if necessary skimmed to that figure as the P.I. needs that higher compression.
The smaller exhaust valve is no detriment, and I seem to remeber the heads with the larger exhaust valves were prone to cracking between the valves?
My engine has double valve springs, so I would look at what is correct for a P.I. engine?

Alec

[Alec]

helo binny,

I just remebered that P.I. engines have shorter push rods than the others. No problem if your engine is orinally a P.I..
If they are the longer ones setting the tappet clearances may be a problem.

Alec

[Binny]

Thanks once again for your reply Alec, it’s much appreciated.

Did you have your 219016 head skimmed and I assume that the height of the head is measured from the head gasket face to the rocker cover gasket face?

My 219016 head measures 3.475” and I’m slightly concerned that reducing it to 3.3” might lead to the valves hitting the piston crown.

It’s not really clear whether my pi should have single or double valve springs and I have no idea if the push rods are the original pi items or were changed when the later head and carbs were fitted. I have a complete engine in a donor pi that I’ve had since 1981 so I could use the shorter push rods from that if necessary, in fact I’m wondering if it might be better to use the complete head from that.

What at first seemed like a simple job is rapidly becoming more complicated

[Alec]

Hello Binny,

yes head face to the top of the head where the rocker cover gasket sits.

The standard P.I. ration is 9.5 to 1 if I remember correctly. I skimmed my head to go for 10 to 1. They should not clash with the pistons.
I have a 1975 issue parts book which shows double valve springs for 2000, 2,5 and P.I., but with different numbers for the valve caps.

As you have a P.I. head I would use that and see what springs are fitted.

Triumph changed things continually during production, and not always for teh better.

Alec

[Binny]

Thanks Alec.

I’m intrigued as to why to you opted to use a 219016 head on your own pi. If it’s because of the better flow characteristics then I might skim mine to 3.3” and use the valve spring set up from my donor car which I’m sure will be double.

Whichever head I use is going to have new valve guides installed, the guides that I bought in 1988 were intended to go in my donor car’s head so it might be a case of completing a job I started thirty seven years ago

[Alec]

Hello Binney,

I didn't change the original head that came with my car, perhaps I should double check the number but I'm reasonably sure that is the head fitted?

Alec