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Triumph TR6 - Cylinder Head

I just purchased a new cylinder head from one of the big 3. It is a CR series 9.5:1 head as used in 75-76 part # UKC 1420. It appears to be a NOS factory original head. The guy I ordered it from said they had it so long the original crate was falling apart and they had to re-crate it!!! Everything looked good until I noticed something odd. On the head there are 14 holes for where the studs pass thru and directly inboard of these there are another 14 holes that I assume are water passages. The odd thing is that I have found little pieces of wire inside some of these holes. They look to be similar in size to a coat hanger. Aside from the obvious question as to how they got in there in the first place is is how do I get them out?. I have a theory that Triumph hung the heads by steel wires in the painting process before they were milled, maybe they just snipped off the ends and left the remaining bits in place?
Brett Evans

Problem solved!!! I used a powerful round magnet that just fit into the holes and was able to lift the rods high enough to get some very small needle nose pliers on them to pull them out. A couple even came out of the hole for the water pump!!! Still doesn't answer the question as to how they got in there though
Brett Evans

If you have a compressor, it might not be a bad idea to blow out all of those holes just case there is more floating around in there you can't see.

rw loftus

Brett- I find this interesting that you say it is a 9.5:1 stock head for the 75-76 year.
Don't think that was even close to a CR ratio for that year.
They were very low compression by then.
Maybe Steve will chime in.

What is the # on the side of the head

if your head is a low compression one, look at the lug sticking out at the distributor side of the head. that should be 1/4 inch thick and 1/8 inch for a high compression head.
Don't forget to compare the spacing of the inlet ports because it varied with the different years. If they are not the same with the original head you took out, then your exhaust manifold will not fit.

I hope this helps.
Kypros Christodoulides

One last thing,
when you put the assembled head on to the block, use a high quality head gasket as cheap ones leak and don't make any compression. Believe me as I have used 2 cheap ones and had no compression both times, until I used a Payen gasket and solved the problem.
Kypros Christodoulides

The head is part # ukc1420 and was used on the fuel injected CR series in 1975-1976 and is 9.5:1. On the North American CF series the compression was only 7.5:1. The number on the side of the head is 219015. The narrow inlet heads were only fitted to early TR6's so there shouldn't be a problem there. I must have removed half a dozen pieces of wire and some appear to have some kind of slag on them. Welding wire perhaps? I can't imagine how they got in there unless someone put them there on purpose. Disgruntled worker? Sloppy quality control?
Brett Evans

Why did you get this particular head? How will you set it up to optimize what you have? With some rather minor tweaking, I've upped my 71 stock 8.5 CR to a mite over 9.0CR which is about what I think optimizes pump gas in the US. Do you plan to set yours up with PI to maximize what you can get from this head?
Doug Baker

Hi Doug, My 1973 CF series came stock with 7.25:1. The British PI CR series versions came with 9.5:1. Both cars use the same block, crank, pistons, and camshaft. Even the cylinder heads use the same size valves. The emissions control equipment on my car are miminal and easily removed/plugged. That leaves the fuel injection system used on the CP/CR series which was primitive at best and extremly unreliable. (yes I know there are good quality fixes out there, but very expensive). My ZS carbs can easily be adjusted to provide more fuel than the engine can handle (as evidenced by all the cars I see at shows with black smoke coming out of their tail pipes). I don't think US fuel will be a problem as I believe it's only an issue with 10.0:1 and higher. Lastly cost played a factor. My head needed to be rebuilt due to sticking valves. Most of the places that advertise head rebuilding come in at around 750.00 and they want my old head in exchange. Just the parts alone at one well known site can run over 1000.00 before any head work is done. I got this head for 600.00 with the valves and springs already installed and ready to go. And I got to keep my head, so I can still rework that if needed.
Brett Evans

Bret if you wanted low cost, you should have removed the valves from your cyl. head cleaned them and changed valve guides and you are done.
Kypros Christodoulides

I said cost was only one of the factors. I can still rework my old head if I want and my car doesn't have to be down while I'm doing it. I'm not going to race the thing but I won't cry if I get a little more power.
Brett Evans

For cheap power try to up the C/R as much as the available fuel will allow, not forgetting to change the pushrods or raise the pedestral for correct geometry,also giving it a bit more timing. If you can port the head yourself it would be a plus.
Raising the C/R automatically imoroves performance all accross the rev. range.
Kypros Christodoulides

Thanks Kypros, I really appriciate your input. It means a lot to me that you and the other members take the time to share your expertise. I can use every bit of it!!! I did get shorter pushrods. One question I might have is if I should stick with ngk bp6es plugs or should I use something else?
Brett Evans

Brett, if you are increasing the C/R it means that you are also increasing the running temperature of the engine. In effect you might try a cooler spark plug if you experience pre-ignition, but from personal experience from modifying my engine I have found that what you are using is adequate for the purpose. Do the mods and then read the spark plug. If you experience detonation you will see foreign particles on the spark plug and you should immediately change over for a cooler spark.If you see only a fine ash color with very little deposit, then you are O.K
Glad to have been able to help.
Kypros Christodoulides

This thread was discussed between 10/05/2013 and 17/05/2013

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