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Valve spring swap.

G'day you fullas, David from NZ here, been checking your site for info for years and finally decided to join the masses. I'm about to swap the old 179 for a 202, I'll be using my Yella Terra head but 1 outer valve spring broke a while ago. I replaced it with a std coil off a spare 173, I may as well replace the lot before the 202 goes in. What I need to know is... did Yella Terra use 1 brand of coils? I bought the head new around 1990. I measured the coils when I had it apart but can't find the dimensions from YT (YT 4327). Crow do a similar item (CC 4327) but they are different sizes. I don't want to spend more dough having the head machined if I don't have to. Originals are the best option.
Have a good weekend!

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The Crow cams springs 4327 are a fairly heavy duty spring and probably more suited to a big hydraulic or solid lifter performance cam. If your engine combo is fairly mild ? you would be better off with the crow 4823 or 4719 spring as these will not require any further machining. They are both single springs with a damper inside as I think the Yella Terra originals would have been ?. The 4327 springs are a double spring will definately require machining.If you have a big cam / big rev combo you may have to go with the stronger springs to suit and do the required machining :)

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Cheers,
John.

My YT springs are doubles... not single with a damper. Have broken 1, the rest can't be far behind. The 179 has an LC XU1 cam, the 202 is getting a billet Wade 373 (LJ GTR XU1)and would much rather do a staight swap of coils instead of extra machining. It's surprising the cost of stuff these days, I did the 179 back in '96 myself, and all up cost less than $900. This time the 202 block alone has cost $726, new cam was $290, gasket sets I got cheap from Trademe, as well as all bearings, rings etc. New pistons were cheaper than expected at $305 (ACL +40s) I couldn't imagine just giving it to a shop and saying 'do it'.
Cheers.

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They don't make em like they used too!

are s#!t IMO - they were duals with very little seat pressure, i once measured a set that had only 45# on the seat!!

its things like this that are assumed like "its a dual spring, it'll be ok" that lead to below average performance.

i can recommend a single spring thats good for 120# on the seat and 7000 rpm if you wish, can be used with stock retainers and no spring seat machining as im sure the crow ones can be also.

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I can get singles as well, but with doubles if one breaks you can still drive home... like I did. Although it took about a week to find the problem, but the carbs were stripped and reset, the fuel pump got the same, as well as the dizzy (Mallory twin point at the time) Eventually I ripped the rocker cover off and no3 inlet was not looking very healthy. Only took abot 20min to replace with a std coil, and it seems to work very well. But, I would prefer to swap with what it's always had.

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They don't make em like they used too!

While they are an improvement over stock,The YT's are no where near as good as a well ported head.

i recall a fella requiring a quick replacement head for a 186 as he had dropped a valve during a burn out (he had a good 186 head with big valves and good springs and a mild street port job)

he purchased and bolted on a YT to get him out of trouble while fixing the good one and the difference was staggering.

the open porting on the yt lost any and all the mid range he had achieved with the ported stocky. note there was no real alteration to the exhaust port, they were cleaned up and left stock

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After 4 years ... it runs..Yeah!

Spose it all depends on how big the cam is.

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They don't make em like they used too!

Back again! I've just bought a 12 port head, has bigger valves (but same as YT) single springs with dampers. Put a new manifold gasket up to it and even that looked good. Still haven't got the 202 in yet, but might try the 12 port on the 179 first... real test. Only thing I don't like is the big combustion chambers, I looked for 6 months for a 2.85 head, but there doesn't appear to be any here. Never mind... I'll shave a heap off this one too.

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They don't make em like they used too!

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