Valve springs

apsmith49921

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I have BTR springs in my 4v. Had good luck with them the 2 hours it's run so far lol. I once heard they're just rebranded Manley springs
 

Jposey66

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I run the BTR SP005's in my PI upgraded 97 and love them. Reving it to redline often with no issues. LOL
 
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Booboo

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I am on the fence about which cams to get. Below is what I am considering. Any recomendation? The heads are stock PI heads with +1mm oversize valve and the springs mentioned in this thread. I do not want to loose low end power but want as much power increase as possible.

1 - Stage 2.5 - 228/230 dur - .575/.55 lift - 11.5 + 1.5 LSA
2 - Stage 2.0 - 224/226 dur - .55/.53 lift - 11.5 + 1.5 LSA
3 - EX262AH - 226/230 dur - .55/.55 lift - 113 LSA

Would it be better to get the springs that are good to .550 (instead of the .600 lift springs) for any of these cams?
 

apsmith49921

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The 262 is a good cam. The 550 lift springs would probably be fine with all those except the top one.

What intake manifold are you going to run with these?
 

Snorky

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I am on the fence about which cams to get. Below is what I am considering. Any recomendation? The heads are stock PI heads with +1mm oversize valve and the springs mentioned in this thread. I do not want to loose low end power but want as much power increase as possible.

1 - Stage 2.5 - 228/230 dur - .575/.55 lift - 11.5 + 1.5 LSA
2 - Stage 2.0 - 224/226 dur - .55/.53 lift - 11.5 + 1.5 LSA
3 - EX262AH - 226/230 dur - .55/.55 lift - 113 LSA

Would it be better to get the springs that are good to .550 (instead of the .600 lift springs) for any of these cams?
Get the .600" lift springs. Since you have aftermarket hopefully stainless valves you will clear the mhs 2.5 if properly degreed. I would do one of the mhs cams.. the comp 262 makes for a great daily cam. Awesome power under the curve
 

apsmith49921

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Not sure when the stock PI intake peaks but may be worth looking into depending where you degree the cams
 

Snorky

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These are the Valves - MMR Valves
Yeah, those with the mhs 2.5 would work. But again.. it needs to be degreed on point. The mhs stage 2s will be a little more forgiving on the degreeing front. Have you degreed cams before or are you willing to learn to do it?

As for the btr springs I have used them before. i like them.
 
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Booboo

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Yeah, those with the mhs 2.5 would work. But again.. it needs to be degreed on point. The mhs stage 2s will be a little more forgiving on the degreeing front. Have you degreed cams before or are you willing to learn to do it?
I have not degreed cams yet but am planning on learning. Do you think the 2.5 cams are risky with PTV clearance? Do you think there would be a big difference in performance between the 2s and the 2.5s?
 
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Booboo

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I forgot to mention, these heads are going on a stock 97 NPI short block. Does that make a difference for PTV clearance?
 

Snorky

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I forgot to mention, these heads are going on a stock 97 NPI short block. Does that make a difference for PTV clearance?
If you are running npi heads that's more of a question about air flow at certain lift ranges. Personally I would call Jordan at MHS and be real with him about your uses and goals. The 2.5s would be cool but the stage 2s will probably be more useful.
 
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Booboo

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If you are running npi heads that's more of a question about air flow at certain lift ranges. Personally I would call Jordan at MHS and be real with him about your uses and goals. The 2.5s would be cool but the stage 2s will probably be more useful.
Not NPI heads, a NPI shortblock. The heads are PI.
 

Snorky

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Not NPI heads, a NPI shortblock. The heads are PI.
Ah.. in that case i would probably run the 2.5s. The piston dish isn't the area of concern of ptv clearance. It's the piston skirt. Thr aftermarket valves give you an additional(I think) .030" of clearance which allows for the 2.5s to run. I would give it a go and just take your time degreeing them
 

Notthenow

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PTV occurs on the outer edge of the piston crown, the dish isn't involved at all. Degreeing is a must, even for stock cams if you want both sides of the engine the same as the timing gears can be +/- several degrees. Aftermarket valves usually have a thinner margin and can provide up to .040 extra clearance. The Trick Flow adjustable crank gears are a great help.
 

96blak54

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An over sized valve in a pi head means you installed a valve thats half the weight of the original valve. No aftermarket spring is needed. Your stock valve springs are far adequate enough for what you have planned.
 

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