1.7 rockers on an 86?

[accidentprone86]

can i put 1.7 rockers on my stock 86 motor. If so will it have any gains? What might be some problems other then pisten to valve clerance?
Also what would the lift from the cam with the 1.7s be?
Please give me any info. I have the opertunity to buy some original cobra rockers for 100 bucks.

 

[Michael Yount]

They should bolt right on with no problems. The stock cam should have valve lift of .444" with the stock 1.6 rockers. The 1.7 ratio will result in .444 X 1.7/1.6 = .472" peak lift; it's simple math/ratios. Reduction in p to v clearance is only about .005" (5 THOUSANDTHS) with this swap - you needn't worry about it.

They will tax your stock, tired valve springs more than the 1.6's -- so look for signs of valve float at lower rpm than before. How much will they help? Impossible to predict - we've seen tests that have shown anywhere from no gain to 12-15HP depending on the set up. For $100, I'd give it a try. Keep in mind you may have to alter valve covers/gaskets to get enough clearance for them. Particularly the baffle under the oil filler neck.

 

[04sleeper]

I would try it as Michael mentioned. Just spend the extra few bucks and get some new valve springs to take advantage of them. Also now would be a good time for some new valve guide seals as well.

Good Luck.

 

[Realmongo]

Will the 1.7s fit under the stock valve covers?

 

[N8Miller]

Will the 1.7s fit under the stock valve covers?

usually not.

i would so try the 1.7s.

 

[Michael Yount]

mongo - read the whole thread.....

 

[accidentprone86]

these were stock cobra rockers, i dont know if cobras had different valve covers or not.
dose anyone else have any input?
What can i expect with these?

 

[Michael Yount]

The Cobras did have different valve covers - I bought a set through ebay when I put 1.7's on mine. They'll clear no problems -- but your stock covers won't without work.

 

[mustangjoe87]

They should bolt right on with no problems. The stock cam should have valve lift of .444" with the stock 1.6 rockers. The 1.7 ratio will result in .444 X 1.7/1.6 = .472" peak lift; it's simple math/ratios. Reduction in p to v clearance is only about .005" (5 THOUSANDTHS) with this swap - you needn't worry about it.

They will tax your stock, tired valve springs more than the 1.6's -- so look for signs of valve float at lower rpm than before. How much will they help? Impossible to predict - we've seen tests that have shown anywhere from no gain to 12-15HP depending on the set up. For $100, I'd give it a try. Keep in mind you may have to alter valve covers/gaskets to get enough clearance for them. Particularly the baffle under the oil filler neck.

my motor only has 67,000 miles on it do you think i can get away with stock springs?

 

[N8Miller]

my motor only has 67,000 miles on it do you think i can get away with stock springs?

joe,
your motor could have 67,000 or 167,000.... its more about how it was driven.

 

[mustangjoe87]

what im saying is i'd like to put them on now and not buy springs cause i plan on afr's in the future, its 67,000 driven conservativly most of the time.

 

[Daggar]

I do hope you're also planning on a set of pistons to go with those AFRs. None of the AFR heads will install over your 86 flat tops without wither piston notching or new pistons with valve reliefs. Twisted Wedge heads, well.... that's a different story.

 

[mustangjoe87]

I do hope you're also planning on a set of pistons to go with those AFRs. None of the AFR heads will install over your 86 flat tops without wither piston notching or new pistons with valve reliefs. Twisted Wedge heads, well.... that's a different story.

i have an 87 not an 86

 

[Michael Yount]

...put 'em on Joe...

 

[Realmongo]

You are referring to the stamped steel black covers?

The Cobras did have different valve covers - I bought a set through ebay when I put 1.7's on mine. They'll clear no problems -- but your stock covers won't without work.

 

[QDRHRSE]

The stainless comp cams rockers will fit under the stock valve covers once you take the baffles out. The downside with those is that they are expensive. Otherwise I've tried a bunch of other things like doubling the gaskets, grindind and clearancing the insides of the valve covers...stuff like that. There are better ways to make power for the same amount of money and a lot less hassel.

 

[Michael Yount]

Mongo - yes; the factory went to stamped steel to reduce noise. In 93 they're plain stamped steel; in 94/5, they have the "Cobra" logo in script stamped into them.