I am looking in to getting some roller rockers for my 86 and was wondering which ones to get. what are you guys runnin and why. i wanted the 1.6 but i heard a 1.6 in 1.5 out was good combination to. also this is going on a daily diver and are the roller tip rockers going to give me more reliability than the full roller? is there anything else i should do at the same time, springs or anything? im a newbie at this stuff so please give me some advice.

i also noticed there are 7/16" and 3/8" which ones do i need?

thanks guys

 

Do you have an early or late 86? Iron or aluminum heads?

If it's an iron head, early86, you've got a few mods to make to the heads.

Jake

 

i believe it has the alum heads. how can i find out for sure?

 

Other than the casting material being a different color and feel;

The iron heads have press in rocker studs and the aluminum jobs are screw in.

The iron heads do not have guide plates, the aluminum ones have (what some call) guide plates.

On the iron heads, the pushrods go down through elongated slots in the head.

The iron heads have perimeter valve cover bolts (4), but I'm not sure about the aluminum heads, most have center bolt covers, but I'm not sure about the first ones that came out on the Vette in late 86. If they're stock and you have center bolt valve covers, they're aluminum.

Iron and Aluminum heads take different spark plugs; different seating.

Jake

 

Use a magnet.

 

 

well i have the alum heads, like i thought, thanks on clarifying that one guys, now what rockers would you sugest for a competly stock at the moment with bolt ons to come?

 

Well, I vote for CompCams Pro Magnum roller rockers, full rollers. But you may have a clearance issue with them.

Seems that I recall the Chevy aluminum heads need a narrow body roller rocker because of the clearance issue. CompCams has a toll free Tech Support Line that can answer that for you if no one posts on that point.

If you valve covers have drip tabs on the under side they may need to be ground off too, for clearance.

Jake

 

pro magnums rollers , narrow body,SELF aligning 1.6 on both in & out..the stock stud are 3/8" and are screwed to 7/16" heilcoils into head (standard).. you will have to change to longer studs any way, SO you have to option to choose 7/16" Rockers rollers with 7/16" studs..on the valve covers jake is right moding to drip tabs, you will also need to mod the tin boxes,,they need to be shorten at least 3/4"...three more places need adjustment , one is the underside of the corvette emblem must be flattened level. the other is the half of the oil filler underside, left side when faceing it..each of pillars could also need some thinning to added clearance.

in addition, springs should be changed, comp or cranes, to provide a bit more seat pressure, Part # WG2535 Crane(i think). while doing this valve seals could also be replaced.

PS: the orginal guide plates are used in conjunction with stamped self aligning rockers(stock), these guides plates ARE REAL and ARE the same as comp guide plates replacement..in my installation i choose not to remove them. i am using Comp Pro Magnums, SElf aligning, 1.6, with 7/16 studs and the orginal guides plates...i tried using without guides and bendt 4 four push rods...the reason is that at high RPM the rollers lifters "have a tendency to relax a bit" causing momentary lack of pressure, loosening the push rod and relieving the postion of the rocker!

 

Dennis, are you sure about that guide plate issue? I've never fooled with them but I've read several posts on the Forum and in a couple of the mags that said they were only installed at the factory to aid in engine assembly.

That they should be ditched and aftermarket, hardened guide plates installed instead.

What's up with the wheel bearings?

Jake

 

ok .. . the l98 with 113 heads..HAS guide plates And self aligining Stamped rockers, STOCK.. THESE plates help guide the pushrods in extreme condition.This MYTH about using them as factory assembly has not been proven, by any means OR hard FACTS. the General installed them for a reason. i removed them for testing ( i did mention to you earlier that i would cut them and install only as spacer,, well i didn't)., I DID test with rockwell gauge, that i used for other purposes, and BOTH test near the same, (not very hard any way 47rc).aftermarket guides plates are not needed. so I think its BS using aftermarket plates.. Both types ARE the SAME material/hardness wise.... I ALSO HAVE replaced RR's in my 87, 3years ago ANd it still runs with factory guide plates. and self aligning roller rockers.. THERE IS NO SIGN OF BINDING! now this is my opion..i tried to get answers, BUT i needed some HARD facts!

rear wheel bearing are a bit loose, so i ordered new today, my price was 150.00 CND each.. thats a good deal.

 

Wow, Dennis, you seem all steamed up over the guide plate issue. I've read it in a couple of different places and several members have posted the same thing.

But if it's facts you need, I'll do my best to track down the sources I've come across. I don't believe this was concocted just to sell guide plates though, as inexpensive as they are.

Also, CompCams does specifically recommend not using the self-aligning rockers in performance applications. But I'll site the source of that recommendation too.

Gotta remember to keep a separate file on all my sources: Note to Self . . .

Anyway, we'll put this issue on the back burner until I can come up with my sources.

Jake

 

not steamed at all ....i gather/distrubute facts all day...Simply put "what parts can i use and which will work" is best the senario rather then suggestive guessing.

however, i can relieve the issue of harden guide plates(aftermarket) and stock plates, based on hardness testing . i can also say " 113 heads L98, have guide plates with self aligning stamp rockers as stock", based on 3 rebuilds with photo gallery. I can say that, "longer stud bolts should be used", based on the broken one i have in hand. i can say that , "comp cam have specific recommendation to thier products" and "percieve thier guidelines as ulimate when used with THIER PRODUCTS"...and finally that technique is "known as stack selling" . Although tips/suggestion help make choices, they should be validated to ensure feasiblity.

BTW: having significately increased the ability to desipher pros /cons, could not have been done with out your knowlegable help.

 

Correct me if i'm wrong 88-99 use self aligning rockers.
My 86 with aluminum heads used non self aligning with guide plates. I used crane energizer rollers and they are not narrow body. With the stock covers i had to shave the bolt towers and remove the drip tabs to make them work.

 

One little point here guys. The 1986 vett never had 113 heads. For that matter neither did the 87.

 

87,88,89 did have guides plates, with self- align stamped rockers with 113 alum, these stamped rockers had small ridges on both sides of the tip. i had to examine them closely to determine.

So your are saying that wide body Cranes fit? what part number were the crane Roller rockers? ..the reason i ask is becuz when i did test fit with wide body rockers with orginal VC modified, still did not fit.

 

READ thread #7 & #2 & #14

...this is the point i was making earlier " suggestive Guessing"

 

I don't see anything in those threads that make any difference but if you got any money to put up,,,,,,

I know for a fact that GM never made 113 heads til 88. I took the Aluminum heads off my 87 and recently bought a set of 113 heads off a 90 to put on instead.

 

Late 86 and 87 alum heads were the 128 casting. They did not have the d ports that the 113's have.

 

You know, I've been puzzling my puzzler over this issue. Not because I'm **** about being right, but just so I don't give incorrect information to anyone. So I spent a little while this morning going through some of my back issues of Corvette Fever and VETTE magazines thinking that it was in one of them that I saw it; about the "guide plates".

Didn't find it though, but I don't give up easily. I've got a few tricks up my sleeve to try to find the source.

Anyway, you know how it is when you find one thing while looking for something else?

Well, I found a Tech article by Chris Petris in Corvette Fever Feb 2001, inwhich he says that the C4 comes with a High Volume oil pump, not the standard volume pump that comes on the Caprice, etc. He went on to write that he's occasionally found the wrong (standard volume) pump installed on a C4 engine after it had been rebuilt. The article was in response to an owner's complaint of low oil pressure at idle.

I just mention this because so often this pump voulme question comes up. Six months from now the issue will come up again and I won't for the life of me, be able remember where I read it.

I hope you younger guys, with the sharp memories, will come to my rescue. LOL

Jake