Dont use 1.7 rockers with stock heads?

Coupe5oh · 04-14-2002, 08:36 PM

This is a quote off the MAC website:

"To enhance the total package, high quality roller rockers (direct bolt on) with a 1.6 to 1 ratio need to be installed. The use of high quality roller rockers will help equalize cam performance from cylinder to cylinder. Stock rockers are stamped and their ratios are inconsistent, be sure to use only high quality roller rockers. Caution: with stock rate springs and heads, do not use more than 1.6 to 1 rockers. Stock springs are not designed for more valve action."

Glad i didnt already buy mine, so i guess im getting 1.6's, but how hard is it to replace the stock springs with newer ones, if i decide to just do the springs? thnx

Dark_5.0 · 04-14-2002, 10:40 PM

I know many many people using 1.7 rockers with stock heads and springs with no problems after years of use.

Later,

Mach 1 · 04-14-2002, 10:50 PM

Just because MAC says something on thier web site doesnt make it gospel. 1.7's work great on stock springs, as long as the springs are in serviceable condition.

fiveohpatrol · 04-15-2002, 12:03 AM

My stock springs had about 100k on them when i put my 1.7's on originally. A few months later, I noticed that my valves were floating at about 5300 rpm and higher.

I put on a set of comp cams springs (about $70), which installed very easily, and the problem went right away. Also the car seemed to pull harder on higher RPM's as well.

juiceman · 04-15-2002, 01:46 AM

thats a rediculous statement. 1.7 rockers are the same as running 1.6 rockers with a higher lift cam. so i guess theyre saying you cant get a cam either. unless of course you buy new heads and springs. you can use 1.7 rockers on stock motors and thats what they are primarily used for

84LX89GT · 04-15-2002, 02:39 AM

My engine in my '89 has 1.7 roller rockers on it with 120,000 miles and there's no problems so far after they were installed by the previous owner at 80,000 miles.

byrnech · 04-15-2002, 11:12 AM

I had the same results as fiveohpatrol, I installed them with about 65k on the odometer and they were great for about a month or two then the valve float set in. It would just fall on its face after 5000. When my crank snapped and I get my new motor I gave them to a friend, Same thing with him. He gave them to another friend and the same thing. Stock springs are notoriously weak.

Mach 1 · 04-15-2002, 12:40 PM

I put the 1.7's on a 1990 Lincoln Mark VII (5.0 HO, identical engine) at around 75K, and they were fine. I took them off again at around 100K before I sold the car, and had no problems the whole time. Car ran good and made plenty of power throughout the RPM range.

Maybe the Lincolns get superior valve springs?

Piston · 04-18-2002, 09:20 AM

I had 1.7RR installed on my 94gt on stock heads. They gave me a nicer sounding idle and added some power. If you have low miles on your car go for it. If you are extremely cautious go with the 1.6RR.

RoadWarrior · 04-18-2002, 09:25 AM

I cant see the rockers needing better springs. From what i understand the only time (besides if one goes) that you need to change springs is if you go with a more extreme cam. Because if you have an big bad cam you can start to get floating valves because the spring cant hold the lifter on the cam. But roller rockers alone should not need new springs.

88quickGTVert · 11-28-2015, 12:36 PM

Quote:

Originally Posted by Coupe5oh

This is a quote off the MAC website:

"To enhance the total package, high quality roller rockers (direct bolt on) with a 1.6 to 1 ratio need to be installed. The use of high quality roller rockers will help equalize cam performance from cylinder to cylinder. Stock rockers are stamped and their ratios are inconsistent, be sure to use only high quality roller rockers. Caution: with stock rate springs and heads, do not use more than 1.6 to 1 rockers. Stock springs are not designed for more valve action."

Glad i didnt already buy mine, so i guess im getting 1.6's, but how hard is it to replace the stock springs with newer ones, if i decide to just do the springs? thnx

Speaking from experience, I had 1.7's on my 89 LX, after 2 1/2 years of driving/street racing, I needed the stock heads (springs worn and valve job) done over. Some of the rockers we're also loosened up even after being torqued to 20 ft lbs. At that time engine had about 60 thousand miles. Get the upgraded springs when using 1.7.
The heads are the weak point of the 5.0 engine.

04-14-2002, 08:36 PM	#1
Coupe5oh Registered Member Join Date: Nov 2001 Location: SanAntonio, Tx Posts: 734	Dont use 1.7 rockers with stock heads? This is a quote off the MAC website: "To enhance the total package, high quality roller rockers (direct bolt on) with a 1.6 to 1 ratio need to be installed. The use of high quality roller rockers will help equalize cam performance from cylinder to cylinder. Stock rockers are stamped and their ratios are inconsistent, be sure to use only high quality roller rockers. Caution: with stock rate springs and heads, do not use more than 1.6 to 1 rockers. Stock springs are not designed for more valve action." Glad i didnt already buy mine, so i guess im getting 1.6's, but how hard is it to replace the stock springs with newer ones, if i decide to just do the springs? thnx __________________ Police package 5spd 90 Lx, Stock original motor, 3.27grs, BM fan, fms 10.5 clutch, D&D quadrant, and adjuster, ADS chip, 180 stat, mac cai, mac h-pipe, mac subframe connectors, ASP crank pulley, ripper shifter, 26x10.5 M/T sport pros welds. 246 hp according to analyzer Race weight: 3,120 E.t-13.57 with 26x10.50's e.t. streets. 1.88 60' mph- 99.92 mph

04-14-2002, 10:40 PM	#2
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I know many many people using 1.7 rockers with stock heads and springs with no problems after years of use. Later, __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

04-14-2002, 10:50 PM	#3
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	Just because MAC says something on thier web site doesnt make it gospel. 1.7's work great on stock springs, as long as the springs are in serviceable condition. __________________ 2002 GT 1993 GT (SOLD) '93 Mustang GT RHC member #142

04-15-2002, 12:03 AM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	My stock springs had about 100k on them when i put my 1.7's on originally. A few months later, I noticed that my valves were floating at about 5300 rpm and higher. I put on a set of comp cams springs (about $70), which installed very easily, and the problem went right away. Also the car seemed to pull harder on higher RPM's as well. __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

04-15-2002, 02:39 AM	#6
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	My engine in my '89 has 1.7 roller rockers on it with 120,000 miles and there's no problems so far after they were installed by the previous owner at 80,000 miles. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

04-15-2002, 01:46 AM	#5
juiceman Registered Member Join Date: Jan 2001 Location: ny Posts: 197	thats a rediculous statement. 1.7 rockers are the same as running 1.6 rockers with a higher lift cam. so i guess theyre saying you cant get a cam either. unless of course you buy new heads and springs. you can use 1.7 rockers on stock motors and thats what they are primarily used for

04-15-2002, 11:12 AM	#7
byrnech Registered Member Join Date: Jun 2001 Location: Anderson, TX. Posts: 166	I had the same results as fiveohpatrol, I installed them with about 65k on the odometer and they were great for about a month or two then the valve float set in. It would just fall on its face after 5000. When my crank snapped and I get my new motor I gave them to a friend, Same thing with him. He gave them to another friend and the same thing. Stock springs are notoriously weak. __________________ 331 10:1, AFR 185's, TFS-R intake

04-15-2002, 12:40 PM	#8
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	I put the 1.7's on a 1990 Lincoln Mark VII (5.0 HO, identical engine) at around 75K, and they were fine. I took them off again at around 100K before I sold the car, and had no problems the whole time. Car ran good and made plenty of power throughout the RPM range. Maybe the Lincolns get superior valve springs? __________________ 2002 GT 1993 GT (SOLD) '93 Mustang GT RHC member #142

04-18-2002, 09:20 AM	#9
Piston Registered Member Join Date: Jul 2000 Posts: 77	I had 1.7RR installed on my 94gt on stock heads. They gave me a nicer sounding idle and added some power. If you have low miles on your car go for it. If you are extremely cautious go with the 1.6RR. __________________ Stock Bottom End 302. With TFS stage II ported and milled heads. Anderson B2 cam with 1.6RR. Hooker Full Tube Headers flowing into offroad H-Pipe out Hooker mufflers. Ported Edelbrock Preformer Upper/Lower. Lots of other Goodies... Just bought a nice forged 331 stroker kit for a new block that should be ready to take 650hp of abuse.

04-18-2002, 09:25 AM	#10
RoadWarrior Registered Member Join Date: Apr 2000 Location: Edmonton,Alberta,Canada Posts: 317	I cant see the rockers needing better springs. From what i understand the only time (besides if one goes) that you need to change springs is if you go with a more extreme cam. Because if you have an big bad cam you can start to get floating valves because the spring cant hold the lifter on the cam. But roller rockers alone should not need new springs. __________________ Fast Company

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