Lifters

[Freejax]

Hey guys I am at the stage of rebuilding my lifters and I found 4 of the 12 completely seized, they will not compress to get the snap ring out. Any suggestions? I have one soaking in gas to see if it will free up, I am glad I decided to rebuild them because I would really hate to have installed them again. What are your thoughts on roller lifters, cam and rockers and are they made for our Corvairs, mine is the 67 500 with 95 HP motor.

[bbodie52]

Carburetor parts dip might be more effective at dissolving any build-up that could be causing the components to be stuck.

[azdave]

What are your thoughts on roller lifters, cam and rockers and are they made for our Corvairs, mine is the 67 500 with 95 HP motor.

They are around (I have an unused set for a future build) but in my opinion, are not worth the troubles and investment on a basic, stock engine. I would only do roller rockers on a performance build.

[Freejax]

My plan is to get a better cam, go dual exhaust, polish the heads and get a harmonic balancer. Do you think the roller gear would be a benefit to this build up?
What types of troubles do they have?
How much of an investment is it?

PS thanks for the dip tip, I have one soaking in some now but no luck after 24 hours.

[bbodie52]

If you Google Corvair Roller Cam you will find numerous articles and listings that discuss the use of a roller cam in a Corvair engine. I believe the advantages of a roller cam (on any engine) were primarily in that they would permit higher valve spring pressures to control valve float at high RPMs, and the camshaft grind could be more radical with faster valve opening and closing since the camshaft lobes did not require the the more-gradual ramps used with conventional hydraulic lifters. I believe the use of solid lifters in an aluminum engine was more problematic in keeping proper valve clearances because of the differences in aluminum expansion (there was some experimentation mentioned with hydraulic roller cam lifters by American Pi), and the cost is significantly higher. I'm not sure such a radical and expensive engine modification would be warranted on a street engine.

Good luck with your research. Let us know your conclusions for your application.

[Scott V]

(there was some experimentation mentioned with hydraulic roller cam lifters by American Pi), and the cost is significantly higher

the corvairkid site says the hydraulic roller cam was finished in 2004. american pi did all the development work/testing/etc. you can get the cams from american pi. http://www.corvairkid.com/190cid_02.htm

-Scott V.

[91blaze]

I don't see the hydraulic roller cam on american-pi, only the solid roller. Only place I have found with the hydraulic roller cam is Corvair Specialties.

Freejax- I don't know if a roller cam is worth the investment for you, it's more something for a bigger build. It does cost 1150 for the hydraulic roller cam system.

[Scott V]

I don't see the hydraulic roller cam on american-pi, only the solid roller.

its not on the site. email them for all the info.

the picture on the other site is the american pi hydraulic roller cam. the guy got it from american pi. then he puts it on his site & says he made it. real funny. its even on blue background like the stuff on the american pi site. some people...................

-Scott V.

[flat6_musik]

Hey guys I am at the stage of rebuilding my lifters and I found 4 of the 12 completely seized, they will not compress to get the snap ring out. Any suggestions?

One of my favorite sayings is "do you wanna spend money, or do you wanna go fast?" I think the roller cam would be one expensive non-effective performance mod......although I DO think they are a beautiful addition to have on a hot motor, just I wouldn't expect much from it on a lower-performance setup.

[Tom Z]

My plan is to get a better cam, go dual exhaust, polish the heads and get a harmonic balancer. Do you think the roller gear would be a benefit to this build up?
What types of troubles do they have?
How much of an investment is it?

IMHO, for a 'stock' 95hp I'd get a cam with a new gear properly installed and new lifters with the cam..PERIOD..you'd want to tear down and *CLEAN* the whole engine,tho, especially the oil passages..any head work other than 'stock' often goes in the "wrong direction" -ie "polishing", so I'd just have the stock 'valve job' done along with having the head gasket surfaces "made equal" again..

[corvair70]

If a lifter is properly pumped up isn't it impossible to compress it to release the ring.
Don't you have to some how release the oil.
Now my bad lifters I could compress by just pushing on them in place in the car.

[Freejax]

Thanks for the tips guys, I think I have decided to do a new cam and lifters because I am worried about the cam with having the four bad lifters running for who knows how long.

[bbodie52]

Proper break-in and treatment of a new camshaft is important. Here are some guidelines from Crane Cams...

Preventing cam and lifter wear

Always Install New Lifters on New Camshafts!

The first 10 minutes of running on a new camshaft are the most critical. If a failure occurs during this break-in time period, no corrective action can be taken to save it. The number one cause of new camshaft failure is the use of old lifters. New lifters MUST be used.

A "cupped" lifter...was found on a worn out lobe. If this lifter were reused, there would be an instant failure of the replacement camshaft. Normal lifter face areas have a spherical shape with .002" crown. It is not flat across the contact surface as many people assume.

There must be a moly coating between the cam lobe and lifter, in order to prevent metal-to-metal contact. Before installing your new cam, coat all lobes and the bottoms of each lifter with a moly disulphide based assembly lubricant, such as Crane Super Moly Lube (Part Number 99002-1).

Use a high quality 30 or 40 weight oil, preferably a Pennsylvania base oil, or a high quality Pennsylvania based multi-viscosity oil, such as 10W-30 or 20W-50.

Also, for extra protection, an antiwear additive (zinc dithiophosphate) must be added, such as Crane SuperLube (Part Number 99003-1).

IMPORTANT! Do not allow the engine to run UNDER 1500 RPM for the first half-hour or so.

Also, change RPM frequently to direct oil to different places. Slow idle speeds or continued operation of the starter will result in severe cam and lifter wear during the initial start-up period. Prime the carburetor before starting, so that you may immediately start the engine and bring it to break-in RPM. Try to place a load on the engine, such as normal driving conditions, in order to insure proper operating temperatures and distribution of lubricant.

REMEMBER . . . the first 10 minutes are the most important in a new camshaft's life. Tests have shown that if there is no spalling or metal pick up during the first 10 minutes to one hour of operation, the cam will last a normal life. After you have completed the "break-in," immediately change oil and filter. Regularly maintain your engine, its oil and filter, and valve lash adjustment. Your reward will be an engine that delivers maximum horsepower and performance.

On a Corvair engine, the camshaft is held in place by an aluminum cam gear that is pressed on, and by a thrust washer and woodruff key. Unlike many engine designs, there is no bolt that secures the gear on the camshaft. It is very important that the gear is properly heated, aligned and pressed on correctly to ensure a proper fit and no damage to the gear during installation. As seen below, Clark's Corvair Parts stresses the importance of a new gear and proper installation to prevent a failure in this area. Considering the degree of difficulty and the amount of work involved in removing and replacing a Corvair camshaft, this is an important area to consider and to get right during an engine overhaul.

[bbodie52]

Here are some added thoughts comparing the 95 hp and 110 hp engine configurations, and the 140 hp engine as well...

Differences between 95 hp, 110 hp and 140 hp engines...

The 110 hp distributor (1110319) Centrifugal advance curve is more gradual with the same peak timing advance as the 95 hp (Automatic) unit, but peak is reached at 4800 RPM for the 110 hp engine instead of 4200 RPM for the 95 hp (Automatic). the automatic transmission engine centrifugal advance starts at a much higher RPM than the 110 hp engine. Both the 110 hp and 95 hp (Automatic) initial (idle) timing are the same, at 14° BTDC. The 95 hp engine with manual transmission has an initial timing setting of only 6° BTDC, so the distributor for that engine has a higher maximum centrifugal advance timing setting that was increased by 8°, to match the total advance reached by all three engines. (For that reason using a 95 hp manual transmission distributor on a 110 hp or 95 hp (Automatic) engine would result in too much total advance — by 8° — which could produce high RPM detonation (pinging) and potential engine damage).

The 110 hp and 95 hp (automatic) engines both share the same vacuum advance curve. The 95 hp manual transmission engine has a different vacuum advance curve.

Distributor timing and advance curve details are provided and graphed in the specifications published by the GM Heritage Center. Owners should be aware of the impact that having the incorrect distributor on a given engine can have, since too much advance at the wrong engine RPM and load can promote detonation, which can seriously damage an engine if it is allowed to continue. The correct distributor timing and advance curves may also permit the use of lower octane fuel without engine detonation occurring under many driving conditions.

The 95 hp engines use the same 312° duration camshaft. The 110 hp engine has a high-performance 340° duration camshaft with more valve lift.

The 95 hp engine had an 8.25:1 compression ratio. The 110 hp engine had a 9.25:1 compression ratio.

To summarize, both the manual and automatic transmission 95 hp engines had the same compression ratio and camshaft grind. The distributor timing and advance curves for the two 95 hp engines were modified to adjust for the different driving load presented by the automatic transmission vs. the manual transmission. Low-octane Regular fuel was recommended due to the lower compression ratio.

The increase in horsepower found in the 110 hp engine is attributed to a higher compression ratio and a high-performance camshaft. A modification was made in the distributor timing and advance curve to match these performance changes, plus a recommendation for use of a higher-octane Premium fuel was added to compensate for the higher compression ratio. This engine was equipped with a harmonic balancer in place of the 95 hp engine's standard crankshaft pulley to compensate for the greater stresses expected on the engine crankshaft at higher horsepower settings.

Understanding these engineering changes and the reasons behind them will help as you make choices in modifying your 95 hp engine for increased performance. A high performance camshaft with low compression ratio 95 hp heads would likely produce an engine in the 104 hp range that would better-tolerate the use of Regular fuel. The small valves, single exhaust system and dual carburetors are the limiting factor. This same engine coupled with dual exhaust and an electronic fuel injection system with distributorless computer-controlled ignition might reach a better performance, but would still be limited in comparison with the 140 hp cylinder heads. Those heads would increase the compression ratio to 9.25:1 and would provide better-breathing with the larger valves and exhaust ports. (The 110 hp and 140 hp engines share the same camshaft).

[Freejax]

So an update on my engine rebuild, things have been busy this winter here in Canada. My wife had the honey do list like hardwood floors, repaint interior of house, start developing basement, blah blah blah, y'all know what thats all about. I have a 1967 500 being delivered to my house this weekend, its funny because its the exact same car as mine, even colour. The body and interior is shot but it is a complete car so I paid for $400.00 for a parts car, I like having extra parts on hand now that the American dollar is higher then our funny money.
I have a dilemma though, I soaked my pistons in some pretty nasty stuff and they came out with lots of carbon on them and they did not pivot to well after being soaked, also two rings disintegrated as I was trying to remove them. I am thinking new pistons and rings from Clarks, Should I go 30 over on my 95HP motor while I have it apart. I did a big engine order from Clarks with a better cam, harmonic balancer, electronic ignition, rebuilt carbs, valve job, four speed transmission and I have a totally dismantled engine. Look forward to your knowledge, car still under tarp in Canada!