[SeventyThreeGT]

Would I gain any performance in using a stock solid cam and lifters over a stock hydrolic cam and lifters? I'm guessing that my engine is basically stock 1.9L (don't know what the pos have done to it) with some bolt on's; exhaust, header, hot electronic ignition, weber 32/36, mildly ported intake, electric fan, flat top pistons I think. Anyways, I'm gonna be pulling the head here shortly to replace the head gasket and am wondering if putting in the used solid cam I have would be benificial.

Thanks,
Jon

 

[RallyBob]

The factory solid cam is worth a few hp....exactly how much it's worth with your other mods I can't say, but it is better in terms of performance. The intake lobe has 4 degrees more duration and the exhaust lobe has 9 degrees more duration than a factory hydraulic camshaft.

HTH
Bob

 

[SeventyThreeGT]

Do you think using the solid cam would be worthwhile for my quest of a little more power? I can live with the noise of solids. The solid cam and lifters will plug right in where the hydraulic ones were right? And are the valve spring rates and rockers of the two cams the same?

Also, will a '70 head fit a '73 block ok? I fear my head may be cracked.

thanks,
jon

 

[kwilford]

Bob, can I ask the question another way? For the engine example given, if a person were buying a new cam in any event, does a solid grind give any performance advantage over a hydraulic grind of a like-grind, EXCEPT the increased rpm that a solid lifter allows? To get the advantage of the increase in duration, can't he just order a hydraulic cam ground such (such as OGTS's Torquer Cam) and stay with hydraulic lifters (new ones, of course)?

In other words, is it true a hydraulic lifter pumps off at around 6000 rpm, but the solid lifter will go much higher, so long as OTHER limitations aren't reached first (such as weak valve springs causing valve float, or intake/carburation limiting high end breathing, or crank and/or rod failure, etc.).

Based on the example given, I suspect that this engine seldom will see more than 6000 rpm, so would the solid lifter (and cam ground to same) provide significant (if any) performance gain? But it will require more maintenance and somewhat more associated noise.

Does that sound right?

As for the '70 head, it will fit the later block just fine. The later (post 'mid '72, 12 bolt head) chain case on your block is designed to be flush with the block deck and then bolted to the head with the extra two bolts that the earlier head doesn't have. So two things to watch for:

1) If you get the block decked, the chain case must also be decked the same amount (I did mine at the same time) or it will stick above the block deck.

2) Since the later case and block are flush, you must use the later head gasket (without the cork gasket at the front), and just put RTV sealant in and around the unused holes in the chain case.

HTH (pending RallyBob's comments on my solid cam questions)

 

[RallyBob]

Do you think using the solid cam would be worthwhile for my quest of a little more power? I can live with the noise of solids. The solid cam and lifters will plug right in where the hydraulic ones were right? And are the valve spring rates and rockers of the two cams the same?

You'd see more power, but as I said I'm not sure exactly how much more. Probably 5-8 or so, nothing earth-shattering. But noticeable.

Worth noting is that while the solid lifters and cam will physically fit where there were once hydraulics, the factory solid cams were all 3-bearing designs, so if the 3-bearing cam is used in a 4-bearing head you will need to plug the 3rd (of 4) cam bearing or you will have a massive internal oil leak and will lose oil pressure.

The later hydraulic heads have stiffer valve springs than the solid heads, so no worries there. In fact you'd have the ability to rev the engine a bit higher as a result.

Bob

 

[RallyBob]

Bob, can I ask the question another way? For the engine example given, if a person were buying a new cam in any event, does a solid grind give any performance advantage over a hydraulic grind of a like-grind, EXCEPT the increased rpm that a solid lifter allows? To get the advantage of the increase in duration, can't he just order a hydraulic cam ground such (such as OGTS's Torquer Cam) and stay with hydraulic lifters (new ones, of course)?

Keith, if a cam grind is otherwise identical but one is used for solids and another for hydraulics, then there will be barely a performance advantage using solids. Short of the extended rpm range the solids are capable of.

But, (and you knew there was one of those, right?), most solid cams with 'identical' specs as those of a hydraulic cam are not really identical. There's usually more lift area for a given duration with a solid cam, so performance will be enhanced by this variable. So the apple will probably outperform the orange, even with the same lift and advertised duration.

Bob

 

[SeventyThreeGT]

Darn, I thought for sure '70's had four bearing solid cams.

Whats a good way to plug the cam bearing oil hole?

Maybe I should just use the '70 head and put the '73 valve springs in it?

 

[Gary]

..Whats a good way to plug the cam bearing oil hole?

Rotate the unused cam bearing so that the oil hole in the head is blocked.

 

[apassens]

And how about a reversed engineered situation

I am attempting the exact opposite scenario:
I do have a new cam (4bearing) for solid lifters (They do exist!), the engine is a 3 bearing 1.9 and I do have a spare 1.9E head I thought of using since that's 4 bearing one.

What would the issues be to bring the 1.9 E head to the early model block and is the 1.9E the right approach - I do have larger valves, but would have to face machine cost no matter which is used so it might not be a true advantage anymore...

Any way of salvaging the 3 bearing one?

FYI: Carb is a 40mm Weber sidedraft and 296º cam/11.2mm valvelift.
I was told that the rpm range is 2-7k (peek at 6k) on the cam.

Thanks!Andreas

 

[RallyBob]

I am attempting the exact opposite scenario:
I do have a new cam (4bearing) for solid lifters (They do exist!), the engine is a 3 bearing 1.9 and I do have a spare 1.9E head I thought of using since that's 4 bearing one.

Yes, later European solid lifter cams had 4 cam bearings as do aftermarket solid cams, this is most definitely true. I should have clarified that I was refering to OEM stock US-spec cams.

What would the issues be to bring the 1.9 E head to the early model block and is the 1.9E the right approach - I do have larger valves, but would have to face machine cost no matter which is used so it might not be a true advantage anymore...

There is no definitive performance advantage to either head. If the later head is a US spec head, then it is more prone to crack than the earlier head, due to induction hardened exhaust seats.

On the other hand, if you intend to explore the upper rpm limits of that cam frequently, having a 4th cam bearing aids in valvetrain rigidity. The 3-bearing heads were known to have cam and valvetrain failures in racing use from this. I have personally never broken a cam in half as some people have, but I have had rocker studs break on cylinder #3, and this was always on 3-bearing heads, never on 4-bearing heads....and always at sustained 7500-8000+ rpms.

HTH,
Bob

 

[SeventyThreeGT]

Would it be alright to use the used cam bearings from the hyd. cam and put the solid cam in? And after the 3rd bearing is rotated to block off the oil, will it need to be align bored or somthing?

I tore the head off today and found that the head gasket split the top layer from the bottom between the 2 and 3 cylinders, and the cam button wasn't even screwed into the cam and was pretty well chewed up and the lifters were pretty worn and concaved. But all the solid cam things are like new yet.

Thanks,
Jon

 

[SeventyThreeGT]

Well, looks like I'm going to use the '70 head. While cleaning up my '73 head I found two nice cracks running cross ways through the #2 and #3 exhaust valve seats.

Is there anything else needed to use a '70 head on a '73 block other than putting some rtv in the extra 2 bolt holes and adding lead additive to the gas? And will a 71-75 head kit work on the 70?
And why does the 70 head have valve rotators on the intake valve springs? The 73 has them on the exhaust only. Should I reuse the rotators on the intake or use the standard retainers?

thanks,
Jon

 

[nobody]

As for the head, the biggest concern is the front timing cover. Later years were taller and tapped for the extra 2 bolts. So depending on the cover, that will determine which head gasket to use.

Ok mix and match cams, heads, lifters, bearings. Cams, swap them all you want. Heads, again pick the best and go with it. On the lifters they seat into a particular cam lobe and swapping them around is risky at best. They should go back in the same order as removed. On a 3 bearing head new bearings are like 35 bucks from OGTS and don't need to be line bored. This is an area that can give you alot of grief with oil pressure and cam wear. It's my opinion to be safe and replace them whenever possible. The cost of the bearings now is cheaper than taking it back apart to do it.

 

[kwilford]

Yep, what Dave said. New cam bearings are good.

But make sure that you get the correct bearings for the 3-bearing head; last time when I tried to buy them from OGTS, they only had the "under-size" (smaller outside diameter) bearings, which do NOT work on some 3-bearing heads. The heads with the larger journals are marked with a "triangle" stamped on the side of the head. And the only cam bearings OGTS had were "semi-finished", and "split", which my machinist did NOT like. He did not have the required boring tools to "finish" Opel CIH cam bearings, and he thinks the solid bearing is also superior. So he brought in "solid", "pre-finished" cam bearings (designated "OP3" in the parts book) and we were both happy.

And I would also consider doing the following (at a minimum):

1) Install hardened exhaust seat inserts (and make sure that the valve installed heights are correct)
2) Buy a new cam (either the "Torquer" or "Combination" cam from OGTS, or an equivalent "street" grind)
3) New lifters. No question. And I suggest hydraulic lifters for most street engines
4) new head gasket (it had to be said) and all other gaskets (including water jacket O-ring seal)
5) new timing chain
6) new valve stem seals. And I would consider getting the head stem guides machined to accept the "umbrella" style seals versus the "o-rings" which I don't believe were on either intake or exhaust on my '69 head. They are on the intake on the '71 and and both on the latest (post '75?) heads
7) and check the guides themselves. New guides are quite easily installed now, and often leaky guide seals are really a result of worn guides.
8) surface (deck) the head

HTH

I am not sure about the rotators. I thought they were just on the exhaust valves on both my '69 and '71 head. But if you install hardened seats, they aren't as important

 

[tekenaar]

Stock O-ring valve seals

I believe O-ring seals were actually used in conjunction with the steel "umbrellas" (at valve spring retainers) on exhaust valves and that intakes used a version of "umbrella" seals at the tops of the valve guides.

 

[nobody]

Kieth, deck the head or block is a huge no no for a begining CiH builder. Ok unless they have a degreed pulley on hand and or a machinist that can fix the timing by modifying the pully without detonating the motor. I've built a lot of motors and a redecked head or block is worth it's weght in scrap iron. I'm a motor builder and decking anything means you picked a bad one or are trying to make a problem worse. Please don't mention a change in cam to crank timing without mentioning the down side.

Sorry, pet pieve of mine.

 

[GTJIM (R.I.P.)]

Replacing Rotators

If you install hardened exhaust seats then the rotators on the exhaust valves can be removed and not used - BUT - The old exhaust valve springs will now be too short to be used without the rotator. However all is not lost - intake springs and retainers can be used on the exhaust valves as long as a spring spacer is used to make the installed height of these springs the same as it is on the intake valves. This is because the exhaust spring seat is cut deeper into the head, than the intake spring seat, to allow for the rotator to fit under there on the exhaust.

 

[SeventyThreeGT]

I would like to put my 73 valve springs on my 70 head because of the mention of them being stiffer. Is this a direct swap? And because I'm not installing hardened seats, will I need to use the rotators on the intakes? And if the rotators are needed, can I simply just replace the retainer with the rotator or will the spring height be changed?

 

[Scott McDonald]

And because I'm not installing hardened seats...

Before being concerned too much with anything else, I think you should reconsider not installing hardened seats. Boosting performance with old seats (with old anything), will just accelerate their destruction, and possibly lend itself to more costly repairs in the foreseen future. You should heavily weigh the possibility of replacing your timing chain and tensioners now as well.

Or you could run avgas @ $3.00-$8.00US per gallon. I do not know what is in lead additive, and don't trust most additive companies.

If your going to run a solid cam, get yourself some solid lifters. Kent cams has some. They also have an adjustable timing gear, if you're inclined to mill your head. If you decide otherwise, at the very least, have your solid lifters resurfaced/hardened before installing a new cam. If you intend on using the solid cam you have, be sure-be very sure-be very, very sure that you install them in the same order you extract them.

If you are going to run a stock cam, I wouldn't worry to much about spring swapping. But if you need to, use intakes in both applications per GTJim. This will most likely involve going to a machine shop, where they could magnaflux(highly recommended), and install hardened seats/bearings reasonably.

 

[GTJIM (R.I.P.)]

'73 0n '70

Yes you can just change the '73 valve springs onto the '70 head - just use everything from the late head. I think that the valve collets are different too with a square groove instead of a round groove in the valve stem. So you will need to use the keepers that match the valves that you use.

This talk of "Intake Valve Rotators" is mystifying as I (and others!) do not think that intake valves had rotators on early or late heads - can you upload a picture of your bits and pieces showing us what you mean by "Intake Valve Rotators" Please?

Below is an exploded diagram of Opel valves - the Intake on the left and the exhaust on the right with #36 being the exhaust valve "rotator"
The second drawing is and exhaust valve assembly.