Hi, well I got my heads off (blown head gaskets) and pulled on of the lifters to look at my cam, and guess what? They are not roller lifters, just Hydraulic flat tappet, why is this? It looks like someone was in the engine before, not sure if they ****ed with it or not, anyone have any ideas?

 

Ummm, yeah, I have an idea.... I'm sureNo big surprise. I'm surprised you're surprised. Ought to be one of The Rules of car repair: Anything one person can do right, somebody else will be willing to do half-a$$ed, cheaper.

I'd almost be willing to bet your block stapming won't match your car's VIN, and the heads will be 193s. "Yeah it's a 350, they're all the same, this one'll fit a 91."

See my signature for help in understanding how to analyze the situation.

 

Well, I cant find the engine vin, but the heads are 083's, and it is still a Hydraulic lifter engine, just not hydraulic roller, it has the right pistons to.

 

Uh... Are there flat tappet lifters on a roller cam?? Or is it at least a flat tappet cam?
Time to upgrade eh?

 

Are the freeze plugs brass? Maybe its a marine longblock. Alot of them used non-roller camshafts and 083 heads.

 

I guess I didnt look to see if the freeze plugs are brass.

How can I visually tell the difference between a Flat tappet cam, and a roller cam? Do they look different?

Where is the engine code? for the VIN. I bought this car, running like ****, and it has a blown headgasket. So, I dont know exactly what's up with it.
----------
Does anyone have evidence these are supposed to be a roller motor? My machinist is saying it is not a roller motor, and is suppose to be just a hydraulic flat tappet. I dont know, that's why I am asking.

 

All 1987-up gm "corporate" smallblocks have camshafts with hydrualic roller lifters..... trucks, cars, TPI, TBI, etc. The VIN for the car will be on a pad on the passenger side of the motor just above the water pump. It will have the last digits of the VIN of the car if it is original.

Maybe it is the original engine (and someone changed the cam and lifters), look in the lifter valley for three threaded holes. These are used for the spider that holds the lifters in their bores. If the bosses are not there, it is a older block which explaines the non roller lifters......

You can tell your me-can-ick that GM stopped using non roller lifters around 1986-1988 in everything EXCEPT replacement/crate engines....

Kevin

 

Ok, what are these threaded holes? and where are they located? Got a sample picture?

I looked for the vin tag, and cannot seem to locate it on the engine. I am not a newbie around cars, just all of this mis information I am getting about this car is starting to **** me off. I havnt been able to find any hard facts about anything, My Machinist, is a ASE certified engine builder, that has been running his shop for 20+ years, and he's also my dad, but I am beginning to think he doesnt know ****. Seems to me he is stuck in the 80's. and cannot comprehend newer engines, Does anyone know where there is solid information about the engines in these cars? He is saying it is only a 8.5-1 compression. I am very frustrated, and ready to go back to imports. this is stupid.

 

its not stupid. its an engine. one that someone modified. If its not a roller. no big deal. Not the end of the world. Its like anything else, you play the game with what you got.

 

Ya, I am ok with the engine, I just think its stupid that everywhere I look I get a different answer as to what's what, and no solid facts on anything. Ya, I am gonna play with what I have, and this way, cams are cheaper, it still has the correct flat top pistons, I need to measure the bore to make sure it is a 350 though.

 

Pass side of the block, on a "pad" sort of part of the head deck, in front of the head



In this pic, it's the square looking place in teh top center of the pic, right above the freeze plug.This is not correct. All blocks have the provisions; however, most TBI engines got flat-tappet hydraulic cams up through 95. Trucks and Caprices in particular.That would be typical. It's quite unusual these days to see anything but hyd lifters, except in race cars. Very few people use solid lifter cams.By looking at the lifters. They DO NOT interchange; so if the cam was one kind but the lifters were the other, none of it would survive more than a few minutes after initial start-up.

Like ljnowell and I both said, somebody has just changed it. Flat-tappet cams are cheaper. Cost less too. Somebody cheaped out. Not the least bit unusual.Yes... right here. However, "the engines in these cars" is a whole different matter from "the engine in THIS car". None of us can tell what someone has done to it over its lifetime.Yeah I know what you mean... there's ALOT of misinformation floating around out there, like the one about "all" engines from 87 up having roller lifters... just simply not true.

How do you know it has flat-top pistons? Are the heads off?

If it REALLY has flat-tops, and it's REALLY been rebuilt, then it's almost certain that the tops of the pistons are .020" farther "down in the hole" at TDc than stock, which would have been about .025". So, using .045" deck clearance, .030" overbore, .039" head gasket (FelPro 1004 or 7733-PT2), 64cc chambers, and 6cc valve reliefs, the CR is about 9.3:1.

 

There is ALOT of mis-information within this thread.

Camaro, Caprice other B/D bodies as well, and Corvette engines all came with roller cams and lifters

Trucks/Vans/Suburbans up to 3/4 ton had flat-tappet hydraulic cams. Some of the blocks were machined for roller lifters, some were not, some lacked the 3 stand-offs and the raised lifter bores all togather. The 1+ ton trucks and vans mostly had roller cams and lifters.

Every 305 TBI truck engine I have seen post mid year 1993 has had a roller cam (which corrensponds with a GM HP/TQ rating increase to 185 HP/275 TQ on that engine).

 

I'm not really sure what the criteria was for getting a roller lifter cam from the factory in the late 80s.... my 1988 4wd silverado 1/2 ton has the 5.7L TBI with roller lifters and 2 bolt mains. All stock 208k miles.

 

He did mention he was doing head gaskets on his engine, so if he's got the heads off already, then he could already know for certain its got flat top pistons in it.

As far as the 'roller-vs-nonroller' cam thing, the general rule of thumb is that the car V8s got roller cams, and the light trucks did not, although all the block did have the provisions for the roller cam components cast into them (the cars and trucks used the same blocks). Notice I said 'general' rule of thumb. Its not 100% set in stone.

This is what a non-roller setup looks like:



This is what a factory roller cam setup looks like:

 

Thats funny, my brothers 88 305tbi 2wd 1/2 ton truck had flat tappet lifters.

 

I know, my old 1991 1500 4wd suburban had the 350 TBI like my truck but it had flat tappets and 4 bolt mains..... Newer motor without roller lifters. The holes weren't drilled and tapped for the spider either.

 

I have seen alot of the blocks up to about 1992 that weren't even cast with the stands in the lifter valley for the roller cams. The lifter bores were also not the raised type with the machined flat top for the link dogbones.

 

ok guys lets get back to the help out fellow 3rd gener

who cares about the specifics of the roller block years its not helping

take the timing cover off the motor and look at the front of the cam after you take off the timing gear

if there is a cam retainer plate on the front of the cam I would start to worry

shine a light down the lifter holes and look at the profile of the cam if it looks like the cam comes to a sharp point you should be ok if it is much more rounded on the ends then you might have gotten someone who decided to put flat tappets on a roller cam

lets try to help people instead of proving one another wrong

I am not trying to tell people what to do

its just a suggestion
\
also look at the very middle of the lifter valley. if there is three small threaded towers then it is a roller block. as others have stated this does not mean the motor came with a roller cam

any other questions please ask

 

If he took a flat tappet lifter out of it, obviously it is NOT a roller cam in there now.

 

You sound pretty sure of yourself eh? You think it's beyond some goofball backyard "mechanic" to drop in a new set of flat tappet lifters?
Stranger things have happened...
If he's staring at that area now, i'd want to be fairly sure it's a flat tappet cam. Then upgrade it anyway, because it's undoubtedly a LAZY one.

 

Wow, I dont think i saw anyybody arguing, we are DISCUSSING the wide variety of blocks that are found in GM production vehicles and the fact that there is no rhyme or reason to it. As far as helping him, I believe that pictures were posted above, showing the differences. what else needs to be done?

 

From sofakingdom:
Enough said about that.

A roller cam's ramp profile is so different from a flat one that the edge of a flat lifter would probably dig into the roller cam lobe the very first revolution, eh.

 

I understand how they work, and how they are not compatible.
I also understand that he is having some car trouble right now.
I think if I pulled flat tappet lifters out of an engine that *could/should/may* have been a roller, it would 'behoove' me to take that peek and confirm a matching camshaft.
But that's just me. I really like to have visual confirmation of things. Helps me sleep well at night eh?

 

I agree. Although, I think we can be fairly sure that whatever is there is garbage. If it were me, and it was a roller block i would be looking at taking it back the other way. Of course all of this may be moot, because we still DONT HAVE A CASTING NUMBER or any other info from the OP about it.

 

If I recall correctly, You can run solid roller lifters on a hyd roller cam shaft. Its to help with the valve float.

 

Right:

The main thing at this point, rather than bicker about what motors did or didn't come with roiller lifters, is to realize that THIS CAR DID come with them; but somebody either swapped cams, or swapped short blocks, or swapped SOMETHING, such that they're now GONE.

No big mystery or cause for confusion and bewilderment. Somebody swapped something. Happens all the time. End of story.

If you want roller lifters back, you'll have to get them from somewhere and swap them back in. Cam, lifters,timing set, spider, dog-bones, retainer plate, and all. Or, a "retrofit" roller cam, link-bar lifters, and a cam button.

Again, no great mystery, not hard to understand, pretty simple explanation for a pretty common thing that pretty commonly happens. Kind of like, your RPO code list says your rear end has posi, but there's not one in there. What happened? Somebody swapped something out. Probably tore up the original, and did the low-bid replacement thing to get it back on the road. Same here.

 

kinda like, i know my car has 3.73's cause the rpo says so!

 

Haha, wow this sure blew up overnight, I really appreciate all of the input,

And yes The heads are off the car, it has the flat tops, with the valve reliefs.

I checked it out, and it does have a flat tappet cam also.

I ran the serial number on the block, turns out it is a GM factory replacement Long block, and as mentioned above, Those came with Flat tappet cams, So I am guessing someone blew it up under warrenty and got it replaced, or something along those lines.

Yup Drivers side head gasket is blown. haha a nice piece of it is missing. The pass side was getting ready to go also.

Here is a picture with just the drivers side head off, the other one is already off to, but dont have a pic, here you can see it's NOT drilled for the roller lifter holder, and you can also see the pistons.


----------
OH, well a crummy pic, you cant really see anything LOL. but yes, it is there, And I think I figured it out, gonna do some port work to the 083 heads, new valve job, and put it back together, I have to buy some stuff first though.

I am so excited I cant wait to get it running.

 

I am glad you are getting to the bottom of your problems

if you want to go a step farther and check the cam get a slide ruler and measure the amount of lift the lifter has when it goes up and down

all the exaust should be close and all the intake should be close

also look at the bottoms of all the lifters for damage

soak all your pushrods in gas and then blow them out with air

get her back on the road!!!!!!

 

I would not take a chance on the cam. A cam kit is cheap. Find one that will match the heads/intake. Have matching springs put on the heads when you have them redone.

You might even consider having the heads milled for a little more compression. They may need to be resurfaced anyway.