Hi all, I ordered the Cloyes 93145 timing chain kit off rock auto but when I went to put it on the holes do not line up on the cam sprocket with the cam. I was wondering if it's possible that if the previous owner put a different cam in it that's why the holes don't line up? Or maybe rock auto sent the wrong one? Engine is a 5.7 tpi out of an 89 GTA. On a side note would a gear drive work or are they no good because of the knock sensor?

Old sprocket.

New sprocket. Holes don't line up.

 

This is a quick and dirty reply because I'm about to walk out the door.

87+ SBC in Camaros and Firebirds had a step nose roller camshaft so a retainer on the front can control camshaft walk. This caused a reduced bolt pattern circle on the nose of the camshaft. Either your car has an older engine transplanted into it so someone swapped an older style cam into the engine.

No you don't want to run a gear drive.

 

Yup; the engine has a cam that's not for a factory roller cam. The cam retainer for the factory's roller system intrudes into the area where those bolts had been since 1955. Almost certainly, that's a flat-tappet cam, not a roller-tappet one.

The engine might be "out of" a 89 350 TPI car butt it didn't come there originally, in that condition. I'm reminded of d00d who advertised in the classifieds in the newspaper back in the 70s, that he had a pair of heads "out of a Vette", and being mesmerized by the V word like most young uninformed men which I mos def was at the time, I went to look at them. He took me out to abuncha Vette parts cars in his back 40, opened one of em's door, and, "out of a Vette", pulled a pair of 327 2-bbl heads. I (not so politely) informed him that even though I saw them come "out of a Vette" with my own eyes, that he had a body orifice he could put them INTO now. Sounds like you've got something similar on your hands.

 

I appreciate the responses this is my first time tearing into an engine so I definitely don't have an eye for that stuff. This might be a stupid question but from my understanding isn't a roller camshaft better than a flat tappet cam? I don't understand why someone would change that unless the engine itself is older and they just put TPI stuff on. Also I still need a timing chain kit so should I just order a kit for an 86 firebird off rock auto? Thanks for your guys help!

 

Yes absolutely. In ALL WAYS except ONE.

The simple answer is the ONE way a roller cam is inferior (to a buyer) than a flat.

Mr. Green.

A better approach might be, see what cam is in that motor to begin with; and decide, on that basis, whether to put a roller one back in. That's not an entirely easy question to answer though.

Let's start with the basics: identify what you've got. What's the block casting number? What numbers can you find on the end of the cam?

 

I didn't see any numbers on the cam.

 

Your engine has a 1987+ block with provisions for a roller cam. Do you have the intake manifold off the engine so you can take a picture of the valley for us?

Some 87+ blocks were cast with the bosses for a roller cam but not machined for the roller cam. Some engines like in trucks didn't have a roller cam. Your block is drilled and tapped for the screws for the retainer for the step nose cam. If may or may not have the 3 bosses drilled and tapped in the valley for the dog bone retainer. I've seen the 87+ blocks with flat tappet cams drilled and tapped for none of it, part of it, and all of it.


Comp Cams 08-1000 Hydraulic Roller Lifter Installation Kit.

Note: There are two different center to center spacings between the bolt holes on the front of the block that retain the cam. 3.630 and 3.320. The above picture is only as an example of what the roller cam installation hardware looks like. Use the kit with the right spacing for your actual block. 08-1000 or 08-1001.

 

unfortunately I never had the intake manifold off. I only went to the fuel rail so I could put new injectors in. I was gonna run it how I bought it for a season then I was thinking about putting heads and a cam in it next year. But the engine does have around 110k miles on it so I thought I would at least put a new timing chain on.

 

I guess return the timing set and get the earlier timing set that will work with your cam.

 

Thanks for your help. Im gonna try this one https://www.summitracing.com/parts/mel-48500t-9 it says with works with non roller cams.

 

I can't make a recommendation if you should or shouldn't use that timing chain set because I've never used it myself. I'm sure others here can that have used it before.