I think you are going to find you installed the camshaft off a tooth or more on the sprocket on the new MID engine from the sound of things. Did you degree in the camshaft when you installed it?

I have seen an engine bend an exhaust valve due to coolant in the cylinder. One valve, not eight. In this case the cylinder filled with coolant through a pin hole in the exhaust port. The valve and pushrod were bent, the axle in the solid roller lifter broke as well. This happened when my buddy tried starting the engine not knowing he had a cylinder full of coolant.

Steve Demirjian
Race Engine Development

 

MTI assembled the complete short-block including the cam. I just told them to put it in straight up. I'll have to look into that possibility, I just took it for granted the cam was in correctly.

Steve I took your advice and switched to Evan's coolant, that is if I ever get out of the garage. Talked to you a couple of weeks ago on the phone. Thanks for your input and advice.

 

Steve is the man. If I could only find a seasoned LS1 block to send him I'd be getting a Darton MID block, too

I have wanted one of these blocks for the longest time.

 

Well it seems everyone I've talked too says there is no way the coolant did this. This is the first time I've had to deal with a problem like this so I wasn't sure what the coolant could do in the cylinder. I've had 3 very experienced automotive people tell me they think the cam was put in wrong. I guess I'll tear the front of the motor apart this weekend and see what I find. These pistons are brand new and are still very shinny on the top (so it is very hard to see any marks on them), Im used to seeing an eye lash on the piston when there is contact. The motor never did start so I guess the pistons never got hit hard enough to make a noticable mark, but just enough to bend the valves

If the cam is installed properly I'm running out of ideas as to what the problem is.

 

Im just going to toss this out here, but isnt it NOT recommended to run 1.7 or 1.8 rockers with a highly aggressive cam such as this? Also, if the heads were milled would you need shorter pushrods?

I'm just thinking maybe some messed up geometry might have caused this (but i dont claim to be any sort of expert ;p)

 

1.7 is the stock roller rocker ratio.

 

I dont think its cam related, if that was the case intake vlaves would of been bent also. Cam is degreed correctly. My guess would be roker arms not being the correct ones. Or its the exhaust valves not being correct hight or diameter.

 

The intake valve chases the piston, and the piston chases the exhaust valve. If the cam is retarded like several people are telling me it would of only hit the exhaust side.

You guys keep forgetting this complete valve train already ran and was fine.

 

What springs? Stock length valves?

 

Crane double springs, not sure on the part#, but they are the stock O.D. Not sure on the length of the valve either, they are whatever GTP uses. If the length of the valve was a problem how come I didn't have a problem on the original motor?

 

I know what you mean.

 

One question....why would you bump the motor insteadf of turning it by hand? Ouch Bumping the motor will damage anything just as much as starting the motor. You should always turn the motor slowly by hand to check for interference. I agree though, cam was possibly installed incorrectly.

 

Me too, * 2 though.

 

Doc - I'm no expert by any means, but just reading over these posts, you keep wondering why there wasn't a problem with the first motor, MTI could have had the cam degreed correctly on the first motor, and when they put the second motor together for you, possibly they were off a tooth or so on the cam?? That could be a difference from the first to the second motor, just a thought. Sucks to hear about this though, I have been a fan of MTI and their big motors for a long time, and hearing about this stuff really makes you wonder how do you know who's reliable anymore?

 

I checked everything on the first motor. When I got the replacement motor back since I was using all the same parts I didn't think anyhting would change, tolerance or clearance wise. So naturally I just tried to fire it up after it was installed. Whatever happend, happend the first time the motor turned over. I tried starting the motor for a good time before I found that the valves wern't closing. When I was refering to "bumping the motor over" this was after I already discovered the valves were bent and wanted to see if they were hitting, figured whatever damage I had was already done.

 

The first motor all MTI did was the rotating assembly. I paid a local GM mechanic (friend of a friend) to degree the cam and assemble the rest of the short-block. When that block screwed up I sent the complete short-block back to MTI to be fixed.

 

Did MTI install the cam and degree it on the 2nd motor?? Your friend did it right on the first motor it sounds like, but MTI could have messed the 2nd one up and that may have helped put you in this spot now. Just something to check out.

 

Im getting ready to tear the front of the motor apart and see whats going on

 

Cool, hopefully it's something they did wrong so you have some recourse, not just bad luck

Can you take pics when you tear it down? Also, did MTI say anything about you tearing it down and not them? I would think they would like to see it to make sure you didn't tamper with crap, etc, I know you wouldn't, but in case they try to pull some crap like that.

 

That's actually a good recourse if you discuss the **** with them it always helps. I had a install of a suspension that I questioned a few years ago because the initial turn-in was sloppy and there was nothing I could do without a lift and spring compressor. After discussing with the Tuner I found out there are more options we had with the right approach...turns out it was the upper shock tower camber plate, which was really eating into the sheetmetal actually, a quick replacement tower brace and boom no more slop.