902 heads, flattops, MTS-10 cam install... Advice??

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902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Thu Apr 14, 2011 6:13 pm

A few weeks ago Dave was selling some parts, and I was interested in a better cam... The ones he advertised seemed a bit too radical as I don't have the funds for shaft rockers. He suggested an MTS-10 which seemed like a good choice to me so I bought it. I knew I'd need a new timing set anyways so got that and a front cover gasket set and tore into it last weekend. A bit of history is due... The previous engine was (I was told) a 1974 472. Which had lots of power but also an oil consumption issue. I found this out after a refresh with all new gaskets, a timing set, and new brass freeze plugs. While I had the heads off I also did some mild bowl smoothing and cleaned the carbon off the valves and reassembled the heads. Drove it like that for 3 years and a couple years ago the oil consumption got worse, like a quart every 2 months- blue smoke out the drivers side tailpipe worse under load. I had dug up some valve seals for a Chevy V-6 head at work, so did the rope trick and changed out the crappy plastic seals on the front 3 cylinders for the Viton seals. Didn't use as much oil but still a touch of blue smoke out the pipe... The oil consumption began getting bad again so I pulled it in at work and pulled the head. No oil around the valve stems but first piston is black and the rest look decent.... Yanked the engine and tore it down and found that cylinder had a broken second ring. Crap!!! Rebuild time. I figured I'd start by having the crank checked and turned if necessary, that way I could reinstall the empty block and heads to build the headers from the Hooker BBC kit I bought from the tire tech for $100.... After getting the crank turned ten-ten and getting the headers made I called Marty at MTS to find out about rebuild kit prices, and how much the shop wanted to bore the block.... And realized I'd have a couple grand into just a mild rebuild on the 472. I really wanted a 500 in the car, so I went scroungin' the yards, and found a '76 Eldo with 63K on the odo and only the Q-jet missing off the motor. I bought it up for $225 and tax as a core motor. Got it home and when refreshing this engine I broke a couple exhaust bolts in the heads. No problem, just swap on the ported ones and change out the pan to front sump and get it running. I looked at one of the rod bearings and a main and they looked OK. On the stand it cranked over but no spark, swapped the Hei cap/coil- nope. Changed out dizzy and it lit off, heard a bit of knocking. Pulled pan and checked the dipstick tube routing- looked ok so reinstalled pan after Plastigaging all the rod bearings, which were OK. I figured maybe the pan was barely grazing a crank counterweight since it only happened occasionally on revving it up... Anywho, started installing this cam, and when I got the cover off the chain was WAY LOOSE, like 1.5" of slop. I have been emailing Dave during the cam install, and then while checking preload realized the valve seal issue... Crap, the heads hafta come off to change the rest, and I didn't remember shortening the guides... So I'm undoing the head bolts and then realize these are 902 heads?? I thought '74 had 120cc heads???? Apparently the 472 was a '73.engine, installed new early '74- so its the 79cc chambers, and I got'em on flattops. Dave thinks this is about 11.6-1 from what I told him, and what I mistook as a minor clearance issue with the pan has actually been the motor detonating at highway speeds. My drive to work and back is only 5 miles, lotsa stoplights and a limit of 45 MPH for one mile, the rest is 35 MPH. Temp barely gets to 160 degrees once I get to work. I also thought maybe a rod bearing with the warmer weather, and recently did a quart of Lucas and 5 of 30 wt Rotella plus a filter. The dizzy has a lighter spring kit from when it was on the 472.... I don't see it in the budget to change pistons to get the C/R down, was thinking about dizzy spring change to heavier, no vac advance, maybe some carbide work in the chambers to make them bigger and also smooth out the bump between the valves (D- shape instead of heart-shape, and open the curved side to the gasket ring like it is alongside the valves. Also thinking maybe E-85 may help, a lower thermostat, etc. Any ideas guys?? Pros or cons?? If I can get it to live on 92 and octane booster or 92 and E-85 mix.... Dave mentioned he's surprised its still alive, and now that the sloppy cam is gone, I'm a bunch concerned.....
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby dave brode » Thu Apr 14, 2011 6:57 pm

Dr,

As I see it, you have two choices;

1. swap pistons

1a - low comp 71-73 pistons for 8.5-1 ish
1b - 70 copies [Egge -pricey - 9-1 or so
1c forgings from vendors for 10-1 to 10.2-1.

2. swap to 120cc heads. 8.8-1 or so.

Btw, since the engine has been rattled hard, check the ring clearance [up/down]. The ring lands may be really beat up.

Imo, you can't run E-85 without a MAJOR carb recalibration. Stioch is like 9.7-1 vs 14.7-1 for gas. Even with race gas or avgas, I would not try it with 40 year old, maybe hurt already cast pistons. If you rattle it good one time, you'll have scrap metal.

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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Thu Apr 14, 2011 8:12 pm

I would not try it with 40 year old, maybe hurt already cast pistons. If you rattle it good one time, you'll have scrap metal.
A very valid point here. So, I guess the $2 question is ultimately-- better to stay closer to 8 to 1 or go 10 to 1?? What suits the smaller chambers better? Which C/R works better with the MTS-10 cam??? And I would like to say in front of everyone on the board here a HUGE thank you to YOU Dave. Not only have you helped me with the cam install from several states apart, but on discovering my unintentional mistake of too much compression, you have put enough doubt and common sense into my head to keep me from tearing this motor up any worse than I may have already. I will have to tear into the shortblock and change pistons, I don't see the logic in putting 120cc heads on a likely-wounded motor. THANK YOU DAVE for selling me not only a cam, but for being honest with me to tell me I'm doing something stupid that I will later regret. I owe YOU big-time!! Its been rattling occasionally for probably the last 8-9 months, which I mistook for a possible bottom end problem. Getting the oil pressure gauge installed disproved that, with cold idle pressure at 50 PSI and warm idle never below 40 PSI.
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby yellowroket » Thu Apr 14, 2011 8:25 pm

Are you looking for a hot rod, daily driver or a cruiser? I just filled my blazer up today (built SBC 10.1 comp iron headed runs on 93) and at $4.22 a gallon and a 30 gal tank $126 SUCKS!! Something to think about cause it just keeps going up. Im far from an expert but I think the MTS10 would run good in a low compression motor and save some money at the pump too.

Robbie

P.S could always check your pistons out as Dave said and if they look alright could swap the large chambers on.
Caddy powered and Corn fed. 11.26@122....bring on the 10s
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Thu Apr 14, 2011 9:07 pm

The Kustomsledd pics are in my Gallery here, been building this car the last 14 years to be a body-dragging daily driver leadsled. '50's style but with a Cad motor, power steering/Hydraboost 4-wheel disc brakes, power windows and door poppers, motorized tilt column and Taurus motorized pedals, motorized tilt nose, rearview camera system, and eventually a thumpin' stereo system for the classic metal I grew up with and love. There's not a stock panel left on the body, which has been chopped, angle-channeled, suicide doors, nosed and decked, Frenched lights all around, trunk and hood molded shut, custom oval rear window, fuel filler, marker lights, 3rd brake/turn light, Flamethrowing taillights, etc... Oh yeah, did I mntion the custom 26 gallon fuel tank I built to feed the Caddy??
On the pistons, even if they look ok if I'm going to the effort to pull them out to look at them I'm gonna change them out for my own peace of mind, for pistons that will work with the better smaller chamber heads which I already ported, and that I am buying seals and springs for... I would also change out rods/mains and have the big ends of the rods checked. I guess the only real question is cast or forged, read 87 or 92 octane??
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Ted in Olympia » Thu Apr 14, 2011 9:43 pm

If the timing chain was this loose it most likely has a few miles on the engine. So I would figure on boring out the engine and oversize pistons. The 472 block is also the same block so you have two you can choose from, maybe one of them is okay standard? I'm partial to forged pistons but they will cost $200-$300 more so it's up to you. This does not sound like a daily driver so I would not worry about spending an extra 20 cents for premium gas. The biggest advantage to forged pistons is that you are ready for anything you want to do with it in the future.

If you want stock 8.5 pistons than these are good deal,
http://cgi.ebay.com/ebaymotors/Silvolit ... _641wt_944

I just threw some stock standard pistons in the garbage today with rods, if you want I can dig them out for you and you can have them for $40 shipped. They have been rained on all day but I would think they would be fine, but I better make sure. But if you bore is bad it will not matter.

I also have a set of 1970 pistons on rods for $120 shipped.

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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Thu Apr 14, 2011 10:19 pm

Sold the 472 engine and the 120cc heads off this one last fall after doing the engine swap. I was unsure about the 62,000 miles the Eldo had, but the speedo cable ws hooked up and the foot pedal wear was minimal, so I'm thinking it WAS actual miles on the 500 I now have. Other than being parked and tarped for the winter snow (no side glass installed yet), I drive it every day 10 miles round trip to work, 6 days a week. Its not a museum piece... Ted I would be interested in those pistons/rods if they are early 500 with the small chamber heads. We are currently scrounging/saving for the better valvesprings for these heads that will work better with the MTS-10 cam, as I don't trust the weak stock valvesprings. My 902 heads are currently off the 500 and apart, I trimmed the guides .125 to allow for the cam's lift increase. The bores look really nice, no top ridge, can even see some crosshatching.... I'm in Hobart IN just off the tip of Lake Michigan.... I do know none of the yards around here have any early 500 engines- I was lucky to find the one I did, it came in only a week before I saw it....
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Ted in Olympia » Thu Apr 14, 2011 10:29 pm

The pistons look just like the ones in the eBay ad, they give you about 8.2 compression and are stock from 71-73, these pistons are stock. The only problem I can see with them is that somebody was going to polish the side of the rods and only did one, but I would not worry much about this. I would only make about $10 on these.

The 1970 pistons give you about 9.2 compression.

TED
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Cadiac » Thu Apr 14, 2011 11:19 pm

I thought I had detonation problems with the 70 500 in the Dodgorado! I haven't tried premium because I'm going to put a 76 engine in it's place anyhow and drive it little. When the weather was cold I drove the crap out of it with no trouble. Soon as the weather warmed it began to ping when the temp passed 200. I have the #10 cam in a 76 500 in the 67 GMC PU. I like it and would buy another. Stock rebuild except for the cam, shaft rockers, Edelbrock intake. Also--My very 1st 500 rebuild, -I had someone put together for me. Bad mistake, nightmare I won't bother to describe but also early soap dish pistons 120cc heads. Ya it felt weak.
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Thu Apr 14, 2011 11:40 pm

I think the rained-on pistons will do just fine Ted, they're probably cleaner than mine right now... lol I'm thinking if I get pistons for 87 octane fuel that is a better choice for a driver than to need to run 92 octane. Plus I don't see fuel coming down any time soon so it also makes sense to shoot for using cheaper fuel to mazimize the fun factor...PM or email me what you need for shipping to NW IN area and will get a money order to you, don't have or trust Paypal....
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Cadillacs R Us » Fri Apr 15, 2011 7:07 am

DR chop.........I have 7 of the 71-74 500 pistons with rods----bearings---and rings that have 18 miles on them :yikes: FREE The broken piston still has the bearings, but no rings.

If you get one piston on the rod from Ted....then all you need is standard rings for that piston.....

This was a standard rebuild 15 years ago that I wrapped a piece of alum. over the 2115 divider for some stupid reason and it got sucked into the chamber and broke the top corner off lol

Give me a call.....260-347-2821.......Ron

EDIT: Wait-I might have an extra piston--rod , but would still need new rings for one piston.....I will look in my barn sometime today to verify.
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Fri Apr 15, 2011 7:22 am

Hey Ted, it would be easier to just send one rod/piston thru the mail, huh?? What would you want for just one?? I would forever be in Your debt too, as well as Dave and Ron's... Lol. Ron I will call after 6 PM, as I am at work presently...
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Ted in Olympia » Fri Apr 15, 2011 7:33 am

Same amount of work to send one or eight, but if you want one it would be $22. Find out what number you are missing and I will try to give you the correct marking.

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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Fri Apr 15, 2011 7:47 am

Sounds like a plan then, I need to fit each to specific cylinder anyways so will need to figure out what is what first. I may have you send me a flexplate too depending on what mine looks like when I yank the block out... Hopefully I can get this fixed and get in some cruises this summer...
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Cadillacs R Us » Fri Apr 15, 2011 8:48 am

:no: Guess not on the barn find.....75 and 76 pistons is all I have without tearing into another engine :thumbdown:

oh, the rod is marked no.8 with the broke piston, just to fill in the number.......

Remember to run a 280 ball hone in the cylinders with cast rings....you probably allready know that lol

Looks like I'm about a hundred miles from you on the map........

Ron
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Fri Apr 15, 2011 9:12 am

Guess we are back to Plan A again... lol. Such is life, nothing good comes easy. A fact I have had drilled into my head over the years building this car. Ted, looks like I WILL need what u have then, and I still may end up getting a flexplate too. Gotta drag the cherrypicker home from work and yank it this Sunday... Aint old cars fun?? lol
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Ted in Olympia » Fri Apr 15, 2011 10:01 am

I'm confuse Ron, Do you still have the 7? and just cannot find the 8th?

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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby Cadillacs R Us » Fri Apr 15, 2011 10:24 am

Cadillacs R Us wrote: :no: Guess not on the barn find.....75 and 76 pistons is all I have without tearing into another engine :thumbdown: found only the wrong 75-76 pistons :metal:

oh, the rod is marked no.8 with the broke piston, just to fill in the number.......

Ron


What I could not find was another 71-74 soapdish 500 piston so that Ted would not have to ship (one) accross country......

Yes, I do have the seven rod--piston (71-74 500 soapdish) assembly ready to go.........and number 8 assembly has the broken piston... :jack:... So much easier to talk on telephone for me to keep things straight lol

Ron
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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby dave brode » Fri Apr 15, 2011 8:46 pm

Glad to help.

If I was putting that cam in a low CR engine, I would put it in at 4-6* advanced.

Ted's '70 pistons would work nicely :devil:

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Re: 902 heads, flattops, MTS-10 cam install... Advice??

Postby DrChop » Sat Apr 16, 2011 5:12 am

I have the cam right at 6 degrees advanced.... Sorry I did not call last night Ron, I was worn out from work the last few days. New guy changed out an F-150 intake early this week and somehow an 8mm bolt got dropped into #8 cylinder.... When he started it we could hear it pinging around inside the 4.6..... :eyepopping: it was my job to pull the head which is a bear on those motors. Sent it out and found #8's exhaust valve was bent... I got the head back n spent the last 2 days reinstalling it, only to find its got a rod knock at the back of the motor... :banghead: Got home last night to watch Friday Night Smackdown and assed out on the couch... Too much stress lately I guess... Ron the 7 pistons would be better. Shipping would also be better than across the country. I will check this out regarding bore sizes and see where its at as far as piston fitting goes.... Then I will let Ted know and hopefully get the last one needed. Note to self---bring home Cherrypicker and motor stand from work... lol
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