[Probird]

I've mounted a crank trigger to my new Allpontiac front motor plate. I've probably put 70 passes on it with this setup this season. From day 1 of this new setup the crank trigger pickup has rubbed the trigger wheel after a pass. I widened the gap when I first noticed it. I put it at a little more than the recommended gap and it has never rubbed at idle. It's clearanced itself quite a bit now and is way more than the recmomended gap. So much so that I think it was the cause of a big boom at half track last Saturday night when it didn't fire in one of the cylinders but in the headers. I'm guessing it's just rubbing going down track or at launch. I did find today the 2 bottom bolts had come loose where it attaches to the timing chain cover and the top ones were a little loose. That would explain why it keeps clearancing itself more and more. I know they were all tight when it was put together at the beginning of the season.

For you all that run one of these motor plates: How tight do I need to attach it to the timing chain cover? Have you had any problems with the bolts working loose? Will the engine still move enough with the bolts tight that the trigger pick up will rub? I guess I will locktite the bolts this time and change the sensor and see if it still rubs and keep a close eye on it. Any other suggestions?

[Tom Vaught]

The Butlers had a front cam driven distributor and the crank trigger on their stuff about 5 years ago. Seemed like every pass the engine would vibrate so much that the distributor would move.

I think that Travis told me that he finally used some form of support device to keep things in position better. Seemed to work later after he got his design worked out.

So the suggestion is maybe a more rigid mount attached to the cylinder head vs the normal crank trigger mount.

Tom V.

[BruceWilkie]

Sounds like the plate may be flexing fore/aft. My friends Chevelle has 4 rods to front and mid plates that go fore/aft to frame to stop that sort of movement.

He wasnt running crank trigger at the time he did it, just did it for "insurance" of not cracking a trans case...that was back in the days before it was common knowledge that solid trans mount was the likely cause of his case failures. His bracing of the plates stopped the case crack problem with solid trans mount. These days runs poly trans mount but still uses his fore/aft braces.(and a crank trigger)

[johnta1]

Rick, do you have fore and aft bars on the engine?
(keeping the engine from moving fore and aft)

I would say there is a lot of flexing in the plate and with the timing cover being aluminum also, probably a lot of movement for the pickup.

Do you use locktite on the bolts?



Looks like Bruce treed me, too slow typing.

[Probird]

Originally Posted by johnta1

Rick, do you have fore and aft bars on the engine?
(keeping the engine from moving fore and aft)

I would say there is a lot of flexing in the plate and with the timing cover being aluminum also, probably a lot of movement for the pickup.

Do you use locktite on the bolts?



Looks like Bruce treed me, too slow typing.

No, I didn't loctite the bolts originally. I did loctite them this evening after taking everything apart. I'm still using the original type motor mounts in lieu of fore/aft limiters.

[janderson]

Loctite (red) bolts/studs, solid sleeve(s) locating timing cover to block. Front and mid plates, poly trans mount and longitudinal limiters...never a problem with any movement and never re-adjusted the pick-up.

[sdbob]

I'll never have something like that $.Question though,I was wondering why the plate doesn't have a flange top and bottom to limit flex,like an 'I' beam? I guess the front ,rear bars accomplish same thing.

[gman005]

Rick I haven't had a problem with my trigger. I have it mounted on the driver side. If you want any pictures pm my your number and i'll send them to you.

[WARPed]

Originally Posted by janderson

Loctite (red) bolts/studs, solid sleeve(s) locating timing cover to block. Front and mid plates, poly trans mount and longitudinal limiters...never a problem with any movement and never re-adjusted the pick-up.

Same here, I used studs